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On-demand production system of apparel on the basis of Kansei engineering Yoshio Shimizu, Tsugutake Sadoyama, Masayoshi Kamijo, Satoshi Hosoya, Minoru Hashimoto, Tsuyoshi Otani, Kouich Yokoi, Yousuke Horiba, Masayuki Takatera, Michael Honywood and Shigeru Inui Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan Keywords Production innovation, Textile technology Abstract This paper argues for the immediate use of Kansei engineering to help deal with the chaotic situation of poorly implemented and disconnected technologies. A theoretical criticism of the current industrial capitalism, together with the promotion of a new post-industrial form of capitalism, lays the foundation for an explanation of how this transition can be achieved through a proper understanding of Kansei. A detailed explanation of the interactive production system apparel demonstrates the benefits to both manufacturers and consumers. The paper concludes that the application to apparel is just one of the many potential applications to improving the lifestyle and enjoyment of individuals in the entire society.
International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 32-42 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520333
1. Introduction Any daily newspaper or television news report will testify to the chaotic state of the world when seen from any perspective you care to choose: political, economic, or spiritual to name just a few. We believe that immediate action is needed to address these issues and improve our quality of life. Some people argue for technology as a solution to these problems, but we would argue that these very technologies are partly responsible for the current situation, due to their rapid development at this point in history. The technology itself is not evil, indeed it is often useful in its specific purpose and in its immediate environment. We often fail to consider the broader environment and the impact such technology produces. Technology when correctly applied can produce splendid results. The corollary is that the technology when poorly applied generates disastrous results. Many parts of the world face serious environmental pollution caused by technological advancements poorly applied. The recent power blackout in the north-eastern part of the United States (August, 2003) was caused by the lack of mutual relationship between various technologies. So how do we break this cycle of crises? Many argue that advancing technology is a key to ride out future crises. As stated earlier, we feel that modern technology is effective within a limited domain; its strength is in the
specific purpose they were designed for, but their weakness is in the way they interact with the wider community. We would argue that these technologies should be managed from a much broader perspective than the current case. Technology operates closely with our work and everyday life, and therefore has a strong impact on our consciousness. If these technologies develop new functions, such as interactivity, then we believe that they can change people’s concept of how they interact in and with the world around them. Figure 1 shows a sample of our argument, namely Kansei network technology. This technology links different technologies together, adjusting the system for the betterment of the whole. This Kansei network technology is just one part of Kansei engineering. As shown in Figures 2(a) and 3(a), Kansei is concerned with sophisticated human abilities such as sensibility, recognition, identification, relationship making, and creative action, which are considered the basic abilities in network formation. Kansei forms the basis of the Kansei network world, with its rich features as shown in Figure 2(b). Kansei engineering is concerned with a wide assortment of fields as shown in Figure 3(b).
On-demand production system 33
Figure 1. The Kansei network technology makes good relations among many kinds of technology
Figure 2. Kansei makes N-dimensional network world
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Figure 3. Kansei and the region of Kansei engineering
Sensory engineering focuses on the short term emotions. Kansei product technology focuses on medium term reactions. Kansei culture, sociology and philosophy focus on taste and sentiment over the long term. Kansei engineering can be said to spin and weave everything, from the atom to the spirit, in the pursuit of kansei products. As a result, Kansei engineering can produce a society rich in culture. 2. Industrial capitalism and post-industrial capitalism Our present society is based on capitalist economy dominated by mass-production systems. But it is found to be lacking in meeting the demands placed on it by our modern society. Therefore, we propose a new production system to replace the current status quo, with the ability to meet the demands of our society. We call this the on-demand or interactive production system. 2.1 The distribution-based economy supporting industrial capitalism In our industrial capitalistic economy, we aim for full production and consumption within the system to maximize its effectiveness. To this end, the products are standardized so that they can be more easily processed and produced. The resulting industrial product lacks individuality. It is one more “thing”, one of many as a result of trying to maximize capital or labor resources. In this economic model, the most efficient way to exploit the “thing” is to circulate it through a market, with essentially a one-way flow. It is argued that this one way flow results in the “thing” being pushed from the business onto the consumers. For this reason, the industrial capitalist economy is maintained by this mass-production/mass-consumption economy, and is shown in Figure 4. This is also known as the physical distribution economy.
On-demand production system 35 Figure 4. A mass-production and mass-consumption system with one way distribution
The core of this approach relies on standardized products, manufactured at cheap price through economies of scale, and shipped off to consumers through a maze of intermediate layers such as wholesalers, retailers and a number of transportation handlers. The cost to the consumer is not so cheap because along the way, each intermediate party is required to secure an appropriate profit for handling the product. Because the “thing” is produced in large quantities, they often remain unsold. This surplus supply to the actual demand results in dead stock. Not only does this dead stock produce inefficiencies in the system by gathering dust, it can also lead to a further burden on the environment by first consuming valuable resources in its production, only to be returned in the form of pollution or part of the ever growing waste dumps, which blight our communities. Another result of this system is the over-production of certain products, causing excessive supply and causing prices to plummet in order to stimulate demand. As businesses are forced to cut costs to win competition, they remain on an endless cycle of diminishing profits. It is often difficult for entrepreneurs to escape this make-to-stock production because of the lack of a viable alternative. 2.2 Kansei distribution supporting post-industrial capitalism We think that a few would object to a new improved system of capitalism, which accents the positive aspects of the current system, while minimizing the negative aspects. In our modern age society dominated by science and technology, we argue for a post-industrial form of capitalism, which offers stability and wealth for the many, not just the few. We think that such a system should be a collaboration between the producer and consumer. In a physical distribution economy, the focus is often on the planning, design, manufacture, distribution and marketing with little direct contact between the consumer and those beyond the retail level. We believe that workers involved in the manufacturing process require an active meaning to their labor, which does not
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exist currently. Instead, the workers are marginalized as small cog in the greater economic machine. We would argue that if producers and consumers could collaborate on the design and production of a product, the mutual opinion would produce a more creative and superior product. We call this end result as an interactive product in recognition of the collaboration that takes place from the two-way flow of information. We broaden the perspective of the product to include the interaction itself as a part of the product, not simply a by-product. The resulting distribution economy can be called as Kansei distribution, meaning, the joint design production system between the producer and consumer. More precisely, we have decided to call this system as “The Interactive Production System”. For a concrete example of how this theory can be expressed in practical terms, we will explain in more detail the interactive production system apparel (IPSA), as shown in Figure 5. 3. Technology elements for IPSA 3.1 Evaluation of materials for clothes 3.1.1 Circular multi-axes testing machine. A circular multi-axes testing machine was developed (Figure 6) to measure the tensile anisotropy of fabrics. Fabric is typically an anisotropic material in tensile property. In conventional tensile tests, warp, weft and bias direction or shear tests are required. Tensile property of fabrics without structural orthogonality, such as twill, is not well known. We developed the testing machine which could measure the tensile property of multi-directional fabric at a time. 3.1.2 Transverse compression testing machine for single fibers and yarns. Transverse compression characteristics of yarns and fibers affect the tactile felling of textiles. But there is no commercially appropriate testing machine. We developed a transverse compression testing machine, which utilized a piezo-stack and microscope.
Figure 5. An IPSA
On-demand production system 37
Figure 6. Apparatus for valuation of materials for clothes
3.1.3 Bending testing machine for single fiber/yarn. We can measure only the dynamic minute deformation bending by the vibration method. In pure bending, we cannot measure single fiber. We developed a novel flexural-rigidity measuring machine for the single fiber/yarn, which utilizes centrifugal forces. 3.1.4 Trellis shear tester for fabrics. We developed a trellis shear tester which gives uniform shear deformation under small tension to obtain the initial shear modulus under small tension. 3.2 Kansei retrieval system for interactive design selection As for an on-demand apparel production, selected product items can be enormous, depending on such differences as the kinds, colors, forms and the material. Differences of product evaluation between individual customers also vary according to their society reversion, self-representation, greed, and physiological body characteristics. Accordingly, some proposals of products corresponding to individuals are required. We have proposed a Kansei retrieval system (Figure 7), in which customer users can search apparel products through several stores. In this system, the user can search the products by inputting category information and/or other Kansei measurement values. A unified format of category information of apparel products suited for the search was developed. In the search, some methods to reflect the differences in the use of Kansei terms between the individuals were also investigated. 3.3 Individualized clothes’ pattern making Apparel manufacturers have been struggling to meet the needs and wants of their customers without sacrificing the efficiencies and profits gained through
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Figure 7. Interactive design selection Kansei retrieval system
mass production While conventional order-made clothes are ideal, they are also expensive because the processes involved are complicated and far from automatic. In order to establish an interactive apparel pattern making using CAD at a reasonable cost for customizing clothes, it is essential to employ three-dimensional pattern (Figure 8). We focus on the development of a clothes measurement system using a three-dimensional digitization of the shape when clothes are worn. Moreover, we attempted to develop a pattern-making system that is three-dimensionally interactive, using measurement data from a given
Figure 8. Individualized clothes’ pattern making
model to provide accurate information for individual pattern design. The three-dimensional measurement data was converted by coordinate column to build a cross section line model. We created a human body model with ten control points, which were capable of being modified by scaling magnification. A clothes model can be modified interactively and suitably with a body model. Pattern fitted size information from the three dimension shape was created, thus allowing us to simulate clothes pattern fitting for individual body shapes.
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3.4 Evaluation of comfortability and health 3.4.1 Kansei measurement. The purpose of our study is to construct an evaluation method for clothing comfort by measuring the multiple relationships between the human and clothes In order to design comfortable clothes, we should measure the physiological and psychological effects of clothes on the wearer (Figure 9). Clothes and human have multiple relationships. For conscious consideration, clothing comfort can be evaluated by sensory tests. For subconscious considerations, the measurement of physiological response is the only method of evaluating clothing comfort. Actual evaluation of clothing comfort is achieved by both physiological and psychological evaluations. We call the evaluation of the comfort by measuring a multiple relation, a Kansei measurement. 3.4.2 Effect of clothing pressure by waist belt on brain activity. The condition of brain in brain activity resulting from the pressure exerted on the abdomen by waist belts was evaluated using an electroencephalogram (EEG) measurement (Figure 10). We investigated the possibility of estimating the psychological and physiological stress arising from waist belts in clothing
Figure 9. Kansei measurement
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Figure 10. Effect of clothing pressure by waist belt on brain activity
based on EEG measurements. Waist belts are often daily attire for both men and women. In this study, electrodes were fixed to the scalp, and EEG was measured for states of abdomen pressure and non-pressure as exerted by the waist belts. Additionally, sensory tests for sensations of tightness, arousal, and feelings of comfort were carried out. Frequency analysis of the measured EEG data was carried out and brain activity, as reflected in the intensity of alpha waves under the conditions of pressure exerted by waist belts, was evaluated. The intensity of alpha waves decreased significantly under waist-belt pressure when compared with the intensity of waves in non-pressure conditions. The slow wave intensity increased as a result of pressure, and it decreased after the pressure was released. Therefore, it seemed to be generating a slight blood circulation disorder in the pressure. This means that the subjects could not evaluate the lowering degree of the arousal of the brain by sensory tests. The pressure exerted on the body by clothes has been seen to be a problem not only from the standpoint of sensuous comfort, but also in terms of its effects on physiological functioning and health caused by oppressiveness. 3.5 Development of products 3.5.1 Kenaf blended shirt. We developed the Kenaf blended shirt in cooperation with Flex Japan Co Ltd. Kenaf is an annual plant, and we evaluated its comfort on the user (Figure 11). We demonstrated that Kenaf shirts feel cooler, prevents sweat and possess a comfortable feel. We also proved that the warmth stress of Kenaf shirt is smaller than that of conventional shirts. 3.5.2 Comfortable socks. We developed “RL” type socks (Figure 12). Comfort of the new type and normal type socks was evaluated by physiological reaction
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Figure 11. Kenaf shirt
Figure 12. Design of comfortable socks
and subjective evaluation. The following were measured: muscular activities of the lower leg during walking, sole pressure, electrocardiogram in the wear and clothes pressure by the socks. From this analysis, the clothes pressure of the socks affected muscular activities and heart rate variability under walking, and it became clear that the comfort was influenced as a result. In the future, plane shape of the foot and solid shape must be considered in the clothes pressure index in order to design the socks which suit Japanese people. 3.5.3 Conservation cover. A conservation cover was developed (Figure 13). For example, for people whose breast were damaged by cancer operations. They could wear it when they take a bath in public spa without feeling too self-conscious because of any scarring.
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Figure 13. A conservation cover after breast cancer operations
4. Conclusion In this paper, we started by identifying concerns we have in society at large from the poorly implemented use of technology. We argued for a new paradigm of tackling these problems using Kansei. We demonstrated how this would affect a post-industrial capitalism to replace the current system. Then we showed several concrete examples of how this can be achieved at a practical level through the IPSA. This impacts every stage from individual fibers, fabric and textiles through apparel design and production. In terms of the broad application of Kansei, the IPSA is the only practical outcome. We believe there are many other areas of daily life where these concepts can be introduced, in such broad areas as physical products (design, manufacture and retail), computer software (user interface, education, database) and urban planning and control. These are just some of the projects being conducted by our department. We feel that this is a field rich in possibility and worthy of further investigation.
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Improvement of drape simulation speed using constrained fabric collision
Improvement of drape simulation speed 43
In Hwan Sul and Tae Jin Kang School of Materials and Engineering, Seoul National University, Seoul, Korea Keywords Simulation, Computer aided design, Fabric production processes Abstract Garment is generally a 3D object made of 2D fabric. So, it is necessary to predict the garment drape shape when designing fabric patterns. There are several methods to simulate fabric drape, but the calculation times are long for practical use. The bottleneck of the drape simulation is the collision detection between fabric and human body and self contact detection of the fabric itself. We assumed that the fabric collision occurs only locally to reduce the number of possible collisions. We made the fabric patterns into finite elements and each element was given a local area number so that only elements within certain area can contact with other ones.
1. Introduction Fabric drape prediction is essential for both textile area and computer graphics area. In computer graphics, drawing realistic fabric is needed because a normal outfit covers more than 80 per cent of the human body. In textile area, fabric drape is required for a 3D apparel CAD in which the objective is to design more fit clothes to each individual’s body size. The fabric drape is a bottleneck problem for the 3D apparel CAD development. Fabric itself is a combination of many fibres and the complex behaviour of fibre bundle is difficult to predict. Many textile scientists and computer graphics scientists have done research on this problem. Several methods were tried to model the fabric behaviour such as finite element method (FEM), finite difference method, continuum approach and so on. At present, particle-based method has the advantage of shorter calculation time than other methods. Even, the dynamic simulation of fabric movement is possible as the computer speed is improved. But, the dynamic simulation is not practiced yet, because of the long calculation time that is composed of collision detection and particle movement calculation. Collisions in fabric simulation can be separated into two categories: fabric-to-body collision and fabric-to-fabric collision. In the particle-based method, the fabric and body are composed of triangular and quadrilateral meshes. The more particle number guarantees more realistic drape with more calculation time. If we reduce the number of fabric particles, the collision check of fabric-to-fabric and fabric-to-body takes long time because the number of calculation is proportional to the square of the number of elements. Without collision checking, fabrics will penetrate into the body or
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into the fabric itself resulting in an unrealistic drape. The total calculation time of each drape simulation varies due to the number of fabric elements and number of body elements, but collision checking took the major calculation time in our study. So, it is necessary to reduce the calculation of collision checking for the faster drape simulation. When we reduced the possible number of collisions in vertical and angular directions, the total calculation time decreased considerably. 2. System configuration We made 2D pattern design program, mesh generation program and 3D drape engine. Each program was written in C++ language and 3D drawing was done using OpenGL. 2.1 2D pattern design We saved each pattern shape into the straight lines and B-spline curves. The pattern shape can be inputted by mouse or script language of our format. The curved sections are represented by order 3 B-spline and approximated as straight lines only at the mesh generation (Figure 1). 2.2 Pattern mesh generation Each garment patterns area drawn using 2D CAD tool and meshes are constructed. We used triangular mesh because garment patterns can have very
Figure 1. 2D drawing
sharp indents (darts) and internal holes. Triangular meshes can cover these Improvement of complex shapes more effectively than the quadrilateral ones. In the FEM, the drape simulation mesh shape is important because poor mesh configuration results in more speed error. In the particle-based modelling, bending moment is calculated with respect to each element edge. So, too poor element geometry such as very high aspect ratio is not preferable. So, we adopted Delaunay triangulation to 45 guarantee good element configuration. We used rational numbers for node coordinates instead of simple integer or real numbers. Because even if we used Delaunay radius checking to find good element shape, there are some situations where very high aspect ratio element comes out as a result. If the element aspect ratio is very high, calculations using integer or real numbers have inherent round-off error. We represented each node coordinate with rational number form, that is, numerator over denominator. Both numerator and denominator are integers. Garment pattern shapes are also generally non-convex with internal holes. Moreover, they have characteristics such as darts, which enable 2D fabrics to form 3D garment. Darts are sharp-angled indents and sometimes we need indent of angle zero for design or conceptual purpose. When the dart angle is zero, the nodes lying on dart collapse into the same coordinates so that we cannot construct the mesh only with node coordinates. We compared the exterior node’s rotation direction and enabled the correct mesh generation of angle zero darts (Figure 2). This feature is a characteristic of 3D apparel CAD compared with other mechanical CAD systems. 2.3 3D pattern sewing To construct the 3D garment, we need to combine each 2D pattern data into one. This is equivalent to sewing real patterns fabrics to make a suit. The difference is that the boundary elements’ shape is temporarily changed, where the sewing occurs. The changed element shape can regain its original shape by recording the original element edge length (Figure 3). 2.4 Body data We used real human 3D body scan data instead of dummy. The 3D data were obtained from several Korean women aged between 20 and 25 years by
Figure 2. Pattern mesh generation
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Figure 3. Sewing of pattern pieces
Cyberwarew wholebody 3D scanner. The original scan data resolution was high enough, but the data size was as much as 8 MB. So, we approximated the original point data by B-spline surfaces to reduce the data size and to manipulate the body data more easily. First, the body point data is sliced into about 100 pieces of layers with respect to height (z-coordinate). Then each slice has closed-loop cross-sections depending on each body part. Second, the closed-loops are approximated into B-splines with 15-25 data points. Third, each B-spline is classified into six body parts, namely head, bodice, left arm, right arm, left foot and right foot. Fourth, six body part slice curves are interpolated into 3D B-spline surface. As the human body parts are cylindrical in shape, the radial direction control points are interpolated periodically. By compressing the point data into B-spline surface data, we can reduce the whole data size by 90-99 per cent and generate the body mesh of any resolution we want (Figures 4 and 5).
Figure 4. B-spline interpolation of the raw body scan data
Improvement of drape simulation speed 47
Figure 5. Body mesh data of various resolutions
2.5 Motion capture data The motion data were fitted to the body mesh data so that the virtual catwalk simulation is possible. The file format used was Biovision (*.bvh) file and the data were composed of initial pose data and motion per frame data. The number of motion frames was 30 frames per second. Each bone of the motion data was assigned with a cylinder, whose mass centre line is identical to the bone axis. The body mesh elements within certain cylinders are designated to its correspondent bone. As the bones of the motion data move, the mesh elements related to their bones follow the same movement (Figure 6). 2.6 Drape engine Each fabric node has the same mass and thus same gravitational force The forces inflicted to the nodes are gravitational force, tensional force, bending force and air resistance force. The gravitational force is applied to the z-direction. The tensional force is obtained by the strain occurred at the element edges. The bending force is calculated with respect to two nodes facing across the same edge. Air resistance force is introduced to simulate more realistic movement and to work as damping force. If the compression occurs, the compression force is transferred to neighbour edge so as to simulate fabric
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Figure 6. Motion capture data
buckling. Different fabrics have different material properties, but fabric material property is not our concern in this paper. Hence, we used the same material properties for the fabrics. 2.7 Collision detection We used triangular mesh for the fabric and triangular or quadrilateral mesh for the body. Each element to element collision is converted as point under triangle problem. To check that a certain point lies under the opposite direction of the element normal, the element and the point are translated and rotated so that the triangular element lies on the xy plane with normal vector (0,0,1). Then, the z-coordinate shows whether the point lies under the element or not. Element to element collision is checked by repeating the point under triangle tests. 3. Experimental 3.1 Collision detection constraint Generally, the garment patterns are positioned at a certain range of body part when putting on clothes. Sometimes, the garment can flap by wind or else, but we can assume that garment patterns do not move far from the original wearing position for most parts. So, we that the patterns will collide assume with body part or other patterns at the same height (z-coordinate) and same radial position. We checked each collision detection by the following constraints. . Height constraint. Elements should lie vertically in the 10 per cent range of the body height. . Radial constraint. Elements should lie radially in the Pi/2 range. The height constraint was used for both fabric-to-fabric and fabric-to-body collision checks. The radial constraint was used only for the fabric-to-body
collision check, because clothes can have self-contact in the radial direction, Improvement of such as long skirts. drape simulation 3.2 Simulation results We tested the drape speed using height and radial direction constraints. The number of body mesh elements and cloth mesh elements are as follows. The cloth was a straight silhouette blouse and only bodice data were used as the body data. The drape was calculated until the total nodal energy showed no further decrease. The total calculation time increases exponentially as the number of mesh element increases. The use of constraints shows the reduction of calculation time (Table I).
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3.3 Virtual catwalk simulation Figure 7 shows the virtual catwalk simulation, where body data is not fixed, but walking like a real human does The simulation starts with static drape (Figure 5(a)) where the body is not in motion and the simple short one-piece dress is draped. This static drape takes 26 s (616 cloth mesh elements and 2,724 Calculation time (s) # of body mesh element 420 420
# of cloth mesh element
No constraints
With vertical constraints
With radial constraints
With both constraints
296 445
339 497
305 462
312 479
288 446
Table I. Drape calculation time
Figure 7. Virtual catwalk simulation
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body mesh elements) and the dynamic drape (Figure 5(b)) is executed. For fast drape, we did not do full-time drape calculation for all fabric mesh elements because this does not allow real time simulation at all. Only fabric elements that do not have contact with the body are draped and others that are in contact with the body are closely translated after the body movement. Some fabric elements that have collisions within the fabric or with the body are checked and draped again. Using this method, the dynamic drape for the short one-piece dress was done in real time. But for the long dress, it took much time and real time drape was not possible (Figure 7). 4. Conclusions We devised the 2D CAD design tool and 3D drape engine. As the number of body and cloth mesh element increased, the total calculation time also increased exponentially. Most of the calculation time was spent on collision checking. By constraining the vertical and radial direction collision checks, the calculation time can be reduced. The virtual catwalk was simulated using motion capture data at real time for the short one-piece dress. Further reading Breen, D.E., House, D.H. and Wozny, M.J. (1994), “Predicting the drape of woven cloth using interacting particles”, Proceedings of SIGGRAPH 94, Annual Conference Series, ACM, ACM Press/ACM SIGGRAPH, Computer Graphics Proceedings, pp. 365-72. Farin, G. (1998), Curves and Surfaces for CAGD, 4th ed., Academic Press, New York, NY. Yu, W.R., Kang, T.J. and Chung, K. (2000), “Drape simulation of woven cloth using explicit dynamic analysis”, Journal of the Textile Institute, Vol. 91 Part I No. 2, pp. 285-301.
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Real-time per-pixel rendering of textiles for virtual textile catalogues
Real-time per-pixel rendering 51
Andy Spence and Mike Robb School of Mathematical and Computer Sciences, Heriot-Watt University, Edinburgh, UK
Mark Timmins School of Textiles and Design, Heriot-Watt University, Galashiels, Selkirkshire, UK
Mike Chantler School of Mathematical and Computer Sciences, Heriot-Watt University, Edinburgh, UK Keywords Electronic commerce, Simulation, Textile technology Abstract We present recent results from an EPSRC funded project VirTex (Virtual Textile Catalogues). The goal of this project is to develop graphics and image-processing software for the capture, storage, search, retrieval and visualisation of 3D textile samples. The ultimate objective is to develop a web-based application that allows the user to search a database for suitable textiles and to visualize selected samples using real-time photorealistic 3D animation. The main novelty of this work is in the combined use of photometric stereo and real-time per-pixel-rendering for the capture and visualisation of textile samples. Photometric stereo is a simple method that allows both bump map and colour map of a surface texture to be captured digitally. It uses a single fixed camera to obtain three images under three different illumination conditions. The colour map is the image that would be obtained under diffuse lighting. The bump map describes the small undulations of the surface relief. When imported into a standard graphics program these images can be used to texture 3D models. The appearance is particularly photorealistic, especially under changing illumination and viewpoints. The viewer can manipulate both viewpoint and lighting to gain a deeper perception of the properties of the textile sample. In addition, these images can be used with 3D models of products to provide extremely accurate visualisations for the customer. Until recently, these images could only be rendered using ray-tracing software. However, recent consumer-level graphics cards from companies such as Nvidia, ATI and 3Dlabs provide real-time per-pixel shading. We have developed software that takes advantage of the advanced rendering features of these cards to render images in real-time. It uses photometrically acquired bump and colour maps of textiles to provide real-time visualisation of a textile sample, under user-controlled illumination, pose and flex.
1. Introduction The photorealism of a computer-generated 3D scene illuminated by light sources can be enhanced in various ways. At a simple, yet effective level a technique known as texture mapping is commonly used to this end. This involves “pasting” a digital 2D image onto a 3D object composed of polygons to give it the appearance of having a textured surface (Figure 1(b)). Photorealism
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Figure 1. Virtual mannequin
Figure 2. Effect of change in illumination conditions on the appearance of a knitted textile
is certainly enhanced by doing so, but an object rendered in this manner appears unnaturally smooth. Furthermore, the texture itself will be unreactive to the changing illumination conditions. These drawbacks limit the usefulness of texture mapping in e-commerce applications for the textile industry. The objective of this EPSRC project VirTex (Virtual Textile Catalogues) is to address and solve these issues with a view to achieving high-fidelity photorealistic 3D animations. The word “texture” is of course usually associated with rough or bumpy surfaces in the real world. The appearance of such surfaces can change dramatically when illumination conditions are altered (Figure 2). It is important to model this effect if scene photorealism is to be enhanced. This is especially true for animations in which a textured object is moving relative to the light source. Modelling the effect is essentially what is achieved by relighting
techniques whereby a texture is reproduced under user-specified illumination conditions using the data derived from multiple images of the texture under varying illumination. Not all relighting methods are suitable in this case, however. For example, Malzbender et al. (2001) introduced polynomial texture maps as an effective way to model luminance, but it is the scene which is reconstructed. This method therefore does not lend itself to mapping a texture onto a 3D object. Instead it is useful to think of a geometric object and its texture as separate entities as with texture mapping. In this case “bump mapping” which was introduced by Blinn (1978) is the appropriate technique, however. A bump map is used to store information about the topography of a texture in terms of its surface normals. Since normals are a key element in lighting calculations this technique actually allows the surface of an object to both appear rough and also be reactive to changing illumination conditions (Figure 1(c) and (d)). Importantly this is achieved without an increase in the geometric complexity of the object itself. The fact that both bump map and its integrated form, the displacement map (Figure 3), are universally used in computer graphics applications is also noteworthy. In addition to the bump map, information pertaining to the colour of the texture is also required. This albedo map, technically defined as the ratio of reflected light to that incident on the surface, must also be determined. It can then be used as a texture map in the rendering process to achieve a high degree of photorealism. Whilst it is possible to utilise both bump and albedo texture maps in standard 3D packages, rendering is not carried out in real-time. However, for interactive applications real-time rendering is a must. Recent consumer-level graphics cards from companies such as Nvidia, ATI and 3Dlabs provide real-time per-pixel shading. The advanced rendering features of these cards allows software to be developed which uses the photometrically acquired bump and albedo maps to provide real-time visualisation under user-controlled illumination, pose and flex.
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Figure 3. Displacement map obtained by integrating the bump map. Corresponding area of the textile also shown
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In Section 2 the photometric stereo method which is used to capture the data required to generate the bump and albedo maps is described. How these maps which define the texture are utilised for real-time visualisation is then considered in Section 3. Conclusions regarding the whole process are finally drawn in Section 4. 2. Determining the bump map and the colour map of a textile texture Photometric stereo (PS) is a classic computer vision technique for shape estimation which has been extensively researched over many years and has found applications in diverse areas such as surface inspection, classification and recognition. Woodham’s (1980) original algorithm is based on reflectance maps which were introduced by Horn (1986). Significantly, a reflectance map links the topography of a textured surface to the intensity of its corresponding image. Woodham demonstrated that three images of a surface under different illumination conditions are sufficient to uniquely determine both surface orientation and the albedo or colour map – from the intersection of the three reflectance maps. Since this method presents a relatively simple way of obtaining the bump and albedo maps of textile samples it has therefore been utilised in our work for the VirTex project. Over the years the PS algorithm has been refined and modified to cope with less than ideal conditions such as when shadows, specularities or interreflections are present (Coleman and Jain, 1982; Hansson and Johansson, 2000; Lee and Kuo, 1992; Rushmeier et al., 1997; Schluns, 1997; Yamada et al., 1998). The three-image algorithm is still sufficient, however, to recover the surface normals and albedo for a diffuse surface with no shadows. In this case, Lambert’s law applies such that the intensity value of a pixel is proportional to the cosine of the angle between the illumination vector l, and the surface normal n, of the corresponding surface facet scaled by the texture albedo r. This is written in terms of a dot product in equation (1). iðx; yÞ ¼ r ðl · nÞ
ð1Þ
The direction of the illumination vector which points towards the surface facet is limited to that within a hemisphere above the facet. It is therefore intuitive to define it in terms of polar coordinates using the tilt angle T, and the slant angle s. These parameters are equivalent to the angles of latitude and longitude, respectively, and can be measured. l ¼ ðl x ; l y ; l z ÞT ¼ ðcos t sin s; sin t sin s; cos sÞT
ð2Þ
Three images are captured under different illumination conditions in the PS algorithm and thus provide three simultaneous equations which can be written in the following form.
2 3 2 l 1;x i1 6 7 6 6 i2 7 ¼ r6 l 2;x 4 5 4 l 3;x i3
l 1;y l 2;y l 3;y
l 1;z
3
7 l 2;z 7 n 5 l 3;z
ð3aÞ
or equivalently i ¼ rLn
ð3bÞ
It is therefore apparent that if both intensity and illumination vectors have been measured, then the unknowns can be determined by inverting the illumination matrix L. t ¼ L 21 i
ð4Þ
where t ¼ rn; and is the scaled surface normal. Rather than storing the three elements of t ¼ ðt1 ; t2 ; t3 ÞT ; it is preferable to convert these data to separate the albedo from the surface normal. However, this does not imply the use of an extra storage variable. This is because the surface normal n can be written in terms of two variables p and q, which are the partial derivatives of the surface. ð2p; 2q; 1ÞT n ¼ pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi p2 þ q2 þ 1
ð5Þ
where p¼
dz dx
ð6aÞ
dz ð6bÞ dy These partial derivatives and the albedo are calculated from the scaled surface normal t at each pixel position as follows. t1 ð7aÞ p¼2 t3 q¼
q¼2
r¼
t2 t3
qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi t12 þ t 22 þ t32
ð7bÞ
ð7cÞ
The results are stored as images: images p and q define the bump map for the texture whilst its corresponding colour map is the albedo image. For real-time per-pixel rendering, it is these images which are used as input for our custom 3D application (Figure 4).
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Figure 4. Utah teapot rendered in real-time using a photometrically-acquired textile bump map
It is noted that a standard consumer 3D application was used initially in our work (Figure 1). In this case, the required input was a displacement map (Figure 3) rather than a bump map. This was generated by a frequency domain integration of the partial derivatives to obtain height. The method used in our work is similar to that presented by Frankot and Chellappa (1988).
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3. Real time visualisation The rendering of knit-wear and cloth materials has been researched by several authors (Chen et al., 2003; Gro¨ller et al., 1995; Xu et al., 2001; Yasuda et al., 1992). Whilst these methods make use of 3D rendering techniques and achieve excellent photorealistic quality, they do not run in real-time. With the lumi-slice technique, a single frame can take anywhere from 15 to 30 min to be rendered. Another disadvantage is that this method requires the user to specify the weave pattern used to construct the material. In order to allow rendering in real-time there are several tasks required to visualise the bump map and colour map images produced by the photometric stereo algorithm described in Section 2. These include the conversion of the image data into the internal data format used by the graphics accelerator, the configuration of each stage of the programmable graphics pipeline, and the transmission of geometry through the graphics pipeline. 3.1 Configuration of the graphics pipeline Before loading the data in the graphics accelerator we need to use the pre-processing algorithm to calculate the outward normals that are used to define the bump map. This section describes the usage of these data to implement per-pixel bump-mapping in hardware. Implementation of the graphics pipeline requires four separate stages to be designed. They are (1) pre-processing stage, (2) vertex transformation stage, (3) per-pixel lighting stage, and (4) rendering stage. 3.1.1 Design of the pre-processing stage. Using the photometric stereo method, the initial texture data exists in the form of a set of monochrome images in floating-point format. The first image defines the albedo colour map. The other two images define the P and Q partial derivatives of the surface with respect to each axis. The first image is converted for use by the graphics hardware simply by scaling and converting the image data from 32-bit floating point down to 8-bits. Conversion of the two gradient images is achieved in the following way. Given the values of gradient it is possible to calculate the equivalent angle in radians for each pixel:
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dz 21 21 dz fp ¼ tan ðpÞ ¼ tan fq ¼ tan ðqÞ ¼ tan dx dy 21
21
ð8Þ
From these two angles, it is possible to calculate the partial derivatives of the surface, and the normal vector from the normalized cross product of the two values: p0 ¼ ðcosðfp Þ; 0; sinðfp ÞÞT
q0 ¼ ð0; cosðfq Þ; sinðfq ÞÞT n ¼ jp0 £ q0 j
ð9Þ
It should be noted that the outward normal n which is given by its value is required for equation (5) is not actually calculated until rendering. The main reason for doing this is to save on storage space and transmission bandwidth for networked applications. The resulting vector is then scaled and biased for compression into an 8-bit signed RGB colour value. However, with future graphics accelerators such as the Nvidia’s GeForce FX, it will be possible to use the floating-point data directly. 3.1.2 Vertex transformation. The transformation of vertex information is implemented using a vertex program, as this is the most efficient way of implementing the algorithm. A detailed explanation of this algorithm is described in “Efficient Bump Mapping Hardware” (Peercy et al., 1997). Rendering a bump-mapped model requires that the two additional direction vectors (tangent normal and binormal) specifying the local tangent space for the vertex are sent along with the outward normal, vertex and texture coordinates. For each vertex, the location and direction of the current light source is transformed into the tangent space. This allows the half-angle vector between the eye vector and the outward normal to be calculated. This vector must also be normalised before being used in the lighting equation. This is achieved by using two texture cube maps to implement vector normalisation. As per-pixel lighting is required, the lighting equation is implemented in the register combiner stage. To allow the texture coordinates to match the scale of a 3D model, two texture matrices are used to transform the texture coordinates prior to rendering. 3.1.3 Per-pixel lighting. Per-pixel lighting of the graphics pipeline is implemented using the register combiner unit of the graphics chip. It is noted that not all consumer-level graphics cards are programmable in this way; Nvidia’s Geforce4 Ti4600 has this feature and this card has been used in our work. It allows the lighting model to incorporate ambient, diffuse and specular components on a per-pixel basis. At this point, the following texture data are available: (1) pixel colour of the base texture, (2) light source direction normal, (3) half-angle normal, and (4) encoded 8-bit RGB normal from the bump map texture.
The register combiner units are used in the following way. The first register unit is always used to calculate the dot products between the light-source direction normal and, the half-angle and bump map normal. The second register combiner is always used to implement the diffuse colour calculation. The remaining six register combiner units are used as required to raise the dot product result to the corresponding specular power. The final register combiner unit is used to combine the ambient, diffuse and specular lighting values together. 3.1.4 Rendering stage. For this project, Bezier patches were chosen as the basic geometric primitive There were two reasons for this decision. The first reason was that animation and CAD users have used these in the past. The other reason is that the evaluation stage of this primitive can be easily modified to calculate the required tangent space coordinates. The base texture and bump map texture are loaded into the graphics accelerator texture memory as 8-bit RGBA textures. The alpha channel of the base texture is used to define a transparency map, while the alpha channel of the bump map texture is used to modulate the specular term of the lighting model, and so define a gloss map. In order to implement the trimmed surfaces, the regions of the patch removed are made invisible by setting the alpha channel to zero. Two other texture units are used to implement the normalisation stage using an environment cube-map. One of the two vertex programs is used to render the patch using either a directional or local point light source. Each patch of the geometric model is evaluated in software and sent to the graphics accelerator. 3.1.5 Human-computer interaction. To allow the user to view the model with as much freedom as possible, the user interface has been designed to allow the user to control the position of the model, light sources and camera independently. The operations supported include rotating the model, rotating and zooming both camera and light-sources. All objects can be allowed to rotate automatically, to brake automatically, or to only rotate whenever the user moves the mouse. Light sources are rendered as a sphere to give the user feedback as to where the light source is located and moving. 3.1.6 Applications of photometric texture acquisition with 3D modelling. To demonstrate the usage of this technique with the existing 3D graphics hardware, we have taken the original Utah Teapot and applied a photometrically-acquired bump-mapped texture of a knitted textile onto each Bezier patch. The final model is then rendered in real-time using OpenGL. Movement of the light source demonstrates how the bump-mapped texture can be used to generate photorealistic images. It should be noted that while bump mapping greatly improves the detail of the surface facing the observer, giving the illusion of a rough surface, when the same surfaces are viewed edge on, it is obvious that the surface is smooth. This is demonstrated in Figures 4 and 5.
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Figure 5. Utah teapot rendered in real-time using photometrically-acquired textile bump maps
4. Conclusions In this paper, we present a method of photometrically acquiring the image of a textile in terms of a bump map and a texture map. We have used the acquired data to implement real-time rendering of textured 3D models. With
high performance graphics capability rapidly becoming available on consumer level hardware, this technique can be easily used to create virtual catalogues accessible by standard web browsers. This technology could also be applied to CAD and CAGM to allow designers to rapidly prototype designs in virtual reality. References Blinn, J.F. (1978), “Simulation of wrinkled surfaces”, ACM Special Interest Group on Computer Graphics and Interactive Techniques, pp. 286-292, Also in Tutorial: Computer Graphics: Image Synthesis, pp. 307-13. Chen, Y., Lin, S., Zhong, H., Xu, Y., Guo, B. and Shum, H. (2003), “Realistic rendering and animation of knitwear”, IEEE Transactions on Visualization and Computer Graphics, Vol. 9 No. 1. Coleman, E.N. and Jain, R. (1982), “Obtaining three-dimensional shape of textured and specular surfaces using four-source photometry”, Computer Graphics and Image Processing, Vol. 18, pp. 309-28. Frankot, R. and Chellappa, R. (1988), “A method for enforcing integrability in shape from shading algorithms”, IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 10 No. 4, pp. 439-51. Gro¨ller, E., Rau, R. and Straßer, W. (1995), “Modeling and visualization of knitwear”, IEEE Transactions on Visualization and Computer Graphics, Vol. 1 No. 4. Hansson, P. and Johansson, P. (2000), “Topography and reflectance analysis of paper surfaces using a photometric stereo method”, Optical Engineering, Vol. 39 No. 9, pp. 2555-61. Horn, B. (1986), Robot Vision, MIT Press, Cambridge, MA. Lee, K.M. and Kuo, C.C.J. (1992), “Shape reconstruction from photometric stereo”, Computer Vision and Pattern Recognition ‘92, Illinois. Malzbender, T., Gelb, D. and Wolters, H. (2001), Polynomial Texture Maps, Siggraph, pp. 519-28. Peercy, M., Airey, J. and Cabral, B. (1997), “Efficient bump mapping hardware”, ACM Special Interest Group on Computer Graphics and Interactive Techniques. Rushmeier, H., Taubin, G. and Gueziec, A. (1997), “Applying shape from lighting variation to bump map capture”, Eurographics Rendering Workshop Proceedings ’97, pp. 35-44. Schluns, K. (1997), “Shading based 3D shape recovery in the presence of shadows”, Proc. First Joint Australia and New Zealand Biennial Conference on Digital Image and Vision Computing, Techniques and Applications, Auckland, New Zealand, pp. 195-200. Woodham, R.J. (1980), “Photometric method for determining surface orientation from multiple images”, Optical Engineering, Vol. 19 No. 1, pp. 139-44. Xu, Y., Chen, Y., Lin, S., Zhong, H., Wu, E., Guo, B. and Shum, H. (2001), “Photorealistic rendering of knitwear using the lumislice”, ACM SIGGRAPH, pp. 391-8. Yamada, T., Saito, H. and Ozawa, S. (1998), “3D reconstruction of skin surface from image sequence”, Proc. Of MVA98: Workshop of Machine Vision Applications, pp. 384-7. Yasuda, T., Yokoi, S., Toriwaki, J. and Inagaki, K. (1992), “A shading model for cloth objects”, IEEE Computer Graphics and Applications, Vol. 12 No. 6. Further reading Barsky, S. and Petrou, M. (2001), “Colour photometric stereo, simultaneous reconstruction of local gradient and colour of rough textured surfaces”.
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Cook, R.L. (1984), “Shade trees”, Proceedings of the 11th Annual Conference on Computer Graphics and Interactive Techniques, pp. 223-31. Hanrahan, P. and Lawson, J. (1990), “A language for shading and lighting calculations”, ACM Special Interest Group on Computer Graphics and Interactive Techniques, pp. 289-98. Heidrich, W. and Seidel, H. (1999), “Realistic, hardware-accelerated shading and lighting”, Proceedings of the 26th Annual Conference on Computer Graphics, pp. 171-8. Ikedo, T. and Ma, J. (1997), An Advanced Graphics Chip with Bump-mapped Phong Shading, pp. 156-65. Kautz, J., Heidrich, W. and Seidel, H. (2001), “Real-time bump map synthesis”, Proceedings of the ACM SIGGRAPH/EUROGRAPHICS Workshop on Graphics Hardware, pp. 109-14. Lastra, A., Molnar, S., Olano, M. and Wang, Y. (1995), “Real-time programmable shading”, ACM Special Interest Group on Computer Graphics and Interactive Techniques, pp. 59-66. Lindholm, E., Kilgard, M. and Moreton, H. (2001), “A user-programmable vertex engine”, Proceedings of the 28th Annual Conference on Computer Graphics and Interactive Techniques, pp. 149-57. McAllister, D., Lastra, A. and Heidrich, W. (2001), “Efficient rendering of spatial bi-directional reflectance distribution functions”, ACM Special Interest Group on Computer Graphics and Interactive Techniques, pp. 109-14. McCool, M. (2001), “SMASH: a next generation API for programmable graphics accelerators”, Technical Report CS-2000-14, Department of Computer Science, Computer Graphics Lab, University of Waterloo. McCool, M. and Heidrich, W. (1999), “Texture shaders”, Proc. of the 1999 Eurographics/SIGGRAPH workshop on graphics hardware, pp. 117-26. McCool, M., Qin, Z. and Popa, T. (2002), “Shader metaprogramming”, Proceedings of the Conference on Graphics Hardware, pp. 57-68. McGunnigle, G. (1998), “The classification of texture surfaces under varying illumination direction”, PhD thesis, Department of Computing and Electrical Engineering, Heriot-Watt University. Peercy, M., Olano, M., Airey, J. and Ungar, P. (2000), Interactive Multi-Pass Programmable Shading, pp. 425-32. Perlin, K. (1985), “An image synthesizer”, ACM Special Interest Group on Computer Graphics and Interactive Techniques, pp. 287-96. Robb, M. (2003), “From MCGA to GeForce FX and radeon – the history of PC graphics hardware”, Research Memo CS-2003/01, Heriot Watt University. Available at Web site: http://www.macs.hw.ac.uk/texturelab Spence, A.D. (2003), “Optimal illumination for three-image photometric stereo”, Research Memo CS2003/02, School of Mathematics and Computer Science, Heriot-Watt University. Available at Web site: http://www.macs.hw.ac.uk/texturelab
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Smart clothing: a new life
Smart clothing: a new life
Lieva Van Langenhove and Carla Hertleer Department of Textiles, Ghent University, Zwijnaarde, Belgium Keywords Textiles, Product innovation
63
Abstract After technical textiles and functional textiles, smart textiles came into force a few years back. The term “smart textiles” covers a broad range. The application possibilities are only limited by our imagination and creativity. Hence it is not simple for the readers of the many articles that have been published to distinguish where reality ends and where fiction begins. In this paper, it is further explored what smart textiles precisely mean. In a second part, an analysis is made of the possibilities, the state of affairs and the need for further research, including research in the Department of Textiles at the Ghent University (Belgium).
1. Introduction The term “smart textiles” is derived from intelligent or smart materials. The concept of “Smart Material” was, for the first time, defined in Japan in 1989. The first textile material that, in retroaction, was labelled as a “smart textile” was silk thread having a shape memory (by analogy with the better known “shape memory alloys” which will be discussed later in this paper). The continual shrinkage of the textile industry in the Western world has amply raised the interest in intelligent textiles. Smart textile products meet all criteria of high-added value technology allowing transformation to a competitive high-tech industry: from resource-based towards knowledge-based; from quantity to quality; from mass-produced single-use products to manufactured-on-demand, multi-use and upgradable product-services; from “material and tangible” to “intangible” value-added products, processes and services. 2. Definition of intelligent clothing What does it mean exactly, “smart textiles”? Textiles that are able to sense stimuli from the environment, to react to them and adapt to them by integration of functionalities in the textile structure. The stimulus and response can have an electrical, thermal, chemical, magnetic or other origin. Advanced materials, such as breathable, fire-resistant or ultrastrong fabrics, are according to this definition not considered as intelligent, no matter how high-tech they are. The extent of intelligence can be divided in to three subgroups (Zhang and Tao 2001a, b, c): (1) passive smart textiles can only sense the environment, they are sensors; (2) active smart textiles can sense the stimuli from the environment and also react to them, besides the sensor function, they also have an actuator function; and
International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 63-72 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520360
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(3) very smart textiles take a step further, having the gift to adapt their behaviour to the circumstances. On principle, two components need to be present in the textile structure in order to bear the full mark of smart textiles: a sensor and an actuator, possibly completed with a processing unit which drives the actuator on the basis of the signals from the sensor. Although smart textiles find and will find applications in numerous fields, this paper is limited to clothing. However, clothing can be interpreted in a broad sense. It involves, for example, wearable smart textiles meant for medical applications, designed to fulfil certain functions, but apart from that without any fringes. Also casual clothing is possible, which is expected to be functional as well as fashionable. It also embraces sports clothing, where the comfort factor is even more critical. Finally, smart textiles could be sold as a gadget, where the intelligent character will be more an accessory (Spielerei). Initially, smart clothing will find applications in those fields where the need for monitoring and actuation can be of vital importance, such as a medical environment, and with vulnerable population groups, in space travel and the military. Such applications will enable demonstration of the benefits of smart textiles. This will slowly break down barriers for use, and so the range of users will widen to applications such as sports and leisure, the work environment and so on. 3. State-of-the-art 3.1 Overview The first generation of intelligent clothes uses conventional materials and components and tries to adapt the textile design to fit in the external elements. They can be considered as e-apparel, where electronics are added to the textile. A first successful step towards wearability was the ICD + line at the end of the 1990s, which was the result of co-operation between Levi’s and Philips. This line’s coat architecture was adapted in such a way that the existing apparatuses could be put away in the coat: a microphone, an earphone, a remote control, a mobile phone and an MP3 player. The coat construction at that time did require that all these components, including the wiring, were carefully removed from the coat before it went into the washing machine. The limitation as to maintenance caused a high need for further integration. The most obvious thing to do was integrating the connection wires of the different components into the textile. To this end, conductive textile materials are appealed to. Infineon (http://www.wearable-electronics.de/intl/ fotos_vorbereitungen.asp) has developed a miniaturised MP3 player, which can easily be incorporated into a garment. The complete concept consists of a central microchip, an earphone, a battery, a download card for the music and an interconnection of all these components through woven conductive textiles. Robust and wash-proof packing protects the different components.
No matter how strongly integrated, the functional components remain as Smart clothing: a non-textile elements, meaning that maintenance and durability are still new life important problems. In the second generation, the components themselves are transformed into full textile materials. Basically, five functions can be distinguished in an intelligent suit, namely: sensors, data processing, actuators, storage, and communication. 65 They all have a clear role, although not all intelligent suits will contain all functions. The functions may be quite apparent, or may be an intrinsic property of the material or structure. They all require appropriate materials and structures, and they must be compatible with the function of clothing: comfortable, durable, resistant to regular textile maintenance processes and so on. 3.2 Sensors The basis of a sensor is that it transforms a signal into another signal that can be read and understood by a predefined reader, which can be a real device or a person. The senses of a person are well known: eyes, ears, touch, nose, and taste. As for real devices, ultimately most signals are being transformed into electric ones. Electroconductive materials are consequently of utmost importance with respect to intelligent textiles. Of course, apart from technical considerations, concepts, materials, structures and treatments must be focusing on the appropriateness for use in or as a textile material. This includes criteria like flexibility, water (laundry) resistance, durability against deformation, radiation, etc. Materials that have the capacity of transforming signals into electric ones are for instance the following. . Thermocouple: from thermal to electrical. . The Softswitch technology (http://www.softswitch.co.uk): from mechanical (pressure) to electrical. It uses a so-called “quantum tunnelling composite (QTC)”. This composite has the remarkable characteristic to be an isolator in its normal condition and to change in a metal-like conductor when pressure is being exercised on it. Depending on the application, the pressure sensitivity can be adapted. Through the existing production methods, the active polymer layer can be applied on every textile structure, a knitted fabric, a woven or a nonwoven fabric. The pressure sensitive textile material can be connected to the existing electronics. . Fibre bragg grating (FBG) sensors: from mechanical through optical to electrical. This is a type of optical sensor receiving a lot of attention in recent years. They are used for the monitoring of the structural condition of fibre-reinforced composites, concrete constructions or other construction materials. At the Hong Kong Polytechnic University, several important applications of optical fibres have been developed for
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the measurement of tension and temperature in composite materials and other textile structures (Tao, 2002). FBG sensors look like normal optical fibres, but inside at a certain place they contain a diffraction grid that reflects the incident light of a certain wavelength (principle of Bragg diffraction) in the direction where the light is coming from. The value of this wavelength linearly relates to a possible elongation or contraction of the fibre. In this way, the Bragg sensor can function as a sensor for deformation. 3.3 Data processing Data processing is one of the components that are required only when active processing is necessary. So far, no textile materials are available that can perform this task. Pieces of electronics are still necessary. However, they are available in miniaturised and even in a flexible form. Research is going on to fix the active components on fibres (Ficom project, http://www.fibercomputing. net). Many practical problems need to be overcome before real computing fibres are on the market: fastness to washing, deformation, interconnections, etc. 3.4 Actuators Actuators respond to an impulse resulting from the sensor function, possibly after data processing. Actuators make things move, release substances, make noise, and many others. Shape memory materials are the best-known examples in this area. They transform thermal energy into motion. Because of its ability to react to a temperature change, a shape memory alloy can be used as an actuator and links up perfectly with the requirements imposed to smart textiles. Shape memory alloys exist in the form of threads, which makes them compatible with textile materials. Although shape memory polymers are cheaper, they are less frequently applied. This is due to the fact that they cannot be loaded very heavily during the recovery cycle. Until recently, few textile applications of shape memory alloys are known. The Italian firm, Corpo Nove, in co-operation with d’Appolonia, developed the Oricalco Smart Shirt (http://textile.t4tech.com/Application.asp#). The shape memory alloy is woven with traditional textile material resulting into a fabric with a pure textile aspect. The trained memory shape is a straight thread. When heating, all the creases in the fabric disappear. This means that the shirt can be ironed with a hair dryer. Real challenges in this area are the development of very strong mechanical actuators that can act as artificial muscles. Performant muscle-like materials, however, are not yet within reach (First World Congress, 2002). Materials that release substances already have several commercial applications. However, actively controlled release is not obvious. Obviously, controlled release opens up a huge number of applications as drug supply systems in intelligent suits can also make an adequate diagnosis.
3.5 Storage Smart clothing: a Smart suits often need some storage capacity. Storage of data or energy is most new life common. For sensing, data processing, actuation, communication, they usually need energy, mostly electrical power. Efficient energy management will consist of an appropriate combination of energy supply and energy storage capacity. Sources of energy that are available to a garment are for instance, body heat, 67 mechanical motion (elastic from deformation of the fabrics, kinetic from body motion), radiation, etc. Infineon (Lauterbach et al., 2002) had the idea to transform the temperature difference between the human body and environment into an electrical energy by means of thermogenerators. The prototype is a rigid, and thin micromodule that is discretely incorporated into the clothing. The module itself is not manufactured out of textile material. However, the line of thought is introduced. The use of solar energy for energy supply is also thought of. At the University of California, Berkley, a flexible solar cell is developed which can be applied to any surface (Chapman, 2002). As mentioned earlier, energy supply must be combined with energy storage. When hearing this, one thinks of batteries. Batteries are becoming increasingly smaller and lighter. Even flexible versions are available, although less performant. Currently, the lithium-ion batteries are found in many applications. For some applications where large temperature variations occur, it may be useful to store the thermal energy as well. Phase change materials (PCMs) have the ability to do so and are already introduced in the textile industry. 3.6 Communication For intelligent textiles, communication has many faces: communication may be required: . within one element of a suit, . between the individual elements within the suit, . from the wearer to the suit to pass instructions, and . from the suit to the wearer or his environment to pass information. Within the suit, communication is currently realised by either optical fibres (Park and Jayaraman, 2002), or conductive yarns (Van langenhove et al., 2002). They both clearly have a textile nature and can be built in the textile seamlessly. Communication with the wearer is possible for instance, by the following technologies. . For the development of a flexible textile screen, the use of optical fibres is obvious as well. France Telecom (Deflin et al., 2002) has managed to realise some prototypes (a sweater and a backpack). At certain points, the light from the fibre can come out and a pixel is formed on the textile surface. The textile screen can emit static and dynamic colour images. In order to increase the resolution, the concept will need to be reviewed, as currently one pixel requires several optical fibres. Nevertheless, in this
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way, these clothes are uplifted to a first generation of graphical communication means. Pressure sensitive textile materials (http://www.softswitch.co.uk, http:// www.tactex.com) allow putting in information, provided a processing unit can interpret the commands.
Communication with the wider environment does not allow direct contact, so wireless connections are required. This can be achieved by integrating an antenna. The step was also taken to manufacture this antenna in textile material. The advantage of integrating antennas in clothing is that a large surface can be used without the user being aware of it. In the summer of 2002, a prototype was presented by Philips Research Laboratories, UK and Foster Miller, USA on the International Interactive Textiles for the Warrior Conference (Boston, USA). 4. Smart textiles at the Department of Textiles at the Ghent University The research concerning smart textiles at our University focuses on the development of textile sensors for medical purpose. These sensors will be used for monitoring heart rate and respiration of children in a hospital environment. It is commonly known that conventional sensors are clearly present and often cause problems when used for long term monitoring (e.g. skin irritation). Textile sensors are developed to overcome these and other inconveniences. The textile sensors, data handling, transmission and an alarm function will all be integrated in a suit, called the IntelliTex suit. This imposes special requirements on the electronics: small dimensions, washable packaging, low power consumption, etc. 4.1 Heart rate and ECG measurements To measure the heart rate and even an ECG, the Textrodes were developed. The Textrodes have a knitted structure and are made of stainless steel fibres (by Bekintex). They are used in direct contact with the skin. Conventional electrodes are used in combination with an electrogel. The electrogel establishes a good conductive contact between the skin and the electrode, which results in an improved signal. However, the patient does not experience electrogel in a positive way. Whenever the skin is in sustained contact with the gel, there is a possibility that skin irritation and softening occurs. This imposes restrictions on the use of conventional electrodes for long term monitoring. When using the Textrodes, this limitation is overcome because no electrogel is needed. The Textrodes make direct contact with the skin. A compromise has to be found between the sense of comfort and intensity of the contact with the skin. A knitted structure has the advantage of being
stretchable. Elasticity is a required property for close fitting of the suit Smart clothing: a around the thorax. new life The choice of stainless steel was led by the following properties: . it is a very good conductor, . the fibres have a good touch, . 69 it has a low toxicity to living tissue, . there is little or no danger for contact allergies because of the very low degree of nickel, . it can easily be washed without losing its properties, and . it can be manipulated as a textile material. From the test results, it clearly appeared that the electrode’s textile structure is a parameter that has to be considered. When changing the structure, a different contact surface with the skin is obtained. Finer structures with more protruding fibres for instance, will more easily adapt to the heterogeneous skin surface, which results in a more intense contact between the electrode and skin. In turn, this results in a lower impedance of the skin electrode system. The patient’s comfort must always be borne in mind. An electrode having a large number of protruding metal fibres will be more likely to cause skin irritation or to provoke an annoying sensation with the carrier. Since no electrogel is used, an optimal contact between the electrode and skin will have to be realised through the structure and composition of the electrode itself. Obviously, this contact will improve by putting more pressure on the electrode. Once again, a decrease of impedance is observed limiting the influence of noise signals. To measure the ECG, a three-electrode configuration is used (Neuman, 1998). Two measurement electrodes are placed on a horizontal line on the thorax, a third one, acting as a reference (“right leg drive”), is placed on the lower part of the abdomen. In order to assess their performance, the signal originated from a conventional electrode (gel electrodes by 3 M) and the textile electrodes were recorded at the same time. The results of these measurements are shown in Figure 1. The figures obviously prove the accuracy of the signal of the textile electrodes. The quality and the reliability of the signal will be compared to the standard electrodes in extensive clinical testing. To make the monitoring belt attractive to children, the textile sensors for monitoring the heart rate are integrated in the ears of Mickey Mouse (Figure 2). 4.2 Respiration measurements Another textile sensor, used for measuring respiration, is developed. The “Respibelt” is also made of a stainless steel yarn, knitted in a belt (Figure 2). Figure 3 shows the result of monitoring respiration rate with the Respibelt.
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Figure 1. Conventional electrodes (a, b, c) versus textile electrodes (d, e, f) in three different configurations
Figure 2. Belt wit integrated textile sensors
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71 Figure 3. Short and long term monitoring with Respibelt
It demonstrates that a time constant and stable signal are obtained during 30 minutes. This stability holds on for several days. 5. Need for further research The potential of intelligent textiles is huge. One can think of many applications for each of the examples given earlier. The other way around, starting from an application, the basic concepts have to be defined and evaluated for their use in or as a textile product. Selection of materials, structures and production technologies are the first step in the design. The actual research phase will be long and hard for many cases. Basic items that need to be addressed to come to a real breakthrough and to innovation are: . transformation and conversion mechanisms to define the basic concept, . new materials, and . new structures that can offer the requested functions. Conductive materials, metals as well as conducting polymers, are already being used in many applications: antistatic working, EMI shielding, heating, transport of electrical signals, etc. Inherently conducting polymers (ICPs) are fascinating, dynamic, and molecular systems suitable for applications in many domains of intelligent clothing: polymer batteries, solar energy conversion, biomechanical sensors, etc. Some materials are already available, be it at laboratory level. Some substantial disadvantages, which have to be overcome, are the instability of the polymer in the air, the weak mechanical properties and the difficult processing. However, in the United States one has managed to spin the first polyaniline fibre (Santa Fe Science and Technology Inc., Santa Fe, USA). Another class of materials that will play a major role without any doubt in many intelligent clothes are optical fibres. They are well known from
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applications in electronics, but the range of deformations to deal with in textile applications is of a different order and causes problems that restrict the number of applications at present. 6. Conclusion Textiles are present everywhere and any time. No one ever leaves the house without having been occupied with textiles. The economic value and impact of textiles is gigantic. The advent of smart textiles makes it possible to bring the traditional textile sector to a level of high-technological industry. Moreover, it appears that this is only possible by intense co-operation between people from various backgrounds and disciplines. Technology domains such as biotechnology, computer science, microelectronics, polymer chemistry, material science, etc. look at textile possibilities from another point of view. The development of smart textiles starts to come at cruise speed. A part of the new materials and structures has already reached the stage of commercialisation, a much larger part however, is still in full development or still has to be invented even. This applies especially for the very smart textiles. This phase is to be reached by 2010, so at medium term. References Chapman, K. (2002), “High tech fabrics for smart garments”, Concept 2 Consumer, September 2002, pp. 15-19. Deflin, E., Weill, A. and Koncar, V. (2002), “Communicating clothes: optical fiber fabric for a new flexible display”, AVANTEX Proceedings, 13-15 May 2002. Lauterbach, C. et al. (2002), “Smart clothes selfpowered by body heat”, AVANTEX Proceedings, 15 May 2002. First World Congress (2002), First World Congress on Biomimetics and Artificial Muscles, 9-11 December 2002, Albuquerque, USA. Neuman, M.R. (1998), “Biopotential amplifiers”, in Webster, J.G. (Ed.), Medical Instrumentation – Application and Design, Wiley, New York, NY, pp. 233-86. Park, S. and Jayaraman, S. (2002), “The wearable motherboard: the new class of adaptive and responsive textile structures”, International Interactive Textiles for the Warrior Conference, 9-11 July 2002. Tao, X. (2002), “Sensors in garments”, Textile Asia, January 2002, pp. 38-41. Van langenhove, L. et al.et al., (2002), “Intelligent textiles for children in a hospital environment”, World Textile Conference Proceedings, 1-3 July 2002, pp. 44-8. Zhang, X. and Tao, X. (2001a), “Smart textiles: passive smart”, Textile Asia, June 2001, pp. 45-9. Zhang, X. and Tao, X. (2001b), “Smart textiles: active smart”, Textile Asia, July 2001, pp. 49-52. Zhang, X. and Tao, X. (2001c), “Smart textiles: very smart”, Textile Aisa, August 2001, pp. 35-7.
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Developing portable acoustic arrays on a large-scale e-textile substrate
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E. Grant, K.A. Luthy, J.F. Muth, L.S. Mattos and J.C. Braly Department of Electrical and Computer Engineering, Center for Robotics and Intelligent Machines, North Carolina State University, Raleigh, North Carolina, USA
A. Seyam, T. Ghosh, A. Dhawan and K. Natarajan Department of Textile and Apparel Technology and Management, North Carolina State University, Raleigh, North Carolina, USA Keywords Textiles, Computer applications Abstract This research deals with the production of electronic textiles (e-textiles) demonstrators. Initially, the research dealt with the creation of 4 £ 5 microphone array on a large area conformal textile substrate. Once the interface electronics were connected to the 4 £ 5 microphone array, this system became an effective acoustic array. Here, a new acoustic eight microphone array design has been designed, fabricated and tested. Changes were made to improve microphone array performance, and to optimize the associated software for data capture and analysis. This new design was based on UC-Berkeley mote microcomputer technology. The mote-based system addresses the issue of scaling acoustic arrays, to allow for distributing microphones over large-areas, and to allow performance comparisons to be made with the original 4 £ 5 microphone acoustic array.
1. Introduction The research reported deals primarily with the production of electronic textiles (e-textiles) acoustic array demonstrators. To create portable acoustic arrays on flexible textile substrates, an understanding of textile designs and processes is required, to allow the fabrication of conducting lines in woven substrates, including the use of floats to create windscreens for the microphone sensors. Similarly, an understanding of the design and manufacture of flexible substrates from electronics had to be gained to produce autonomous miniature electronic circuits that will flex when embedded in a textile substrate. The acoustic array technology developed included textile substrates, microphone arrays, and all associated interface electronics and software. UC-Berkeley mote-based technology was used as the basis of the interface electronics. The software needed to capture acoustic array data and transfer this for further analysis, was resident of the Mote-based technology. The modular design of The research program was funded by the DARPA MTO Division, the program manager was Dr Elana Ethridge. Draper Laboratories, Inc. and MCNC were also involved and contributed technical and administrative support.
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Mote-based technology allowed microphone arrays to be scaled up, to produce large distributed arrays, or to allow other geometric configurations of microphones to be experimented on too. 2. Acoustic triangulation and beam-forming methods Triangulation techniques are used to calculate the position of a sound source based on time delay measurements and geometric relationships. Many acoustic triangulation algorithms exist, but they all are limited by the geometric arrangement of the acoustic array. If the acoustic array dimensions are small, it is difficult to precisely measure time delays associated with low frequency sound sources. Also, acoustic arrays with small dimensions do not allow for sensor redundancy, due to lack of useful space to add additional sensors. For example, with a two-dimensional array, only the relative azimuth angle of a sound source can be determined using a small area, tightly-packed array. In addition, to determine the elevation angle of the sound source, the acoustic array must be three-dimensional (Luthy, 2003; Luthy et al., 2002; Muth et al., 2002; Walworth and Mahajan, 1997). Beam-forming is a directional listening technique that is based on accurately measuring the time delays between the signals received by the individual elements, e.g. microphones, in an array. Beam-forming is a good method to apply when sound sources must be tracked, because it does not require the array elements to be physically moved during the listening phase. Sound sources are commonly displayed using a waterfall plot that keeps record of a target’s location at each instant in time (Luthy, 2003; Luthy et al., 2002; Muth et al., 2002). Much like triangulation, beam-forming relies heavily on the geometric arrangement of the system. A larger aperture is not only ideal, but also necessary to adequately characterize a particular frequency. For military applications, the sound source spectrum of interest is in the range 20-200 Hz, which makes a large area acoustic array using microphones as an acceptable solution for precise and sensitive sound source measurement. 2.1 An eight-microphone acoustic array system The goal of this project was to develop an autonomous portable acoustic array that could be replicated to produce a distributed sensor system over a large area. This demonstrator was to be in the form of a robust, conformable and single person deployable acoustic array on a textile substrate. Table I shows the specifications for a single eight-microphone portable demonstrator for use as a single element in a future distributed system. After the developed portable demonstrator was constructed, experiments were conducted into real-time sound source localization using a triangulation algorithm (Walworth and Mahajan, 1997). The sound source localization experiments with the portable demonstrator confirmed once again, as in the work of Luthy et al. (2002), that an acoustic array can be implemented using a textile substrate, and that it can give accurate sound source localization.
The benefit of this new approach in developing acoustic arrays is that the Portable acoustic embedded electronics makes each array a wholly autonomous system, one that arrays can be configured for distributed sensing tasks when it interacts with other similar systems. 3. Portable acoustic array designs 3.1 The prototype The original prototype acoustic array design had microphones attached to the array and the associated signal amplification circuitry was located externally to the array (Figure 1(a)). The microphone amplifier design was based on a standard operational-amplifier wired in a non-inverting configuration, and biased to operate from a single supply. A block diagram of the amplifier circuitry and the interface for the acoustic array is shown in Figure 1(b). The prototype acoustic array wiring configuration required separate power lines (one for the microphone and one for the op-amp) and a ground line for every node. A decision was made to move the acoustic array design to a wiring arrangement that used the same embedded twisted-pair wires for carrying both node power and microphone signal. The use of twisted-pair wire only, a Acoustic array Microphones Sensor attachment Electronics Size Applications
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Portable demonstrator Eight omni-directional microphones attached to fabric Solder connection Located on fabric in separate container Unrolled: 1 m diameter Real-time sound source localization
Table I. Portable demonstrator construction and projected system descriptions
Figure 1. (a) 4 £ 5 microphone acoustic array matrix; and (b) block diagram of microphone circuit
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Figure 2. The 2 m diameter, eight-microphone array with one center microphone and seven radial microphones
multi-signal approach, required that wire interconnects needed to be formed within the fabric. Several methods of forming interconnects exist and were evaluated in detail by Dhawan (2001) and Dhawan et al. (2002). For prototyping and demonstration, standard soldering was the method of choice for wiring and component interconnect. Output data signals from the microphones were transmitted from the fabric to an audio acquisition system. This acquisition system was capable of sampling up to ten channels simultaneously and recording these channels on a personal computer. The beam-forming software, developed using MATLABw, was then applied to these signals thereby demonstrating the principle of a fabric-based acoustic array. Having built and successfully applied the acoustic array shown in Figure 1(a), and having determined its performance characteristics, the next project became the design and fabrication of a filter circuit for eight microphones. This circuit will use SMD technology and be mounted on a flexible circuit. A new prototype textile acoustic array is shown in Figure 2. It is approximately 1 m in diameter with eight embedded microphones. One microphone is embedded in the center of the array and the other seven are evenly spaced around the perimeter. This positioning scheme removes bilateral symmetry and therefore reduces endfire ambiguity when beam-forming. Figure 2 also shows the signal wires and the mote with which they will interface. The top-side of the mote is shown in Figure 3 and consists of Atmel’s 90LS8535 microprocessor, a 4 MHz clock, and status leds. The underside of the mote features 256 K external EEPROM as well as a 916.5 MHz RF transceiver. A microphone/mote interface was developed. This accessory board provides variable gain for each microphone signal and allows the array to adjust to a higher gain to listen for objects farther away, or to lower gain if the sound source begins to saturate the analog to digital converter. This feature is
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77 Figure 3. The top-side of the NC-mote whose design is based on the UC-Berkeley mote concept
particularly desirable if arrays are used in tandem. The array closer to the source needs less gain to keep from saturating while that farther away may require a larger gain to detect the same source. The arrays are calibrated such that saturation should not occur until the sound source detected reaches a level of approximately 110-120 dB A. This is roughly equivalent to the noise level associated with a plane taking off. Figure 4 is a graphic demonstration of the information transfer. The microphones of the array relay their information to the variable gain amplification board. The output of this board is sampled by the analog to digital converters of the mote. If the A/D converters are saturated, the mote lowers the gain on the amplifier board; if a low signal is detected, the gain is increased. Once adequate information has been sampled, the mote transmits its data via RF to a mobile base station. Here, the information is processed and displayed for the user. 3.2 The 4 £ 5 microphone portable demonstrator When developing the original acoustic array as a portable demonstrator, triangulation only was used for sound source localization Triangulation is less
Figure 4. Information cycle, from detection, processing, to transmission to user
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expensive in terms of processing time and, it is possible to implement triangulation in electronic hardware alone, i.e. without using a computer. All amplification and triangulation circuitry in the portable acoustic array was housed in a plastic tube that was located at one end of the array. For ease of portability, the fabric that hosts the acoustic array was then rolled around the plastic tube. 3.3 Triangulation Triangulation with the portable demonstrator system is achieved initially by setting a threshold voltage proportional to a calibrated sound level. Currently, when the portable acoustic array receives a sound impulse that exceeds the calibrated threshold, the first microphone to detect the sound initiates a counter and locks in a value of zero for itself in memory. Then, each microphone that detects the same impulse latches into memory the value that the counter currently holds at the time of detection. This process continues until all the microphones have detected the sound and latched a value into memory. Once the data from every microphone in the array have logged its recorded reading the values are read into a BasicX microcontroller for processing. The resulting azimuth angle of the sound source is then displayed on an LCD screen incorporated in the tube. Two different algorithms were developed to determine the coordinates of the sound source. These algorithms were first simulated and then tested on the portable acoustic array system. The first algorithm used the geometrical relationship between the microphones and the sound source to localize the sound source. This algorithm assumed that the sound source was always located in the far-field. Based on measured time delays and using these geometrical relations, the position of the sound source was calculated. A knowledge-based voting scheme was developed to eliminate any problems with ambiguities. This algorithm worked very well in simulation, and it did not create singularities, which is a common problem with all triangulation algorithms. The second triangulation algorithm implemented used the mathematical approach developed by Walworth and Mahajan (1997). In this algorithm, the measured time delays, and the known coordinates of each array element were used to solve the exact coordinates of the sound source. Simulation and experimentation using this algorithm show that there are singularities present and that the algorithm is not robust when dealing with ambient noise and inaccurate time delay measurements. However, a novel algorithm was developed that exploited the redundancy available from having a large number of microphones available. This resulted in an algorithm that mitigated the singularity issue. 3.4 Beam-forming software During this project, simulation software was developed to verify and validate all the experimental results. Beam-forming simulation software was initially
developed to simulate the directional sensitivity of planar acoustic arrays Portable acoustic where the sound sources were located in the plane. The plots generated under arrays simulation offered a way to visualize and predict experimental data. So, the software had to be expanded to include the capability of simulating 3D array configurations and to generate 3D sensitivity plots. Figure 5(a) shows the results of beam-forming software, given a 1 kHz signal generated 79 approximately 908 from the array axis at a distance of 1.5 m. Later revisions of the beam-forming simulation software were expanded to include the analysis of the recorded sound from the portable acoustic array. Since these data were stored in a personal computer it allowed both beamforming and beam-steering analysis to be performed. At this point in the project, the simulation software operated as acoustic sonar and, with the addition of waterfall plots, the software helped to illustrate what was occurring during acoustic array simulation. The final version of the beam-forming software included polar plots of the directional intensities, i.e. a polar plot of the position of a sound source relative to the array, azimuth and elevation of the sound source, a waterfall plot of directional intensities and a waterfall plot of the audio frequencies present in the signals received (Figure 5(b)).
3.5 Microphone array geometry The second-generation system attempted to improve acoustic array performance by altering the microphone geometry. During simulation with the earlier 4 £ 5 element array, whose layout is shown in the plot of Figure 6, system ambiguity was observed when the sound source was perpendicular to the broad side of the array or at 908 with reference to the array’s center. This is shown with the spurious spikes in the leftmost image of Figure 7. Also shown in this figure is a simulation with the sound source located at 08. In this orientation, there is one obvious directional beam with only insignificant extraneous beams.
Figure 5. (a) Simulated 3D and overhead beam patterns (left) vs corresponding experimental data (right), and (b) screenshot of final beam-forming simulation software
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Figure 7. Beam-forming simulations for the rectangular array of Figure 1. Multiple beams are observed with a 1 kHz sound source at 908 (left), but are not present when located at 08 (right)
The new array layout attempts to obtain a more consistent beam pattern regardless of the position of the sound source. This would help to eliminate any confusion caused by spurious beams as demonstrated. To accomplish this, the array was laid out in a circular pattern (Figure 8). Furthermore, it was laid out such that there are seven elements along the perimeter and one in the center (only eight are used as there are only eight ADC ports available on the mote). The simulations of Figure 9 show that the acoustic array geometry as proposed gives more consistent results and is less likely to introduce confusion. Although there are many extraneous spikes in the diagrams, it is important to realize that a longer spike equates to higher confidence, so these particular spikes do not carry as much weight as those in the rectangular simulation at 908. With the maximum distance between microphones of approximately 1 m, this array is best suited for frequencies greater than 350 Hz. For better performance at lower frequencies, a much larger array would be needed. For example, minimal spacing for the detection of a 20 Hz signal is 17.25 m and for 100 Hz is 3.45 m. These would be more ideal for beam-forming with military targets (characteristically 20-200 Hz), but due to space limitations in the development environment, this was not feasible.
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Figure 8. Eight element array configuration for NC-mote based sensing
Figure 9. Beam-forming simulations of eight element circular array at 0, 45, and 908, respectively, given a 1 kHz sound source
4. Software overview The software involved is responsible for the control of data acquisition, the communication between motes or base computer, and processing of the data for beam-forming. For data acquisition, the program must sample and store data on command from the base node and then transmit that information back to the base node for processing. This can be done either directly through the serial port or through an intermediary mote that essentially serves to provide RF capabilities to a PC. To facilitate the RF operation, a board was created based on the mote programmer that simply performs RS232 communication. The new board layout was designed for this. Then, the home computer must process the information gathered and present it to the user. 4.1 Data acquisition software The data acquisition software is largely dependant upon the hardware components available on the mote. Data must not only be sampled and stored at an appropriate frequency, to sample the target acoustic source, but also each of the eight channels must be sampled fast enough that the sampling delay between the channels can be considered negligible. Owing to the stringent timing requirements of this program, it was coded in assembly.
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As outlined earlier, the mote has three types of memory: 512 bytes of internal SRAM, 512 bytes of internal EEPROM, and 256 kb of external EEPROM. Ideally the external EEPROM would be utilized, as it allowed for a considerable amount of sampling of the target signal. This memory is serial and accessed via the I2C protocol. While this does not require much of the processor’s resources, it is regrettably slow with a maximum write time of 5.0 ms. While faster, the internal EEPROM is also too slow due to its large write time of 2.5-4.0 ms. The SRAM is the only viable solution as it can be written in two clock cycles (0.05 ms), but it is important to note that the data must share its meager 512 bytes with the program stack. Fortunately, the array software required that only 16 bytes of the SRAM be dedicated for the stack. This meant that 496 bytes of the SRAM were available for storing data from the microphones. The analog to digital converter output on the mote has a 10 bit resolution, requiring 2 bytes of storage per sample. This allows for only 31 samples which is insufficient, so the data are left aligned to ignore the lower 2 bits thereby allowing 62 samples per microphone. Ideally, all eight channels would be sampled simultaneously. The mote’s ADCs do not sample simultaneously so it is necessary to sample all eight channels as fast as possible to make the timing difference appear negligible. Using the ADC in free running mode and the maximum 2 MHz ADC clock (given a 4 MHz system clock), samples were taken at approximately 154 kHz. In this example, the eight samples taken at 154 kHz are only taken for every 640 Hz so a software timer must be introduced to meet this requirement. Timer counter 0 is set-up for this purpose. This timer uses the system clock (4 MHz), prescaled by a factor of 32, or 125 kHz (otherwise the count necessary would be larger than 1 byte). At this frequency, the counter counts to 195 every 1.5625 ms, corresponding to a counter frequency of 640 Hz. After eight ADC samples, the ADC is disabled. After timer counter 0 counts to 195, the counter is reset and the ADC is enabled. The timing associated with the ADC and timer counter 0 interrupts were taken from an oscilloscope. The main program primarily serves to initialize the system for data collection and to communicate with the base station. The program first awaits a start signal from the base computer (or polls the RF receiver) instructing it to begin sampling. Once received, the necessary hardware is initialized and the interrupts are enabled. The ADC and OC2 interrupts the performance of the sampling operation until the SRAM is full, then stop collecting data. Control is returned to the main program that transmits the collected data (either through the UART or the RF transceiver). 4.2 Base station software All of the beam-forming and visualization are done on a base computer with which the mote or motes must communicate. The communication is facilitated by a Java program that transmits simple commands through the serial port and
accepts the response. When the samples are taken, they are stored sequentially Portable acoustic such that the adjacent bytes are from different microphones. These data are arrays reorganized in preparation to be run through the Matlab beam-forming software discussed earlier. Matlab beam-forming software can also be translated into Java without losing the elaborate visualization capabilities. The code for this program is generated.
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5. Conclusions and future work An investigation of the feasibility of developing a large-scale acoustic array on a textile substrate has been presented here. The first portable demonstrator developed showed that the relative azimuth angle of a sound source is determined using a two-dimensional planar array. It was also shown that to determine the elevation angle of the sound source, a three-dimensional array is required. Experimentation showed that to reduce error due to singularities, and to determine time-delay measurements, a re-design of the electronic interface circuitry was necessary. This portable acoustic array system also showed that it could be used for real-time target tracking without the need for any post-processing of the signals being received. The development of a three-dimensional array is seen as a desirable addition to future large-scale acoustic arrays. Much of the future work in this area will be in the development of materials and devices that can be incorporated into the textile environment. A flexible circuit is currently awaiting production. References Dhawan, A. (2001), “Woven fabric-based electrical circuits”, Masters thesis dissertation under the supervision of T. K. Ghosh, A. Seyam, and J. Muth, North Carolina State University. Dhawan, A., Ghosh, T., Seyam, A. and Muth, J. (2002), “Woven fabric-based electrical circuits”, Proceedings of the Textile Technology Forum, 23 October 2002, Industrial Fabrics Association International and the Textile Institute, Charlotte, NC. Luthy, K.A. (2003), “The development of textile based acoustic sensing arrays for sound source acquisition”, MS thesis Department of Electrical and Computer Engineering, North Carolina State University, Raleigh. Luthy, K.A., Mattos, L.S., Braly, J.C., Grant, E., Muth, J.F., Dhawan, A., Natarajan, K., Ghosh, T. and Seyam, A. (2002), “Developing a portable acoustic array on a large-scale e-textile substrate”, 2002 Fall Session Symposium D on Giant Electronic Substrates, Paper 1.9, 2-4 November 2002, Materials Research Society, Boston, USA. Muth, J.F., Grant, E., Luthy, K.A., Mattos, L.S., Braly, J.C., Dhawan, A., Seyam, A. and Ghosh, T. (2002), “Signal propagation and multiplexing challenges in electronic textiles”, Fall Session Symposium D on Giant Electronic Substrates, 2-4 November 2002, Materials Research Society, Boston, USA. Walworth, M. and Mahajan, A. (1997), “3D position sensing using the difference in the time-of-flights from a wave source to various receivers”, Proc. 8th Int. Conf. of Advanced Robotics (ICAR ’97), 7-9 July 1997, Monterey, CA, pp. 611-16.
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The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Thermal regulating functional performance of PCM garments Ying Bo-an, Kwok Yi-Lin and Li Yi Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong, People’s Republic of China
Yeung Chap-Yung Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, People’s Republic of China
Song Qing-wen Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong, People’s Republic of China Keywords Textile technology, Textiles, Thermal conductivity Abstract By analysing the physical mechanisms of heat and moisture transfer through textiles with PCM and carrying out the test of thermal regulating functional performance of PCM garment in climate chamber, the thermal regulating functional performance of PCM garments have been analysed and discussed in this paper. Both numerical solution and experimental results show that during the phase change process the rate of temperature rise of garment with higher PCM add-on level was lower than that with less PCM. From theoretical analysis and experiment curve, the parameter of k was proposed and discussed, which is used to represent the rate of temperature change and the thermal regulating functional performance of PCM garments. It has been demonstrated that the higher the PCM add-on level contained in the garment, the lower is the value of k, and slower the temperature raised in the garment, the higher is the effect of thermal regulating.
International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 84-96 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520388
1. Introduction Based on the development of microencapsulated phase change materials (MicroPCM), it was demonstrated that the MicroPCM can be incorporated into the spinning dope of manufactured fibres (e.g. acrylic), incorporated into the structure of foams, and coated onto fabrics for smart textile application (Shim et al., 2001). The fabrics incorporated with MicroPCM are called “PCM treated fabrics” or “PCM fabrics”. PCM garment is made of PCM fabrics. As a kind of smart garments, the thermal properties of PCM garment are dynamic and have active responsive. That is, its thermal properties are related to the change of temperature and time. For example, when the environment temperature reaches the PCM melting point, the physical state of PCM in the garment will change from solid to liquid along with the absorption of heat, while the temperature of the PCM in the garment keeps constant at melting The authors would like to thank The Hong Kong Research Grant Council and The Hong Kong Polytechnic University for their financial support.
point, therefore, it can regulate its temperature automatically by itself. As the reverse thermal regulation performance occurs during the cooling process, the environment temperature comes to its freezing point. So, the PCM garment can provide a cooling effect caused by heat absorption of the PCM and a heating effect caused by heat emission of the PCM to human body. The PCM garments are designed to use under special environmental conditions in which it need to offer desired temperature lasting for definite period of time. So we are mainly concerned about its thermal properties during phase change, because once the PCM fabrics temperature has gone out of the phase change range, the PCM garments is no longer effective as an active thermal. In order to evaluate the thermal properties of PCM garments and PCM fabrics, some research works have been conducted. Pause (1995) developed the concept of dynamic thermal insulation to measure the transient effect on the insulation value of PCM fabrics, and pointed out that the total insulation of PCM fabrics is comprised of basic insulation and dynamic thermal insulation that was determined from the duration of the temperature variation during the phase change. The dynamic thermal insulation was calculated by comparing the times for achieving the end temperature of the phase change range of the samples with and without MicroPCM and with reference to the basic thermal insulation of the samples. The thermal insulation is given in units of thermal resistance. In 2002, a new test instrument and measurement index was pointed out by Hittle and Andre (2002). The index of temperature regulation factor (TRF) is used to indicate the temperature-regulating ability of PCM fabrics, which is a dimensionless number less than or equal to one, and the TRF for PCM fabrics will always be less than the TRF for non-PCM fabrics. The test for PCM garments was carried out by Shim et al. (2001) in a warm and a cold chamber. The value of heat loss from a thermal manikin was measured and used to quantify the effect of PCMs in clothing on heat flow from the body during temperature transients. In this study, the physical mechanisms of heat and moisture transfer through PCM textiles are analysed; the test of thermal regulating functional performance of PCM garment is carried out in climate chamber, and the phenomenon of temperature change for the garments with different PCM add-on level and without PCM are analysed and discussed. From theoretical analysis and experimental curve, the parameter of k is proposed and discussed, which is used to represent the rate of temperature change and the thermal regulating functional performance of PCM garment. The value of k can be calculated by utilising non-linear regression analysis techniques based on the experimental data. The results indicate that the higher the PCM add-on level contained in garment, the lower is the value of k, and slower the temperature raised in the garment, the higher is the effect of thermal regulating occurred during phase change process.
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2. Physical mechanism On the basis of the mechanism of heat and moisture transfer in porous textile and the phase change process occurred in microcapsule, which is combined with textile, a new mathematical model was developed by Li and Zhu (n.d.) The energy balance is established in equation (1) cv
›T ›ðC f 1f Þ ›ðC f 1f Þ ¼ 4l lv þ 42 ll 2 lhl!g S 0v ðC* ðTÞ 2 C a Þ ›t ›t ›t › ›T ›F R ›F L K mix 2 2 q_ ðx; tÞ þ þ ›x ›x ›x ›x
ð1Þ
In this equation, the first term on the right-hand side describes the heat of moisture sorption or desorption of vapour by fibres, the second term describes the heat of moisture sorption or desorption of liquid water by fibres, the third term describes the heat of evaporation of water, the fourth term describes the heat change by conduction, the fifth and the sixth terms describe the heat related to radiation, and the last term describes the latent heat gains and loses from the micro-PCM. For the melting process, the latent heat related to PCM can be expressed by equation (2). 31 Rm _qðx; tÞ ¼ 2 m hT K ml ðT P 2 Tðx; tÞÞ hT Rm ð2Þ 2 1 þ K ml Rm r l ðx; tÞ where rl(x, t) is the radius of the latest phase interface of the outer spherical shell, expressed by: K ml R2m ½T P 2 Tðx; tÞ r_l ¼ hT rm lm
h i hT R2m rl þ ðK ml 2 hT Rm Þr2l
ð3Þ
In the above equations, TP its the melting point of PCM (K), T(x, t) is the temperature of the flow fields at x in the porous textile with PCM, lm is the latent heat of fusion of PCM (kJ/kg), Kml is the thermal conductivity of liquid PCM (W/m K), hT is the heat transfer coefficient between the microspheres and the flows surrounding them (W/m2 K), rm is the density of the PCM (kg/m3); Rm is the radius of microPCM-spheres, and 1m is the volume fraction of PCM. The relationship between the volume fraction of liquid phase (1l), water vapour (1a), fibres (1f), and PCM (1m) expressed by: 1l þ 1a þ 1f þ 1m ¼ 1:
ð4Þ
The number of the microspheres per unit volume n is related to the fractional volume of the microPCM-spheres, which is written as equation (5).
More detailed mathematical analysis can be found in the work of Li and Zhu (2003) 1 n4pR2m Rm ¼ 1m : 3
ð5Þ
In the testing condition (described in the Section 3), there is no liquid phase involved ð1l ¼ 0Þ and no radiation factor considered, so in the energy balance equation (1) the item of 2, 3, 5, and 6 can be ignored, the porosity of the fibre (1) is equal to 1a, and the proportion of the sorption of water vapour by fibre (4) is equal to one. Therefore, the energy balance equation for PCM fabrics and non-PCM fabrics under test condition can be simplified as equations (6) and (7). The energy balance for PCM fabrics: ›T ›ðC f 1f Þ › ›T cv ¼ lv þ K mix 2 q_ ðx; tÞ ð6Þ ›x ›t ›t ›x The energy balance for non-PCM fabrics: cv
›T ›ðC f 1f Þ › ›T ¼ lv þ K mix ›x ›t ›t ›x
ð7Þ
Here cv is the volumetric heat capacity of the fabric (kJ/m3 K), lv is the heat of sorption or desorption of vapour by fibres (kJ/kg), Cf is the water vapour concentration in the fibres of the fabric (kg/m3), Kmix is the thermal conductivity of the fabric (W/m K). Considering in the test, all the testing data are measured at the coated surface (where x [ ½L 2 d; L; 0 , d ! 1) by testing sensors, the boundary condition can be written by equation (8), where Tab is environment temperature as a constant (K), ht is convection heat transfer coefficient (W/m2 K). ›T K mix 1 ¼ 2ht ðT 2 T ab Þ ð8Þ ›x x[½L2d; L using equation (8), we obtain equations (9) and (10) › ›T ht ›T K mix ¼2 ›x ›x x[½L2d; L 1 ›x x[½L2d; L ›T ht ¼2 ðT 2 T ab Þ ›x x[½L2d; L K mix 1 The substitution of equation (10) into equation (9) leads to
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ð10Þ
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› ›T h2t ¼ ðT 2 T ab Þ K mix ›x ›x x[½L2d; L K mix 1 2
ð11Þ
Substitution of equation (11) into equations (6) and (7) leads to the energy balance equations for PCM fabrics and non-PCM fabrics at the surface of fabrics, which is expressed by equations (12) and (13). The energy balance for PCM fabrics: ›T ›ðC f 1f Þ h2t cv ¼ lv þ ðT 2 T ab Þ 2 q_ ðL; tÞ ð12Þ ›t x[½L2d; L ›t x[½L2d; L K mix 1 2 The energy balance for non-PCM fabrics: ›T ›ðC f 1f Þ h2t ¼ lv þ ðT 2 T ab Þ cv ›t x[½L2d; L ›t x[½L2d; L K mix 1 2
ð13Þ
The rate of temperature change at the surface of fabric can be obtained from equations (12) and (13), and expressed by equations (14) and (15). For PCM fabrics: ! ›T 1 ›ðC f 1f Þ h2t ¼ lv þ ðT 2 T ab Þ 2 q_ ðL; tÞ ð14Þ ›t x[½L2d; L cv ›t x[½L2d; L K mix 1 2 For non-PCM fabrics: ! ›T 1 ›ðC f 1f Þ h2t ¼ lv þ ðT 2 T ab Þ ›t x[½L2d; L cv ›t x[½L2d; L K mix 1 2
ð15Þ
The difference between the mathematical model of PCM fabric and non-PCM fabric is the latent heat which gains and loses from the micro-PCM. It can be expressed by equation (16) at the surface. 31m Rm q_ ðL; tÞ ¼ 2 hT K ml ðT P 2 TðL; tÞÞ hT Rm ð16Þ 2 1 þ K ml Rm r l ðL; tÞ Considering equations (4), (12)-(16), it shows that the volume fraction of PCM (1m), which is dependent on PCM add-on level, significantly influences the heat energy changing through the porous textiles and the temperature change at the surface of fabric. The more the value of PCM add-on level, the higher is the value of 1m, and it gains or losses more heat energy from the micro-PCM, so when more heat flux delayed through the PCM fabric a strong thermal regulation performance happened, and therefore a slow temperature change occurred in the surface of the fabric.
3. Experimental 3.1 Test samples and apparatus In the test of thermal regulating functional performance of PCM garment, the PCM microcapsule was developed by The Institute of Textiles and Clothing, The Hong Kong Polytechnic University, and the diameter range of these PCM microcapsules is about 5-15 mm as shown in Figure 1. The melting point of the PCM used in the experiment is 26-288C. The MicroPCM was coated onto the inner surface of the fabric, and the operating procedure also included drying and curing. The PCM add-on level in each test sample is shown in Table I. This experiment was carried out in the temperature and humidity controlled chamber. The temperature change in the PCM garments was measured and recorded by the thermal sensor and related control system.
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3.2 Test design In the test, it aimed at testing the effect of sharp temperature change on the samples. The climate chamber was set with the temperature at 358C and humidity 60 per cent. The samples were equalised and treated at controlled room temperature of 23-248C and the humidity 60 per cent and they were put into the climate chamber quickly (simulating surrounding temperature change from 23-24 to 358C). Data recording time was started 3-5 s after the sample was put into the chamber, it lasted for 13 min and more than 7,500 groups of data of temperature
Figure 1. A SEM photo of PCM microcapsules with magnification of 3000
Order 1 2 3 4 5
Sample code
PCM add-on level (g/m2)
Remark
s-c1 s-20 s-40 s-80 s-120
0 20 40 80 120
Treated softer and bender only Treated with MicroPCM, softer and bender As above As above As above
Table I. Test fabrics
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were obtained by testing system automatically as ten groups of data were recorded evenly per second.
90
3.3 Test results Based on the test plan, the temperature change of each samples was measured and recorded. As the test system recorded about 7,500 groups of data during 13 min for each sample, we summarised the results each minute by using boxplot char. The test results of sample without PCM (s-c1), with lower PCM add-on level (s-20), and with higher PCM add-on level (s-120) are shown in Figures 2-4. 4. Analysis and discussion 4.1 The rate of temperature change (k) The equations (14) and (15) express the temperature change rate at the surface of PCM fabrics. By the numerical solution of the equation, the temperature distributions in the fabrics during phase change process are shown in Figure 5, which shows that the temperature increases initially in the fabrics, and it gradually reaches equilibrium with the environment. Here the heat of sorption is insignificant due to the relatively low rate of moisture sorption in the fibres. The rise in temperature in the fabric is mainly due to the heat flux from the environment. During the transient process the temperature rise of non-PCM fabrics is higher than PCM fabrics, and it is higher with less PCM than that with more PCM. The energy is absorbed and stored in the PCM during the rise in temperature when the melting point of the PCM is reached, which can be expressed by last item in equation (14).
Figure 2. Temperature change of s-c1
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Figure 3. Temperature change of s-20
Figure 4. Temperature change of s-120
The same phenomenon of temperature change of each sample with different PCM add-on level and without PCM can be found by this experiment, as shown in Figures 2-4. For instance, the result of comparing sample s-c1 (without PCM) and s-120 (with PCM 120 g/m2) are represented as boxplot chart in Figure 6. From the results, we see that during the phase change process the rate of temperature rise of garment with PCM was lower than without PCM, and the rate of garment with higher PCM add-on level was lower than that with less PCM add-on level. The results demonstrated the temperature regulating
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Figure 5. Temperature distribution in the fabrics
functional performance of PCM garments under the temperature change environment during the phase change process. Both numerical solution and testing result show the same trend of temperature change for samples with PCM and without PCM. In order to describe the rate of temperature change, we introduce the asymptotic mathematical equation (17) to express the trend of temperature change. T ¼ T ab 2 ðT ab 2 T 0 Þe2kt
ð17Þ
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Figure 6. The comparison of temperature change for sample with PCM and without PCM
where the value k represents the changing rate, the variable T represents temperature of testing sample, the variable t represent time, Tab denotes the environment temperature and T0 is the start temperature of testing sample ðt ¼ 0Þ: Hence we define that the rate of temperature change of PCM garments is expressed by index k. 4.2 The influence of PCM add-on level on the value of k Based on the test data, by utilising non-linear regression analysis techniques (such as in software SPSS(10.0)) the rate of temperature change (k) of each sample can be calculated through the mathematical model (17). The results of the value of k are summarised in Table II and are shown as boxplot chart in Figure 7. From the result, it has been demonstrated that the higher PCM add-on level contained in garment, the lower is the value of K, and slower the temperature raised in the garment, the higher is the effect of thermal regulating occurred during the phase change process. The one-way ANOVA analysis was carried out to determine the influence of PCM add-on level on the value of k. The outputs are listed in Table III. From the results, we see that the PCM add-on level significantly influences the value of k Indexes
S-c1
S-20
S-40
S-80
S-120
k value
0.57 0.49 0.49 0.60
0.54 0.45 0.57 0.56
0.39 0.42 0.43 0.41
0.35 0.41 0.36 0.42
0.30 0.24 0.22 0.31
Table II. The calculating results of k value
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Figure 7. The boxplot of k value with PCM add-on level
Index Table III. k value One-way ANOVA Between groups analysis of the influence Within groups of PCM add-on level on the value of k Total
Sum of squares
df
Mean square
F
Sig.
0.203 2.865 £ 10 – 2 0.232
4 15 19
5.082 £ 10 – 2 1.910 £ 10 – 3
26.610
0.000
(P , 0.001). Through these analyses and discussion, it has been demonstrated that the rate of temperature change can be expressed by the index of k value well, the more PCM contained in the PCM garments is, the less k their value will be, which indicates the slower temperature rise when the PCM garments under the condition of sharp temperature change. Further, linear regression analyses were carried out to find the relationship between the value of k and PCM add-on level. The outputs are listed in Table IV. Table IV demonstrates that the value of k has good linear relationship with PCM add-on level, with r 2 ¼ 0:819 ðP , 0:001Þ: 4.3 The relationship of the value of k with the indexes of the thermal regulating capability (Id and Dtd) The indexes Dtd * Id is used to describe the dynamic thermal regulating capability, in which Id is the mean of the heat flux delayed by phase change Table IV. Relationship between indexes and PCM add-on level (g/m2)
Index k value
Regression equation
The value of correlation coefficient
Significance
¼ 0.544 2 0.023 (PCM add-on level)
20.905
P , 0.001
during phase change period, Dtd is the time duration of phase change, so the total heat energy change related to phase change is expressed by Dtd * Id (Ying et al., 2003). The relationship between the value of k and the index of the thermal regulating capability (Dtd * Id) can be seen from Table V and Figure 8, which indicated that the k values have strong linear relationship with the indexes Dtd * Id with r 2 ¼ 0:828 ðP , 0:001Þ: It has been confirmed from another aspect that the value of k can better express the thermal regulating function performance of PCM garments.
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5. Conclusion By analysing the physical mechanisms of the heat and moisture transfer through textiles with PCM and carrying out the test of thermal regulating functional performance of PCM garment in climate chamber, the phenomenon of temperature change for the garments with different PCM add-on level and without PCM have been analysed and discussed. Both the numerical solution and experimental results show that the temperature rises initially in the garment, and reaches equilibrium with the environment gradually. During the phase change process the rate of temperature rise of garment with PCM was lower than without PCM, and the rate of garment with higher PCM add-on level was lower than that with less PCM. From the theoretical and experimental analyses, the rate of temperature change and the thermal regulating functional performance of PCM garment can be expressed by the parameter of k value, which have good linear relationship with PCM add-on level and was
Index k
Regression equation
The value of correlation coefficient
Significance
¼ 0.521 2 0.0082 (Dtd * Id)
20.91
P , 0.001
Table V. Relationship between indexes (Dtd * Id) and the value of k
Figure 8. Relationship between index (Dtd * Id) and k value
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significantly influenced by PCM add-on level. It has been demonstrated that the higher PCM add-on level contained in garment, the lower is the value of k, and slower the temperature raised in the garment, the higher is the effect of thermal regulating occurred during the phase change process. References Hittle, D.C. and Andre, T.L. (2002), “A new test instrument and procedure for evaluation of fabrics containing phase-change material”, ASHRAE Transactions, Vol. 108. Li, Y. and Zhu, Q.Y. (2003), “A model of coupled liquid moisture and heat transfer in porous textiles with consideration of gravity”, Numerical Heat Transfer, Part A, Vol. 43 No. 3, pp. 501-23. Pause, B. (1995), “Development of heat and cold insulating membrane structures with phrase change material”, Journal of Coated Fabric, Vol. 25, pp. 59-68. Shim, H. and McCullough, E.A. et al. (2001), “Using phase change materials in clothing”, Textile Research Journal, Vol. 71 No. 6, pp. 495-502. Ying, B., Kwok, Y., Li, Y., Zhu, Q.Y. and Yeung, C.Y. (2003), “The analysis of indexes tested and methods used for textiles with phase change materials”, Journal of Polymer Testing (in press). Further reading Li, Y. and Zhu, Q.Y. (n.d.), “A mathematical model of the heat and moisture transfer in porous textiles with phase change materials”, Textile Research Journal (in press).
The Emerald Research Register for this journal is available at www.emeraldinsight.com/researchregister
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
The mechanics of plain woven fabrics G.A.V. Leaf Leeds, UK
Mechanics of plain woven fabrics 97
Keywords Mechanics, Textiles Abstract A procedure for estimating the low-strain mechanical properties of plain woven fabrics is presented. A quantity prominent in the equations is the contact length at the yarn cross-over, which has not been estimated till the moment. A consideration of Peirce’s rigid thread model leads to a method of estimating the contact lengths from a knowledge of the fabric sett and yarn crimps. A comparison of the theory with some experimental results is given in this paper.
1. Introduction The analysis of the relationships between the properties of the components of plain woven fabrics (yarns, sett, yarn crimp, etc.) and the mechanical properties of the resultant fabrics has been the subject of many analyses over the past 50 years or so. In a series of papers, Leaf and Kandil (1980), Leaf and Sheta (1984) and Leaf et al. (1993) described a consistent approach to this problem that leads to closed form equations for such relationships. These are restricted in application (for example, they apply only to fabrics subjected to small deformations), but they have a general interest in which they provide an insight about the form of the relationships, that may be useful in applications to more general situations. As pointed out by Leaf (2002), they also lead to the discovery of relationships among the mechanical properties themselves. This has led to suggestions (Leaf, 2001) about how the difficult-to-measure shear modulus might be estimated. The series of papers mentioned above does not provide a self-contained and unambiguous method for estimating the mechanical properties from a knowledge of the yarn properties, fabric sett and yarn crimp in the fabric, for reasons that will be explained in Section 2. This paper is intended to deal with this problem. 2. Peirce’s models The foundations, on which the analyses are based, are the models of plain woven fabric developed by Peirce (1937). Of the two models, the simpler model assumes that the yarns are infinitely flexible, they have circular cross-sections and are incompressible and inextensible. The yarn path in these circumstances consists of circular arcs and straight lines, as shown in Figure 1, which also defines the notation used by Peirce. In addition to the quantities shown on the diagram, Peirce also introduced the yarn crimps
International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 97-107 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520397
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Figure 1.
c1 ¼
ðl 1 2 p2 Þ ; p2
c2 ¼
ðl 2 2 p1 Þ p1
and the sum of the yarn diameters D ¼ d 1 þ d2 ¼ h1 þ h2
ð1Þ
It is easily shown that the combined lengths of the contact regions, AB and CD, is Du1 and consequently, the length of the “free” region BOC is l 1 2 Du1 , where l1 is the warp modular length ABOCD. Leaf and his co-workers used this model to derive equations relating to the mechanical properties of the fabric (exemplified by the extension moduli E1 and E2, bending moduli B1 and B2, and shear modulus G) and the geometrical parameters such as the warp and weft spacings ( p1 and p2), the modular lengths (l1 and l2), the yarn diameters (d1 and d2), and the flexural rigidities (b1 and b2) of the yarns. There is an element of inconsistency here, in that Peirce’s model assumes that the yarns have zero flexural rigidity. However, the analyses use the flexible thread model as a relatively simple basic yarn shape to calculate the strain-energy in the yarns when the fabric is deformed. A typical equation relating the mechanical and geometrical parameters is that for the shear modulus, namely:
p1 ðl 1 2 Du1 Þ3 p2 ðl 2 2 Du2 Þ3 G ¼ 12 þ p 2 b1 p1 b2
21 ;
developed by Leaf and Sheta (1984). In order to obtain the theory to fit the available set of experimental data, it was found necessary to modify the free lengths suggested by the model, l 1 2 Du1 and l 2 2 Du2 , by lengthening them.
Leaf and Sheta modified them to l 1 2 k1 Du1 and l 2 2 k2 Du2 , and chose k1 and k2 so as to best fit the experimental data. This is hardly a satisfactory procedure since it is difficult to justify the equations thus derived for any future predictions of the mechanical behaviour of other fabrics. The question therefore arises as to whether the shorter contact lengths expected when the yarns possess rigidity can be calculated. This calculation requires the use of Peirce’s more complex second model in which the yarns are assumed to have non-zero flexural rigidity. The second model is shown in Figure 2. The yarn path is now curved, following the cross thread cross-section over a smaller distance than before. Now, let the angle of contact CED be f1, as shown, where 0 # f1 # u1, then the free lengths become l 1 2 Df1 , and l 2 2 Df2 . The full set of equations derived by Leaf et al., modified in this way, is then 12p2 b1 b2 ðl 1 2 Df1 Þ3 cos2 u1 1þ E1 ¼ ; p1 ðl 1 2 Df1 Þ3 sin2 u1 b1 ðl 2 2 Df2 Þ3 cos2 u2
Mechanics of plain woven fabrics 99
12p1 b2 b1 ðl 2 2 Df2 Þ3 cos2 u2 ; 1þ E2 ¼ p2 ðl 2 2 Df2 Þ3 sin2 u2 b2 ðl 1 2 Df1 Þ3 cos2 u1
B1 ¼
p2 b1 ; p1 ðl 1 2 Df1 Þ
B2 ¼
p1 b2 ; p2 ðl 2 2 Df2 Þ
p1 ðl 1 2 Df1 Þ3 p2 ðl 2 2 Df2 Þ3 þ G ¼ 12 p 2 b1 p 1 b2
21
Figure 2.
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In Section 3, we investigate the means of estimating the value of f1, to be used in these equations. 3. Calculation of the contact lengths As shown in Figure 2, the central line of the warp thread in the flexible thread model consists of circular arcs of radius D/2 (AB and CD) with a curved elastica (BOC) joining them. The curved path is created by distributed forces acting over the contact regions. By symmetry, we need to consider only the OCD portion and this section is isolated in Figure 3. Here, the distributed forces are balanced by a vertical force V1 at o, vertical since it is assumed that there are no external forces acting on the fabric. This is the situation described by Peirce (1937). If we define rectangular axes Oxy with origin at o and Oy perpendicular to the plane of the fabric, the bending moment at a point P(x, y) on OC is M ¼ V 1x This produces a curvature in the yarn, which at C is equal to 2/D, since CD is an arc of a circle of radius D/2. If the bending law for the yarns is M ¼ b £ curvature it follows that V 1 xc ¼
2b1 ; D
ð2Þ
where xc is the x-coordinate of C. The curvature at P is 2dc/ds, where s is the arc length OC and c is the angle between Ox and the tangent at P. Hence, the general equation of equilibrium is
Figure 3.
Mechanics of plain woven fabrics
2b1 dc=ds ¼ V 1 x Since dx ¼ ds cos c; we obtain 2b1 cos c dc ¼ V 1 x dx; which on integration yields
101 2
V 1 x ¼ 2b1 ðsin u1 2 sin cÞ
ð3Þ
where we have used the fact that at O, x ¼ 0; c ¼ u1 : At C, x ¼ xc and c ¼ f1 : Therefore, from equation (3), we obtain V 1 x2c ¼ 2b1 ðsin u1 2 sin f1 Þ
ð4Þ
Substituting for xc from equation (2) leads to V1 ¼
2b1 D 2 ðsin u1 2 sin f1 Þ
ð5Þ
From Figure 3, sin f1 ¼
CF ðp2 2 2xc Þ ¼ ; CE D
which leads to V1 ¼
4b1 Dð p2 2 Dsin f1 Þ
ð6Þ
when equation (2) is used. Equating the values of V1 in equations (5) and (6) gives sin f1 ¼ 2 sin u1 2
p2 D
ð7Þ
Consequently, if u1 and P 2 =D are known, f1 can be calculated. Note that f1 must lie between 0, when point contact is made between the yarns at D, and u1, when the fabric would be jammed. Hence, from equation (7), p2 p2 # sin u1 # min 1; 2D D Peirce also showed that n p o 2 Fðk; wÞ ; s ¼ m1 F k; 2 where
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m21 ¼
b1 V1
p u1 k ¼ sin þ ; 4 2 p c k sin w ¼ sin þ ; 4 2
102
and F(k, w) is an elliptic integral of the first kind. Hence the arc OC is given by n p o 2 Fðk; wc Þ ; OC ¼ m1 F k; 2 where
p f1 k sin wc ¼ sin þ 4 2
Since the arc CD ¼ Df1 =2; we find that n p o l 1 ¼ 2ðarc OC þ arc CDÞ ¼ 2m1 F k; 2 Fðk; wc Þ þ Df1 2
ð8Þ
ð9Þ
Note that, using equations (5) and (7), m21
b1 D 2 ðsin u1 2 sin f1 Þ D 2 p2 ¼ ¼ ¼ 2 sin u1 2 V1 2 D
ð10Þ
Peirce also derived the following equation for the y-coordinate of P: nh p i h p io y ¼ m1 F k; 2 Fðk; wÞ 2 2 E k; 2 Eðk; wÞ ; 2 2 where E(k, w) is an elliptic integral of the second kind. Now h1 Dð1 2 cos f1 Þ ¼ yc þ 2 2 which leads to nh p i h p io h1 ¼ 2m1 F k; 2 Fðk; wc Þ 2 2 E k; 2 Eðk; wc Þ þ Dð1 2 cos f1 Þ 2 2 ð11Þ 4. Some numerical calculations Peirce (1937) derived a number of empirical relations based on calculations using his theoretical equations. Particularly useful were
1=2
u1 ¼ 1:82c1 ; ðu1 in radiansÞ; based, apparently, on calculations involving only five values of u1 and c1, and 4 1=2 h1 ¼ p2 c1 ; 3
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ð12Þ
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which he had originally derived using the flexible thread model. The above equations make it possible to confirm these relations. The calculations take the following form. If p2 =D and u1 are given, equation (7) can be used to find u1. wc can be found from equation (8) and m1 =D from equation (10). From equations (9) and (11), we obtain l 1 =D and h1 =D; respectively. Finally, c1 can be obtained from l 1 =D c1 ¼ 21 p2 =D Figure 4 shows a plot of log u1 against log c1. The influence of p2 is apparently relatively small. Ignoring p2, the best-fitting line to the data is 1=2
u1 ¼ 1:88c1
in very good agreement with the Peirce’s equation. 1=2 The ratio h1 =p2 is plotted against c1 in Figure 5. The best-fitting single 1=2 line h1 =p2 ¼ 1:32c1 ; is in very close agreement with equation (12).
Figure 4.
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Figure 5.
5. Application to experimental data The only source of data, currently available to the author, that provides information to test the above theory is the thesis by Kandil (1981), though the data are summarised by Leaf and Kandil (1980). Kandil measured all the geometrical and yarn parameters, in addition to the extension and bending moduli of the fabrics. At a later date, the shear modulus of the same fabrics was estimated by Leaf and Sheta (1984). In practical applications, the easiest fabric parameters to measure are p1, p2, l1 and l2. When these are known, c1 and c2 can be found and equations (12) and (13) yield estimates of u and h. D is then calculated from equation (1), after which u can be found from equation (7). The equations quoted in Section 2 then yield the theoretical estimates of the fabric mechanical properties, provided b1 and b2 are known, which can be compared with the measured values. The various mechanical properties will be dealt with separately. 5.1 Extension moduli The experimental moduli, Ee, are plotted against the theoretical estimates Et in Figure 6. There is a reasonable general agreement, though the theory has a tendency to overestimate the real extension modulus, particularly for some of the weft-ways moduli. For most fabrics, the calculated values of f2 (i.e. the contact angle in the weft direction) were zero, i.e. the theory suggests that in this direction only point contact was made between the threads. When this
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Figure 6.
occurs, there is a divergence between the geometry of the flexible thread module (use to derive the basic mechanical equations) and that of the rigid thread model (used to estimate the contact angles). The only way to achieve such point contact in the former is when the weft thread is straight, a situation that does not occur in the rigid thread model, except under very extreme conditions. This divergence may explain some of the differences between the theory and experiment. 5.2 Bending moduli Figure 7 shows a plot of the experimental Be values against their theoretical estimates Bt. There is some tendency here for the theory to underestimate the experimental values, particularly for the less flexible fabrics with higher values of B. Again, those showing the greatest diversions from the theory are fabrics for which f2 ¼ 0: An exception to this trend is the warp-ways bending modulus for fabric Y1, for which the theory tends to overestimate the experimental value. This fabric has an unusually high f value in the warp direction. 5.3 Shear modulus The results for shear modulus are very disappointing, since the theory seriously and consistently underestimates the experimental values, as can be seen in Figure 8. There is, however, a good correlation between theoretical and experimental values. It is difficult to explain the under-estimation, though the form of equation for G suggests that this will happen if the estimates of contact angle are too low. Another possibility is that it is notoriously difficult to measure G. Leaf and
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Figure 7.
Sheta (1984) used a very round-about route to estimate G experimentally, and some of the assumptions made in their procedure could have been too gross. In recent papers, Leaf has returned to the problem of estimating G and more work in this area is needed. 6. Conclusions This paper has presented a further instalment in the development of a consistent set of equations for estimating the mechanical properties of plain woven fabrics. A prominent feature in the equations is the contact angle between the warp and weft threads, and the lack of a means of estimating this has precluded the practical application of the equations. At present, a procedure has been developed for estimating the contact angle that requires only a knowledge of the warp and weft spacings and crimps. The results of comparisons with the experimental data are mixed. Except for fabrics with very small contact lengths, the estimates of extension and bending moduli are reasonable, bearing in mind the difficult nature of many of the measurements involved. The equation for shear modulus consistently underestimated the actual shear modulus, and more work is needed in this area.
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Figure 8.
References Kandil, K.H., (1981), PhD thesis, University of Leeds. Leaf, G.A.V. (2001), “Analytical plain weave fabric mechanics and the estimation of initial shear modulus”, J. Text. Lust., Vol. 92, pp. 70-9. Leaf, G.A.V. (2002), “Analytical woven fabric mechanics”, Int. J. Clothing Sci. Tech., Vol. 14, pp. 223-9. Leaf, G.A.V. and Kandil, K.H. (1980), “The initial load-extension behaviour of plain-woven fabrics”, J. Text. Inst., Vol. 71, pp. 1-7. Leaf, G.A.V. and Sheta, A.M.F. (1984), “The initial shear modulus of plain woven fabrics”, J. Text. Inst., Vol. 75, pp. 157-63. Leaf, G.A.V., Chen, Y. and Chen, X. (1993), “The initial bending behaviour of plain-woven fabrics”, J. Text. Inst., Vol. 84, pp. 419-28. Peirce, F.T. (1937), “The geometry of cloth structure”, J. Text. Inst., Vol. 28, pp. T45-T96.
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Fibrous assemblies: modeling/computer simulation of compressional behaviour William W. Roberts Jr and Norman B. Beil Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia, USA Keywords Textiles, Simulation, Compressive strength, Mechanical properties of materials Abstract We develop a model to relate the mechanical properties of individual fibers and how they are arranged in a fibrous assembly to the bulk properties of the fibrous assembly. The model allows the prediction of the bulk properties of the fibrous assembly during compression from the physical properties of its component individual fibers, considering both static and kinetic friction at contacts between fibers. Computer simulations are run for several cases with specific friction conditions applied in order to compare predictions of this model with experimental results and with van Wyk’s theory of the uniaxial compression of an initially random fibrous assembly. These computer simulations demonstrate a reasonable ability to predict the undetermined constant K in van Wyk’s theory. The computer simulations also show a significantly greater number of fiber-fiber contacts being formed than theories based only on the diameter and arrangement of fibers have predicted. The predicted contacts have a wide range of contact forces, while only a small percentage of them do not slip. The model may be used to investigate phenomena associated with the compression of fibrous assemblies, such as fiber crimp, hysteresis, and orientation effects.
1. Introduction An important problem that has been researched by fiber and textile scientists and engineers for over 50 years is modeling the compression and recovery behaviour of fibrous assemblies. In this paper, we discuss the goal of relating the mechanical properties of individual fibers, and how they are arranged in a fibrous assembly, to the bulk properties of the entire assembly. Applications of this work include, predicting the properties of wool or fiber fill based on the fibers and the processing used, designing insulation that retains its insulating properties after being compressed, developing materials for acoustic noise and vibration control, understanding fibrous cytostructural invadopodia in malignant tumor cancers, and simulating other medical fibrous malfunctions. The computational aspect of solving this problem is the focus of the present research. Selected computational results have been reported by Beil and Roberts (2002a, b); further computational results are discussed in this paper. Much research over the past 50 years has been directed towards improving the model proposed by van Wyk (1946). Various workers have pointed out International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 108-118 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520405
The work in this paper constitutes selected aspects of the overall mathematical modeling, computer simulation, and virtual prototyping underway in the Mathematical-Computational Modeling Laboratory (MCML) at the University of Virginia. The computer simulations were carried out on the IBM RS/6000, SGI Octane, and Sun SPARCstation 10 machines in MCML.
weaknesses in van Wyk’s theory: that most compression curves deviate substantially from van Wyk’s pressure – in inverse-volume-cubed equation, van Wyk’s constant K is one-to-two orders of magnitude less than that expected from the theory, there is a nonrecoverable strain during initial compression and a mechanical hysteresis during compression-release cycling, and finally it fails to account for different compression properties of different types of fibers that have the same parameters in the equation. Such observations indicate that any successful model of compressible fibrous assemblies must include fibers that are neither straight nor randomly oriented, as well as the frictional effects from the interactions between fibers in contact as they slip. Any such model is by nature much more complicated than that proposed by van Wyk, and the power of modern computers appears necessary to obtain meaningful results. 2. Mathematical-computational model of a fibrous assembly First, we formulate a model for a single fiber in three-dimensional space which has mechanical properties that are realistic and are based on quantities that are easily measured. Second, we carry out computer simulations to carefully track the motions of individual helix-shaped model fibers in an initially randomly oriented assembly of such fibers and carefully capture the interactions between the fibers when and where fiber-fiber contacts occur and persist as nonslipping, slipping (with frictional forces included), or transitional (nonslipping-to-slipping or slipping-to-nonslipping) contacts. Third, we make use of the results of the computer simulations and view them on the global scale to determine the behaviour of the overall fibrous assembly as the assembly undergoes compression. Important objectives include the computed pressure-volume relationship of the fibrous assembly during compression and decompression of the assembly, the number and types of fiber-fiber contacts that occur during compression and the force interactions between fibers in contact, the effects of fiber crimp, and the phenomenon of hysteresis during compression-release (compression-decompression) cycling. The model used to represent an individual fiber is derived from the “General Theory of the Bending and Twisting of Thin Rods” of Love (1944). Love’s static model is modified by including a mass-acceleration term in the force equilibrium equations to account for the dynamics and the three-dimensional motions of the fiber in time. This model may be thought of as a three-dimensional extension of the model used by Smith and Roberts (1994) to model flows of crimped fibers through two-dimensional transport ducts. The equations used in the model enforce conservation of linear and rotational momentum and in addition impose a condition of inextensibility on the fiber. Such an inextensibility condition was used by Nordgren (1974) in modeling the free fall of a circular pipe with water onto a rigid surface, and also by Mansfield and Simmonds (1987) for the motion of a sheet of paper issuing from a horizontal guide, from which it was adapted by Smith and Roberts (1994).
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Conservation of momentum in the model is derived from a force balance on a small segment of fiber. The resulting vector momentum equation at time t in the time-evolutionary, computer simulations is:
›F ›2 x þ f þ mg ¼ m 2 ›s ›t where F is the internal force in the fiber, the fiber coordinate s is the distance measured from one end along the centerline of the fiber, f is the external applied force per unit length of fiber, m is the mass per unit length of fiber, g is the gravitational acceleration, and x is the position of a point on the fiber. Conservation of angular momentum is applied by a moment balance on a small segment of fiber, leading to the vector moment equation:
›M þt£Fþm¼0 ›s where M is the moment in the fiber, t is the local unit vector directed along the tangent to the centerline of the fiber, and m is the applied moment per unit length of fiber (no relation to the mass per unit length m in the above vector momentum equation). The right-hand side of this vector moment equation is the zero vector as the rotary inertia is neglected, which, according to Nordgren (1974), is permissible because shear deformation is neglected in the constitutive equations. The constitutive equations are where the most critical assumptions are made concerning the behaviour of the fiber. Love uses the “ordinary approximate theory”, a generalization of the classical Bernoulli-Euler theory of elastic rods, which assumes the following linear relations between the moments in the rod and the curvatures: M ¼ Gp þ G0 q þ Ht where for an initially curved rod, G ¼ Aðk 2 k0 Þ;
G 0 ¼ Bðl 2 l0 Þ;
H ¼ Cðt 2 t0 Þ:
Here A, B, and C are stiffness constants (A and B are bending stiffnesses, and C is torsional rigidity), G, G 0 , and H are local components of the internal moment, k and l are two components of bending curvature and t is the “twist”, k0, l0, t0 are the initial unstressed values of k, l, and t, and p and q are orthogonal local unit vectors normal to the local unit tangent vector t. The bending stiffnesses and torsional rigidity A, B, and C are related to the fiber diameter d and the fiber modulus of elasticity E by: A ¼ B ¼ E pd 4 =64;
C ¼ 0:7B:
To complete the specification of the model, an additional assumption must be made, and since Love’s model rests on the assumption of a small extension of the fiber centerline, it is reasonable to assume that the fiber is inextensible. Interactions between contacting fibers are modeled through repulsion forces normal to the centerlines of the fibers and through frictional forces that act perpendicular to the normal forces. When two fibers overlap, a repulsive force of magnitude f n ¼ kn ðdc 2 d n ÞH ðd c 2 dn Þ is applied to both fibers along the shortest line connecting their centerlines, where kn is a positive constant, dn is the normal distance between the centerlines, dc is the cut-off distance for the interaction (for a circular fiber, this is a constant equal to the fiber diameter d ), and H is the Heaviside unit step function. This force is included in the external applied force term of the momentum equation. The points where the line of contact intersects the surface of each fiber are called contact points. To model static friction at a nonslipping contact between two fibers, it is necessary to include a force that resists slippage between the contact points. We provide this by including an attractive force between the friction points, which are defined as the contact points at the beginning of each time step in the computer simulations. An attractive force of magnitude f f ¼ kf df is implemented to act between the friction points, where kf is a positive constant and df is the distance between the friction points. Only the component of this force perpendicular to the normal force is included in the equations. kf is chosen large enough so that slippage is essentially precluded; but since the normal component of this force is ignored, rolling between the fibers is allowed. A static friction coefficient ms is assumed; and when the frictional force ff exceeds msfn, the contact is reclassified as a slipping contact. The classification of contact points into slipping and nonslipping contacts follows the work of Carnaby and Pan (1989). Slipping contacts are assumed to obey the relation f f ¼ mk f n ; where the kinetic friction coefficient mk is lower than the static friction coefficient ms. It is impractical to try to model computationally an entire fibrous assembly, which may contain many thousands of fibers and even greater number of contacts. Instead, we focus on a representative “cell” volume within the fibrous assembly being modeled and impose appropriate boundary conditions on the ends of the fiber portions (i.e. the fibers within the computational “cell” volume) at the cell walls. This ensures that the model behaves as a representative part of the assembly being modeled. We have chosen to model an initially “cubic unit cell” within the assembly, whose length is determined by placing a fixed number of fibers randomly in the cell, then adjusting the ratio of the length of the cell to the diameter of the fibers, and repeating the process until the desired initial volume fraction is obtained.
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The boundary conditions imposed on the six walls of this cell are intended to represent forces and moments transmitted within the fibers across the walls. Indeed, it is important that the boundary conditions do not suppress the tendency of the ends of the fiber portions to move vertically in proportion to the amount of compression. Consequently, we adopt a position/force boundary condition which incorporates linear springs between the points where the ends of the fiber portions would be, if they were moved vertically in proportion to the amount of compression, and the ends of the fiber portions themselves. Each fiber portion end is assigned to the face of the unit cell that it initially touches, and a relatively weak spring resists motion in the plane of that face, while a much stronger spring resists motion perpendicular to that face. In addition to this position/force boundary condition, an orientation/moment boundary condition is needed; for these simulations, we decided to fix the orientations at the cell walls at their initial values. Fiber portions that pass from the top to bottom of the cell are not included; typically, about 10 percent of the randomly generated fibers are in this class and are not included. All other fiber portions, that consist of at least half of one helical loop, are included in the computer simulations. 3. Results of the computer simulations Side views of the unit cube cell, depicting a representative model fibrous assembly which contains 50 helix-shaped fibers, before and during compression are shown in Figure 1. The fibrous assembly is viewed initially before the start of the compression (left panel – initial volume); and, as the top wall is depressed, it is viewed at a compression of 70 percent of its initial volume (right panel). Here, the initial configuration is taken to be identical to
Figure 1. Side views of a unit cube cell, depicting a representative model fibrous assembly (Case: Std. Crimp1-Dyn) containing 50 fibers that constitute a fiber volume fraction of 0.8 percent, before compression (left panel) and during compression, as the top wall is depressed, to 70 percent of its initial volume (right panel)
that of the standard crimp case D – herein referred to as Std. Crimp1 – considered by Beil and Roberts (2002a, b), in which the fibers constitute an initial volume fraction of vf0 ¼ 0:8 percent: However, in contrast to the earlier cases considered by Beil and Roberts (2002a, b), for which the mass per unit length m was set to zero, and the acceleration and gravitational acceleration terms were zero, in the vector momentum equation, here we retain these two terms dependent upon the mass per unit length m and we calculate explicitly the resulting dynamics and the three-dimensional motions of the fibers in time during the time-evolutionary computer simulations for the compression of this representative model fibrous assembly – herein referred to, with the dynamics included, as Std. Crimp1-Dyn (i.e. “the standard crimp with dynamics” case). The computed pressure and the computed number of fiber-fiber contacts which occur and are tracked computationally in this Std. Crimp1-Dyn case during fibrous assembly compression are displayed in Figure 2 over the computed range of volume fraction, starting from the initial volume fraction of 1.00 to the volume fraction of 0.70 at 70 percent compression of the initial volume. The number of fiber-fiber contacts is found to increase by almost double from approximately 30 to a little less than 60 and the pressure in the fibrous assembly is found to increase from zero to a little over 20 during the compression to 70 percent of the initial volume (The pressure unit is E=ð109 Þ; where E is the fiber modulus of elasticity). Van Wyk’s theory consists of two parts: prediction of the number of contacts in the assembly and of the pressure-volume relationship during the compression stage. In order to explore the latter, we consider in Figure 3 the results of the computer simulations for three standard crimp cases: Std. Crimp1-Dyn and Std. Crimp1 and Std. Crimp2 and two high crimp cases: High Crimp1 and High Crimp2. Of these cases, only the Std. Crimp1 case has been
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Figure 2. Computed pressure and computed number of fiber-fiber contacts that occur and are tracked during compression of the representative model fibrous assembly Std. Crimp1-Dyn from the initial volume fraction of 1.00 to the volume fraction of 0.70 at 70 percent compression of the initial volume
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Figure 3. Pressure versus the inverse cube of the volume – computed for three standard crimp cases, including Std. Crimp1-Dyn, and two high crimp cases during their compressions to 70 percent of their initial volumes
studied earlier with respect to determination of the van Wyk constant K ( Beil and Roberts, 2002a), but the extent of the compression investigated at that time was a compression to only 75 percent of initial volume; this case and the latter three cases have been studied with respect to determination of the pressure Poisson ratio (Beil and Roberts, 2002b). For the three standard crimp cases, the helix angle a, which is defined as the angle between the fiber’s tangent and the centerline of the helix, is taken as 308 and the helix radius is taken as 3.5 times the fiber diameter d. For the two high crimp cases, the helix angle a is increased to about 498 and the helix radius is taken as 7.0 times the fiber diameter d. In all cases, the fiber diameter d is adjusted to ensure that the fiber volume fraction remains unchanged at 0.8 percent fiber volume fraction. First, it is important to note in Figure 3 that the pressure curves for the two standard crimp cases Std. Crimp1 (with the mass per unit length m set to zero) and Std. Crimp1-Dyn (with m not set to zero and with the acceleration and gravitational acceleration terms retained in the vector momentum equation) entirely overlap and are virtually identical – thus indicating that the neglect of these terms in the momentum equation by Beil and Roberts (2002a, b) was a reasonable and valid approximation. Indeed, both the acceleration term, for the slow time compression considered, and the gravitational acceleration term are several orders of magnitude smaller than the internal force and applied force terms for realistic fiber assemblies of wool and other typical fiber fill. Second, it is important to note that both high crimp cases lie at substantially higher pressures and have substantially greater numbers of fiber-fiber contacts (Figure 4) than the three standard crimp cases. The van Wyk constant K, which is dimensionless, may be defined as the slope of the pressure (given in terms of E) plotted against the inverse cube of the fiber volume fraction. Experimental values for K have been given by Dunlop (1974, 1979, 1981), who reports values in the range of 0.0028-0.0250 for compression of various types of wool in a piston-cylinder apparatus and who reports values in the range 0.024-0.060 for wool, terylene polyester, Courtelle
acrylic, and viscose using an acoustic impedance technique. The higher values obtained with acoustic measurements are probably the result of the lack of slippage occurring for the small displacements observed. There is no standard way to obtain K from a nonlinear pressure vs inverse volume cubed curve, but rough estimates may be obtained by using the flattest parts of the curves at the high compression levels. From the results of the computer simulations plotted in Figure 3, estimated values of the van Wyk constant K are determined as: 0.033 (Std. Crimp1 and Std. Crimp1-Dyn), 0.039 (High Crimp2), 0.040 (Std. Crimp2), and 0.044 (High Crimp1). These estimates of the van Wyk constant K determined through the computer simulations for the several standard crimp and high crimp fibrous assembly cases modeled are in line with and fall very near or within the ranges of experimental values determined from the experiments performed. The other aspect of van Wyk’s theory, predicting the number of contacts in a fibrous assembly, while difficult to verify experimentally, is easy to compare using our model. In Figure 4, the computed numbers of contacts are plotted against inverse volume for the three standard crimp and two high crimp cases. Van Wyk’s theory predicts that the initial number of contacts should be a little less than 30 for the three standard crimp cases and a little more than 40 for the high crimp cases and that the number of contacts should increase in direct linear proportion to the inverse volume by about a factor of 1.43 in the compression of these fibrous assemblies to 70 percent of their initial volumes (i.e. 1:43 ¼ 1=ð0:70ÞÞ: Indeed from the computer results displayed in Figure 4, it is apparent that the initial number of contacts does seem to fall within or reasonably close to the initial values predicted and that the increases in the number of contacts do vary roughly linearly with inverse volume. However, note that the increases in the number of fiber-fiber contacts in all five cases are much greater than the predicted 1.43 factor increase. The computed number of fiber-fiber contacts in the numerical simulations are found to increase by much greater factors of 1.90
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Figure 4. Number of contacts versus inverse volume – computed for three standard crimp cases, including Std. Crimp1-Dyn, and two high crimp cases during their compressions to 70 percent of their initial volumes
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Figure 5. Mechanical hysteresis depicted through pressure versus volume during the ninth compression-release cycle computed for the representative model fibrous assembly case: Std. Crimp1-Dyn
(Std. Crimp1 and Std. Crimp1-Dyn), 2.13 (High Crimp2), 2.96 (Std. Crimp2), and 3.18 (High Crimp1). This marked difference is probably the result of van Wyk’s neglect of the effect of fibers crossing each other’s paths as the assembly is compressed. Also, it should be noted that there is a wide range of contact forces in each simulation, with most of the contacts slipping at any given time, but with the stronger contacts tending to be nonslipping. Mechanical hysteresis is found to be a dominant phenomenon during pressure-release cycling in the computer simulations, for which we are able to predict the amount of frictional energy dissipated as a function of time. Plotted in Figure 5 is pressure versus volume computed during the ninth compression-release cycle for the Std. Crimp1-Dyn case. For the first cycle, we compress the fiber assembly to 70 percent of its initial volume; and once the 70 percent target volume is reached, we record the corresponding pressure as the target pressure (for future cycles) and reset all slipping contacts to nonslipping contacts before beginning to decompress the assembly at the same rate as was previously compressed. Following Dunlop’s (1974, 1979) experimental procedures, we allow the pressure to drop to 10 percent of its maximum value before resetting the contacts and starting the next cycle. For all subsequent compression cycles, including the ninth hysteresis loop shown in Figure 5, we follow the same procedure, except that the target pressure achieved in the compression stroke of the first cycle is used as the criterion (instead of 70 percent volume) to determine when the compression stroke ends and the decompression stroke begins. It is clear in the computer simulations that hysteresis, such as this loop depicted at the ninth cycle in Figure 5, persists and does not go away with repeated cycling. There is also a small but significant irrecoverable compression at the bottom of the first five or so cycles, in which the assembly loses at least 2 percent of its original volume. We do not find that this irrecoverable compression continues significantly for as many cycles as has been experimentally reported, which may be a result of our neglect of viscoelastic effects. Indeed, by the sixth cycle, very little additional
irrecoverable compression seems to occur, and the curves continue to trace approximately the same path. Dunlop (1983) observed the same tendency in one of his models using friction blocks and nonlinear springs to model the bulk behaviour of an assembly. Since real fibrous assemblies continue to lose volume for several more cycles, it is likely that something is lacking in both models. One possibility is the neglect of viscoelasticity, since viscoelastic behaviour would certainly prevent fibers from springing back entirely to their original shapes. Another possibility in the case of wool would be the effect of scales, which could have a ratcheting effect on the volume of an assembly. 4. Conclusions The mathematical-computational model presented in this paper represents efforts to obtain the bulk compressional properties of a fibrous assembly from the properties of the individual fibers within the fibrous assembly. The model not only allows exploration of the characteristics of a fibrous assembly under compression at a level of detail impossible to achieve through experiment, but also allows inclusion of effects that are very difficult to account for quantitatively through theory alone. Factors that can be accounted for in the model include initial arrangement and configuration of the fibrous assembly, fiber crimp, various types of friction, distribution of contact forces, and steric exclusion of fibers. Once the essential characteristics of a fibrous assembly have been captured, it should present no special problem to model oriented fibrous assemblies such as slivers and yarns. In the future, as computer power continues to grow, it may be possible to model higher order fibrous assemblies, such as fabrics, at the level of individual fibers, which would be a great advance in understanding and predicting their properties. References Beil, N.B. and Roberts, W.W. Jr (2002a), “Modeling and computer simulation of the compressional behaviour of fiber assemblies, Part I: comparison to van Wyk’s theory”, Textile Res. J., Vol. 72 No. 4, pp. 341-51. Beil, N.B. and Roberts, W.W. Jr (2002b), “Modeling and computer simulation of the compressional behaviour of fiber assemblies, Part II: hysteresis, crimp, and orientation effects”, Textile Res. J., Vol. 72 No. 5, pp. 375-82. Carnaby, G.A. and Pan, N. (1989), “Theory of the compression hysteresis of fibrous assemblies”, Textile Res. J., Vol. 59, pp. 275-84. Dunlop, J.I. (1974), “Characterizing the compression properties of fiber masses”, J. Textile Institute, Vol. 65, pp. 532-6. Dunlop, J.I. (1979), “Acoustic emission from wool during compression”, J. Textile Institute, Vol. 70, pp. 364-6. Dunlop, J.I. (1981), “The dynamic bulk modulus of fiber masses”, J. Textile Institute, Vol. 72, pp. 154-61. Dunlop, J.I. (1983), “On the compression characteristics of fiber masses”, J. Textile Institute, Vol. 74, pp. 92-7.
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Love, A.E.H. (1944), A Treatise on the Mathematical Theory of Elasticity, 4th ed., Dover Publications, New York, NY. Mansfield, L. and Simmonds, J.G. (1987), “The reverse Spaghetti problem: drooping motion of an elastica issuing from a horizontal guide”, Journal of Applied Mechanics, Vol. 54, pp. 147-50. Nordgren, R.P. (1974), “On computation of the motion of elastic rods”, Journal of Applied Mechanics, Vol. 41, pp. 777-81. Smith, A.C. and Roberts, W.W. Jr (1994), “Straightening of crimped and hooked fibers in converging transport ducts: computational modeling”, Textile Research Journal, Vol. 64, pp. 335-44. van Wyk, C.M. (1946), “Note on the compressibility of wool”, J. Textile Institute, Vol. 37, pp. T285-92.
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Processing and quality of cashmere tops for ultrafine wool worsted blend fabrics
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B.A. McGregor Department of Primary Industries, Attwood, Victoria, Australia
R. Postle Department of Textile Technology, University of New South Wales, Sydney, New South Wales, Australia Keywords Wool fabric, Textile finishing Abstract This study has focussed on three main areas. First, an evaluation of the physical attributes of cashmere tops available to commercial spinners; second, the influence of processing variables on the efficiency of producing cashmere tops from raw Australian cashmere; and third, the influence of design of cashmere ultrafine wool blends on the fibre curvature of tops. Testing the physical attributes of cashmere tops from traditional and new sources of supply, was followed by statistical analyses based on factors of origin, processor and other determinants. The analyses demonstrated important processor effects and also that cashmere from different origins shows commercially important variations in fibre attributes. It was possible to efficiently produce Australian cashmere tops with Hauteur, tenacity, extension, softness and residual guard hairs quality attributes equivalent to those observed in the best cashmere tops. The blending of cashmere with wool resulted in a reduction of the mean fibre curvature of the blend compared with the unblended wool. The present work demonstrated that the fibre curvature properties of blended low crimp ultrafine wool tops were closer to the properties of pure cashmere tops than were tops made from blended standard high crimp ultrafine wool. The attributes of textiles made from the relatively rare Australian low curvature cashmere could enhance the marketability of both Australian cashmere and low curvature wool.
1. Introduction Cashmere is a rare exotic animal fibre used to produce soft luxurious apparel. It is expensive to purchase, and needs specialist processing, details of which are kept as tightly guarded secrets. Given the lack of technical information available on the dehairing, worsted processing and quality of cashmere textiles, a series of experiments have been completed (McGregor, 2001). This report is part of that larger study which compared the quality and processing of Australian cashmere into tops and the blending and knitted fabric properties of low fibre curvature and high fibre curvature ultrafine wool when blended with Australian cashmere. This project was financially supported by the Rural Industries Research and Development Corporation and Department of Primary Industries, Victoria. The authors thank Dr Xungai Wang, Dr Mike Young (UNSW); and Mr Kym Butler, Biometrician, Agriculture Victoria, Werribee.
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Forte´ Cashmere Company believed that Australian cashmere had the length of Mongolian cashmere (Hopkins, 1987), a source often used for cashmere top making, but provided no data. The Italian processor Nesti (1989) believed that Australia had the potential to produce fine cashmere of 100 mm length, capable of producing a top with a Hauteur of 55 mm. Such a product had not been seen, but no evidence was provided to support his view. Within few years, according to Levinge (1993), companies had developed the ability to produce 50 mm Chinese top that matched the performance of Australian cashmere. Despite these views, no commercial processing of Australian worsted cashmere yarn has occurred other than the processing of knitwear samples by Dawson International (Smith, 1987, 1992) and sampling trials by Forte´ and their customers (Anonymous, 1991). In 1992, Smith said that the worsted garments made from 17.5 mm Australasian cashmere displayed superior handle to garments made from 15 mm Chinese woollen spun cashmere. He reported that these garments did not pill, cockle or stretch. An earlier report provided details of the raw wool top making performance and the quality of the pure wool and cashmere tops that were processed into 30 tex single yarns and knitted into plain jersey fabrics (McGregor and Postle, 2002). It has been demonstrated that Australian dehaired cashmere has greater length after carding, lower fibre curvature and lower resistance to compression than dehaired cashmere from traditional sources (McGregor, 2000a, 2001). These data are the first objective evidence available indicating that Australian dehaired cashmere should perform at a superior level during top making than cashmere from Iran and Mongolia. This paper provides details of: (1) a survey of the physical attributes of international cashmere tops available to commercial spinners; (2) the influence of processing variables on quality attributes of Australian cashmere tops; and (3) the influence of design of cashmere ultrafine wool blends on the fibre curvature of tops. 2. Methods 2.1 Survey of attributes of international cashmere tops available to commercial spinners Samples of commercial cashmere tops (n ¼ 25) were provided by manufacturers in Europe, Iran, China and Australia and were collected by the author. Fibre classed as Cashgora by cashmere marketing agencies and processed into tops was included. Mean fibre diameter (MFD) and diameter distribution (coefficient of variation, CV(D) and per cent . 30 mm), fibre curvature (FC, 8/mm), medullated fibre incidence (per cent w/w) and diameter (white samples only) were determined by mini coring dehaired cashmere
samples or guillotining tops. Following aqueous scouring, two subsamples were measured twice (8,000 counts for each measurement) using the OFDA100 (IWTO, 1995, 1996). Fibre length was measured by Almeter (IWTO, 1985). Resistance to compression was determined according to AS 3535 (1988). Not all samples were tested for Hauteur. Samples of top were measured for bundle tenacity and bundle extension using the Sirolan-Tensor (Yang et al., 1996). The strain rate was set at 20 mm/min and the gauge length at 3.2 mm. Attributes were modelled as a function of origin and processor using multiple regression with factors (Genstat, 2000). There was no evidence of interaction between the origin and processor. Residual standard deviation of regressions (RSD) and correlation coefficients are provided. The initial geographical origins could be sensibly grouped into broader regions without losing any explanatory power of the model. The final origins were: West Asia (Iran, Turkey, Afghanistan), Eastern Asia (China including inner Mongolia, but excluding Xinjiang Autonomous Region), Central Asia (Western Mongolia, Xinjiang Autonomous Region of China), New (only one top from New Origins was available) and Cashgora. For fibre curvature, Iran was a separate origin. Some data were presented as box plots, showing the median, upper and lower quartiles with outliers, plotted in country or origin groups. 2.2 Influence of processing variables on quality attributes of Australian cashmere tops Cashmere was purchased to specification from the Australian Cashmere Marketing Corporation. It was sampled by core testing and shipped to Cashmere Processors Ltd, Auckland, New Zealand, who had been dehairing cashmere for 10 years. Following dehairing, the bulk of the cashmere was carded, gilled thrice with a draft of 4-5 and shipped to the University of New South Wales. Combing trials were undertaken on a PB25L worsted combing machine designed for fine and short wools of 21 mm and finer (N. Schlumberger et Cie, Guebwiller, Haut-Rhin, France) by adjusting the distance from nipper to drawing-off rollers with the setting altered from the minimum of 23-42.5 mm. For the experiment described in Section 3, the setting was set at 25 mm. To maintain combed sliver cohesion, it was necessary to apply twist at a rate of 4 tpm. Following finisher gilling, Almeter samples were given 36 turns of twist within 10 min, and were tied and stored. Tops were tested for a range of physical attributes using the methods described earlier. Fibre length on second grade cashmere and noils was measured using a modified length after carding procedure (LAC) and tops by Almeter (IWTO, 1985). 2.3 Influence of design of cashmere ultrafine wool blends on the fibre curvature of tops This study was undertaken as a replicated experiment. This experiment had nine treatments. The design was: Blend/(WT * BR) £ 3 replicates. Blend was analysed as: Control (CM), specified as 100 per cent Australian cashmere;
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Blends, blends of cashmere with wool and the pure wool treatments. WT, wool type had two levels: SW, standard high crimp ultrafine wool tops; LCW, soft handling low crimp ultrafine wool tops. BR, referred to blend ratio and had four levels specified as: 75, 50, 25 and 0 referring to the percentage of cashmere in the blend. In the graphical representation of results, BR 100 refers to the control, CM. Raw wool was tested as described for cashmere. Wool was processed into tops and following combing, but before gilling, was allocated at random into three replicates and treatments. Following three blending gillings and two finisher gillings tops were sampled. Data are given for selected measurements. 3. Results 3.1 Survey of attributes of international cashmere tops available to commercial spinners Data from all origins have been pooled and summarised in Table I. 3.1.1 MFD. The MFD of cashmere tops ranged from 15.2 to 19.3 mm (Table I, Figure 1). Modelling indicated that origin was significant (P , 0:001), but processor was not significant (P . 0:25) and the model accounted for only 50 per cent of the variation (r ¼ 0:71; RSD ¼ 1:05). This suggests that once cashmere is combed, it is less influenced by the effects of processor that affect the attributes of dehaired cashmere. 3.1.2 Fibre curvature. No significant regression could be modelled. Origin was only significant at P ¼ 0:06: Fibre curvature of tops was strongly related to MFD (Figure 1) with curvature declining 5.48/mm for each 1 mm increase in
Top attribute
Mean
SD
17.3 1.2 MFD, mm CV(D), per cent 21.3 1.2 Per cent of fibres . 30 mm 0.6 0.4 Fibre curvature, 8/mm 59.2 5.0 Resistance to compression, kPa 6.1 1.2 Incidence of medullated fibre, per cent w/w 0.4 0.5 Mean medullated fibre diameter, mm 34.3 9.1 Table I. Hauteur, mm 39.4 4.5 Mean, SD and range of CV(H), per cent 42.6 7.0 pooled data for Hauteur, per cent of fibres , 25 mm 21.3 11.5 attributes of Hauteur longest 5 per cent, mm 70.5 6.2 international cashmere Barbe, mm 46.7 4.5 tops and a comparison CV(B), per cent 37.8 5.0 with the attributes of Ratio Hauteur: MFD, mm/mm 2.37 0.38 the experimental Bundle tenacity, cN/tex 10.3 1.0 Australian cashmere top Bundle extension, per cent 38.8 6.3
Present Maximum Minimum experiment 19.3 23.8 1.6 68.5 8.3 1.5 51.7 45 57.4 51.1 82 54 47.8 2.96 12.0 50.0
15.2 19.8 0.1 48.9 3.7 0.1 26.8 28 31.8 6.9 59 37 31.2 1.52 8.3 19.5
16.6 20.6 0.2 48.4 3.7 0.1 33.9 42 45.0 20.1 76 50 12.0 2.49 11.2 50.0
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Figure 1. Various fibre attributes of cashmere tops from different origins
MFD. The linear regression constants for the relationship between FC and MFD were: FC ¼ 150:9 2 5:4ð0:80ÞMFD: RSD ¼ 6:7; r ¼ 0:81; P , 0:001: 3.1.3 Resistance to compression. The fitted model included only origin and processor (RSD ¼ 0:52; r ¼ 0:87). Resistance to compression of tops was poorly related to fibre curvature or the product of fibre curvature and MFD (Figure 1) with the spread of data points being reduced with the variate MFD· FC. 3.1.4 Hauteur. Hauteur ranged from 28 to 45 mm (Table I, Figure 1). The regression for top hauteur (RSD ¼ 3:46; r ¼ 0:90) included only origin (P , 0:001) and processor (P ¼ 0:044) with origin alone accounting for 74 per cent of the variation. This model predicted that the longest tops came from New Origins with the tops from East Asia 7 mm shorter and that from Western Asia 11 mm shorter. 3.1.5 Bundle tenacity and extension. The ranges in bundle tenacity and bundle extension are shown in Figure 2. Prediction modelling for bundle tenacity revealed that origin and processor were only significant at P ¼ 0:1 and they were excluded from the final model. Only Hauteur was significant (Figure 3). The linear regression constants for the relationship between tenacity (cN/tex) and Hauteur (mm) were: tenacity ¼ 5:5 þ 0:12 ð0:04ÞHauteur: RSD ¼ 0:86; r ¼ 0:55; P , 0:01: 3.2 Influence of processing variables on quality attributes of Australian cashmere tops The amount of cashmere recovered after dehairing was similar to that predicted by the core testing undertaken by the Australian Wool Testing
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Authority. The visual inspection of the coarse hair removed during dehairing indicated that all the cashmere was removed during dehairing. Of the cashmere dehaired, 8.4 per cent was of inferior length grades of which nearly 5 per cent was discarded as short fibre machine droppings (Table II). The reported scouring yield of 94.9 per cent, was less than expected, as the mean washing
124 Figure 2. Box plots of bundle tenacity and bundle extension of cashmere tops from different origins (IR, Iran; WA, West Asia; CH, China; CA, Central Asia)
Figure 3. The relationship between bundle tenacity and Hauteur of cashmere tops (pooled data from all origins)
Processing step Total weight of hair-in raw cashmere less samples (AWTA tests) Weight of cashmere down less samples (AWTA tests)
Table II. Reconciliation of cashmere fibre weight during purchase, sampling and processing
Weight of dehaired cashmere at end of dehairingb Cashmere (in sliver form) Second grade cashmere Short fibre machine droppings Total (not adjusted for moisture)
Weight (kg)
Proportion dehaired cashmere per cent
372.9a
–
125.3a
–
116.6 4.7 6.0 127.3
91.6 3.7 4.7 100.0
Notes: aValues adjusted for moisture content; and bvalues provided by dehairer and not adjusted for moisture.
yield of the purchased bales and grower lots (when adjusted for the weight of the lots) was 96.6 per cent. Results of the comb setting adjustment trial are shown in Figure 4 and the regression constants are given in Table III. Increasing the comb setting significantly increased the Hauteur of the combed cashmere and the production of noil. Following cashmere combing at the setting of 25 mm, the mean ^ SD noil yield was 16:0 ^ 0:3 per cent (n ¼ 81). Details of top and noil fibre attributes are shown in Table IV. The properties of the experimental top are compared to the international tops in Table I.
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Figure 4. The relationship between the comb setting, fibre length of the combed sliver and noil production for the experimental Australian cashmere
Response variate Hauteur Noil MFD Noil CV(H)
Regression constant 30.9 2 25.3 13.9 2132.4 95.5
Dependent variate
Regression coefficient (se)
r
RSD
P
Comb setting Comb setting Hauteur Hauteur Hauteur
0.43 (0.07) 1.72 (0.11) 0.07 (0.02) 3.6 (0.8) 2 1.18 (0.15)
0.95 0.99 0.85 0.92 0.97
1.17 1.81 0.14 5.61 1.10
0.01 0.001 0.05 0.02 0.005
Table III. Regression and correlation coefficients for the relationships between the setting on the comb, properties of the combed cashmere sliver and the quantity of noil
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3.3 Influence of design of cashmere ultrafine wool blends on the fibre curvature of tops The fibre curvature of the blended tops was affected by Blend, WT and BR (all P , 0:001; Figure 5). Fibre curvature of the pure tops before aqueous scouring were: CM 31.2, LCW 61.2, SW 96.38/mm; sed 1.13; P , 0:001 and after aqueous scouring were: CM 48.9, LCW 74.7, SW 108.58/mm; sedCM-WT 1.4, sedWT 0.9; P , 0:001: Increasing blend ratio reduced fibre curvature and CV(H) (Figure 5). 4. Discussion 4.1 The effect of processor on cashmere top attribute Typically cashmere woven goods for fine men’s suiting consist of blends with super 120s, 130s, 140s or 150s wool. Sometimes such fabrics consist of 100 per cent cashmere, but usually they contain only 10 or 20 per cent cashmere. Cashmere is added to improve the fabric handle and marketability. For such classic fabrics, fine worsted yarns are usually used. Knowledge of the
Length (mm)
Barbe (mm)
MFD (mm)
Med (per cent w/w)
Tenacity (cN/tex)
Short machine droppings 4.7 – Second grade cashmere 3.7 23.4 Machine waste and losses 5.0 – Noil 16.0 13.5 Fibre in tops , 25 mm 9.0 In top Fibre in tops . 25 mm 61.6 41.8 Note: Med, incidence of medullated fibres.
– 35.8 – 17.3 In top 50.2
– 17.3 – 15.0 – 16.0
– 0.3 – 0.1 – 0.1
– 10.2 – 7.0 In top 11.2
Description
Table IV. The relative amount, fibre length and other attributes of Australian cashmere following dehairing and combing
Figure 5. The fibre curvature and CV Hauteur of the blended cashmere and wool tops showing affect of blend ratio and wool type. The effective standard error is plotted as an error bar with pure cashmere
Proportion (per cent)
attributes of cashmere tops would aid yarn design, but information on cashmere tops is difficult to attain in the public domain. This analysis reports significant effects of processor and origin on the Hauteur of cashmere tops. Effects of processor on cashmere length are very important as the length of cashmere affects the price of cashmere (McGregor, 2000b) as well as spinning speed and yarn linear density. It is clearly in the interests of those aiming to produce fine cashmere yarns to determine which processors can maximise the length after carding of dehaired cashmere and/or the Hauteur and from which origins suitable cashmere may be attained. The fibre curvature of tops appeared to be less than that of dehaired cashmere (McGregor, 2000a), probably reflecting the removal of noil (McGregor, 2001). However, in this analysis the effect of processor includes: both difference in processing between dehairer processors and effect of subsequent processing, i.e. differences between cashmere top makers; and the differences due to fibre processed as a result of selection or purchase decisions. This analysis is not able to differentiate between these causes, where appropriate. For example, it has been demonstrated that dehairer processor affected the yellowness and lightness of commercial lots of cashmere (McGregor, 2000a). This may suggest that processing treatments such as scouring and drying conditions or the actual origin of cashmere purchased may affect the measured colour. The effect of top maker processor on Hauteur of cashmere tops may be due to the differences in machinery, machinery operation, processing operations etc. and/or the quality of dehaired cashmere processed. 4.1.2 Bundle tenacity There are no reported data on the bundle strength of the cashmere top. Modelling by Yang et al. (1996) showed that a 10 per cent decrease in bundle tenacity roughly doubled the spinning ends-down and was equivalent to a decrease in Hauteur of 9 mm. On this basis, they concluded that bundle tenacity was potentially the third most important property in wool tops after MFD and Hauteur. Higher tenacity fibres result in less fibre breakage and the potential use of the worsted spinning system. Worsted spun yarns are used to produce a wider range of more durable woven fabrics than is available from woollen spun short cashmere. In the present study, the tenacity of the experimental Australian cashmere was at the high end of the results from the survey (Table I). The tenacity of cashmere tops in the survey was dependent on Hauteur, a finding reported for wool by the developers of the instrument (Yang et al., 1996). The mean value reported here for the bundle tenacity of cashmere tops appears to be about 5 per cent less than those reported for 18-25 mm wool tops that had a mean Hauteur of 69 mm (range 50-96 mm, Yang et al., 1996). If adjustment is made for the difference in Hauteur (30 mm) using the regression constant for top Hauteur (0.1206 cN/tex/mm), then cashmere tops would have a bundle tenacity of
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25 per cent greater than that reported for wool tops. The bundle extension of these cashmere tops was similar to those reported for wool (Yang et al., 1996). 4.2 Cashmere processing The dehairer was able to separate all the cashmere identified in the AWTA core tests. The recovery of all the cashmere was that no cashmere was lost in the separated coarse hair. The visual inspection of the coarse hair confirmed this result. In the reconciliation of the fibre some of the weights have not been corrected for moisture content, as samples were not available and so care needs to be exercised in interpreting these values. Of the cashmere dehaired, 8.4 per cent was of inferior length grades of which nearly 5 per cent was discarded as short fibre machine droppings. The cashmere of suitable length for further worsted processing was 91 per cent of the cashmere weight obtained by dehairing. The second grade cashmere droppings had a length after carding (LAC) of 23 mm and are potentially suitable for certain woollen spinning applications, such as blending with wool or cotton in high twist yarns. The LAC of the dehaired cashmere was 28.8 mm compared with the mean maximum raw fibre length of 75.3 mm (McGregor, 2001). This indicates that the dehairing and carding processes resulted in a decrease in length by approximately 61 per cent. It is highly likely that the fibre length of the dehaired cashmere was reduced during carding, as is experienced during the carding of wool. In order to maintain the length of the dehaired cashmere fibre it is advisable for the Australian cashmere industry to investigate more suitable carding processes, including appropriate lubricants, for the long cashmere produced in Australia. It is likely that longer dehaired cashmere could be produced by keeping separate the longer cashmere produced during the first dehairing pass. This was deliberately not done in this experiment. 4.2.1 Combing. The regression coefficients obtained in the comb setting test indicated that for every 5 mm increase in the settings, the following changes occurred in the resulting combed sliver: Hauteur increased by 2.1 mm, CV(H) declined by 2.4 per cent, noil increased by 8.6 per cent and MFD increased by 0.13 mm (Table III). The results also indicate that it is possible to obtain a Hauteur of 50 mm, but that noil losses will approximate to 50 per cent. This may be commercially acceptable as Nesti (1989) reported that some outer Mongolian and Iranian cashmere is combed, but the loss of noils was reported to be as high as 35-38 per cent, a loss that would dramatically increase the cost of the yarn. Even after this level of noil removal, Nesti reported that the average length of the top was 33-38 mm and was therefore unfit for spinning finer counts than metric 40s (,25 tex). Improved rectilinear combs can produce tops from 17 mm cashmere that have a Hauteur of 44.5 mm, a CV(H) of 45.7 per cent while keeping waste at 8.5 per cent (Certo, 2001). The level of medullated fibre in the Australian cashmere top was at the lower end of that reported for
sampled tops and the diameter of the medullated fibres was averaged for the sampled tops (Table I). When the comb setting of 25 mm was used, the 42 mm Hauteur of the cashmere top was 55 per cent of the mean maximum raw cashmere length. The length properties of these cashmere tops place them at the middle to upper level of world cashmere tops (Table I). The ratio of the Hauteur of the experimental cashmere to the MFD of the top, was 2.49 mm/mm compared with the mean values obtained for international cashmere tops of 2.37 mm/mm and Certo’s (2001) recent report on a modern combing machine of 2.62 mm/mm. The improvements in lubrication may explain the increase in the ratio of Hauteur/MFD of wool reported over the past 15 years. In fine wool tops processed by Kurdo et al. (1986) this ratio averaged to 2.82 mm/mm and with commercial fine wool tops examined by McGregor (2001) the mean (^ SD) ratio of Hauteur/MFD was 3.41 (0.22) mm/mm (range 3.13-3.69 mm/mm). Use of this mean and upper range ratio indicates that the potential Hauteur for Australian 16.6 mm cashmere is 56-61 mm. 4.3 Influence of design of cashmere ultrafine wool blends on the fibre curvature of tops Fibre curvature of raw wool affects the measured softness (compressibility or yielding to pressure) and stiffness of raw wool (Madeley et al., 1998; Swan, 1994; van Wyk, 1946). There has been a debate over the use of low curvature soft handling ultrafine wool, but low curvature ultrafine wool is relatively scarce. Only 5 per cent of 18-18.5 mm wool lots can be expected to have a resistance to compression ,7.3 kPa (Whiteley et al., 1986). In a commercial flock bred for 16-18 mm low staple crimp frequency wool only 12 per cent of the wool tested had a fibre curvature of , 808/mm (McGregor and Toland, 2002). The present work demonstrates that when raw wools of differing fibre curvature were blended with cashmere of a much lower fibre curvature, there was a significant decline in fibre curvature of the blended tops. The implications of this are that the subsequent textiles should have a lower resistance to compression and are potentially softer. The present work demonstrated that the fibre curvature properties of blended low crimp ultrafine wool tops were closer to the fibre curvature properties of pure cashmere tops than were tops made from blended standard high crimp ultrafine wool. 5. Conclusions Cashmere tops show commercially important variations in fibre attributes. Origin of cashmere and processor were the major determinant of cashmere top Hauteur. Cashmere from Australia can be efficiently processed to produce tops of long Hauteur, high tenacity and low fibre curvature compared with traditional cashmere and Australian cashmere is likely to have a softer handle. Differences in raw wool and raw cashmere fibre curvature attributes were
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translated into different blended fibre top properties. The fibre curvature properties of blended low crimp ultrafine wool tops were closer to the fibre curvature properties of pure cashmere tops than were tops made from blended standard high crimp ultrafine wool. The attributes of textiles made from the Australian low curvature cashmere could enhance the marketability of both Australian cashmere and low curvature ultrafine wool. References Anonymous (1991), “Hugh Hopkins visits pool”, Cashmere Australia, Vol. 12 No. 3, p. 5. AS 3535-1988 (1988), “Wool – method for the measurement of resistance to compression”, Standards Association of Australia, Melbourne. Certo, A. (2001), “Improved wool quality with a rectilinear combing machine”, International Textile Bulletin, Vol. 47 No. 6, pp. 48-50. Genstat Committee (2000), The Guide to Genstat, Lawes Agricultural Trust, Rothamsted. Hopkins, H.W. (1987), “Cashmere and the United States”, Proceedings 2nd International Cashmere Conference, Lincoln College, New Zealand, Agtell Public Relations, Christchurch, pp. 18-26. IWTO-17-85 (1985), “Determination of fibre length distribution parameters by means of the almeter”, International Wool Textile Organisation, Ilkley, Yorkshire, UK. IWTO-47-95 (1995), “Measurement of the mean and distribution of fibre diameter of wool using an optical fibre diameter analyser (OFDA)”, International Wool Textile Organisation, Ilkley, Yorkshire, UK. IWTO-57-96 (1996), “Determination of medullated fibre content of wool and mohair samples by opacity measurement using an OFDA”, International Wool Textile Organisation, Ilkley, Yorkshire, UK. Kurdo, K.O.A., Whitely, K.J. and Smith, L.J. (1986), “The influence of resistance to compression on the processing performance of superfine wools. 1: Topmaking”, Journal Textile Institute, Vol. 77, pp. 104-18. Levinge, R. (1993), “Visit to processors May-June 1992”, Cashmere Australia, Vol. 13 No. 3, pp. 10-11. McGregor, B.A. (2000a), “Quality attributes of cashmere”, Proceedings of the 10th International Wool Textile Research Conference, SF 1-10, Deutsches Wollforschungsinstitut, Germany. McGregor, B.A. (2000b), “Recent advances in marketing and product development of mohair and cashmere”, Proceedings VII International Conference on Goats, INRA, Nouzilly, pp. 631-7. McGregor, B.A. (2001), “The quality of cashmere and its influence on textile materials produced from cashmere and blends with superfine wool”, PhD thesis, The University of New South Wales. McGregor, B.A. and Postle, R. (2002), “Single yarn knitted fabrics produced from low and high curvature superfine Merino wool”, Wool Technology and Sheep Breeding, Vol. 50, pp. 691-7. McGregor, B.A. and Toland, P.C. (2002), “Fibre-curvature and staple-length relationships in a low staple-crimp-frequency, fine-wool Merino flock”, Wool Technology and Sheep Breeding, Vol. 50, pp. 819-25. Madeley, T., Postle, R. and Mahar, T. (1998), “Physical properties and processing of fine Merino lamb’s wool. Part 1. Wool growth and softness of handle”, Textile Research Journal, Vol. 68, pp. 545-52.
Nesti, G. (1989), “The spinning of cashmere on the worsted and woollen systems”, Proceedings 3rd International Cashmere Conference, Adelaide, Australian Cashmere Growers Association, Guildford. Smith, G.A. (1987), “Breeding, fibre morphology and effects during processing”, Proceedings 2nd International Cashmere Conference, Lincoln, New Zealand, Agtell Public Relations, Christchurch, pp. 165-71. Smith, G.A. (1992), “Letter to the Editor”, Cashmere Australia, Vol. 13 No 2, p. 5. Swan, P.G. (1994), “Fibre specification and staple structure”, Woolspec 94, G1-12, CSIRO, Sydney. van Wyk, C.M. (1946), “A study of the compressibility of wool, with special reference to South African Merino wool”, Onderstepoort Journal of Veterinary Science and Animal Industry, Vol. 21, pp. 99-226. Whiteley, K.J., Welshman, S.J., Stanton, J.H. and Pattinson, R. (1986), “Observations on the characteristics of Australian greasy wool. Part VI: the resistance to compression of Merino fleece wools”, Journal Textile Institute, Vol. 77, pp. 1-8. Yang, S., de Ravin, M., Lamb, P.R. and Blenman, N.G. (1996), “Wool fibre bundle strength measurement with Sirolan-Tensor”, Proceedings of Top-Tech 96, CSIRO, Geelong, pp. 293-304.
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Tactile sensory analysis applied to silk/cotton knitted fabrics R. Chollakup Laboratoire de Physique et Me´canique Textiles (LPMT), Ecole Nationale Supe´rieure des Industries Textiles (ENSITM), France Kasetsart Agricultural and Agro-Industrial Product Improvement Institute, Kasetsart University, Bangkok, Thailand
A. Sinoimeri, F. Philippe, L. Schacher and D. Adolphe Laboratoire de Physique et Me´canique Textiles (LPMT), Ecole Nationale Supe´rieure des Industries Textiles (ENSITM), France Keywords Sensitivity analysis, Silk Abstract Currently, textile industrialists have to consider the sensory aspect in their design and manufacturing specifications. To describe the sensory quality of products, sensory evaluation does exist and is widely used in the food and cosmetics areas. These methodologies have been successfully transposed to tactile evaluation of textile fabrics for different textile materials: plain weave fabrics with different post-treatments and non-woven are used for medical gowns and drapes. In our study, we have asked our trained panel composed of nine assessors to score a list of already defined sensory attributes for different knitted fabrics made of silk/cotton blends. The spinning parameters which have been changed are the type of silk fibre (three types), blending techniques – intimate and draw frame blending – and the silk content. All these parameters can more or less influence the tactile perception of the final knitted fabric. In this paper, the results of our analysis are presented and discussed in order to answer questions such as: “Are these two fabrics different?”, “What kind of difference is there?” or “What are the sensory characteristics of these fabrics?”. The concrete steps of the evaluation will be presented and specifically the training and performance analysis of the panellists who were obliged to adapt their evaluation procedures to small knitted samples. The protocols used to carry out fabrics description and comparisons when all assessors cannot evaluate all the products under study will also be detailed.
1. Introduction In the textile research domain, sensory analysis is very interesting to evaluate the handle of textile fabrics composed of different materials including the blended materials. Tactile sensory analysis for textile fabrics has been carried out mainly through “hand evaluation” with devices such as the Kawabata evaluation system for fabrics (KES-F) (Kawabata, 1980) and fabric assurance International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 132-140 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520423
Spinning processes have been carried out at Ecole Supe´rieure des Industries du Textile et de l’Habillement, Casablanca, Morocco and sensory analysis has been conducted in collaboration with Inge´nierie Mole´culaire et Sensorielle des Aliments et des Produits de Sante´ – UA/UPR ES 581 – Ecole Nationale Supe´rieure de Biologie Applique´e a` la Nutrition et a` l’Alimentation in Dijon (France).
by simple testing (FAST). Many researchers attempt to find the relationships between subjective and objective measurement (Alimma et al., 2000; Cardello et al., 2003; Niwa et al., 2001; Postle and Dhingra, 1989; Raheel and Liu, 1991; Yi and Cho, 2000). It can be proved that tactile sensory analysis is a reliable method used for routine textile testing. Especially, silk fabric which has always been regarded as excellent material in terms of softness, elegant, luster, good resilience and drape, as well as silk scrooping sound have been evaluated by tactile qualities for a long time. However, the fabric handle measurement has often been used only for the silk filament materiel. In the present study, three silk wastes from silk reeling industry as fibre staple – inferior knubbs (SK), filature gum waste (SW), and pierced cocoon (SC) – are considered to be blended with cotton fibre to produce the blended yarn in the cotton spinning system. They represent an outer, middle and mixed portion of the cocoon whose filaments are, respectively, the finest, coarsest and mixed ones. Silk wastes are prepared to be as staple fibres after passing through the preparation processes of degumming, bleaching, drying, conditioning, opening, carding and cutting into 35 mm cut length (Chollakup et al., 2002). Other parameters of the blending factors, such as the blending methods and silk proportions, are also considered in order to understand their influence and importance (Hamilton and Cooper, 1958) for the blended yarn. Two blending methods, intimate blending (Int, before carding) and drawframe blending (Dr) are proceeded with different silk proportions (25, 50 and 75). The purpose of this paper is to study the influence of these blending factors on the ring spinning system, on the blended fibres and yarn characteristics, and especially on the knitted fabrics produced with these yarns by sensory analyses methodologies in order to objectively describe the tactile feeling of these knitted fabrics. 2. Materials and methods 2.1 Blending and spinning processes The physical properties of silk and cotton fibres are given in Table I. Two blending techniques, the intimate and drawframe blending, using silk and cotton fibres at different ratios of 25/75, 50/50, 75/25, as well as the pure component materials are proceeded in the industrial scale machines at Ecole Supe´rieure des Industries du Textile et de l’Habillement, Casablanca, Morocco. Yarns of 30 tex yarn count with a twist factor aNm of 110 are spun in the laboratory scale in a Spintester at ENSITM-LPMT. For pure silk and drawframe blended yarn, it is necessary to add a softener to the silk to prevent an electrical phenomena during carding and drawing processes. The full factorial combination of the spinning factors gives 22 yarn types (two blending types £ three silk waste types £ three silk proportions and four pure components). All these yarns are knitted into weft plain jersey fabrics with stitch lengths of 0.365 cm/stitch using a circular knitting machine. The fabrics are treated to remove the softener that could influence the tactile characteristics
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Silk fibre Inferior knubbs Filature gum Pierced cocoon Cotton (SK) waste (SW) (SC) fibrea (HVI) Length (Peyer’s Almeter AL) Mean length (ML, mm) Upper half mean length (UHML, mm) Fineness (ASTM-D 2130) Fineness (mtex)
Table I. Physical properties of the silk waste and cotton fibres
Strength (ASTM-D 2524) Tenacity (cN/tex) Elongation at peak (per cent) Elongation at break (per cent)
21.1^ 0.6
19.4 ^ 1.6
24.8 ^ 1.2
23.9 ^ 0.6
37.0 ^ 1.6
36.2 ^ 2.8
46.0 ^ 1.2
28.6 ^ 0.5
136
165
156
175
23.9 ^ 1.8 14.0 ^ 0.9 24.7 ^ 1.5
25.6 ^ 1.4 13.6 ^ 0.7 25.7 ^ 2.1
23.2 ^ 1.5 13.3 ^ 0.9 25.8 ^ 2.3
27.3 ^ 1.0 5.4 ^ 0.2 –
Note: aOnly for the cotton fibre, the physical properties are measured using HVI instrument.
using 0.25 per cent wetting agent and 0.2 per cent NaOH (388Be, pH 9) at 758C for 45 min, then washed in water at 808C until pH 7. The fabrics are dried in room atmosphere for 2 days and cut into 20 £ 20 cm swatches. Then all fabrics are subjected to full relaxation using a relaxation vibration machine at 50 Hz following the standard method of AFN G07-102. The fibres (after the last drawing frame), yarn samples and the knitted fabrics are conditioned for at least 24 h at standard conditions of 20 ^ 28C and 65 ^ 2 per cent relative humidity before testing. The blended fibre is characterised by the fibre length, tenacity and elongation, and sliver cohesion. The yarn unevenness and mechanical properties are evaluated following the standard method of ASTM by UT3 device and Tensorapid. The dimensional properties of knitted fabric – wales/cm, courses/cm, stitch length, thickness, and weight – are also measured following ASTM. The data are statistically analysed at a 95 per cent confidence level by one-way ANOVA, and also by three-factor ANOVA design to study the influence of blending factors. 2.2 Sensory analysis The sensory analysis is a particular tool which needs procedures with strict tests to obtain a good reliability for the results (sensory attributes) by limiting the problems linked with perception. The methodologies dedicated to the sense of the taste have been transposed to the tactile sensing (Philippe, 2002). The results obtained are based on the work of a trained panel composed of nine assessors who have first chosen by consensus (NF ISO 11035, 1995; Stone et al., 1974) the appropriated attributes to describe the tactile perception of textile fabrics (a minimum attributes, which will allow one to give the maximum amount of information). Later on, assessors have been trained to quantify each attribute in a reliable way after 28 sessions. Then the sample sizes of training procedure are
changed from 22 £ 35 (method of Philippe, 2002) to 20 £ 20 cm to be appropriated with knitted fabric size. Hence, a second training procedure needs to be carried out again in this fabric size. Two knitted fabrics are tested all along the sessions in order to evaluate the proficiency of the panel. The trained assessors evaluate some 15 descriptors of the fabrics retained by consensus in an earlier work (Philippe, 2002) and rank them into a non-structured scale. The obtained results can be displayed under specific visualisations. The so-called “profile” is the simplest and the most commonly used. It represents, for one or several product(s), the relevant attributes versus their intensity and expresses its tactile description. Moreover, the principal component analysis (PCA) is used to simplify the complex data representation and interpretation by considering the correlations between the attributes. So, it is possible to seek out factors or components in which the attributes have a great deal in common, and to highlight the product similarities and/or differences. Some statistical tools using the scores given by assessors to describe the fabrics are used. The tools classically used are ANOVA, means comparisons and PCA (Depledt, 1998) using the Tastel software version 2001 (ABI Informatique, France).
3. Results and discussions 3.1 Blended bundle fibres and yarns characteristics For all pure component yarns, the one way ANOVA (Table II) shows that the cotton yarn has the same CV per cent as the silk yarns, except for the filature gum waste (SW) which gives the more unevenness results. The hairiness results show that the cotton yarn is, as it can be expected, less hairy than all silk yarns. However, the mechanical properties of silk yarns show higher tenacity and elongation than the cotton yarn. The global results of blended yarn unevenness and mechanical properties show that the intimate blending provides more yarn regularity and resistance than the drawframe blending (Table II). Regarding the silk type effect, the fibre fineness tends to decrease the yarn unevenness (CV per cent) and increase the tenacity. These results corroborate earlier study (Tsubouchi et al., 1993) relative to the tenacity of the 70/30 silk/cotton blending. Yarn evenness increases with the silk proportion. Matsumoto et al. (1991) found the same tendency in the polyester/silk blending. This result shows that the presence of silk in blended yarn is advantageous. The correlation between the characteristics of the blended bundle fibres at the last passage of drawing process and those of the blended yarn is calculated by the stepwise multiple regression as shown in Table II. It shows that there are two important sliver parameters affecting the yarn characteristics, the sliver cohesion and the bundle fibre tenacity. The sliver cohesion has a reduction effect on the yarn unevenness and increases its tenacity. The grand means of the sliver cohesion calculated for each factor level and the mean
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SK
Silk wastes SW SC
C
Silk proportions 25 50 75
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Tex 30.93a 30.06b 30.87ns 30.08ns 30.53ns CV (per cent) 14.71a 15.69b 14.40a 16.49b 14.71a Hairiness 7.44a 7.63b 7.21a 7.84c 7.57b Tenacity (cN/tex) 14.67a 13.82b 15.12a 13.36c 14.25b Elongation (per cent) 6.29ns 6.30ns 6.52a 5.97b 6.40a One way ANOVA
30.33ns 30.59ns 30.55ns 15.46b 15.16ab 14.71a 7.20a 7.64b 7.77b 13.31b
13.75b
15.67a
5.82c
6.21b
6.87a
Pure components
Tex 30.75ns 29.18ns 29.42ns 32.23ns CV (per cent) 14.91ab 18.18c 14.02ab 15.36b Hairiness 7.66b 8.75d 8.30c 6.99a Tenacity Table II. (cN/tex) 15.96a 16.71a 16.63a 13.79b Factorial ANOVA of Elongation three blending factors 7.68a 7.37a 7.77a 5.78b and one way ANOVA of (per cent) a the pure components on Notes: signifies the best quality in terms of the yarn characteristics compared to b and c the 30 tex yarn , respectively, at p # 0.05 for each factor, one-way ANOVA is carried out for pure components; ns characteristics no significant difference.
values for the pure components, considered as references, support the effects of three blending factors on the yarn characteristics (Table II). 3.2 Sensory analysis Figure 1 shows the average panel data during the first and second repetition after four and ten sessions for one of two knitted fabrics used as control samples. We observe some significant differences in the attribute profiles of the first and second repetition after four sessions (dotted line curves), but a degree of similarity after ten sessions (continue line curves). In order to study the influence of three blending factors on the sensory hand attributes of 22 types of knitted fabrics, each fabric is tested twice and the presentation order is randomised for each assessor (Table III). Two way ANOVA (subject in a random factor and fabric in a fix factor) and interaction subject/fabric has been performed to identify the significant factors for each attributes (Table IV). Eight attributes are significantly different at minimum p # 0:05 including granulous and greasy which have an important subject/fabric interaction. These two attributes appear as relevant after the PCA with a good similarity between six subjects at minimum. The profiles, for eight pertinent attributes, of the pure component fabrics are shown in Figure 2. The cotton fabric is more soft, greasy, elastic and less
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Figure 1. Mean panel ratings of hand attributes obtained from two repetitions after four and ten sessions for one of two control knitted fabric
Yarn characteristics CV per cent Hairiness Tenacity Elongation
UHML 0 + 0 ++
Characteristics of fiber bundles Tenacity Cohesion Elongation at peak ++ + 0 0
2 22 22 +++ 0
0 0 0 0
Notes: 0 means no significant or neglected influence; during stepwise multiple regression; +, 2 means positive or negative significant influence at p # 0.10; ++, 22 means significant influence at p # 0.05; and +++, 2 2 2 ¼ significant influence at p # 0.01.
granulous than the silk fabric. Silk fabric is expected to confer a smooth and soft touch. The smoothness was not one of attributes rated by the panel and for the studied fabrics which have no finishing process except for the washing before the sensory analysis as explained in Section 2.1. The three silk fabrics have likely the same characteristics. The descriptive factor/product matrix is drawn up, from which a PCA is obtained. Figure 3 shows the product map with the first and second principal components. The number of dimensions is reduced from 8 to 2 with still 80 per cent of the total variance explained. Factor 1 contains 46 per cent variability and is composed of the descriptive factors of greasy, slippery, soft and elastic attributes. In this context, the greasy, soft, slippery and elastic attributes are similar concepts and opposed to the granulous attribute, whereas the rigid and crumple-like attributes are opposed to the falling attribute. Owing to the numerous quantities of fabric (22 types), we try to explain the effects of
Table III. The influences of bundle fiber characteristics on the blended yarn quality
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Table IV. Two way ANOVA of knitted fabric on the hand attributes
Figure 2. Product profiles of the pure component knitted fabric
Attribute Cold-warm Falling Thin-thick Light-heavy Supple-rigid Sticky Slippery Soft Granulous Greasy Hairiness Raised Elastic Responsive Crumple-like
F value of fabrics
F interaction subject £ fabrics
0.70 3.14*** 1.60 0.71 2.33** 0.96 2.62*** 3.94*** 1.82* 3.86*** 0.99 1.63* 7.63*** 1.57 2.13**
1.37* 0.99 0.83 0.96 1.19 1.00 0.97 1.13 2.47*** 1.34* 1.04 1.57** 1.13 1.29* 1.10
Notes: *significantly different at p $ 0.05; **significantly different at p $ 0.01; and ***significantly different at p $ 0.001.
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Figure 3. Product map for 22 types of knitted fabrics
the blending factor on the products characteristics using a three way ANOVA with subject factor as a random factor. These results show that the blending methods, the silk types and the silk proportions change the hand feeling of the fabric. The intimate blended fabrics have less falling and are more rigid and crump-like than the drawframe blended fabrics. Concerning the silk type factor, the inferior knubbs – the finer fibre in this study – gives the blended fabrics more soft, greasy and less granulous and crumple-like characteristics than the filature gum waste. Increasing the silk contents generates a more rigid, granulous and less slippery, soft, greasy and elastic behaviour. 4. Conclusion The effect of the blending type in the spinning process, the silk waste types, and the silk content on the silk and cotton blended yarn and fabric characteristics have been studied and also a new tool, called sensory analysis, has been applied. This work shows that this tool, developed mainly by the food industry, is also well adapted to tactile description of knitted fabrics especially the different blended fibre in fabrics. Three blending factors affect the fibre, yarn and fabric characterisations and also distinguished by sensory analysis. The results show that the differences between the products are clearly perceived by the panel. They are significant and affect the final “touch” of the products. The descriptions globally sustained the expected allegations about cotton/silk products. This research can demonstrate how to process the silk and cotton blending and what is the influence of blending factor on the final product for the customer.
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References Alimma, D., Matsuo, T., Nakajima, M. and Takahashi, T. (2000), “Sensory measurements of the main mechanical parameters of knitted fabrics”, Tex. Res. J., Vol. 70 No. 11, pp. 985-90. Cardello, A.V., Winterhalter, C. and Schutz, H.G. (2003), “Predicting the handle and comfort of military clothing fabrics from sensory and instrumental data: development and application of new psychophysical methods”, Tex. Res. J., Vol. 73 No. 3, pp. 221-37. Chollakup, R., Sinoimeri, A. and Drean, J.Y. (2002), “A blending of Thai hybrid silk wastes and cotton in the cotton’s spinning system”, The Fiber Society Fall Technical Meeting, 16-18 October, Natick, MA, USA. Depledt, F. (1998), Socie´ te´ Scientifique d’Hygie` ne Alimentaire (SSHA): Evaluation sensorielle-Manuel me´thodologique, Lavoisier, Paris. Hamilton, J.B. and Cooper, D.N.E. (1958), “The radial distribution of fibres in blended yarns, Part II: factors affects the preferential migration of components in blends”, J. Tex. Inst., Vol. 49, pp. 687-705. Kawabata, S. (1980), Standardization and Analysis of Hand Evaluation, 2nd ed., The Textile Machinery Society of Japan, Osaka. Matsumoto, Y., Tsuchiya, I., Toriumi, K. and Harakawa, K. (1991), “Irregularities of blended yarns in waste silk spinning system”, J. Seric. Sci. Jpn., Vol. 60 No. 4, pp. 263-9. NF ISO 11035 (1995), Analyse sensorielle – Recherche et se´lection de descripteur, France. Niwa, M., Inoue, M. and Kawabata, S. (2001), “Objective evaluation of the handle of blankets”, Tex. Res. J., Vol. 71 No. 8, pp. 701-10. Philippe, F. (2002), “Contribution a` l’analyse sensorielle tactile des produits textiles par analyse sensorielle”, The`se de doctorat en Sciences pour l’Inge´nieur, Universite´ de Haute-Alsace, Mulhouse, France. Postle, R. and Dhingra, R.C. (1989), “Mesuring and interpreting low-stress fabric mechanical and surface properties, Part III: optimization of fabric properties for men’s suiting materials”, Tex. Res. J., Vol. 59, pp. 448-59. Raheel, M. and Liu, J. (1991), “An empirical model for fabric hand, Part I: objective assessment of light weight fabrics”, Tex. Res. J., Vol. 61, pp. 31-8. Stone, H., Sidel, J.L., Oliver, S., Woolsey, A. and Singleton, R.C. (1974), “Sensory evalution by descriptive analysis”, Food Tech., Vol. 28 No. 11, pp. 24-34. Tsubouchi, K., Imai, T., Akahane, T. and Obo, M. (1993), “Relationship between the physical properties of silk-cotton blend fabrics and the size of the cocoon filament”, Bull. Natl. Inst., Seric., Entomol. Sci., Vol. 9, pp. 89-100. Yi, E. and Cho, G. (2000), “Fabric sound parameters and their relationship with mechanical properties”, Tex. Res. J., Vol. 70 No. 9, pp. 828-36. Further reading AFNOR G07-102, 1982, Essais des tricots, me´thode de relaxation et de mesure des variations dimensionnelles a` la relaxation, France.
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The challenge of changing from empirical craft to engineering design
Empirical craft to engineering design 141
John W.S. Hearle UMIST Core Research, TECHNITEX Faraday Centre, Stockport, UK Keywords Textiles, Computer aided design Abstract Textiles have developed high-quality materials on the basis of highly developed but empirical craft skills. The second half of the 20th century resulted in many academic papers on the analysis of the applied mechanics of fibre assemblies. However, although these researches led to useful qualitative insights, there was almost no quantitative application by the industry. Several factors indicate that the time is now ripe for a change to an engineering design culture. There are major challenges in dealing with assemblies of millions of fibres, with non-linear, visco-elastic-plastic mechanical properties, in anisotropic structures subject to large deformations and strains. The paper describes two approaches to accessible model: fibre rope modelling and TechText CAD. The most useful methodology for modelling yarns, woven fabrics and fabric buckling, is discussed. The priority is to develop a software that industry uses, thus setting up a creative interchange, which will lead to advances.
1. Introduction Over 10,000 years ago, early men and women found ways to collect natural fibres, align and twist them into yarns, and interlace them into fabrics, which were used as clothing, shelter and an increasing range of other purposes. The geometrical and mechanical operations of the design engineer, which are at present occupied by computer-aided design (CAD), were subjectively hidden in the links between the mind and fingers. During the time of the ancient civilizations, simple hand-operated tools had been invented for spinning and weaving. Varied yarns and fabric constructions were being made. But apart from some simple sketches, there was nothing that could be called engineering design in the modern sense. The industrial revolution started in the late 18th century brought new power-driven machines to simulate the old processes and modern engineering initiated. Academic research in mechanics, following Galileo and Newton, led to to the growth of a wide range of manufacturing and construction industries in the 19th and 20th centuries of an engineering design culture, at first with slide rules, draughtsmen and Roark and Young’s Formulas for Stress and Strain, and now with CAD. Engineering design came to the textile industry through the development of the academic subject of the mechanics of machines. The wave of machine and process inventions in the second half of the 20th century brought in control engineering design. But, at the heart of the textile industry is
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the interaction of fibres and yarns with machines and the construction of the products, the old intuitive, qualitative practice remained as the industrial practice. Apart from some relatively trivial mathematics concerned with pattern, dimensions, weight and cost, design was an empirical process, based on experience, trial and error. In a remarkable change of culture, the aesthetic side of textile design in pattern and colour has gone in the last 25 or so years from a suspicion of CAD to its common acceptance. Why has the technical side of the industry not had a similar change of culture? Partly, it is due to the strength of the craft-based experience and the fact that trial-and-error is acceptable for most textile uses. It is also due to the difficulties of the subject. As is recognized by applied mathematicians, who have looked at textile problems, there are major challenges in dealing with assemblies of millions of fibres, with non-linear, visco-elastic-plastic mechanical properties, in anisotropic structures subject to large deformations and strains. Extensive textile research, with numbers running into hundreds of people, began in the 1920s. Peirce laid the foundation with characterization of properties and geometry of structures, but there was little applied mechanics analysis until the formation of Fabric Research Laboratories in the 1940s, which led to a proliferation of research. However, there has been little effort on the part of academic researchers, concerned with their PhDs and publications, to make the advances accessible to industry. Consequently, there was no creative interchange between academic innovators and industrial users. The major challenge at present is to bring this creative interchange. Even in companies with large research departments, applied mechanics has poor relation to chemistry and conventional engineering.
2. The state-of-the-art Nine years ago, the author gave the audit of textile mechanics ( Figure 1). The situation has changed little since then and the use of “solved” is somewhat optimistic. One of the problems has been that, while the earlier work treated the basics of the problems in a simplified way, much of the later work has concentrated on elaborating the mathematics, but leaving this based on unrealistic physical assumptions. A typical example is the work on fibre migration of yarns. A model of complete migration runs into the difficulty of multiple occupation of space at the core of the yarn, just as the spokes of a wheel cannot go to a point at the centre. Treloar was followed in avoiding the problem by postulating a limiting central radius. The published attempts to treat the mathematics more rigorously are not useful, because fibres follow the paths of partial migration and that is the real problem to be studied – but it is poorly defined and so unattractive to mathematical purists.
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Figure 1. Audit of textile mechanics
3. Accessible modelling 3.1 Interaction with industry If the textile industry has to move from empirical craft to engineering design, the priority is to develop a software that is taken up by the industry and easily used. This is most likely to be successful if it first addresses the simple operations, which technologists in the industry have to deal with. This will lead to a culture in which solutions of more difficult design needs are called for. In the last few years, the author has been associated two projects which aim to give practical utility to the mechanics of textile structures. 3.2 Fibre rope modeller The first example relates to a demanding engineering application of a textile structure: high-performance ropes to moor oil-rigs in a depth of 1,000-3,000 m. A typical installation might involve 16 lines with a total length of 30 km, made of a polyester rope with a 1,500-tonne break load and a linear density of about 35 kg/m (35 Mtex). The lines are expected to withstand cyclic loading from wind, wave and current action for 20 years – and the consequences of failure would be severe. Interaction with marine engineers, who have programs to model rig responses, has forced rope manufacturers and textile consultants into an engineering design culture. In connection with US Navy plans, not yet put into practice, to moor large floating bases off-shore, Tension Technology
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International (TTI) was contracted to develop software to model the rope performance. With late support from DTI, fibre rope modeller ( FRM ) is at present being used by a major ropemaker in rope design – perhaps, the first example of a numerically predictive mechanical design of a textile product. FRM followed the modelling of twisted continuous filament yarns, which had given good predictions for large-strain, non-linear, load-extension properties, but was extended in several ways. First, it was necessary to consider the multiple twist levels in rope structures. Secondly, the modelling covered the tension-torque-length-twist relations. Thirdly, because of a need to model fatigue behaviour, internal contact pressures, slip and friction forces were included. This work is described by Hearle et al. (1993) and Leech et al. (1993). 3.3 TechText CAD The second example, also supported by DTI and carried out by UMIST and TTI, was the development of more general software, TechText CAD, for use by the technical textiles industry, though it is also applicable to consumer textiles. The DTI grants are aimed at technology transfer, not at new research, so that our aim was to convert some of the academic work on the structural mechanics of textiles into a CAD package that was easy to use and directed at industrial needs. The programs were planned to cover woven, knit and braid structures, but initial progress concentrated on single-layer woven fabrics with a limited amount of work on weft knit structures. The development has been in three parts. At UMIST, X Chen and X Ai covered structural geometry and P Potluri and V S Thammandra covered uniaxial and biaxial deformation. M Overington of TTI was responsible for the overall program integration. As indicated in Figure 2, the program is in a standard Windows format. To open a new weave structure, there are three options. A weave formula is preferred by numerically inclined users. Point paper is the traditional method, which was developed for hand mark-up. With a computer, it is just as easy and more realistic to use a mesh, clicking on a crossover to switch between warp and weft on top. These forms are shown in Figure 2 for a plain weave. Manipulations such as invert, rotate, enlarge, swap or create herringbone and other patterns, are available. The fabric is then defined by yarn dimensions, warp and weft spacing, and one crimp value. A 3D picture is obtained as shown in Figure 3. This model can
Figure 2. (a) Entry of a weave; (b) choice of method; (c) plain weave formula; (d) point paper and (e) mesh
be zoomed in or out, translated, rotated by angle or mouse and sliced to show the section views, as indicated by the different views of the fabric in Figure 3. Currently, the program allows for circular, lenticular or racetrack yarn cross-sections, as shown in Figure 4. This weave structure and geometry facility, in itself, is a relatively simple application of computing, though the development of the programs was not a trivial exercise. There are many similar examples in the literature. The important point is that it puts the operation into a familiar operating system that takes users out of the tedium of making point-paper diagrams, which is still a common practice, into a fast, easy-to-use IT procedure appropriate to the 21st century. Another facility enables the existing point-paper diagrams to be scanned into the system. Mechanical modelling is based on the energy method proposed by Hearle and Shanahan (1978). The methodology and current limitations are discussed later. The program allows for yarn extension, yarn bending and the flattening of yarn cross-sections. Using a procedure successfully used for FRM, large-strain yarn extension is specified by the coefficients of a polynomial, which matches the measured stress-strain curve. Bending stiffness comes from the measured or estimated values. Flattening, which as discussed below, needs more research to be introduced by an empirical parameter. As this is a technology transfer exercise, the modelling is limited to plain weaves, since there has been little, if any, analytical studies of the mechanics of more complex weaves. The race-track cross-section, which is a useful model for geometrical predictions, is unsuitable for mechanical modelling because of the high bending
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Figure 3. (a) Montage showing insertion of twill weave in point-paper, yarn and fabric parameters, and 3D view of fabric; ( b and c) other views of fabric, and (d) slice through fabric
Figure 4. Yarn cross-sections: (a) circular; ( b and c) race track, and (d) lenticular
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Figure 5. (a) Input of a yarn extension, and (b) computed biaxial deformation
Figure 6. (a) Uniaxial loading with warp extension and weft contraction and (b and c) 3D model under zero load and uniaxially loaded
energy at the sharp corners, which exceeds the reduction in bending energy in the straight sections. Circular, for which a Poisson’s ratio can be used to allow for reduction in diameter, or lenticular, which allows for change of shape as well as volume, is used. Figure 5 shows the input of yarn stress-strain and a computed biaxial deformation. The jump from zero strain reflects the fact that the fabric as specified is not in the stress-free state. In this plot, obtained at an early stage of the work, the adjustment from zero strain does not occur in the computation until the first loading point is calculated. This was changed in later plots. The example in Figure 5 is more easily extensible weftwise than warpwise so that the warp contraction continues due to the high weft extension, even though warp load is increasing. Eventually, some warp extension occurs, probably because yarn extension has become easier. Figure 6 shows a typical uniaxial yarn extension plot, in which warp extends and weft contracts, and the deformation of a 3D model. In this example, the fabric adjusts to zero load by contracting warpwise and extending weftwise. An alternative facility enables the strains to be shown based on the stress-free dimensions. Good agreement between TechText CAD predictions in uniaxial loading and experimental data are reported by Hearle et al. (2001), for plain-weave fabrics in nylon-monofil by Dastoor et al. (1994) and in cotton by Kawabata et al. (1973).
Characterisation of fabrics can be expressed in many ways. Any selected set of independent variables is associated with many dependent variables – and the choice changes. Konopasek, in what led to the commercial program TK Solver, recognized this in modelling Peirce’s woven fabric geometry and developed a network algorithm, which allowed any set of variables to be used as input in order to calculate the total set. TK Solver models are incorporated in TechText CAD in order to make it easier to use. In its current state of development, TechText CAD offers a useful facility for practical use. Many of the limitations are due to lack of knowledge. Current research at UMIST under the TechniTex core research project addresses these problems, some of which are discussed below.
4. Methodology of mechanical modelling 4.1 Problems and procedures The above account describes a way of tackling the most urgent problem in meeting the challenge of changing from empirical craft to engineering design: providing software that industry can use and thus opening the way to a creative interchange between the users and developers. Figure 1 shows that there are a formidable number of problems that require research. The favourable two guiding principles are as follows. (1) We should not be seduced by mathematical analysis, which gives equations to be solved by computing at the end of the process. In the beginning, we should look at problems in terms of how they can best be treated computationally, using graphical and numerical methods to the best advantage. (2) We should adopt a sceptical attitude to the use of software packages that have been designed for other purposes, e.g. finite element programs optimized for modelling the rigid solids. We should look for clever ways that are suited to the behaviour of fibres and fibre assemblies. The general approach should be hierarchical. The properties at a given level are computed from the geometry at that level and mechanical properties at the next lower level, through the sequence fibre ! yarn ! fabric ! macroscopic response. There is an inherent assumption that strains are effectively uniform over the elements involved in the computation. Fibres, yarns and other 1D forms are characterized by the relations between stress and strain in extension, twist and two directions of bending, and planar fabrics by two extension directions, shear, two bending directions and twist. As illustrative examples, the comment on three topics, covering not only the three levels of interaction, but also choosing one that is so well defined that it has been solved and used, one in which mathematics has been dominant and the other in which the use of general engineering programs has been dominant.
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4.2 Yarns and ropes The simplest analysis of the load-extension properties of twisted continuous filament yarns was first derived by Gegauff in 1907 and rediscovered by Platt, 40 years later. It considered four factors of cos u for a fibre at a helix angle u: reduced elongation and increased length; reduced component of tension and increased area of action. Averaging cos4 u from u ¼ 0 at the centre of the yarn to u ¼ a at the surface gives cos2 a as the conversion factor from fibre to yarn for the stress-strain curve. This analysis neglects a number of factors, notably the effect of transverse forces between fibres within the yarn. In 1950, force-equilibrium models were developed which considered these factors. The mathematics was not difficult, but was complicated. One predictive equation comprised five lines. However, the major limitation was that the analysis was limited to small-strain, linear or bi-linear conditions. In 1963, Treloar and Riding presented an energy method that included the effects of transverse forces, lateral contraction, large strains, and non-linear fibre stress-strain relations. Subsequently, the reformulated analysis give five equations that were easily solved numerically on a computer. Agreement between the experiment and theory was excellent, except for a slight difference at low stress due to filaments at the core being slightly buckled in real yarns instead of straight as in the ideal geometry. In later analyses, torque and twist were introduced. This is the basis for the statement in Figure 1 that the mechanics of twisted continuous filament yarns has been “solved”. The crucial step was the change from force-equilibrium to energy methods. Solutions by energy methods can be obtained in three ways. The direct methods depend on the conservation of energy, which was the basis of the above treatment, or on the condition that equilibrium is a minimum energy state. In order to determine the internal forces in ropes, described in Section 3.2, Leech et al. (1993) introduced the Principle of Virtual Work. 4.3 Woven fabrics The majority of papers on woven fabric mechanics have been based on force-and-moment equilibrium, with Kawabata’s saw-tooth approximation being widely used. The mathematical derivations are extensive. Leaf, as described in his paper at this conference, and his colleagues and De Jong and Postle have used energy methods, but in a strongly mathematical form. There are severe limitations to these methods, both in terms of restrictive assumptions in the structural mechanics and in the range of fabrics, mostly restricted to plain weave. According to the author, a more direct approach to modelling by an energy method is preferable. The aim at this hierarchical level is to determine the constitutive relations, probably stored as a numerical database, for a fabric subject to uniform strain.
total energy of a fabric subject to a given set of forces ¼ potential energies of applied forces + yarn tensile strain energy + yarn bending and twisting energy + yarn flattening energy The other inputs needed are the geometry of the structure and a suitable numerical minimisation routine. For elastic systems, energy minima are clearly defined. For inelastic or frictional systems, there will be stable states when both positive and negative deformations lead to an increase in energy. A particular advantage of this approach is the separation of terms, which means that they can be considered individually, thus avoiding most of the complications of interactions, which are unavoidable with force methods. The potential energy terms are products of power or moment and displacement, F £ x or M £ u: Tensile strain energy is known from the experiment or yarn modelling. Yarn bending has been extensively considered in the published work, sometimes involving the use of elliptic integrals to determine elastica paths. In principle, it is well understood that bending energy is given by the integral of the product of bending moment and curvature. Twisting would need to be taken into account when yarns follow 3D paths. A practical problem is that for a yarn of N filaments, the bending stiffness can vary over an N 2 range depending on where the yarn lies between a solid rod and a set of independent filaments. In contact zones, the curvature is partly determined by the yarn bending stiffness, which will be affected by the contact forces, and partly by the resistance to flattening of the crossing yarn. This leads to an aspect of the problem that has been unduly neglected in the past: the effect of yarn flattening on woven (and knit) fabric mechanics. Some clever research is needed both to develop qualitative understanding of the effects and to find the best way of treating it. For monofilaments and perhaps for hard-twisted yarns, it may be adequate just to assume a reduction in diameter at constant volume. For less cohesive yarns, where fibres can move laterally, the problems are more difficult. One approach is to assume a particular yarn shape and then relate flattening energy to the ratio of major and minor axes. As mentioned earlier, racetrack geometry is unsuitable, but lenticular can be used. One problem is how to obtain of the flattening coefficient. The other is that, even for plain weave fabrics where flattening is orthogonal, the assumed geometry may be insufficiently realistic. For non-plain weave fabrics, the “flattening” (really change of area and shape) is multiaxial. The mechanical modelling may be more successful if it is less prescriptive. The state of a fabric can be defined by the positions of yarn centres at a limited number of positions. For a simple plain weave in planar deformation, three positions, one of which is an origin, are sufficient; for out-of-plane deformation,
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two more are needed. In more complicated weaves, some positions within a repeat unit must be included. Yarn extension, bending, twisting, and flattening could be related to the changes in position of the defining points. This provides a framework for an approach to energy minimization. In the simplest application of such a model, a set of linear coefficients could be used to give each energy term. A more complete model could define each term by a set of polynomial coefficients. This has been done successfully for yarn extension. With regard to bending and twisting, where there is a knowledge base, and more importantly in the neglected area of yarn flattening, the research challenge is to find the best way to determine the necessary relations either experimentally or by theoretical yarn modelling. Such an approach divorces the mechanics from any explicit geometry. The role of research in the geometry of fabric structure, which may be needed for purposes such as determination of flow paths, is then to find a suitable geometric model that adequately fits the state of the fabric as given by the specified positions, even if it is not exactly correct in mechanical terms. Some more innovative research may find ways of linking yarn shape to the mechanics. For example, the use of a soft rubber rod or a flexible tube with a soft filling might be effective analogues of a soft yarn; this is a place, where a finite-element package might be useful as a subprogram. 4.4 Fabrics in double curvature A great advantage of textile fabrics when compared with paper and most other sheet materials is that, because of their low resistance to shear and area change, they can deform smoothly in double curvature. This is important in drape and handle of consumer textiles and in conformability of textile preforms for composites. The closest approach to this problem in conventional applied mechanics is plate and shell theory, but this is inadequate to treat the subtleties of textile fabrics. A solution to this problem is needed to achieve a goal of the IT age, the virtual catwalk. The aim is to enable someone buying an article of clothing online to view on a screen how they would really look when moving around in the garment. It is worth noting that there are three levels of reality in such simulations. In cartoons, unrealistic distortion is preferred. For realistic animation, in which film-makers have achieved great success, it is only necessary that the image should look right to the viewer. The third level, which is our concern, is to relate the fabric forms to the actual fabric properties and applied forces. This is much more difficult and some IT specialists, who came optimistically to the problem have retreated. Leaving on one side the dynamic problem, the first step is to model the quasi-static buckling of textile fabrics in complex situations. Most researchers have attempted to solve the total complex problems by the use of finite-element or similar methods. However, such programs are not
designed to tackle the full anisotropy and non-linearity of textile fabrics. The models are thus restricted in their validity, as well as being horrendously expensive in computer power and time. They have not provided practically applicable ways of meeting the commercial needs. According to the author, more fundamental approach is needed. The problems should be tackled from the bottom up not the top down. Research should elucidate the basics of how fabrics buckle in three-dimensions, and find clever ways, which are right for textile fabrics, to build up to the more difficult problems. The simplest case, which was addressed by Amirbayat and Hearle (1986), is buckling of a circular specimen pushed in equally from three equilateral directions. This can be modelled, in a reasonable approximation to reality, by a central dome of double curvature and an outer zone of alternating folds of single curvature. Distorted versions of such a form make up the complex patterns of buckling of fabrics on the sleeves of jackets and in many other situations. The problem has to be solved by minimising the sum of the fabric strain energies of the double curvature zone (in-plane and out-of plane) and the single curvature zones plus gravitational potential energy. The treatment by Amirbayat and Hearle is limited by mathematical approximations, geometry, symmetry and linear elasticity, though accepting the independence of tensile and bending properties, which means that EI does not define bending stiffness. I there is little doubt that better ways of treating the problem could be found, but the approach leads the way to deal progressively with more realistic input of fabric properties and more complicated modes of deformation – and then, hopefully, to practical CAD software.
5. Conclusion The author apologises for any arrogance in dismissing the last 60 years’ research on structural mechanics of textiles, to which he contributed in ways that he would not currently want to follow. However, he presents a clear message on how to meet the challenge of changing from empirical craft to engineering design. . The priority is for academia and IT groups to develop a software that industry would use – and for industry to take it up – thus providing a productive creative interchange. . Some knowledge is ready for technology transfer, but many problems require more research. . Researchers should concentrate on direct computational procedures that are appropriate to the complex behaviour of fibre assemblies and based on simple relationships – and beware of the temptations of complicated mathematics and of software optimized for other materials.
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Approach the total problems hierarchically, with energy methods usually being best. A similar approach is needed to model the interaction of fibres with machines in processing.
References Amirbayat, J. and Hearle, J.W.S. (1986), “The complex buckling of textile materials. Part I: theoretical analysis. Part II: experimental study of theoretical buckling”, Int. J. Mech. Sci., Vol. 28, pp. 339-58, 359-70. Dastoor, P.H., Ghosh, T.K., Batra, S.K. and Hersh, S.P. (1994), “Computer-assisted structural design of industrial woven fabrics. Part III: modelling of fabric uniaxial/biaxial load-deformation”, J. Text. Inst., Vol. 85, pp. 135-57. Hearle, J.W.S. (1994), “Fabric mechanics as a design tool”, Textile Horizons, pp. 12-16. Hearle, J.W.S. and Shanahan, W.J. (1978), “An energy method for calculations in fabric mechanics, Part I: principles of the method. Part II: examples of the application of the method to woven fabrics”, J. Text. Inst., Vol. 69, pp. 81-91, 92-100. Hearle, J.W.S., Parsey, M.R., Overington, M.S. and Banfield, S.J. (1993), “Modelling the long-term fatigue performance of fibre ropes”, 3rd ISOPE Conf., Vol. II, Singapore, pp. 377-83. Hearle, J.W.S., Potluri, P. and Thammandra, V.S. (2001), “Modelling fabric mechanics”, J. Text. Inst., Vol. 92 No. 3, pp. 53-69. Kawabata, S., Niwa, M. and Kawai, H. (1973), “The finite-deformation theory of plain-weave fabrics. Part II: the uniaxial-deformation theory”, J. Text. Inst., Vol. 64, pp. 47-61. Leech, C.M., Hearle, J.W.S., Overington, M.S. and Banfield, S.J. (1993), “Modelling tension and torque properties of fibre ropes and splices”, 3rd ISOPE Conf., Vol. II, Singapore, pp. 370-6.
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Handling evaluated by visual information to consider web-consumers
Visual information
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Sasaki Kazuya, Ikeda Naomi and Shimizu Hiroko Faculty of Education, Utsunomiya University, Utsunomiya-shi, Japan Keywords Internet, Electronic commerce, Textiles, Sensory perception Abstract As the Internet has wide use, it is expected that the opportunities of buying fabrics at online shops will increase. Can Web-consumers catch and evaluate the texture and handling of the fabrics correctly? The aim of this study is to obtain fundamental data for evaluation of the handling of fabrics by visual sensation. Empirical knowledge is important for the evaluation. A questionnaire about the knowledge and image of the fabrics and the experience of buying fabrics at online shops was carried out. As for the handling of fabrics by visual sensation, sensory inspections were performed on 13 fabrics using the Semantic Differential method. As a result, it was difficult to evaluate the handling by visual sensation from fabrics’ pictures on a computer. Though it was difficult, if the images of fabrics have been established earlier, the handling can be caught by visual information.
1. Introduction As the Internet in connection with development of the information technology has wide use, it is expected that the opportunities of buying apparel products at online shops will increase. In this paper, we call the consumer who buys products by using the Internet as a web-consumer. When we usually buy apparel products, visual and tactile information like colour, shape, texture and handling of the fabrics are considered very important. However, web-consumers must evaluate the texture and handling of fabrics only by visual sensation on a computer display without touching them. Ordinarily, they are evaluated by both visual and tactile sensation. Especially, visual sensation is very important for the evaluation. Even the evaluation of the handling depends mainly on visual sensation (Kobayashi, 1990). The visual capture phenomenon, that is the predominance of visual sensation over tactile sensation, in evaluating the handling of fabrics has been clarified (Nishimatsu and Sakai, 1990). In this study, since we considered the importance of empirical knowledge for the evaluation, a questionnaire about the knowledge and image of fabrics and about the experience of buying fabrics at online shops was carried out. As for the evaluation of the handling of fabrics by visual sensation, sensory inspections were performed by the Semantic Differential method. Finally, we aimed at obtaining the fundamental data for the evaluation of the handling of fabrics by visual sensation by comparing the results of the questionnaire with the sensory inspections.
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2. Methods 2.1 Questionnaire We obtained the information about the subject’s knowledge and image for fabrics and about the actual conditions of the use of online shops by means of a questionnaire. The questionnaire was carried out from October to December in 2001 on Utsunomiya University students. We obtained 209 effective samples. The contents of the questionnaire were: (1) their knowledge and image about fibers; (2) their knowledge and image about fabrics; (3) fibers used for their own clothes; (4) the important factors of buying clothes and the reasons of their importance; and (5) the actual conditions and the experience of dissatisfaction in the use of catalog sales and online shops. For the underlined questions above, the subjects answered freely. The other questions were answered by choosing options. 2.2 Sensory inspections When using online shops, web-consumers have to decide to buy or not to buy clothes by the information on a computer. Therefore, if the handling of fabrics imagined by the visual sensation differs with that of the actual fabrics then it creates a problem. To investigate this, sensory inspections were performed. Thirteen fabrics were used as samples. The samples are shown in Table I. All samples were white. The subjects were 31 students from 19 to 22 years of age. The subjects evaluated handling of fabrics according to the ten paired image words shown in Table II. They rated the fabrics into seven categorical scales from 23 to +3. At the end of each inspection, a discriminating test of the fiber and fabric name was carried out. As the subjects were not informed of the name of the fiber and fabric of the samples, they answered by guessing. All the 13 fabrics were inspected in random order. The sensory inspections were performed in four ways: (1) only the visual sensation of the pictures of the fabrics on a display; (2) only the visual sensation of the actual fabrics; (3) only the tactile sensation of the actual fabrics; and (4) both visual and tactile sensations of the actual fabrics. The details of the four inspections are described as follows. (1) Visual sensation on a display. A two-dimensional picture of a 4 cm square of the fabric and a picture of the draped fabric were presented to the subjects on a display simultaneously (as shown in Figure 1) and the
MIU ( £ 102 1) No.
MMD ( £ 102 2)
Thickness Weight (mm) (g/m2) Warp Weft Warp Weft
Fabric
S1 Wool flannel (Nylon 10 per cent) S2 Silk habutae S3 Silk satin S4 Linen plain weave S5 Lyocell plain weave S6 Polyester taffeta S7 Polyester SHIN-GOSEN plain weave S8 Cotton broad S9 Cotton twill S10 Cotton satin S11 Cotton gauze S12 Cotton corduroy S13 Cotton towel
Young’s modulus (MPa) Warp
Weft
Visual information
155
0.69
227
2.16
2.36
1.04
1.21
29.0
32.7
0.13 0.16 0.27 0.24 0.10 0.24
60 71 124 108 69 101
2.31 2.14 1.99 0.97 1.35 1.12
2.21 1.76 0.91 0.62 0.98 1.31
1.15 0.88 0.68 1.97 0.87 0.75
1.05 0.96 0.52 1.76 0.56 0.70
5595.2 4636.5 6265.9 1694.1 3689.7 354.0
4080.3 1205.7 1392.2 1217.2 3276.6 225.2
0.26 0.53 0.21 0.27 0.89 1.33
104 264 88 34 238 310
0.96 0.34 0.83 2.94 1.36 4.27
0.91 0.55 0.81 3.03 0.96 2.39
0.64 4.07 0.78 1.17 2.29 1.71
0.87 0.96 0.95 1.18 1.36 0.99
739.7 1900.2 515.5 409.7 3398.3 748.1 Table I. 365.5 232.0 217.3 89.1 The samples for sensory inspections 34.5 29.1
No.
Very 23
1 2 3 4 5 6 7 8 9 10
Warm Hard Thick Hard to slide Coarse Rough Heavy Rigid Bad handling Dislike
Neutral ^0
Very +3 Cool Soft Thin Easy to slide Smooth Fine Light Flexible Good handling Like
Table II. Paired image words
Figure 1. Display images
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subjects evaluated them. From the results of the preliminary experiment, we added the picture of the draped fabric to give three-dimensional information. The draped fabric was formed by putting a round fabric with a diameter of 25.4 cm on a column with a diameter of 12.7 cm. These pictures were taken with a digital camera under the natural light. (2) Visual sensation of the actual fabrics. The subjects evaluated the handling only by looking at a 30 cm2 of the actual fabric. (3) Tactile sensation of the actual fabrics. The subjects evaluated the handling only by touching a 30 cm2 of the actual fabric in a box. (4) Both visual and tactile sensations. The subjects evaluated the handling by looking at and touching a 30 cm2 of the actual fabric simultaneously. Inspections 1, 2 and 3 were performed in random order. Inspection 4 was performed last. 3. Results and discussion 3.1 Actual conditions of consumer for fibers and fabrics The results from the questionnaires were as follows The rate of the fibers which were known and owned is shown in Figure 2. Natural fibers were widely known. Of all the samples, cotton was best known. Most subjects owned cotton clothes. Figure 3 shows the image of cotton: “high water absorption”, “for general use” and “for under-wear”. Cotton is thus known as a material of daily clothes and under-wear and it is the most familiar fabric. As most subjects owned
Figure 2. The fibers known and owned
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Figure 3. Images of cotton fiber
cotton clothes, it is considered that they have a concrete image of cotton fiber from their daily experience. Although linen, silk and cashmere were less owned, a concrete image was established, the same as for cotton. Synthetic fibers, such as nylon, polyester and acrylic fiber were also known well. Other synthetic fibers, such as SHIN-GOSEN and lyocell, and acetate rayon were hardly known. As for the fabric names, towelling and gauze were well known for their characteristic appearance and touch. However, only about 12 per cent of the subjects knew about broad cloth, twill and flannel in spite of their wide use. This is because very few of the subjects are interested in and are conscious of these fabric names. As an example, the image of gauze is shown in Figure 4. Their image was in the order of “soft”, “medical goods” and “clean”. Gauze is recognized as a medical supply. The image of towelling was also obtained easily because of its general use in our daily life. In fact, they mentioned the handling as “good touch”, “light” and “soft” (Figure 5). Satin and corduroy were also known comparatively well.
Figure 4. Images of gauze
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Figure 5. Images of towelling
Figure 6 shows the result of important matters considered when buying clothes. Both touch and appearance were important. The touch was a little more important than the appearance. Consequently, subjects usually seem to consider both visual and tactile sensations when they select clothes. How many people are using catalog sales or online shops? In this research in Japan, 5 per cent of the subjects used them often and 29 per cent used them occasionally. In other words, more than 60 per cent were negative to their use although Internet users have increased recently. However, it is clear that the social infrastructure of Internet and information technology will be built in the future. Thus, the opportunities of using online shops will increase as a consequence. About 76 per cent of the subjects who were using catalog sales and online shops had the experience of some dissatisfaction. The reasons for dissatisfaction are shown in Figure 7. They were in the order of “ill fitting in size”, “unexpected texture” and “unexpectedly thin”. Since web-consumers cannot try on clothes, there are many possible troubles. Furthermore, they cannot obtain an accurate image of fabrics from a computer display.
Figure 6. Important matters when buying
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Figure 7. The reason of failure using catalog sales and online shops
3.2 Analysis of handling evaluated by visual sensation The results of the sensory inspections of wool flannel are shown in Figure 8 as an example. Wool flannel was evaluated as warm, thick and heavy in the four inspections. It is easy to catch the woollen feature of flannel. However, there was some difference between the evaluation by the visual sensation on a display and by other ways, even for such a characteristic fabric. Evaluation only by the visual sensation on a computer display was considered to be a little different from the actual handling.
Figure 8. Results of sensory inspection of wool flannel
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Figure 9. The score of the image word of “thick” - “thin”
The difference of the scores of “cool-warm”, “thin-thick” and “light-heavy” of wool flannel between the evaluation by the visual sensation on a display and the evaluation by other ways was a little larger than that of the scores of the other image words between them. Figure 9 shows the score of the image word of “thin-thick” for all the samples. Polyester taffeta was evaluated thicker by the visual sensation on a computer display than by other ways. However, polyester taffeta was the second thinnest of the samples when the subjects were evaluated only by the visual sensation of the actual fabric. Actually, polyester taffeta was the thinnest of all the samples, as shown in Table I. Especially, it was shown that judging the thickness of linen, lyocell and polyester taffeta on a display was very difficult. The difficulty of the evaluation of thickness only by the visual sensation was supported by the results from the questionnaire which showed that “unexpectedly thin” was one of the common dissatisfactions when buying clothes using catalog sales and online shops. On the discriminating test of the fiber name, the rate of the correct answer of all the cotton fabrics was high. This is because cotton is the most familiar fabric. The results of cotton towelling are shown in Figure 10 as an example. The rate of the correct answer of towelling was about 70 per cent in all of the four ways and was the highest of the 13 fabrics. It was high even by the guess on a display and was also high in the case of wool flannel and silk satin. On the other hand, the rate of silk habutae was only 25 per cent. If the fabrics have a characteristic surface such as cotton towelling, wool flannel and silk satin,
Visual information
161 Figure 10. Results of the discriminating test of the fiber name of “cotton towelling”
web-consumers can judge the fabrics correctly from the information on a display. As for the fabric name, the rate of the correct answer of towelling, corduroy and gauze was high. The results of cotton gauze are shown in Figure 11 as an example. Subjects have strong images about these fabrics in the questionnaire as shown in Figures 4 and 5. The feature of these fabrics seems to be easy to understand. On the other hand, the rate of the correct answer of silk habutae and polyester taffeta was low. It seems that subjects are not conscious of these fabric names in their daily life as mentioned in the results of the questionnaire. The rate of the correct answer guessed only by the visual sensation of the actual fabrics was a little higher than that of the correct answer guessed only by the tactile sensation of them as shown in Figure 11. The other samples showed the same tendency. The visual information supported by experience greatly affects the ability to judge the fabrics correctly.
Figure 11. Results of the discriminating test of the fabric name of “cotton gauze”
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4. Conclusions In the questionnaire, it was shown that both touch and appearance were considered important when buying clothes. However, web-consumers have to judge the texture and handling of clothes and other textile items only by visual information on a computer display. Actually, they had the experience of some dissatisfaction in selecting the fabrics by the use of online shops. The results of the questionnaire also showed that subjects have concrete images of fibers and fabrics that have distinctive features and are widely used in daily life. From the sensory inspections, some difference was shown between the evaluation of the handling by the visual sensation on a display and that of the handling by the other ways. The evaluation only by the visual sensation on a computer display was considered to be a little different from the actual handling. It is very difficult to catch the accurate texture and handling of textile items only by pictures on a display. Though it is difficult, if the images of the fabrics have been already established through the experience, the texture and handling can be caught by the visual information. The three-dimensional images, such as a picture of a draped fabric, can also give a more accurate image to web-consumers. Online shops need to offer high quality visual information of their products on a display. Furthermore, not only the visual information of the items, but also the knowledge and image of the fiber and fabric for clothing materials is very important to catch the texture and handling of textile items when buying clothes at online shops. Finally, it is desirable that web-consumers are interested in clothing materials and have the concrete images of their texture and handling. Nowadays, children have few opportunities to make things themselves. As we are members of Department of Home Economics Education, we should develop teaching materials that will help the students to learn the relation between virtual reality in computer networks and actual reality through real experience. References Kobayashi, S. (1990), “Senses and fabric hand”, Sen-i Gakkaishi, Vol. 48, pp. 253-8. Nishimatsu, T. and Sakai, T. (1990), “Visual sense and hand”, Sen-i Gakkaishi, Vol. 48, pp. 265-70. Further reading Ikeda, N., Sasaki, K. and Shimizu, H. (2002), “Handling evaluated by visual sensation for web-consumer”, ITE Technical Report, Vol. 26 No. 70, pp. 5-8.
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Modelling strategies for liquid spreading in medical absorbents
Modelling strategies
163
M. Landeryou Department of Medical Physics, University College London, London, UK
I. Eames Departments of Mechanical Engineering and Mathematics, University College London, London, UK
A. Frampton Department of Physics, University College London, London, UK
A. Cottenden Department of Medical Physics, University College London, London, UK Keywords Fibres, Fluid dynamics, Modelling Abstract The use of validated computational models to predict liquid spreading in fibrous materials is an important tool for understanding and optimising the function of absorbent products. The aim of this paper is to review these modelling strategies and their limitations. Experimental methods to find the closure relationships required as an input into Richards’ equation (which describes the fluid transport in porous materials) are discussed. The computational models are validated against the detailed laboratory experiments of the flow of fluid from sources on inclined or horizontal homogeneous fibrous sheets, and are extended to inhomogeneous layered structures. Recent progress towards modelling simple incontinence products is described.
1. Introduction Computational models are increasingly finding an important role in the design of medical absorbents such as incontinence pads and wound dressings. The aim of this paper is to review the different modelling strategies applied to describe fluid infiltration and transport in medical absorbents. While some of these techniques are well established for describing liquid transport in soils, they need to be significantly modified for application to fibrous materials which can form viable structures at very low solid fractions (often less than 10 per cent). Also, with the greater exploitation of composite and multi-layered materials to produce specific liquid handling properties, fibrous absorbents generally have an inhomogeneous porous structure. To tackle these problems, and to develop computational models of fluid spreading in medical absorbents, new closure rules or laws need to be developed. Because of the need for validated predictive models of liquid absorption, we attach importance to numerical schemes that are tested against analytical solutions and idealised
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laboratory experiments. We highlight those areas where progress has been made and some of the substantial difficulties that remain to be addressed. This paper is organised as follows. In Section 2, the different modelling techniques based on Washburn’s and Richards’ equations are described. We show that the Washburn model fails to describe a number of important transport processes due to lack of information about the wicking properties of fibrous sheets. We describe some of the challenges of applying Richards’ equation, and in Section 3, how the closure relations are extracted from idealised experiments; these closure relations are then applied in Section 4 to describe spreading in homogeneous materials. Finally, some of the outstanding questions and future challenges are highlighted in Section 5. 2. Modelling methods 2.1 Washburn’s equation The model most commonly applied to describe liquid infiltration into textiles is that of Washburn (1921). Here, liquid is assumed to be driven into the fibrous material in the same manner as liquid is taken up by a circular capillary tube. For a horizontal flow, or in cases where gravity plays a negligible role, Washburn’s equation predicts that the length of the wetted region increases with the square root of time t, according to pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi L ¼ 2K s Cc t: ð1Þ For a circular capillary tube, the advance of the liquid-air interface is determined from the driving capillary force, which is characterised by the capillary pressure at the front of the meniscus, having magnitude Cc ¼ 2gcos u=rc : The viscous drag on the flow is estimated from Poiseuille’s equation and expressed as the saturated permeability, K s ¼ r2c =8m (m is the viscosity of the fluid). The length of the wetted region may be re-expressed as pffiffiffiffiffiffiffiffi L ¼ krc t; ð2Þ where rc is the capillary radius, and k depends only on the fluid properties. Experimental observations of infiltration into a wide range of textiles have confirmed the dependence of L on t described by equation (2) (see the review of Kissa, 1996). Although often used to characterise the wicking potential of textiles, Washburn equation applying the presents a number of problems. Unlike soils where the void volume can be imagined to resemble a series of various sized pore and throat spaces, and liquid movement can be likened to flow through channels, transport in a fibrous structure is dominated by flow around fibres. This makes a physical interpretation of the “capillary radius” in the Washburn model unclear. Gupta (1988), for example, has suggested a geometrical interpretation of the capillary radius in terms of the space between adjacent fibres. Washburn’s equation also suggests that during liquid advance
the material is fully saturated behind the driving interface, whereas experimental measurements in non-woven fabrics and soils indicate a significant variation in moisture saturation within the wetted region. Without appealing to symmetry or introducing some form of network analogy, Washburn’s equation cannot be applied to describe spreading in two-or three-dimensions. Also, without modification, Washburn’s equation cannot be used to model source driven flows. 2.2 Richards’ equation Liquid transport in porous materials such as soils has, for many years, been modelled using Richards’ (1931) equation. Richards’ equation is a semi-empirical formulation based on Darcy’s law, where the rate of volumetric liquid flow is proportional to the driving pressure, and can be used to define the permeability of the material. This law has been experimentally validated for fibrous materials (for example, see van der Brekel, 1989). In unsaturated conditions, the permeability depends strongly on the degree of local saturation, as the size and number of channels available for flow change. Similarly, the fluid pressure driving liquid flow also varies depending on the local saturation conditions. In order to present and model a well posed problem of liquid flow, Richards’ equation must be closed using relationships between pressure (C), moisture level (Q), and permeability (K). For fibrous materials, these relationships must be experimentally determined, and the experimental methods are described in Section 3. For horizontal flow in a one-dimensional sample from an infinite reservoir (located at x ¼ 0) the development of the change in moisture saturation can be expressed using Richards’ equation as: ›Q › ›C ¼ KðQÞ ; ›x ›t ›x
Qðx ¼ 0; tÞ ¼ 1:
ð3Þ
Richards’ equation is a non-linear advection-diffusion equation and in general resort has to be made to numerical methods to calculate the evolution of the moisture profile, though some progress has been made analytically (Landeryou et al., 2003a). Numerical solutions to this equation are subject to a number of problems as follows. (1) The relationship between moisture and pressure must be analytic, so that Richards’ equation can only be applied to situations where the moisture increases and not to draining flows. (2) Most numerical schemes are susceptible to problems of mass loss, especially when the material becomes saturated, requiring the use of mass conserving formulations of the Richards equation (Celia and Bouloutas, 1990).
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Also, small steps are required to produce stable solutions and minimize errors caused by loss of accuracy during computation. To be able to validate numerical schemes and their implementation, analytical solutions to the Richards equation for flow in fibrous materials are also needed. For horizontal wicking, pffiffi Gardner and Mayhugh (1958) applied a Boltzmann transformation ð~x ¼ x= tÞ; to reduce Richards’ equation to: x~ dQ d dC 2 ¼ K : ð4Þ 2 d~x d~x d~x The wetted region increases with the square root of time, as with equation (1). The moisture profiles in the wetted region are similar, only differing in the length scale; a result that has been experimentally verified for liquid distribution in soils and paper (for example, Chatterjee, 2002a). The length of pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi the wetted region for horizontal infiltration is L ¼ l 2K s Cc t=us ; where us is the saturated moisture content. Both Ks and Cc must be determined experimentally and l is less than unity, indicating that spreading is slower than predicted by Washburn due to the presence of partially saturated regions which locally reduce the effective permeability of the material. 3. Closure relations for homogeneous materials 3.1 Microstructure The microstructure of fibrous absorbents differs significantly from that of many of the more commonly studied porous media. Figure 1 shows the cross section through a typical polyester non-woven sheet and illustrates the low fraction of fibres in the sheet. Although materials consisting of only a single
Figure 1. Cross section through a mounted sample of a polyester non-woven fabric. Only 1/3rd of the thickness of the fibrous sheet is shown
fibre type are often considered homogeneous they have distinct microstructural features, for example, locally dense fibrous regions resulting from consolidation during manufacturing, which affect their bulk absorption properties. 3.2 Measurement of the closure relations in fibrous materials To solve Richards’ equation, the relationships between permeability, capillary pressure and moisture content must be determined. Although many relationships have been measured and proposed for soils, none have been established for fibrous materials. The following discussion shows how these are determined and some of the problems experienced. Some of the experimental methods are reviewed by Landeryou et al. (2003b). 3.2.1 Permeability characterization. The permeability is usually estimated from the ratio of the average flow rate to the pressure drop across a sample mounted in a cell. For medical absorbents, fluid tends to be driven along the sheets, rather than through their thickness. A typical absorbent will be less than 1 cm in thickness, and using a flow cell to measure permeability introduces significant interfacial effects. We have found large variations in permeability for measurements made within flow cells depending on the method used to confine the sample. For this reason, the permeability is measured using gravity dominated flows in an unconstrained sample. For unsaturated flows, to find the relationship between permeability and saturation, liquid is introduced at the top of the sample from a fixed flux source (Youngs, 1964). For large time, T, the permeability associated with a moisture level Q is determined through KðQÞrg ¼ LQ=T;
ð5Þ
where L is the distance moved by the wetted front, and r is the density of the fluid. The moisture level is determined by a gravimetric method. The maximum permeability, Ks, corresponds to saturated flow and is used to normalise the unsaturated values. Saturated flow is found using a reservoir to provide a saturated source, as it is difficult to estimate the point at which a source governed flow exceeds the capacity of the sample. The general trend is for the permeability to increase monotonically with moisture content (Figure 2(a)). Experimental observations also indicate the presence of a percolation threshold of about 40 per cent for moisture content, below which the permeability is very small, and this serves to sharpen significantly the front of the wetted region. 3.2.2 Capillary pressure characterisation. The relationship between the capillary pressure and saturation is measured using a wet porous plate apparatus. This method is well known, and has been applied to characterise absorption and the pore size distribution of fabrics (Chatterjee, 2002b). The sample is placed on a micro-porous membrane to maintain liquid at the contact
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between the sample and a supplying reservoir, under conditions of applied pressure. A pressure is applied by varying the vertical height of the sample in relation to the reservoir, and the volume of liquid displaced is monitored using a balance. A number of practical difficulties may be encountered in a significant fraction of experiments using this method. First, the time taken for the capillary pressure to reach steady state increases as the moisture level decreases. Second, the thickness of the sample (0.5 cm) is a significant fraction of the maximum capillary pressure produced (less than 5 cm), consequently, there is likely to be some loss of pressure within the sample height, leading to an underestimation of the saturation at low pressures. An alternative approach to find the capillary pressure relationship is to measure the steady moisture profile in inclined sheets of material where one end is submerged in a reservoir of fluid (Figure 2(b)). A new approach exploiting magnetic resonance imaging is also currently being investigated to provide more defined measurements (Leisen, 2003). Figure 2(b) shows the capillary pressure as the moisture content increases. Fibrous materials exhibit hysteresis for invading flows compared to receding flows, and for this reason Richards’ equation and the closure relations need to be substantially modified in the presence of draining flows. 4. Transport in homogeneous materials In order to introduce these experimental results into Richards’ equation, we fit analytical functions to the data. A sensitivity study has indicated that the dimensions of the wetted region are determined by the characteristic values of the permeability and capillary pressure; while the functional form of these relationships determines the progress of the moisture distribution. Particular attention is focused on detailed measurements of the moisture profile and the success of this approach is good. Using a simplified absorbent core material (a circular cross section polyester needlefelt), the measured permeability and capillary pressure relationships were fitted to the following functions (Figure 2):
Figure 2. Measurements and fitted relationships of: (a) permeability, and (b) capillary pressure for a sample polyester non-woven fabric, and also shows results for invading fluid where ›Q/›t . 0
C ; Q ¼ exp 2 Cc
ð6Þ
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This has a benefit that the underlying equations can be solved analytically in some instances and enables the accuracy of the numerical solvers to be checked. For horizontal infiltration the length of the wetted region increases as pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi L ¼ l 2K s Cc t=us (Figure 3(a)) and for vertical infiltration the moisture profile Q ¼ exp ð2xg=Cc Þ (Figure 2(b)).
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KðQÞ ¼ K s Q3 :
4.1 Numerical calculations Numerical solutions to the Richards equation were found using a finite difference method, with a forward in time flux conserving scheme. The experimentally determined closure relationships (equation (6)) were included for the sample material. 4.2 Experimental results The moisture profile for demand wicking in a non-woven fabric has been measured with a gravimetric technique (using 1 cm wide samples) in four experiments, where measurements were made once the wetted length had reached a predetermined point. Figure 3 shows the results obtained for moisture distribution and penetration length compared to a numerical simulation using Richards’ equation. 4.3 Application to incontinence pads We proceed to apply the results to interpret the spreading of fluid in homogeneous sheets. The absorbent cores of small reusable pads for lightly incontinent women are often made from non-woven sheets. A laboratory experiment to investigate liquid distribution in small pads has been undertaken, using a curved former to hold the pad in the typical geometry of a product in use. To simplify the experiment only the single major radius of curvature was included. Liquid was introduced using a computer controlled pump at a fixed flow rate. Liquid spreading could then be observed from above
Figure 3. Experimental measurements and numerical simulation in a polyester non-woven fabric – results for horizontal wicking from a source: (a) wetted length, and (b) moisture profile
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and below the sample using video cameras. A preliminary experimental study has indicated a number of different mechanisms of leakage, including: failure to readily penetrate the product, an initial absorption followed by leakage from the lowest point, and poor redistribution due to lack of absorbent material below the maximum wicking height. The model, using Richards’ equation, can be applied to predict the liquid distribution in this simple representation of a small pad by including the effect of geometry, as shown in Figure 4. 5. Transport in inhomogeneous materials The use of layered composite materials has been a widespread advance in absorbent technology, allowing products with superior fluid handling properties, such as high permeability coupled with good liquid retention, to be developed. Although a layered composite may be very complex each layer can be considered homogeneous. Explicitly, including each layer into a three-dimensional model of the fibrous sheet remains a daunting step computationally. The approach currently being adopted at UCL is to develop a single layer parameterisation of the bulk properties of multiple layered structures. While this may be achieved by estimating the effective saturated permeability and capillary pressure, it is the functional form of these relations that is required as an input into computational models. Current progress is directed towards studying transport in multiple homogeneous layers. To illustrate this approach, we present results from numerical calculations for a two-layered fibrous sheet Figure 5(a), where the characteristic values of permeability and capillary pressure are Ksi, Cci ði ¼ 1; 2Þ; the functional forms are the same as in equation (6), and b is the fractional width of layer 1. Guided by the experimental methods, these closure relations are estimated by considering a vertically steady moisture profile from a reservoir and flow in an inclined sheet. The effective permeability is estimated from the coupled set of equations describing uniform flow in inclined sheets,
Figure 4. (a) Plan view of fluid spreading from a point source (at a rate of 0.5 ml/s) on a needlefelt to represent the core of a curved bodyworn pad. Numerical results based on Richards’ equation are shown (b, c) (in the numerical simulation saturation is displayed, where dry is black)
3Cc1 =Cc2
K eff ¼ bK s1 Q31 þ ð1 2 bÞK s2 Q1
;
¼ bQ1 þ ð1 2 bÞQCc1 =Cc2 : ð7Þ Q 1
while the effective capillary pressure is determined from the steady state for infiltration into vertical strips (Figure 5(b)), ¼ be2Ceff =Cc1 þ ð1 2 bÞe2Ceff =Cc2 Q
ð8Þ
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When the difference between the two layers is small, the effective permeability and capillary pressure approximately correspond to the arithmetic and harmonic means of the respective quantities in the two layers. 6. Conclusions and future directions The different modelling strategies applied to describe fluid transport in medical absorbents have been briefly reviewed. An essential character of such models (based on Richards’ equation) is that they contain the functional relation between permeability, pressure and moisture, and as such are more useful for complex and layered medical absorbents than Washburn’s equation. Experimental methods for measuring the closure relationships appear to be well developed, but there still remain some outstanding questions about the methodology. There remains a gap in our understanding as to how best to implement draining flows into these descriptions when the moisture-pressure relation is non-analytic. Some ad hoc approaches where the moisture content cannot drop below a residual value have been proposed for soils, but these need to be refined for fibrous absorbents. Progress made in studying transport of materials formed from homogeneous layers of fibrous sheets is very encouraging, with excellent agreement between the analytical, numerical and experimental results. There are still some challenges though, to obtain a more complete description of absorption by incontinence pads, including the effects
Figure 5. (a) Infiltration in a horizontal strip, and (b) vertical steady for a two layered sample. The fractional width of layer 1 is b ¼ 1/2. The capillary pressure contrasts are indicated
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of external loading, deformations of the material in use and leakage from the product. A medical absorbent encompasses a multiple of scales, from the fibre scale, the sheet thickness, to the size of the product. A general future challenge is to understand the connection between the microscale/structural features and the bulk properties of the resulting absorbent. References Celia, M.A. and Bouloutas, E.T. (1990), “A general mass-conservative numerical solution for the unsaturated flow equation”, Water Research, Vol. 26 No. 7, pp. 1483-96. Chatterjee, P.K. (2002a), “Chapter 1: porous structure and liquid flow models”, Absorbent Technology, Elsevier, Amsterdam. Chatterjee, P.K. (2002b), “Chapter 11: measurement techniques for absorbent materials and products”, Absorbent Technology, Elsevier, Amsterdam. Gardner, W.R. and Mayhugh, M.S. (1958), “Solutions and tests of the diffusion equation for the movement of water in soil”, Proc. Soil Sci. Am., Vol. 22, pp. 197-201. Gupta, B.S. (1988), “The effect of structural factors on the absorbent characteristics of non-wovens”, Tappi Journal, pp. 147-52. Kissa, E. (1996), “Wetting and wicking”, Textile Research Journal, Vol. 66 No. 10, pp. 660-8. Landeryou, M., Eames, I. and Cottenden, A. (2003a), “Infiltration into inclined fibrous sheets”, J. Fluid Mech.(in press). Landeryou, M., Yerworth, R. and Cottenden, A. (2003b), “Mapping liquid distribution in absorbent incontinence products”, J. Engineering in Medicine, Proc. Instn Mech. Engrs, Vol. 217, Part H. Leisen, J. (2003), “Measurements of moisture distribution within non-woven fabrics, using NMR imaging”, Incontinence the Engineering Challenge, Institute of Mechanical Engineers. Richards, L.A. (1931), “Capillary conduction of liquids through porous mediums”, Physics, Vol. 1, pp. 318-33. Van der Brekel, L.D.M. and Jong, E.J. (1989), “Hydrodynamics in packed textile beds”, Textile Research Journal, Vol. 60 No. 8, pp. 433-40. Washburn, E.W. (1921), “The dynamics of capillary flow”, The Physical Review, Vol. 17 No. 3, pp. 273-83. Youngs, E.G. (1964), “An infiltration method of measuring the hydraulic conductivity of unsaturated porous materials”, Soil Sci., Vol. 97, pp. 307-11.
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The study of The study of pressure delivery pressure delivery for hypertrophic scar treatment 173
Lisa Macintyre, Margot Baird and Phil Weedall School of Textiles and Design, Heriot-Watt University, Galashiels, Scotland, UK Keywords Medical appliances, Clothing and accessories, Pressure, Laplace transforms Abstract Pressure garments have been used prophylactically and to treat hypertrophic scars, resulting from serious burns, since the early 1970s. They are custom-made from elastic fabrics by commercial producers and occupational therapists. However, no clear scientifically established method has ever been published for their manufacture from powernet fabrics. The earlier work identified the most commonly used fabrics and construction methods for the production of pressure garments by occupational therapists in UK burn units. These methods have now been evaluated by measuring the pressures delivered to both cylinder models and to human limbs using I-scanw pressure sensors. The effect of cylinder/limb circumference and the effects of the fabric and reduction factor used in pressure garment construction on pressures exerted have now been established. These measurements confirm the limitations of current pressure garment construction methods used in UK hospitals. These results were also used to evaluate the Laplace law for the prediction of interface pressures.
1. Introduction Hypertrophic scars frequently develop following serious burn injury or other wound healing by second intention (i.e. wounds whose edges cannot be sutured together). These scars are: . warm and red/purple in colour due to increased vascularity; . raised, firm and whorl-like in structure due to increased collagen deposition; . tender and may itch; . contractile in nature and may lead to scar contracture if untreated; . scars which remain within the original line of the wound; . active and often regress with time (Ehrlich et al., 1994; Kelman and McCoy, 1980; Lamberty and Whitaker, 1981). Pressure garments have been used in hospitals worldwide to prevent and treat hypertrophic scars since the 1970s. The popularisation of this method of treatment is most commonly attributed to the work done by Larson et al. at the Shriners Burns Institute at Galveston in Texas (Linares et al., 1993) The rationale for pressure therapy is based on the belief that pressure reduces collagen production within the developing or active scar. This belief is backed by years of medical experience and many case studies but has never been
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scientifically proven. Pressure garments additionally often alleviate the pain or itchiness associated with hypertrophic scars and tend to prevent the development of serious contractures (areas of contracted skin over flexor joints which reduce the range of motion). Pressure garments are normally custom-made from elastic fabrics and are designed to exert a pressure of approximately 25 mm Hg on the underlying tissue. This “ideal” pressure has varied over the years and has never been scientifically established. This appears to be due, in part, to the difficulty in applying even pressure to the human body and the lack of actual garment/scar interface pressure measurement in most hospitals, the efficacy of this treatment and the fit of garments normally being assessed subjectively based on individual practitioner’s experience. Some work has been conducted on garment/scar interface pressure (Giele et al., 1997) but no conclusions on the most effective pressure were drawn, much of this research being concerned with developing accurate means for pressure measurement. There are several problems associated with current pressure garment treatment. Fundamental problems in treatment delivery include: . lack of scientifically established guidelines on safe and effective pressure Reid et al. (1987); . pressure is difficult to apply evenly, particularly in concave areas of the body (Collins, 1992; Leung and Ng, 1980); . blistering and scar breakdown may occur if too much pressure is applied too soon, resulting in treatment suspension (Collins, 1992; Leung and Ng, 1980); . the effects of percentage body fat, age, sex, race, etc. on the interface and subdermal pressures delivered using similarly constructed garments is not fully understood; . applied pressure decreases during the course of the day and the life of the garment; . applied pressure varies with movement and the precise nature of these changes has not been measured; . the “reduction factors” used by occupational therapists are often arrived at in an arbitrary manner without considering the differences in fabric properties (Parkinson and Yip Ng, 1994). The aim of this investigation was to develop a system for calculating the dimensions of pressure garments so that they would exert a particular pressure on human limbs. The investigation was broken down into the following stages. (1) Measure the tension in the fabrics currently used to construct pressure garments made in, or supplied to, UK hospitals. (2) Construct a series of cylinder models to represent the range of human limb sizes.
(3) Evaluate the effect of changing cylinder circumference on the pressures The study of exerted by pressure garment samples. pressure delivery (4) Evaluate the effect of changing the fabric used in pressure garment sample construction on the pressures exerted by the samples on cylinder models. (5) Evaluate the effect of changing the reduction factor used in pressure 175 garment sample construction on the pressures exerted by the samples on cylinder models. (6) Evaluate the Laplace law for predicting the pressures exerted by pressure garment samples on cylinder models. (7) Measure the pressures exerted by pressure garment sleeves to human limbs. (8) Evaluate the Laplace law for predicting the pressures exerted by pressure garment sleeves on human limbs. This paper will give a brief overview of the methods used and some of the results of the investigation. 1.1 The theory of the Laplace law The Laplace law has been widely used to calculate the pressure delivered to a cylinder of known radius by a fabric under known tension. However, it was originally developed by Laplace in 1806 to explain the surface tension phenomenon in liquids and their ability to form droplets (Starling and Woodall, 1958) or soap bubbles (Warren, 1979). The original theory was developed to relate the wall tension and radius of cylinders (e.g. blood vessels) to the pressure difference that existed between the pressure pushing the two halves of the cylinder apart and the wall tension pulling the two halves together. This equation can be written: Pressure ðin PaÞ ¼ Tension in the cylinder wall ðin N=mÞ 4 radius of the cylinder ðin mÞ
ð1Þ
or P ¼ T 4 r and is known as the law of Laplace (Warren, 1979), although it is more often referred to as the Laplace law. The origin of the use of the Laplace law for estimating the pressure delivered by pressure garments is unclear. The first specific reference to it is in a paper published in 1984 (Cheng et al., 1983), which states “These observations in fact are adequately explained by the Laplace law”. However, the paper had previously stated . . . “garment tension appeared much the same”, suggesting that fabric tension was not actually measured. Therefore, the assertion that pressure garments appeared to follow the Laplace law was based on the
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observation that the measured pressure increased over areas of low radius of curvature and decreased on areas of high radius of curvature. Clearly concave areas of the body do not make contact with the pressure garment and therefore no pressure is exerted.
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1.2 Using the Laplace law to predict pressures exerted by pressure garments When patients are measured for pressure garments in hospitals it is the circumference of the limb or body part that is measured (not the radius). Therefore it would be more useful if the Laplace law was amended to predict pressure from the fabric tension and circumference of the body part. Since r ¼ c 4 2p; the pressure (in Pa) exerted by pressure garment samples made from a fabric with tension “T” could be predicted for a cylinder of radius “r” (in m) using the Laplace law as follows: Pressure ðPaÞ ¼ T 4 ðc 4 2pÞ ¼ ðT £ 2pÞ 4 c ¼ ð6:283TÞc 21
ð2Þ
This equation may be further modified to predict the pressure in mm Hg, which is the most common unit of pressure referred to in literature regarding pressure garment construction and treatment. Since 1 mm Hg is equal to 133.322 Pa the Laplace predicted pressure in mm Hg would be: Pressure ðmm HgÞ ¼ ð2pT 4 133:322Þc 21 ¼ ð0:047TÞc 21
ð3Þ
2. Tension in fabrics currently used in pressure garment construction in UK hospitals Most (64 per cent) occupational therapists who make pressure garments in UK hospitals use a 20 per cent reduction factor on each circumferential measurement of the patient (according to a survey of all UK burn units carried out in 1997, 53 per cent response rate). Therefore, the fabric in these pressure garments is extended by 25 per cent when they are fitted on the patients. Eighteen fabrics were collected, from UK hospitals and two commercial pressure garment manufacturers, for evaluation. 2.1 Method The fabric tension was calculated for all eighteen fabrics from the load at 25 per cent extension (after 30 s) using a Nene M5 constant rate of extension tensile testing machine. The experimental procedure was based on BS 4952:1992 using sets of five looped samples (7.5 cm wide). The load in N measured in each sample was halved to give the load for one side of the fabric loop. This was multiplied by 100/7.5 to give the fabric tension in newton/metre.
2.2 Results The study of The tension of the fabrics currently used in pressure garment construction in, pressure delivery and for, UK hospitals ranged from 27 to 177 N/m at 25 per cent extension. Figure 1 shows the range of (mean) pressures that would be exerted on a 15 cm wrist and a 72 cm thigh according to the Laplace law, assuming a 20 per cent reduction factor, was used in pressure garment construction. The predicted 177 pressures at the wrist circumference ranged from less than half the recommended pressure to more than twice the recommended 25 mm Hg pressure. The closest predicted pressure at the thigh circumference was less than half the recommended pressure. 2.3 Conclusion If accurate, these predictions show that both circumference of the limb and fabric tension have a significant impact on the pressures delivered by pressure garments if current construction techniques are used. Therefore, the Laplace law was evaluated for the accuracy of the prediction of pressures delivered by pressure garments made from powernet fabrics, which is the most popularly used fabric structure in UK pressure garment construction. 3. Evaluation of the Laplace law for predicting the pressures exerted by pressure garment samples on cylinder models 3.1 Materials One of the powernet fabrics collected to evaluate the fabrics currently used in pressure garment construction was selected as the main fabric for the pressure measurements that follow. It will be referred to as A1. A further ten powernet fabrics were obtained to determine the effect of fabric tension on interface pressure, these will be referred to as pg1-pg5 and pf1-pf5. Therefore 11 different values of fabric tension were represented. 3.2 Cylinder models Twelve rigid cylinders with circumferences ranging from 15 to 96 cm, representing a range of human limb sizes, were used. Expanded neoprene foam was glued around each cylinder to represent the compressibility of human tissue.
Figure 1. Range of interface pressures predicted by the Laplace law based on a wrist circumference of 15 cm and a thigh circumference of 72 cm
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3.3 Determination of the effect of cylinder circumference on pressures exerted by pressure garment samples 3.3.1 Method. 3.3.1.1 Main measurements. The pressure delivered to 12 cylinder models by sets of five pressure garment samples constructed from fabric A1 using a 20 per cent reduction factor was measured using the following procedure: (1) A reduction factor of 20 per cent was applied to the mean circumference of each cylinder model (cylinder model circumference multiplied by 0.8). (2) Five pressure garment samples were constructed from fabric A1 for each cylinder model. Looped samples (10 cm wide) were prepared using the circumferential dimensions described in the first point. (3) The pressure exerted by each pressure garment sample was measured 30 s after it was positioned on the appropriate cylinder model. 3.3.1.2 Secondary measurements. Pressure garment samples made from fabrics pf2, pf3 and pf4 were tested on four-cylinder models (with 19, 30, 37 and 85 cm circumferences) in order to determine whether the effect of the cylinder circumference was constant regardless of the tension of the fabric used. The procedure followed was the same as that described in steps 1 to 3 above. 3.3.2 Results. 3.3.2.1 Main measurements. Figure 2 shows that as the circumference of the cylinder model increases the pressure exerted on it by similarly constructed pressure garment samples decreases. The line of best fit for the “large” cylinder models was described by the power law equation (4) below: P ¼ 402:7c 20:8357
ð4Þ
where P (mm Hg) was the mean pressure (cm) exerted on the cylinder model and c was the cylinder model circumference. The coefficient of determination (R 2) for this equation was significant at the 99.9 per cent confidence limit. The line of best fit for the “small” cylinder models was described by the power law equation (5) (R 2 for this equation was significant at the 99 per cent confidence limit): P ¼ 1527c 21:3247
Figure 2. Mean pressure exerted by pressure garment samples made from A1 showing different trends set by small compared to large cylinder models
ð5Þ
Therefore, two equations would be required to predict the pressure exerted by The study of pressure garments made from fabric A1 using a 20 per cent reduction factor on pressure delivery cylinder models of different circumference. 3.3.2.2 Secondary measurements. The relationship between increasing cylinder model circumference and decreasing pressure was confirmed when fabrics pf2, pf3 and pf4 were tested on four-cylinder models (Figure 3). Again 179 the line of best fit was described by a power law equation for each set of data. 2 Despite the small number of data points the R values for these lines of best fit were all significant at the 95 per cent confidence level. Although these fabrics were measured on only four-cylinder models they did not appear to follow separate trends on the “small” cylinder models and the “larger” cylinder models as fabric A1 did. However, more measurements would be required to confirm that these indications were reliable. 3.3.3 Evaluation of the Laplace law for predicting the pressures delivered by pressure garment samples on cylinder models of different circumference 3.3.3.1 Difference between predicted and measured pressures – main measurements. Figure 4 shows that the Laplace law predicted the pressures exerted by pressure garment samples made from A1 to “large” cylinder models accurately, while it overestimated the pressures exerted on “small” cylinder models. This confirms the trend noted above that fabric A1 behaved differently on “small” cylinder models compared to “large” ones. 3.3.3.2 Difference between predicted and measured pressures – secondary measurements. The Laplace law predicted the pressures exerted by pressure garment samples made from fabrics pf2, pf3 and pf4 on all four-cylinder
Figure 3.
Figure 4.
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models to within ^ 2.0 mm Hg. (The error inherent in the pressure measurement system was ^ 2.1 mm Hg.) 3.3.4 Conclusions (1) The Laplace law accurately predicted the pressures exerted by pressure garment samples on cylinder models of “large” circumference (greater than 30 cm) made from four-different powernet fabrics. (2) The Laplace law predicted the pressures exerted by pressure garment samples on cylinder models of “small” circumference (less than 25 cm) with variable accuracy. The Laplace law overestimated the pressures exerted by fabric A1, which is currently used to produce pressure garments supplied to many UK hospitals. However, the Laplace law accurately predicted the pressures exerted by three further fabrics at both “small” and “large” circumferences. 3.4 Determination of the effect of fabric tension on pressures exerted on cylinder models 3.4.1 Method. Sets of five pressure garment samples were made using a 20 per cent reduction factor from 11 different fabrics having 11 different tensions. The pressure they exerted on a cylinder model with a 37 cm circumference was measured 30 s after they were positioned. 3.4.2 Results. As the tension in the fabric increased the pressure exerted by pressure garment samples constructed from it also increased. This relationship was linear and significant at the 99.9 per cent confidence level. Therefore, pressure garments constructed using different fabrics and one reduction factor are likely to exert different interface pressures. These results confirmed the theory presented in Figure 1. 3.4.3 Evaluation of the Laplace law for predicting the pressures delivered by pressure garment samples made from different fabrics. The Laplace law accurately predicted the pressures exerted by pressure garment samples made from different fabrics (the tensions of which ranged from 33 to 162 N/m at 25 per cent extension) with a 20 per cent reduction factor. 3.5 Determination of the effect of reduction factor on pressures exerted on cylinder models 3.5.1 Method. 3.5.1 Main measurements. Sets of five pressure garment samples were constructed from fabric A1 using 0, 5, 10, 15, 20, 25, 30, 35 and 40 per cent reduction factors for a cylinder model with a 37 cm circumference. The pressure exerted by each of these samples was measured 30 s after the sample was positioned. 3.5.1.2 Secondary measurements. Sets of five pressure garment samples were constructed from fabrics pf3 and pf4 using 10, 20 and 30 per cent reduction factors for a cylinder model with a 37 cm circumference. The pressure
exerted by each of these samples was measured 30 s after the sample was The study of positioned. pressure delivery 3.5.2 Results. As the reduction factor used in pressure garment construction increased the pressure that sample exerted on the cylinder model also increased. This relationship was linear between 0 and 40 per cent reduction factors for fabric A1 and was significant at the 99.9 per cent confidence level. 181 The relationship also appeared to be linear for fabrics pf3 and pf4 between 10 and 30 per cent reduction factors. Therefore, different pressures can be achieved by using a particular fabric and different reduction factors in pressure garment construction. 3.5.3 Evaluation of the Laplace law for predicting the pressures delivered by pressure garment samples made using different reduction factors. The Laplace law accurately predicted the pressures exerted by pressure garment samples constructed from three different fabrics with a range of reduction factors. 4. Determination of some of the factors to affect pressures exerted by pressure garment sleeves on human limbs This investigation was conducted in two parts. First the pressures exerted by pressure garment sleeves on forearms were measured and second pressures exerted on thighs were measured. Eighteen people were enrolled in the investigation. They ranged from 21 years to 64 years old, eight were male and ten were female. A wide range of body sizes and shapes were represented. 4.1 Pressures exerted by pressure garment sleeves on the forearm of 18 participants 4.1.1 Method. Sets of five pressure garment sleeves were constructed using a 20 per cent reduction factor from fabric A1 for the forearms of 18 different people. The limbs were measured accurately at 2 cm intervals and each circumferential measurement was reduced by 20 per cent. A pattern was drafted for each participant. Pressure garment sleeves were cut and assembled carefully following the standard technique used by occupational therapists in UK hospitals using a BS 304 seam. Following construction of the sleeves each participant was re-called and the pressure exerted by each sleeve on the forearm was recorded 30 s after it was positioned. 4.1.2 Results. The mean pressures exerted on participants’ forearms ranged from 16 to 38 mm Hg. No correlation among the mean circumference of the limb, thickness of subcutaneous fat and sex or age of the participant was found. 4.1.3 Evaluation of the Laplace law for predicting the pressures delivered by pressure garment sleeves on human forearms. Figure 5 shows that the Laplace law overestimated the pressures exerted on forearms by 10.9 mm Hg on average (mean difference between measured pressure and that predicted by the Laplace law). These results show that the Laplace law cannot be used to accurately predict the pressures exerted on human forearms. However, when
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equation (5), which described the line of best fit for pressures exerted on “small” cylinder models, was used to predict the pressures exerted on human forearms the mean difference between measured and predicted pressures was only 3.3 mm Hg. Clearly equation (5) is not sufficiently accurate for predicting the pressures exerted by pressure garment sleeves on limbs of small circumference. However, it was calculated from only four measurements and represented a significant improvement on the accuracy of the Laplace law. Therefore, more work on cylinder models of small circumference may hold the key to accurate prediction of pressure on small limbs. 4.2 Pressures exerted by pressure garment sleeves on the thigh of 14 participants 4.2.1 Method. Sets of five pressure garment sleeves were made for the 14 remaining participants as described in Section 4.1.1 except that the participants’ thigh was measured at 2 cm intervals starting 5 cm above the top of the knee cap. Pressures exerted by the pressure garment sleeves were measured 30 s after each sleeve was positioned. 4.2.2 Results. As the mean circumference of the thigh increased the pressure exerted on it decreased. This relationship was linear and significant at the 99.9 per cent confidence level. The mean circumference of thighs measured ranged from 40.9 to 69.9 cm. The mean pressure exerted on thighs ranged from 8 to 19 mm Hg. 4.2.3 Evaluation of the Laplace law for predicting the pressures delivered by pressure garment sleeves on human thighs. The Laplace law accurately predicted the pressures exerted by pressure garment sleeves on thighs. 5. Conclusions (1) A wide range of fabrics is currently used in the construction of pressure garments. These fabrics have a wide range of tensions, and would consequently (according to the Laplace law) exert a wide range of pressures when made into pressure garments following the standard construction technique. (2) Different fabrics exerted different pressures on cylinder models when made into pressure garment samples using the same reduction factor.
Figure 5. Relationship between measured and predicted pressures (using the Laplace law and equation (5)) for pressure garment sleeves made from A1 with 20 per cent reduction factor for forearms
(3) Increasing the reduction factor used in pressure garment sample The study of construction increased the pressures delivered to models. pressure delivery (4) As the circumference of a cylinder model or limb increased the pressure exerted by pressure garment samples/sleeves decreased. (5) The Laplace law predicted the pressures exerted on cylinder models and limbs of “large” circumference to within ^2.1 mm Hg. However, the 183 Laplace law significantly overestimated the pressures exerted on cylinder models and limbs of “small” circumference in some cases. References Cheng, J., et al. (1983), “Pressure therapy in the treatment of post-burn hypertrophic scar – a critical look into its usefulness and fallacies. . .”, Burns, Vol. 10, pp. 154-63. Collins, J. (1992), “Pressure techniques for the prevention of hypertrophic scar”, Clinics in Plastic Surgery, Vol. 19 No. 3, p. 734. Ehrlich, P., Desmouliere, A., Diegelmann, R., Cohen, K., Compton, C., Garner, W., Kapanci, Y. and Gabbiani, G. (1994), “Morphological and immunochemical differences between keloid and hypertrophic scar”, Am. J. Path., Vol. 145 No. 1, pp. 105-13. Giele, H., Liddiard, K., Currie, K. and Wood, F. (1997), “Direct measurement of cutaneous pressures generated by pressure garments”, Burns, Vol. 23 No. 2, pp. 137-41. Kelman, I. and McCoy, B. (1980), “The biology and control of surface overhealing”, World Journal of Surgery, Vol. 4, pp. 289-95. Lamberty, B. and Whitaker, J. (1981), “Prevention and correction of hypertrophic scarring in post-burns deformity”, Physiotherapy, Vol. 67 No. 1, pp. 2-4. Leung, P. and Ng, M. (1980), “Pressure treatment for hypertrophic scars resulting from burns”, Burns, Vol. 6, p. 244. Linares, H., Larson, D. and Willis-Galstaun, B. (1993), “Historical notes on the use of pressure in the treatment of hypertrophic scars or keloids”, Burns, Vol. 19 No. 1, pp. 17-21. Parkinson, J. and Yip Ng, F. (1994), “The properties and comfort of pressure garments for hypertrophic scar treatment”, 75th World Conference of the Textile Institute “Globalization”, p. 79. Reid, W.H., Evans, J.H., Naismith, R.S., Tully, A.E. and Sherwin, S. (1987), “Hypertrophic scarring and pressure therapy”, Burns, Vol. 13, pp. S29-S32. Starling, S.G. and Woodall, A.J. (1958), Physics, pp. 104-7, 116-19. Warren, M.L. (1979), Introductory Physics, W.H. Freeman and company, San Francisco, pp. 212-19.
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Design of textile scaffolds for tissue engineering: the use of biodegradable yarns E. Ekevall, C. Golding and R.R. Mather Biomedical Textiles Research Centre, School of Textiles and Design, Heriot-Watt University, UK Keywords Yarn, Medical appliances, Human biology Abstract The emergence of tissue engineering has led to the development of three-dimensional cellular scaffolds that reconstruct the tissue structure. Research into the use of biodegradable materials in scaffolds has grown; the aim is that when tissue growth is complete, the scaffold degrades completely. This research aims to design novel scaffolds and investigates biodegradable polylactide (PLA) yarns; in particular, poly(L -lactide) (PLLA) yarns extruded in-house. To study degradation and determine the effect on the biodegradable yarns/textiles, they were immersed in phosphate buffer solution (PBS, pH ¼ 7:4) for various durations at 378C. Mechanical properties were evaluated on tensile testing rigs and they were observed, before and after the immersion period. Cells were then cultured (378C, 5 per cent carbon dioxide in air) on the textiles for 1 week. As expected, after immersion, the yarns exhibit a decrease in elongation and tenacity. Initial results indicate that the yarn properties influence cell attachment and spreading.
International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 184-193 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520469
1. Introduction The practice of bioengineering has been in existence since 3000 BC, when the ancient Egyptian’s developed a prosthetic toe constructed from wood, linen and glue (Watts, 2001). The artificial toe was created to be not only aesthetically pleasing but also functional, bearing some of the wearer’s weight aiding balance. Since then, with advances in technology, the design and manufacture of artificial organs have evolved considerably. Numerous organs are supported or replaced by mechanical structures (bionic) fabricated from metals and polymers, which in some cases are stronger and more reliable than the original. Certain organs, such as joints and external limbs, are relatively easily replaced with mechanical structures compared to more complicated internal organs like the heart, lungs and kidneys. Currently, the replacement of internal functioning organs by mechanical devices is usually temporary, with the patient disadvantaged in terms of “living a normal life” and the device often has a limited operating period or the patient is affected. However, some organs, such as the liver, perform too many complicated functions to be replaced by mechanical means alone. Cell culture technology developed in the early 20th century created a requirement for suitable cell culture substrata, with a considerable effort directed towards maintaining differentiated cells in culture (Kleinman et al., 1981; Sittinger et al., 1996). Since then advances in cell culture technology
coupled with the need to replace complicated body parts led to the emergence of Design of textile tissue engineering in the 1990s. Tissue engineering has been described by scaffolds Hutmacher et al. (2001) as “A truly multidisciplinary field that applies the principles of engineering, life science and basic science to the development of viable substitutes, which restore, maintain or improve the function of human tissues.” The concept is to grow cells on substrates artificially creating new 185 organs. One of the first and most memorable examples is the bioengineered “human ear” grown in the lab and successfully transplanted onto the back of a mouse by the Vacanti brothers. Chondrocytes (isolated from bovine articular cartilage) were seeded onto a non-woven mesh of polyglycolic acid; moulded to the shape of a 3-year-old child’s auricle, after immersion in a 1 per cent solution of polylactic acid (PLA) (Cao et al., 1997). Two tissue engineering technologies that have been successfully commercialised are cartilage and skin. The challenge at present is to grow more complicated organs that contain numerous cell types and require a high/regular supply of oxygen, nutrients, growth factors, etc. Current research areas include bone, nervous system tissues, muscles, liver and pancreatic cells (Heidaran, 2000). The aim of this study is to investigate the feasibility of biodegradable textile scaffolds for tissue engineering, their characteristics and degradation properties. 2. Background The advent of tissue engineering led to increased interest into the research of novel substrata, especially biodegradable materials. The objective of using biodegradable materials for the scaffolds is that when tissue growth is complete, the scaffold will degrade leaving only the new tissue. To reconstruct the tissue structure, three-dimensional (3D) scaffolds are required to provide a basic framework for the cells to grow (Mikos and Temenoff, 2000). Hutmacher et al. (2001) describe what they consider to be essential characteristics for a scaffold: . highly porous with interconnected pore network for cell growth and flow transport of nutrients and metabolic waste; . biocompatible and bioabsorbable with controllable degradation and re-sorption rate to match tissue replacement; . suitable surface chemistry for cell attachment, proliferation, and differentiation; . mechanical properties to match those of the tissue at the site of implantation; . be reproducible, processed into variety of shapes and sizes by solid free form fabrication. The ideal substrate needs to recreate the microscopic structure of the organ, reproducing the growth pattern, i.e. irregular or regular. Can a textile scaffold be produced from a biodegradable yarn and fulfil the above objectives? In order
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to answer this question, the potential of biodegradable yarns and textile scaffolds was studied. 2.1 Textile scaffolds Textiles are extremely versatile. The properties of the textile, and consequently the tissue engineering scaffold, can easily be altered by changing the: . fibre/yarn polymer; . fibre/yarn diameter; . fibre/yarn spacing; . manufacturing method, i.e. knitted, woven or non-woven; and . surface properties of the fibre/yarn. As a result, custom-made textile tissue engineering substrata can be specifically designed with the required mechanical and biological properties and are relatively simple to adapt to meet the requirements of other cells. The polymer composition is critical. Owing to the potential viral risk with animal derived polymers, there is a move towards synthetic polymers. Also the material should not provoke an immune response in the body and last long enough for the organ to take shape. 2.2 Polyactide acid PLA has been used for implantable sutures for decades and researched as a promising candidate for tissue engineering scaffolds (Hutmacher et al., 2001; Saltzman, 2000). Lactic acid exists in two optically active forms of isomers, known as L (laevorotatory) and D (dextrorotatory). After condensation, the isomers form L -lactide, D -lactide or meso-lactide which undergo polymerisation to produce poly-L -lactic acid (PLLA), poly-D -lactic acid or poly-DL -lactic acid. The following study investigates PURASORBw PLLA polymer[1] which biodegrades by random hydrolysis: first the molecular weight of the polymer is decreased, then the mechanical properties are affected, with the final stage fragmentation and mass loss until the polymer is completely degraded. PLLA is finally broken down into lactic acid, which in the body, should be eliminated by natural pathways, such as metabolism and excretion. Two models are used to explain the degradation process: bulk erosion (random degradation throughout the polymer) and surface erosion (Gopferich, 1996). Degradation can be affected by factors such as: geometrical shape, size, polymer purity, polymer crystallinity, polymer processing, pH of degradation solution, temperature, implantation site, sterilisation, etc. (Yuan et al., 2002) and considerable research effort is needed to determine the actual method of degradation in biodegradable polymers (Burkersroda et al., 2002). To produce successful tissue engineering scaffolds, factors such as the time taken by the PLLA yarn and scaffold to degrade and how the mechanical properties are affected during this period, must be determined. This study investigates the
properties of PLLA scaffolds and the degradation of PLLA yarns; with Design of textile degradation quantified by the change in material properties. scaffolds 3. Methodology Five PLLA yarns extruded (Table I) by the Biomedical Textiles Research Centre (BTRC), Heriot-Watt University (Wallace, 2002), from PURAC PURASORBw PLLA polymer (derived from corn, density 1.25-1.30 g/cm3; melting temperature 170-2008C; glass transition temperature 55-658C; degradation time .24 months) were investigated. The yarns were compared with the commercial yarn Lactronw, Kanebo\Gohsen Ltd, referred to as PLA G (also produced from corn; tensile strength 0.4 N/tex; Young’s modulus 400-600 kg/m2; and melting point 1758C). The yarns were wound onto cotton reels, conditioned (65 per cent RH and 208C) for 48 h and weighed before the degradation tests. All the yarns were immersed in phosphate buffered saline (PBS) solution (Sigma Aldrich, Poole, UK), pH 7.4, and kept in an oven at 378C, for degradation periods ranging from 1 to 10 weeks. The pH was monitored during the degradation period and the PBS solution changed during week 5. The following properties were measured on a Nene (M5, Nene Instruments Ltd) tensile testing rig (minimum sample number, n ¼ 5) before and after degradation: Young’s modulus, load and displacement at yield point. The initial properties of the yarns are shown in Table II. To compare the yarns, the tenacity and elongation are calculated from the load [tenacity¼ load/tex] and displacement [(displacement/original length) £ 100] at the yield point. Over a 4-week
Yarn name PLLA PLLA PLLA PLLA PLLA PLLA
A B C D E F
Yarn name PLLA A PLLA B PLLA C PLLA D PLLA E PLLA F PLA G
Spinneret ratio 1:4 (no. holes)
Inherent viscosity (dl/g)
Extrusion temperature (8C)
Extrusion rate (rev/min)
Twisted or un-twisted
21 21 21 37 37 15
3.8 3.8 3.8 6 4 1.7
225 225 225 200-235 235 200
100 300 500 100 100 200
Un-twisted Un-twisted Un-twisted Un-twisted Twisted Un-twisted
Tex (g/1,000 m)
Elongation (per cent)
Tenacity (N/tex)
89.5 32 20 85 85 8.5 9.2
3.6 ^ 0.1 79.1 ^ 8.6 3.8 ^ 0.1 2.9 ^ 0.4 1.7 ^ 0.3 3.9 ^ 1.0 27.1 ^ 4.0
0.062 ^ 0.001 0.097 ^ 0.011 0.098 ^ 0.005 0.041 ^ 0.004 0.030 ^ 0.007 0.091 ^ 0.007 0.203 ^ 0.029
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Table I. Yarns produced from PURASORBw PLLA polymer
Table II. Initial properties of the yarns measured to the yield point
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period, in a parallel experiment, the yarns PLLA A, PLLA B, PLLA C and PLLA F were also tested immediately after the immersion period while still wet. After the degradation period, the yarns were removed, rinsed three times with de-ionised water, then conditioned for 72 h before testing. To determine the degradation effects the samples were weighed and observed (sputter coated for 45 s) under the scanning electron microscope (SEM) (Hitachi s-530), before and after the immersion period. Plain knit fabrics were knitted on a 6 in. gauge weft knitting machine, Culzean Fabrics, Kilmarnock, UK, from the PLLA A, PLLA B and PLA G yarns. Fabrics were mounted onto a vice and an Instron (1122, Instron Ltd) tensile testing rig (crosshead and test speed set at 100 mm/min and tension load compression cell 200 N; n ¼ 5) with a probe was used to obtain the load at break. After removing the spin finish, the fabrics were autoclaved in membrane rigs, which created a 10 mm space between the fabric and surface of a 60 mm Petri dish. Dishes were seeded with 22:4 £ 104 Hep G2 cells, a liver cell line (0:8 £ 104 cells/cm2; 88 per cent viability) and cultured (378C, 5 per cent carbon dioxide in air) for 8 days. The cells were observed daily during the culture period, then at the end, detached by trypsin and the cell density calculated. 4. Results The pH of the buffer solution gradually increased throughout the degradation period, even after the buffer was changed in week 5. Figure 1 shows the change in pH over a month for various PLLA yarns under static conditions. A control experiment showed that the oven temperature affected the pH; probably caused by evaporation. The change in tenacity of the yarns during the degradation period is shown in Figure 2. The commercial yarn PLA G had the highest tenacity throughout the degradation period, which appeared to increase. The PURAC PURASORBw PLLA yarns extruded in-house showed a decline in tenacity throughout the
Figure 1. The effect of yarn degradation on the pH of the PBS solution
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Figure 2. The effect of degradation in PBS solution on the tenacity of PLLA yarns
degradation period. The PLLA A yarn showed the most notable decrease in tenacity, which dropped by roughly from 0:065 ^ 0:002 to 0:014 ^ 0:004: The changes over a 4-week period in load at yield point of various PLLA yarns, measured when wet and dry, are shown in Figure 3. The graph shows that as before, when measured wet and dry, the tenacity declines during the degradation period. The tenacity of the yarn PLLA F appears to be lower initially when wet, but both wet and dry values are similar after 4 weeks of
Figure 3. The changes in tenacity of PLLA yarns during degradation, measured when wet and dry
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Figure 4. SEM photomicrograph of PLLA A after degradation
Figure 5. SEM photomicrograph of PLLA E after degradation
degradation. Before the degradation period, when observed under the SEM all the fibres in the yarns were relatively smooth. The following yarns showed definite signs of degradation after 10 weeks in phosphate buffer solution, pH 7.4: PLLA A, PLLA D and PLLA E. The yarn PLLA A shows surface degradation (Figure 4), while the PLLA E yarn shows possible hollowing of the fibres (Figure 5). When knitted, the PLLA A fabric was the strongest, load at break 110 ^ 9 N; while the fabric produced from the commercial yarn PLA G was the weakest, load at break 46 ^ 10 N: After 6-weeks immersed in PBS, pH 7.4, the PLLA A and PLLA B fabrics had lost more than 80 per cent of their strength; unlike the commercial fabric which retained its strength. Hep G2 cells were seeded onto the top of the fabrics. However, majority of the cells were observed on the Petri dish surface, probably due to the large pores in the fabric. When the dishes were observed on day 1, the cells were
attached and spreading on the Petri dish surface. On the PLLA A and PLLA B Design of textile fabrics, some spheroids were observed attached to the yarns, while mainly scaffolds single cells were observed on the yarns in the PLA G fabric. During the first few days, the cells looked healthy and cell coverage on the dishes increased. On day 5, the cells had a more granular appearance and very few cells were observed on any of the yarns. After 8 days, the dish containing the PLLA A 191 fabric had increased in cell number by 86 per cent, but the cells were only 7 per cent viable. The PLLA B and PLA G fabric dishes had a higher viability, 69 and 67 per cent, respectively, but had decreased in cell number by approximately 70 per cent. 5. Discussion The degradation period appeared to have the least effect on the commercial yarn, PLA G, which is probably attributable to the production methods. Extrusion of the PURASORBw PLLA polymer was moisture dependent and it was not possible to control the humidity in the lab. Also during the extrusion process, there may be small variations in the conditions resulting in an irregular yarn. Although lactic acid is found in the body, high concentrations can be toxic. During the first 4 weeks of the degradation period, the pH was monitored to ascertain if high concentrations of lactic acid are released. The pH of all the PBS solutions except the fridge control increased, although the PBS and yarn solutions had a lower pH than the oven control indicating that a small amount of lactic acid is released. The slow release of lactic acid under static conditions is encouraging, especially as some areas in the body are less vascularised. The results are in agreement with Reed and Gilding, who state that initially small amounts of lactic acid are released but this increases as the PLLA is broken down to low molecular weight oligomers (Reed and Gilding, 1981). Increased production of lactic acid may be a problem, particularly with larger scaffolds. The PLLA B, C and F yarns had reasonable initial tenacity values and they remained the most stable over the degradation period. These three yarns had moderate per cent elongation values which also remained relatively stable over the degradation period (Golding et al., 2003). A tissue engineering scaffold manufactured from a PLLA yarn should be rigid and strong enough to keep its shape while the cells grow, but able to move with the body. The properties of the yarns were measured dry and wet; the latter would be the condition inside the body. Although, after 4 weeks degradation, the dry and wet tenacity values are similar, over a longer period they may deviate. It would be useful to monitor the wet and dry values over a longer degradation period to assess the yarn properties more accurately. The yarns appear to undergo surface erosion of the fibres rather than bulk erosion. Gopferich (1996) states that when degradation occurs by surface erosion, it should be easier to predict the degradation rate. To aid surface
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degradation, the textile tissue engineering scaffolds should be designed to have a large surface area to volume ratio (similar to biodegradable sutures) and the amount of PLLA used should be minimised. Cell attachment to the surface of the yarns may slow down the degradation process by impeding the release and removal of lactic acid. However, inside the body, degradation by surface erosion should be safer than bulk erosion where there is the possibility of the fragments migrating. The yarns PLLA A, B and C were produced under the same conditions except for the extrusion rate. As expected, the PLLA B and C yarns had higher tenacity values. Extrusion at a faster rate should align the molecules in the polymer and there may be more crystalline regions holding the fibre together. As a result, less water should enter the structure, which would explain why the degradation period had a smaller effect on these yarns compared to the PLLA A yarn. The degradation process appeared to occur relatively quickly in the PLLA E yarn, which also showed possible hollowing, described by Gopferich (1996) as bulk degradation. This was the only BTRC yarn tested that had a small twist holding the yarn together. It would appear that the twist applied probably opens up the fibres, aiding the absorption of water, speeding up the degradation process. Often to make further processing easier, a small twist is applied to the yarn but if the yarn is for the production of tissue engineering scaffolds there may be degradation implications. Bulk erosion could result in small fragments being dislodged and the scaffold deteriorating, in terms of strength and shape, before the new tissue is formed. Poly(D ,L -lactic-co-glycolic) acid and PLLA films have been shown to be non-detrimental to primary rat liver cells (Cima et al., 1991). Cell attachment and the functions measured were comparable to the controls on collagen-coated dishes. In this initial study, lactic acid was released into the cell culture medium from the fabrics under static conditions over 24 h. Even though the majority of the cells had gone through the pores and attached to the Petri dish, it would appear that over the first few days the release of lactic acid does not affect the Hep G2 cells. After 1 week in culture, the cells had either increased in number but were non-viable or the viability and cell number had decreased by approximately 20 and 70 per cent, respectively. Initially, cell spheroids were observed on the PLLA fibres but they were not observed attaching and spreading; perhaps the fibre surface is too smooth for cell attachment. Only single cell attachment was observed on the immersed PLA G yarns, which appeared to be more loosely packed with a few surface features observed under the SEM. The next stage is to examine cell attachment on the individual fibres and yarns. 6. Conclusion This work shows that there are many factors that must be considered when designing a biodegradable textile tissue engineering scaffold. Factors such as
extrusion speed and twist have an effect on the degradation rate, while the Design of textile initial yarn properties and textile structure will affect cell attachment and scaffolds subsequent growth. With further knowledge, it may be possible to produce PLA yarns with known degradation and cell attachment characteristics for textile tissue engineering scaffolds. In conclusion, biodegradable textile tissue engineering scaffolds look promising for the future.
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Note 1. PURASORBw Monomers and biodegradable polymers, Biochem PURAC. References Burkersroda, F.V., Schedl, L. et al. (2002), “Why degradable polymers undergo surface erosion or bulk erosion”, Biomaterials, Vol. 23, pp. 4221-31. Cao, Y., Vacanti, J. et al. (1997), “Transplantation of chondrocytes utilizing a polymer-cell construct to produce tissue-engineered cartilage in the shape of a human ear”, Plastic and Reconstructive Surgery, Vol. 100 No. 2, pp. 297-302. Cima, L.G., Ingber, D.E. et al. (1991), “Hepatocyte culture on biodegradable polymeric substrates”, Biotechnology and bioengineering, Vol. 38, pp. 145-58. Golding, C., Ekevall, E. et al. (2003), “The effect of degradation on the mechanical properties of biodegradable polylactide yarns and textiles”, Medtex03, International Conference and Exhibition on Healthcare and Medical Textiles, 8 and 9 July 2003. Available at: www. digitalwebbooks.co.uk, Bolton, UK Gopferich, A. (1996), “Mechanisms of polymer degradation and erosion”, Biomaterials, Vol. 17 No. 2, pp. 103-14. Heidaran, M.A. (2000), “Tissue engineering: a biological solution for tissue damage, loss or end stage organ failure”, Iranian Biomedical Journal, Vol. 4, pp. 1-5. Hutmacher, D.W., Goh, J.C.H. et al. (2001), “An introduction to biodegradable materials for tissue engineering applications”, Annals Academy of Medicine Singapore, Vol. 30, pp. 183-91. Kleinman, H.K., Klebe, R.J. et al. (1981), “The role of collagenous matrices in the adhesion and growth of cells”, The Journal of Cell Biology, Vol. 88, pp. 473-85. Mikos, A.G. and Temenoff, J.S. (2000), “Formation of highly porous biodegradable scaffolds for tissue engineering”, Journal of Biotechnology, Vol. 3 No. 2, pp. 114-9. Reed, A.M. and Gilding, D.K. (1981), “Biodegradable polymers for use in surgery – poly(glycolic)/poly(lactic acid) homo and copolymers: 2. In vitro degradation”, Polymer, Vol. 22, pp. 342-6. Saltzman, W.M. (2000), “Cell interactions with polymers”, in Lanza, R.P., Langer, R. and Vacanti, J. (Eds), Principles of Tissue Engineering, Academic Press, FL, pp. 221-35. Sittinger, M., Bujia, J. et al. (1996), “Tissue engineering and autologous transplant formation: practical approaches with resorbable biomaterials and new cell culture techniques”, Biomaterials, Vol. 17 No. 3, pp. 237-42. Wallace, S.R. (2002), Unpublished Data: The Production of PLLA Fibres, Heriot Watt University. Watts, G. (2001), “Walk like an Egyptian”, New Scientist, Vol. 31, pp. 46-7. Yuan, X., Mak, A.F.T. et al. (2002), “In vitro degradation of poly(L -lactic acid) fibers in phosphate buffered saline”, Journal of Applied Polymer Science, Vol. 85, pp. 936-43.
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Material design and textile science for specialty textiles technologies T. Matsuo SCI-TEX, Ohtsu-city, Japan Keywords Textile technology, Design Abstract The relation of material design and textile science to the technologies of textile specialty products are discussed. Concept of material design is explained. The method of differential total material design is presented with an application example. The relation of material design to specialty textiles technology is analyzed. The relation of textile science to material design in terms of specialty textiles technology is also discussed. Some examples of scientific knowledge in terms of data base for material design are presented.
1. Introduction In most advanced countries, textile industry has changed to produce high value added textile products. But globally competitive situation has made textile industry in developing countries also take an interest in supplying such specialty products. In this sense, nowadays technologies of specialty textiles have become more important in the textile industry. In this paper, specialty textiles mean the fabrics for apparel use, which have a certain special value as material base. Textile specialty products need some specific technologies in addition to the ordinary technologies for producing conventional products. On the other hand, R&D activities have so far accumulated a large amount of knowledge in textile science and technologies. It is thought that such knowledge must be effectively used for the development of such specialty product technologies. But there has been almost no text, which is useful for systematically bridging such knowledge to specialty products technologies. On the other hand, there has been almost no literature in which the method for material design for textile products is systematically presented. In this paper, the author tries to present the method as the system of differential total material design (DTMD). In the technology of specialty products, material design is situated at the core part. Data base of knowledge based on textile science must be one of the most useful information sources for conducting the material design. In this paper, the position of textile science and material design will be clarified in relation to specialty textiles technologies. International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 194-203 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520478
2. Method of material design for specialty textile products 2.1 Concept of material design and its character The design of textile products can be classified by the following three kinds of criteria:
(1) the kind of designing object, (2) the range of design phase, and (3) the degree of design freedom. The categories of “material design” and “color pattern design” are introduced in the 1st criterion. The object of material design is related to “property/effect of material products, material structure and material manufacturing method”. Color-pattern design is related to aesthetic effect based on color-pattern of products. But there is a partial region overlapped by these two kinds of designs, in which material visual effect is one of the objective elements. In the case of color-pattern design, CG technology is widely used. But material design work is still usually carried out by trial and error method based on personal experience and knowledge of the designer. Total design and partial design are introduced by the concept based on the range of design phase. The total phases of design consist of “conceptual design” (CPD), “function/effect design” (FED), “basic structure design” (BSD), “basic manufacturing method design” (BMD) and “detail manufacturing method design” (DMD), as explained later in detail. Total design covers all or most parts of these phases. Partial design concerns only a specific phase or some specific phases. The last criterion is the degree of freedom in the product structure of design object. High freedom design is the design in which the designer can creatively settle the product structure at the basic structure design, while modificational design is the design in which the basic structure must be in the neighborhood of a specified structure. Designing textile products of apparel use mostly belongs to the modificational design. The design using high freedom is often required for designing technical textile products. 2.2 The method of differential total material design This method is a kind of material, total, and modificational design. Its feature is to use reference sample. The frame of its system is shown in Figure 1 (Suresh et al., 1997a, b). It is expected that the system will be established as CAD system in the near future. But it is obliged to be carried out manually. In the CAD system, the designer communicates with the system through interface module. But in the case of manual system, he directly carries out all the design works from CPD to BMD or DMD. For the system, factual data of reference sample must be introduced by a certain mean. At least the factual data and knowledge on the relationships between property and structure, and cost estimation module, in the field of the objective product, must be available. The factual data can also be obtained through structural analysis and/or measurements of the reference sample. The knowledge can be obtained from scientific literatures/texts and technical experiences.
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Figure 1. The frame of DTMD
CPD in the system is carried out by conceptually settling the differential feature of the design-objective product from the reference sample. FED is to objectively characterize the feature in the form of difference from the reference sample. BSD is to settle the product structure to realize the FED. BMD is to settle the manufacturing method to realize the BSD. Both BSD and BMD are also differentially conducted based on the factual structure and manufacturing method of the reference sample, respectively. DMD is also conducted to realize BMD, if necessary. 2.3 Detail working steps in DTMD and an example of its application In this section, the detail working steps in DTMD system are explained using a design example (Suresh et al., 1997a, b). At first the objective product species to be designed must be imaged (worsted fabric for black formal wear in the case of the example). The reference sample must be suitably selected in the relation to the imaged product (in this example, it is worsted weave of black formal wear use which the company is commercially supplying). CPD is to conceptually state the feature of the objective product in the form of the difference from the reference. In this example, CPD is: (1) deeper black worsted weave than the reference sample, whose (2) hand is almost equivalent to that of the reference, and (3) production cost can be a little higher.
Working steps for conducting FED in the CAD system are shown Figure 2. In this phase, if necessary, translation from the conceptual expression word to objective word must be carried out. SEN_EXP module for the translation in the CAD system is utilized for this work. The objective word expression must be usually converted into numerical value using knowledge on the relationship between the objective word expression and numerical value, with the assistance of SCI_DB in the CAD system. In this example case, (1) “Black” is converted into L-value. L-value of the reference sample and general knowledge on subliminal threshold of the difference in L-value gives the design as “L must be 11-12”. (2) The KES values of reference sample are: B ¼ 0:09 0:11ðgf cm2 =cmÞ: Hence, the above data are converted to design values of “hand”, as they are. (3) Concerning its production cost, the meaning of “can be a little higher” is translated into the design that cost-up must be within 10 percent. Thus, the result of FED shown in Figure 2 can be obtained.
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Figure 3 shows the working steps to conduct BSD and BMD. In these steps, the factual data (in Figure 3, FACT_DB in CAD system) of reference sample on basic structure and basic manufacturing method are utilized. Knowledge and experiential data on the relationship (SCI_DB and IND_DB) between property and structure must also be fully used. A_BSD in the figure is the assumptive BSD, which can be deduced based on the factual data of the reference sample on basic structure and the information/knowledge on the relation between the basic structure and property. Works of BMD using A_BSD thus obtained, the factual data of reference sample on basic manufacturing method, and knowledge/experiential data on basic manufacturing data in terms of the
Figure 2. Working flow of FED
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Figure 3. Working flow of BSD and BMD
basic structure can derive A_BMD (assumptive basic manufacturing design). Estimated cost (cost_EST) can be obtained based on A_BSD, A_BMD and data base of cost. On the other hand, estimated property (FED_EST) can be obtained based on A_BMD and SCI_DB/ IND_DB. The suitability of A_BSD and A_BMD are judged using SUT_FAB module by comparing the estimated property and cost thus obtained to FED settled earlier. If the result of the judgment is satisfactory, then A_BSD and A_BMD become BSD and BMD, respectively. In the case that the result is not satisfactory, trial works to find BSD and BMD must be repeated according to the steps explained above (Suresh et al., 1997a, b). The result of BSD for this example is: (1) Fiber: Australian wool whose average diameter is 19.7 mm; (2) very thin layer of a certain resin having low refractive index is coated on the surface of the fiber; and (3) the other structural parameters are same as those of the reference. The result of BMD is: (1) After fabric dyeing, chlorination is applied and then the coating by resin X is carried out; and
(2) the other manufacturing parameters are same as those of reference sample.
3. Relations of textile science and material design to specialty textiles technologies 3.1 Relation of material design to specialty textiles technologies Material design is usually situated as the core part in the technology of specialty products. But the latter includes technological means (manufacturing technology) itself to realize the contents settled by the works of material design. On the other hand, the object of the former can include non-specialty products. 3.2 Relation of textile science to material design to specialty textiles technologies Textile science has borne a huge amount of knowledge. As schematically shown in Figure 1, material design of textile products must effectively make use of the data base of this kind of knowledge. But material design must also effectively make use of the industrial factual data accumulated in the company/organization. The latter information is usually more excellent in accuracy in the range of factual experience. On the other hand, scientific knowledge can cover wider range in principle bases. Anyhow, textile science can effectively contribute to the progress of textile products technologies through material design. Hence, it must be desirable that the knowledge of textile science must be stored in the form of data base in which the information is easily accessible for the material designers. 4. Scientific knowledge arranged in the form of attributive specialty items 4.1 Attributive specialty items and their relation to specialty technologies Here, attributive specialty item means the specially featured item of function/effect in terms of specialty products. When textile scientific knowledge is arranged in the form of attributive specialty items, it can be most convenient in its effective use for material design. In the case of design example described in Section 2.3, it is a material design for worsted weave of black formal wear, which has very deep blackness. In this case, the specialty product technology has only one attributive specialty item as “blackness”. But for example, if hollow fiber is adopted to realize lighter fabric, the fiber can give warmer fabric at the same time. Therefore, the specialty product technology has two kinds of attributive specialty items: lightness and warmness. In this paper, specialty product technology corresponding to the individual attributive specialty item is simply called as “attributive technology”. Hence, usual technology of specialty product can include a plural of attributive technologies.
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4.2 The contents of attributive specialty items There can be many kinds of attributive items of specialty. But the author would like to propose one of their systematical classification systems as shown in Table I. It must be noted that this kind of classification is useful for arranging both items of specialty textiles and items of knowledge of textile science.
1. Visual aesthetic effect Surface profile, fabric grain, fabric pattern, texture Dye-ability, color develop-ability Luster Melange effect, fancy effect 2. Sensual aesthetic effect Compression Friction Bending 3. Micro-climate comfort-ability Warmness Coolness Reduction of sweaty humidity Reduction of sweaty stickiness Waterproof keeping lower moisture micro-climate 4. Wearing comfort-ability Stretchiness Lightness Slip-ability Reduction of clinging 5. Easy care Crease/wrinkle resistance Wash-ability, dimensional stability, dry-ability Anti-pilling Soil resistance Moth proofing 6. Garment making-up capability Silhouette formability Sew-ability Garment anti-deformation
Table I. Classification of attributive items of specialty
7. Hygienic, safety, environmental friendliness Non-toxic, environmental friendliness Skin-care, UV-guard Heeling effect Anti-bacteria, smell proof Deodorizing Anti-staticity Flame retardancy
4.3 Examples of scientific knowledge in terms of data base for material design In this section, some examples of scientific knowledge in terms of data base for material design are presented as a trial. In the first part, tactile feeling is simply analyzed in its relation to mechanical properties. This can be a data base for “Sensory expression conversion module” indicated in Figure 1 and SEN_EXP in Figure 2. In the second part, the relationship between property and structure in the bending properties of woven fabrics are simply explained and the technological means to realize the structure are also simply described. They can be used as data bases for “Data base for selecting structure” and for “Data base for manufacturing design” shown in Figure 1. 4.3.1 Tactile feeling (hand) in terms of objective properties. Tactile feeling of fabrics can be explained by connecting principally to their bending, compression, friction properties including surface roughness (Howorth and Oliver, 1958). In other words, it is a feeling caused by some or all of these properties. When a person tries to objectively analyze his tactile feeling of fabric by himself in the relation to fabric mechanical properties by a proper way, he will be able to find the mechanical content of his feeling (Harada et.al., 1997). In the quality of fabrics of apparel use, tactile feeling is one of the important elements of their assessment. Tactile feeling is usually characterized by sensory expression. But sensory expression is often in lack of objective exactness, by nature. In the material design of fabrics, such expression of tactile feeling by sensory words must be translated into expression by such mechanical properties as bending, compression and friction. The translation can be conducted by the above-mentioned proper analysis. If there is a kind of dictionary from the words of tactile sensory expression to the words of mechanical property for the translation, the translation work can be facilitated (Harada et al., 1971). Bending property of woven fabrics in terms of structural parameters and technological means (1) Representative property parameters of the bending property: Bending rigidity B and bending hysteresis HB. (2) The relation of main structural parameters to the property parameter B: B ø K B abc, where KB is a coefficient, a is the fiber bending modulus, b is the number of fiber within a yarn, c is the number of yarn per unit length of fabric (yarn density). KB decreases with an increase in yarn twist and waviness of yarn within the fabric, and with a decrease of contact force at inter-yarn crossing and a decrease of fiber friction coefficient. (3) The relation of main structural parameters to property parameter HB: HB ø bcd þ K HB1 efh þ K HB2 egh
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where d is the fiber bending hysteresis, KHB1 is the coefficient, KHB2 is the coefficient, e is the yarn thickness in the fabric thickness direction, f is the contact force of inter-yarn crossing, g is the pressure of intra-yarn, h is the friction coefficient of fiber. (4) The technological means to realize the structural parameters: a is the selection of fiber, b is the selection of yarn, c is the selection of weave structure, KB is the selection of yarn twist and is decreased by relaxation of fabric at finishing process and weight, reduction treatment at fabric finishing process, d is the selection of fiber, e is the selection of yarn and weave structure, f is the is decreased by relaxation of fabric at finishing process, weight reduction treatment at fabric finishing process and fiber cross-sectional shrinkage at fabric finishing process, g is the is decreased by the decrease of f; weight reduction treatment and fiber cross-sectional shrinkage at the fabric finishing process, h is the decreased by fiber coating with lubricant. 5. Concluding remarks In this paper, the system of (DTMD) was presented. Material design is situated as the core part of specialty textiles technology. Knowledge for conducting the design is supplied from textile science and factual experience in textile industry. Attributive items of specialty usually present the mean for effectively summarizing these kinds of knowledge. In this paper, the relation among material design, textile science and attributive items of specialty are clearly related in terms of specialty textiles technologies. Finally, examples of knowledge based on textile science for tactile feeling and bending properties of woven fabrics in terms of material design are simply presented. Concerning material design system, this paper describes only its frame. But material design will be more important in the relation to specialty textiles technologies in the future. Knowledge based on textile science must be more effectively applied to designing. In this sense, the author expects that material design system will be well established for practical use as a CAD system in the near future. In that case, textile knowledge must be summarized based on textile science as a useful data base for the system.
References Harada, T., Saito, M. and Matsuo, T. (1971), “Study on the Hand, part 3”, J. Text. Machinery Soc., Vol. 17, p. 111. Harada, T. et al., (1997), “Measurement of fabric hand by sensory method and inspection on its effectiveness for worsted woven fabrics”, J. Text. Machinery Soc., Vol. 43, p. 47.
Howorth, W.S. and Oliver, P.H. (1958), “The application of multiple factor analysis to the assessment of fabric handle”, J. Text. Inst., Vol. 49, p. T540. Suresh, M.N., Matsuo, T. and Nakajima, M. (1997a), “Computer-assisted total material design of woven fabrics for apparel use, part 1”, J. Text. Machinery Soc., Vol. 50, p. T146. Suresh, M.N. and Matsuo, T., et al. (1997b), “Computer-assisted total material design of woven fabrics for apparel use, part 2”, J. Text. Machinery Soc., Vol. 50, p. T323.
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Further reading Matsuo, T. (1997), “The design logic of textile products, textile progress”, The Textile Institute, Vol. 27 No. 3.
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Folding algorithms and mechanisms synthesis for robotic ironing J.S. Dai Department of Mechanical Engineering, School of Physical Sciences and Engineering, King’s College, University of London, London, UK
P.M. Taylor School of Mechanical and Systems Engineering, University of Newcastle upon Tyne, UK
H. Liu Department of Mechanical Engineering, School of Physical Sciences and Engineering, King’s College, University of London, London, UK
H. Lin School of Mechanical and Systems Engineering, University of Newcastle upon Tyne, UK Keywords Robotics, Modelling, Textiles Abstract Automating domestic ironing is a challenge to the robotic community, particularly in terms of modelling and advanced mechanism design. This paper investigates the ironing process, its relevant folding algorithms and analysis techniques, presents the advanced mechanism synthesis and introduces cross-disciplinary research. It summarises the second part of the results of a technology study carried out under an EPSRC grant “A Feasibility Study into Robotic Ironing”, and proposes new techniques in developing a folding and unfolding algorithm and in developing a task-oriented mechanism synthesis for robotic ironing.
1. Introduction With the fast expansion of computer technology and the enhancement of living standard, most domestic electrical appliances have been updated to an advanced and intelligent level. This results in new washing machines with intelligent chips and a new generation of clothes. However, for many hundreds of years, the conventional ironing has never been changed. Though improvements have been implemented by altering the steam pressure or by International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 204-214 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520487
J.S. Dai. Tel: +44 (0) 20 7848 2321; Fax: +44 (0) 20 7848 2932; E-mail:
[email protected]; Web site: http://www.eee.kcl.ac.uk/mecheng/jsd/. The financial support from the Engineering and Physical Science Research Council (EPSRC) under grant numbers GR/R90857 and GR/R90840 is gratefully acknowledged.
upgrading the sole plate, or by promoting different fabrics to reduce the occurrence of creases, no significant changes have been made particularly in terms of material handling and traditional steps of ironing. A domestic chore has not been changed substantially during the past century. The domestic iron is still little more than a temperature-controlled flat iron, requiring time-consuming and sometimes strenuous manual operation. However, ironing is usually seen as an unavoidable task and the dullest chore in our domestic work. In a typical household, several hours are spent every week on ironing clothes. In an EPSRC project of studying the feasibility of robotic ironing (Dai and Taylor, 2003a; Taylor and Dai, 2003), focus groups were set up and a systematic survey was carried out (Stewardson et al., 2003). About 70 per cent of the people cited it as an unavoidable chore, whilst 90 per cent among these strongly disliked ironing and 30 per cent relied on some entertainment to distract them from the boring task. With the sluggish progress and superficial changes of ironing products, 85 per cent of them look forward to the revolutionised automatic ironing devices. It is quite clear that there is a tremendous potential market. There is a need ( Dai et al., 2004; Taylor et al., n.d.) to integrate these techniques and to investigate necessary ironing techniques for domestic use and a need to develop a domestic robotic ironing machine. Ironing techniques can be reflected in the basic functional steps as follows: . picking up the items from the washing basket; . sorting the items according to the type of material; . positioning the item, ready to iron the item; . ironing the item; . removing the item; and . folding/hanging the item. During the ironing, a further handling process is required as: . fetching a garment; . stretching and spreading out the garment; . pre-aligning the seams; . placing one part of the garment on an ironing board; . stretching again and shaping the garment; . checking the alignment of the seam; . assessing the severity of the creasing and the action needed to remove them; . ironing the part, checking the result as necessary; . shifting and placing another part of the garment; . stretching and shaping;
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. .
repeating the ironing; and folding.
Most tasks involve garment gripping and handling and require a flexible mechanism(s) which shall complete all tasks. A consequence of this presents momentous challenges to ironing process and provides significant technological challenges for robotics. In these tasks, there is a need for identifying garment items for implementing folding algorithms and for developing dexterous mechanisms for garment handling and manipulation. This paper investigates these needs, to present the research results obtained so far and to propose new techniques in folding and mechanism synthesis. 2. Motion modelling Automatic ironing needs identifying the required path ( Dai et al., 2003) with desired orientation. This starts by looking at the ironing motion produced by an operator. This motion can be considered as a three-dimensional movement with two translational movements and one orientation change ( Dai and Shah, 2003; Shah and Dai, 2002). Thus, a twisting motion on a garment can be represented in an image space (Dai, 2002; Dai et al., 1995) with two axes standing for translations and a vertical axis standing for the orientation of the ironing. Figure 1 shows the ironing movement and orientation of an iron. For ironing a strip of fabric, the ironing motion is shown in Figure 2. For ironing a bedding or a large area of garments, different ironing techniques require different motions which use a large part of orientation as shown in Figure 3.
Figure 1. Orientation and movement representation of an ironing process
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Figure 3. A motion representation of an ironing technique
3. Folding and unfolding The first step of unfolding is to isolate washing masses. Research on saving labour of household work and automation for housekeeping robots has gained importance due to the growing population and fast advancement in electronics. There is a need for a robot to deal with a variety of “non-solid” household objects, for example, putting clothes in order at a specified site. Concrete subtasks involve removing a cloth from the washing machine, spreading out, classifying, folding and putting it in a specified place. In these operations, folding and unfolding garments is an essential step. The prominent research is isolating (Kaneko and Kakikura, 2001) clothes from a washed mass to obtain reasonable results based on the region segmentation of images of washed mass and the determination of grasping points. Isolating is a key technique in picking clothes from washed mass (Hamajima and Kakikura, 1998). The colour imaging techniques are used and region segmentation with lighting is performed.
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Folding and unfolding are more complicated than isolating clothes. Research ( Paraschidis et al., 1995) has been carried out relying on a vision system placed above the table that its visual axis forms an angle of 308 with the vertical, in such a way that the target edge appears at the lower edge of the acquired image. The edge of the perimeter of the fabric is extracted. The folding edge is identified and its coordinates in the manipulator-base co-ordinate system are calculated. The target edge is also identified in the image and the relative distance between the two edges is calculated. The arm is moved along a trajectory that is calculated in real time using the information from the camera. Vision sensing is used for the identification and location of the two edges is to be matched for tracking the target edge during the operation. Some folding tasks have been implemented experimentally. A hand/eye system for unfolding fabric was developed (Ono et al., 1998). In the device, a mobile camera was installed at the end of a robot arm to trace an object motion and a hand was used as a tactile sensor and a fabric thickness check sensor by measuring fingertip distortion. Fabric unfolding was implemented by combining visual sense information for predicting an edge corner and tactile sense information for determining whether the robot hand came into contact and grasped the fabric. However, for a complicated task, new algorithms are required to be produced, which can be implemented in a computer programme and which can be carried by a housekeeping robot. In this, graph theory is tested in garment unfolding to an extent of unfolding clothes from a piled mass for ironing. In complementary to this work, the graph-based method has been used successfully in paper folding, where a paper is divided into several regions according to the net for folding. These regions are numbered and the corresponding adjacency matrix and topological graph are produced. This produces a hereditary matrix which is used for predicting folding sequences and for handling and manipulation ( Liu and Dai, 2002a, b). The algorithms in other disciplines in the study of protein folding have the potential impact. Though they are in different fields, the principle of using automatic assembly in protein folding relying on the chain and fibre structure can be used. A study (Song and Amato, 2001) was carried out by associating the folding problems of flimsy materials to that of protein folding, where collisions were to be sorted out between the material and device with a probabilistic roadmap. The planning strategy of a robot that can tidy-up clothes can be described as follows. Some of the concrete subtasks of this robot are; taking out one cloth, expanding, classifying, folding, and putting it on the specified place including the processes involved in the unfolding task of washed wears. In these processes, they have examined the isolation of cloth from a washed mass, and obtained reasonable results on the region segmentation of images of washed mass and the determination of grasping points.
Implementing the folding algorithms ( Dai and Rees Jones, 2002; Liu and Dai, 2002a, b), region analysis ( Dai and Taylor, 2003b) has been proposed. The technique divides a garment into regions, which were then mapped onto a graph, a set of algorithms is then applied to automate the folding and unfolding. This has now been tested. Figure 4 shows the first step of this technique for developing a folding algorithm. This will then be developed into a set of algorithms for folding and unfolding (Liu and Dai, 2002b) (Figure 5).
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4. Dexterous mechanisms for handling and mechanisms synthesis Handling mechanisms are key elements for automated ironing, which requires dexterous mechanisms ( Dai and Rees Jones, 1999; Dai and Shah, 2002; Dai et al., 1995, 1996; Kelley, 1991; Taylor, 1994) and robotic hands. An anthropomorphic hand intends to mimic a human hand, which has a complex anatomical and sensory structure forming an exceptionally versatile end-effector and which is of particular advantage where the manipulative tasks place a premium on dexterity rather than power ( Dubey and Dai, 2001; Jacobsen et al., 1986). Anthropomorphic hands in this respect make use of human knowledge, relying on a large database for gripper models and sensors for feedback. A typical pneumatically-operated dexterous hand (Caldwell and Tsagarakis, 2000) has multiple degrees of prehension using a skeletal model of the human hand and pneumatic actuators are used to drive the finger joints, making use of compliant drives to produce a “soft” but highly flexible mechanism to handle delicate products and materials. The use of anthropomorphic hands is restricted in many specialised areas and restricted by the high costs and limitation in this type of hands. This results in the wide use of mechanical hands. In a machine context, multi-fingered robot hands are similarly able to perform manipulation tasks with human like dexterity in grasping and manipulating objects of various sizes and weights. Though many mechanical hands were produced, a typical hand was shown at a five-digit hand (Rakic, 1989), which used three motors to control the thumb and two fingers. The thumb can rotate from a position
Figure 4. Region analysis and the corresponding graph analysis
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Figure 5. Corresponding folding algorithm
aligned with the four fingers to opposing positions with three of four fingers. The other fingers use a differential lever to rotate about the finger joints. The design is flexible in its ability to grasp an object in a variety of configurations. Flexible grippers raise much interest. A flexible robotic hand for handling fabric pieces (Ono et al., 1992) in garment manufacture consists of two fingers with two degrees of freedom. One fingertip is from balsa wood and the other from phosphor bronze plate with a strain gauge attached. To adapt to the flexible handling, an eight-axis gripper ( William, 2000) was presented to configure itself in real time to conform securely to a wide variety of part shapes without tool-change interruptions. Using mechanism intelligence, an underactuated hand was produced ( Lalibete´ and Gosselin, n.d.) which generates different grasping configurations with three adaptable fingers but only one actuator. To increase the adaptability, a reconfigurable multifunctional hand ( Dubey et al., 1999; Liu and Dai, 2003) was developed targeting at non-rigid material handling which has high torque motors directly mounted on joints of fingers with reconfigurable fingers. Of the hand, the dexterity of fingers meets the specific target and the reconfigurability (Ghafoor et al., 2000) of fingers meets the demand in handling and manipulation (Figure 6). The design of the mechanism needs to be based on the required ironing functions. This starts from a function table ( Dai et al., 2003) of an ironing process, followed by producing similar coefficients, with a motion matrix developed. These integrate into the functionality of automated ironing machines. The task-oriented design ( Dai et al., 1996) can then be used for mechanism design ( Dai and Kerr, 1991).
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5. Conclusions This paper investigated ironing motion particularly the folding and unfolding techniques by summarising the latest development in this area and proposed a new technique to be applied to automatic ironing and available for a robot
Figure 6. Correlation between functional parameters and design parameters
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implementation. The proposed new technique has potential to implement a related algorithm for automated folding. It further presented the development in gripping and handling mechanisms and proposed a new approach of synthesising dexterous handling mechanisms from the requirements of ironing and handling functions. This opens a new avenue in developing garment handling mechanisms.
References Caldwell, D.G. and Tsagarakis, N. (2000), “‘Soft’ grasping using a dextrous hand”, Industrial Robot, Vol. 27 No. 3, pp. 194-9. Dai, J.S. (2002), “Advances in robotic dexterous manipulation: methodologies for synthesis”, Tutorial to 2002 IEEE International Conference on Intelligent Robots and Systems (IROS), September 2002, Lausanne, Switzerland. Dai, J.S. and Kerr, D.R. (1991), “Geometric analysis and optimisation of symmetrical watt 6-bar mechanisms”, Journal of Mechanical Engineering Science, Proc. IMechE, Vol. 205 No. C1, pp. 275-80. Dai, J.S. and Rees Jones, J. (1999), “Mobility in metamorphic mechanisms of foldable/erectable kinds”, Journal of Mechanical Design, Transactions of ASME, Vol. 121 No. 3, pp. 375-82. Dai, J.S. and Rees Jones, J. (2002), “Kinematics and mobility analysis of carton folds in packing manipulation”, Journal of Mechanical Engineering Science, Proc. IMechE, Vol. 216 No. C10, pp. 959-70. Dai, J.S. and Shah, P. (2002), “Orientation capability of planar serial manipulators using rotatability analysis based on workspace decomposition”, Journal of Mechanical Engineering Science, Proc. IMechE, Vol. 216 No. C3, pp. 275-88. Dai, J.S. and Shah, P. (2003), “Orientation capability of planar manipulators using virtual joint angle analysis”, Mechanism and Machine Theory., Vol. 38 No. 3, pp. 241-52. Dai, J.S. and Taylor, P.M. (2003a), “Research report 2 on the feasibility study of robotic ironing”, EPSRC Report on GR/R90857/01. Dai, J.S. and Taylor, P.M. (2003b), “Region analysis for automated ironing”, Journal of Robotics and Mechatronics, (in preparation). Dai, J.S., Holland, N. and Kerr, D.R. (1995), “Finite twist mapping and its application to planar serial manipulators with revolute joints”, Journal of Mechanical Engineering Science, Proc. IMechE, Vol. 209 No. C3, pp. 263-72. Dai, J.S., Holland, N. and Kerr, D.R. (1996a), “Task-oriented direct synthesis of serial manipulators using moment invariants”, Proceedings of the 24th ASME Biennial Mechanisms Conference, August 1996, Irvine, California, pp. 19-22. Dai, J.S., Kerr, D.R. and Sanger, D.J. (1995), “Intelligent grasping systems”, in Gray, J.O. and Caldwell, D.G. (Eds), Advanced Robotics and Intelligent Machines, IEE Control Engineering Series 51, Chapter 4, Pentland Press Ltd., Peter Peregrinus, Publisher of IEE, pp. 61-9. Dai, J.S., Taylor, P.M. and Sanguanpiyapan, P. (2003), “A QFD analysis of ironing”, International Journal of CAD (in press). Dai, J.S., Taylor, P.M. and Sanguanpiyapan, P. (2003), “Trajectory and orientation analysis of the ironing process for robotic implementation”, International Textile Design and Engineering Conference (INTEDEC), Heriot-Watt University, Edinburgh.
Dai, J.S., Taylor, P.M., Liu, H. and Lin, H. (2004), “Garment handling and corresponding devices – technology in robotic ironing”, 11th World Congress in Mechanism and Machine Science, Tianjing, China. Dubey, V.N. and Dai, J.S. (2001), “Modelling and kinematics simulation of a mechanism extracted from a cardboard fold”, International Journal of Engineering Simulation, Vol. 2 No. 3, pp. 3-10. Dubey, V.N., Dai, J.S., Stamp, K.J. and Rees Jones, J. (1999), “Kinematic simulation of a metamorphic mechanism”, Proceedings of 10th World Congress on the Theory of Machines and Mechanisms, Vol. 1, Oulu, Finland, pp. 98-103. Ghafoor, A., Dai, J.S. and Duffy, J. (2000), “Fine motion control based on constraint criteria under pre-loading configurations”, Journal of Robotic Systems, Vol. 17 No. 4, pp. 171-85. Hamajima, I. and Kakikura, M. (1998), “Planning strategy for task unfolding laundry – isolating clothes from a washed mass”, Robotics and Mechatronics, Vol. 10 No. 3. Jacobsen, S.C., Iversen, E.K. and Knutti, D.F. (1986), “Design of the Utah/MIT hand”, IEEE Conference on Robotics and Automation, San Francisco, California. Kaneko, M. and Kakikura, M. (2001), “Planning strategy for putting away laundry-isolating and unfolding task”, Proceedings of the 2001 IEEE International Symposium on Assembly and Task Planning (ISATP2001), Assembly and Disassembly in the Twenty-first Century (Cat. No.01TH8560), IEEE, Piscataway, NJ, pp. 429-34. Kelley, R.B. (1991), “Research on the automated handling of garments for pressing”, ICAR, Fifth International Conference on Advanced Robotics, Robots in Unstructured Environments, New York, Vol. 1, pp. 796-801. Laliberte´, T. and Gosselin, C. (1), “Simulation and design of underactuated mechanical hands”, Mechanism and Machine Theory, Vol. 33 No. 1, pp. 39-57. Liu, H. and Dai, J.S. (2002a), “Design analysis of a flexible carton-folding system with multiple robotic fingers”, Computer-Based Design: Engineering Design Conference 2002, July, London, pp. 659-66. Liu, H. and Dai, J.S. (2002b), “Carton Manipulation analysis using configuration transformation”, Proc. IMechE, Part C, Journal of Mechanical Engineering Science, Vol. 216 No. C5, pp. 543-55. Liu, H. and Dai, J.S. (2003), “An approach to carton-folding trajectory planning using dual robotic fingers”, Robotics and Autonomous Systems, Vol. 42 No. 1, pp. 47-63. Ono, E., Ichijo, H. and Aisaka, N. (1992), “Flexible robotic hand for handling fabric pieces in garment manufacture”, International Journal of Clothing and Technology, Vol. 4 No. 5, pp. 16-23. Ono, E., Kita, N. and Sakane, S. (1998), “Unfolding folded fabric using outline information with vision and touch sensors”, Journal Robotics and Mechatronics, Vol. 10 No. 3. Paraschidis, K., Fahantidis, N., Petridis, V., Doulgeri, Z., Petrou, L. and Hasapis, G. (1995), “A robotic system for handling textile and non rigid flat materials”, Computer in Industry, Vol. 26, pp. 303-13. Rakic, M. (1989), “Multi-fingered robot hand with self-adaptability”, Robotics and Computer Integrated Manufacturing, Vol. 5 No. 2/3, pp. 269-76. Shah, P. and Dai, J.S. (2002), “Orientation capability representation and application to manipulator analysis and synthesis”, Robotica, Vol. 20 No. 5, pp. 529-35. Song, G. and Amato, N.M. (2001), “A motion planning approach to folding: from paper craft to protein folding”, Proceedings of the 2001 IEEE International Conference on Robotics and Automation (ICRA’01), pp. 948-53.
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Stewardson, D., McGeeney, D., Burdon, C., Foulweather, T. and Gray, F. (2003), “Market research into an automated ironing machine”, Internal Report, RIWP2, Industrial and Statistical Research Unit, University of Newcastle upon Tyne. Taylor, P.M. (1994), “A toolbox of garment handling techniques”, IEE Colloquium on ‘Intelligent Automation for Processing Non-Rigid Products’, (Digest no. 1994/191). IEE, London, UK, pp. 1-14. Taylor, P.M. and Dai, J.S. (2003), “Research report 1 on the feasibility study of robotic ironing”, EPSRC Report on GR/R90840/01,. Taylor, P.M., Dai, J.S., Lin, H. and Liu, H. (n.d.), “Technologies for automated ironing”, International Textile Design and Engineering. William, Townsend (2000), “The barrett hand grasper-programmably flexible part handling and assembly”, Industrial Robot, Vol. 27 No. 3, pp. 181-8. Further reading Amato, N.M., Dill, K.A. and Song, G. (2002), “Using motion planning to map protein folding landscapes and analyze folding kinetics of known native structures”, Proceedings of the 6th International Conference on Computational Molecular Biology (RECOMB), April 2002, pp. 2-11. Breen, D.E., House, D.H. and Getto, P.H. (1992), “A physically-based particle model of woven cloth”, Visual Computer, Vol. 8 No. 5-6, pp. 264-77. Cugini, U., Denti, P. and Rizzi, C. (1996), “Design and simulation of non-rigid materials handling systems”, Mathematics and Computers in Simulation, Vol. 41, pp. 587-93. Du, R., Pande, V.S., Yu Grosberg, A., Tanaka, T. and Shakhnovich, E.I. (1999), “On the role of conformational geometry in protein folding”, J. Chem. Phys., Vol. 111 No. 22, 8 December 1999, pp. 10375-80. House, D.H. and Breen, D.E. (1990), “Particles: a natural parallel approach to modelling”, 3rd Symposium on the Frontiers of Massively Parallel Computation, Proceedings, (Cat No. 90CH2908-2), IEEE Comput. Soc, Press, Los Alamitos, CA, USA, pp. 150-3. Kabaya, T. and Kakikura, M. (1998), “Service robot for housekeeping – clothing handling”, Journal of Robotics and Mechatronics, Vol. 10 No. 3, pp. 252-7. Pande, V.S., Yu Grosberg, A. and Tanaka, T. (1995), “How accurate must potentials be for successful modeling of protein folding?”, J. Chem. Phys., Vol. 103, p. 9482. Seliger, G., Gottschalk, T. and Stephan, J. (1996), “Automated assembly of fabrics with different contours”, 27th International Symposium on Industrial Robots, Robotics Towards 2000, CEU@-Centroal Esposizioni UCIMU, Cinisello Balsamo, Italy, pp. 421-6. Taylor, P.M., Pollett, D.M. and Abbott, P.J.W. (1998), “The influence of environmental conditions on fabric handling”, Journal of Robotics and Mechatronics, Special Issue on Robotics and Non-rigid Materials, Vol. 10 No. 8. Welch, H.L. and Kelley, R.B. (1993), “The analysis of potential mating trajectories and grasp sites”, International Journal of Advanced Manufacturing Technology, Vol. 8 No. 5, pp. 320-8, UK. Xu, B. (1996), “An overview of applications of image analysis to objectively evaluate fabric appearance”, Textile Chemist and Colorist, Vol. 28 No. 5, pp. 18-23.
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Trajectory and orientation analysis of the ironing process for robotic automation
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J.S. Dai Department of Mechanical Engineering, School of Physical Sciences and Engineering, King’s College, University of London, London, UK
P.M. Taylor School of Mechanical and Systems Engineering, University of Newcastle upon Tyne, UK
P. Sanguanpiyapan Department of Mechanical Engineering, School of Physical Sciences and Engineering, King’s College, University of London, London, UK
H. Lin School of Mechanical and Systems Engineering, University of Newcastle upon Tyne, UK Keywords Modelling, Automation, Robotics Abstract Robotic ironing needs multidiscipline and requires a quantitative analysis of garment unfolding and ironing motion. This paper investigates the trajectories and orientation of the ironing process where particular geometry is presented in an analytical way. The trajectories produced from this process are analysed and presented with mathematical models to be possibly implemented in robotic automation. This paper further investigates the orientation of iron during the ironing process. It is revealed that the orientation is dependent on the regions of garment and on the closeness to an operator. The orientation is then integrated into the trajectory and presented in a 3D form in which the vertical axis represent the orientation and horizontal axis represent the position. This type of orientation analysis is then used to find similarity in motions to determine the most effective and efficient way of ironing a garment.
1. Introduction Life in the 21st century is characterized by the ever-increasing pace of technological advancement and the requirement for enhancing the quality of life. This brings a new look at domestic chores we have been enduring for generations. Ironing is one of the dullest and most time-consuming domestic tasks, but has not been changed for hundreds of years. With the development of technology, it is right time to revolutionise the ironing process using robotic automation. For this purpose, it is necessary to study how an ironing process performs and to characterise the ironing motion. It is necessary to divide J.S. Dai. Tel: +44 (0) 20 7848 2321; Fax: +44 (0) 20 7848 2932; E-mail:
[email protected]; Web site: http://www.eee.kcl.ac.uk/mecheng/jsd/
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complex tasks into smaller manageable subtasks for a robot to perform. It should be noted that the way a human operator performing the ironing task might not be the best way of ironing. Nevertheless, the study of manual ironing is essential for the optimisation of the ironing process for robotic automation. This paper focuses on the ironing process, mathematical modeling and representation of the iron trajectories and orientation for the robotic automation. The ironing process is characterised and a mathematical model is proposed that integrates two essential parameters in ironing as the iron orientation and position. An experiment was set-up for the investigation and data are presented in both 2D and 3D orientation spaces. 2. Similarity analysis of an ironing process based on ironing regions The initial study of manual ironing is conducted by analysing videos of both households and professionals performing the ironing. First, the type and regions of a garment are identified. Then the process of ironing is described in detail. This integrates a detailed description from various videos of different ironing regions of a garment into a combined flow chart for the garment to represent the overall ironing process of a garment. For the simplicity of illustration, the ironing process of a shirt is illustrated with detailed description of different ironing regions and the ironing motion. The areas of the shirt covered include the collar front and back, the body front and back and the left and right sleeves. From the detailed description of the ironing process by identifying similarity in the steps involved when a human perform ironing at different regions of a shirt, an overall flow chart for the shirt ironing process is shown in Figure 1(A). The shirt ironing process consists of three main tasks: handling, flattening and ironing. The identifying and checking tasks are considered to be the monitoring and control part of the process. The monitoring and control part is conducted continuously throughout the ironing process. This can be seen clearly by the existence of these identifying sub-tasks in Figures 1(B)-(D), respectively. Each of the identifying task/sub-task is designed to distinguish distinct parameters for different purpose so that an appropriate action is selected to be performed. The overall shirt ironing process flow chart may also be used to represent the general ironing process for other types of garments. 3. Mathematical description of ironing trajectories In Section 2, the overall ironing process for robotics implementation is deduced from the study of how humans perform ironing tasks. In this section, attempts are made to describe the ironing motion mathematically. The ultimate goal is to be able to implement the mathematical description of ironing profiles and path/trajectories for robotics automation.
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Figure 1. (A) Overall shirt ironing process flow chart; (B) handling sub-task; (C) flattening sub-task; and (D) ironing sub-task
3.1 Ironing motion The identified ironing movements are classified into two groups: discrete movement and continuous movement. These two movements are defined as follows. (1) Discrete movement is a distinct iron movement to remove the wrinkles or creases on the ironing garment. This discrete movement will be referred to as the “ironing profile”. (2) Continuous movement is a series of combination of the discrete movements or ironing profiles to remove wrinkles or creases on garment. These discrete movements are integrated into a continuous movement that will be referred to as the “ironing path” or “ironing trajectory”. The discrete movements are generally found in a small ironing area of a garment. The continuous movements are normally found in the larger ironing area.
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3.2 Ironing profile Each ironing profile can be represented by a mathematical function There are a number of ironing profiles, the common ironing profiles identified during the video analysis are shown in Table I. 3.3 Ironing path The ironing path can be represented by simply combining any of the mathematical function of the ironing profile (Figure 2). The ironing path for a shirt shown in Figure 3 is obtained by analysing the video clips of shirt ironing performed by a professional. This gives the ironing path when ironing the front left region of a T-shirt with three separate operations. The first operation gives an ironing path with a combination of ironing profiles in the following order: (1) straight line profile; (2) triangular periodic profile; (3) straight line profile; and (4) curved profile. The ironing path in the follow-on operation gives the following ironing profiles: (1) straight line profile; (2) triangular profile; and (3) curved profile. The third operation gives the ironing path with straight line profile and curved profile. Ironing profile
Table I.
Figure 2.
1 2
Straight profile Curve profile
3
Sinusoidal periodic profile
4
Triangular periodic profile
Mathematical function y ¼ mx+c, e.g. y ¼ 9 (0 # x # 2) y ¼ ax 3+bx 2+cx+d, e.g. x¼ y 3+2y (2 1 # x # 7) y ¼ A Sin mx or y ¼ B cos nx, e.g. y ¼ 2 Sin x (0 # x # 4p) e.g. y ¼ x (0 , x , 2), (6 , x , 8) y ¼ 3 2 (x/2) (2 , x , 6),(8 , x , 10)
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Figure 3. Ironing path and orientation
It is recognised that the complexity of the ironing path reduces as the number of times the shirt is ironed. Therefore, it can be concluded that: (1) the complexity of ironing path is proportional to the amount of wrinkles; and (2) the number of ironing profiles used for ironing increases as the number of wrinkle increases.
4. Orientation in ironing process During the investigation on the ironing path for shirt ironing, the iron orientation is recognised to be an important parameter in the ironing process. Many questions arise regarding the orientation of the iron, some of the questions include: How is the iron orientation related to ironing of a garment? Does the iron orientation have any effect on the efficiency of garment ironing? What is the optimal approaching angle or orientation in ironing and how to define them for a robot? The ironing orientation for a shirt has been investigated from the same video clips of shirt ironing performed by a
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professional. By viewing from the video source, the iron orientation at an instant time over a garment is noted and reproduced as shown in Figure 3. The results illustrate only the approximate orientation and position of an iron over the garment. By defining the positive orientation as the angle from the positive X-axis as in Figure 3, the results show that the orientation of the iron varied from 1808 at the beginning to 908 at the end of the ironing in all three subsequent ironing operations. 5. Experimental approach for determining the iron orientation and position data There are many reasons for obtaining the iron position and orientation data while performing the ironing on garments. The main reason being the numerical data obtained can be used for various purposes in the development of the robotic ironing and form a basis for quantitative analysis for the study of human ironing and robotic automation. The numerical data can simply be used not only for the graphical representation of similarity analysis of various garment ironing, but also for the mathematical modelling and simulation of ironing process. The aim of the experimental approach is to concentrate on the graphical representation of iron position and orientation in preparation for garment ironing similarity analysis. The equipments used in the experiment are iron, ironing board, transparent 10 mm square grid, protractor and tracing paper as shown in Figure 4(a). The garment selected as the starting point for the experiment is a T-shirt. It is considered to be one of the easiest garments to iron because of its geometric shape and symmetric properties. Therefore, the ironing processes for the following regions of the T-shirt are considered to be equivalent: front right sleeve region is equivalent to back left sleeve region, front left sleeve region is equivalent to back right sleeve region, front right region is equivalent to back left region and front left region is equivalent to back right region. Because of this, only four regions of the T-shirt need to be simulated. The four regions of
Figure 4. (a) Equipments used in the experiment; and (b) position and orientation measurement
the T-shirt under investigation are front right sleeve region, front left sleeve region, front right region and front left region. There are two methods devised for the proposed experimental approach. They are the point-by-point method and the region method. 5.1 Method 1 – point-by-point method First, a garment is placed on the ironing board with the part to be ironed spread and stretched ready for ironing. The transparent grid is laid over the garment or the region of the garment to be ironed with the origin of the grid aligned with the ironing board’s geometric centre (Figure 4(b)). The iron with its power switched off is used to simulate the normal garment ironing process over the transparent grid. While simulating the ironing process the iron movement is stopped in the approximate area of the desired position for orientation measurement on the garment. The tip of the iron is used in this case to define the position of the iron on the ironing board. A protractor is then used to measure the iron orientation by taking the positive angle in the anti-clockwise direction from the positive X-axis of the ironing board coordinate frame in Figure 5. The positions X and Y and the orientation u are recorded in the table for further analysis. This method allows the position of the iron to be accurately measured depending upon the grid resolution and the sharpness of iron tip to define the iron as a point device. In this experiment, the uncertainty in position measurement is ^ 10 mm and the orientation measurement is ^58. The results obtained by this method are stored in a table form with positions (X, Y) and orientation u.
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5.2 Method 2 – contour/region method The procedure for position and orientation measurement is the same as Method 1. The only difference is the additional use of a tracing paper laid on top of the transparent grid to record the result. This method is developed from the point-by-point method where it is noted that many of the orientation data are the same in the area close together. It is therefore possible to draw an orientation contour for area with the same orientation. The region with the same orientation can then be derived. This method is a more convenient and
Figure 5. Orientation measurement defined
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faster method to record data and to provide a clear picture of the iron orientation when ironing over different areas of the garment. 5.3 Method selection From experience, the method chosen to obtain the position and orientation data depend on two things: first, on the desired accuracy of the position and its corresponding orientation and next on the size of the region to be ironed. If it is desired to obtain a very accurate position and orientation data, it is recommended to follow Method 1. The position data are obtained one by one and the orientation is pinpointed to that position. But if accuracy is not the main issue of concern Method 2 is the choice as it is an easier and faster method to obtain the data. It should be noted that there are many different ways to iron a garment or a region of a garment. The accuracy should always be the first criterion in method selection, but the size of the ironing region should also be considered. If it is desired to obtain accurate data and the ironing region size is very large (i.e. the size of the ironing board), Method 2 is the suggested choice for large ironing area (i.e. the size larger than an A4 paper). 6. Orientation analysis of ironing 2D representation of the iron orientation The results from the experimental approach are analysed by using “MatLAB” program. An M-File was created for each region under investigation. The results are obtained by either Method 1 or Method 2, the iron orientation data at its corresponding position at X and Y are mapped onto the X and Y matrix for use in MatLAB to represent the analysed ironing surface. The mapping was first complete on a spreadsheet so that it could be easily modified and used in MatLAB as well as for any other purposes. The variable “C” is used to represent the unreachable region by the iron (i.e. the edge of the ironing board) and the non-garment region. Ideally, this should not have a value (i.e. zero) since it does not represent any orientation of the iron as this area is impossible to be ironed. The variable “C” was given some appropriate constant so that the significance of iron orientation can be clearly illustrated. The M-File written for each iron region therefore contains three array of matrix X, Y and Z (Theta). This is then used to produce a graphical representation for further analysis. The colour orientation – grid region diagram was then produced for each garment region by using “pcolor” command in MatLAB. The orientation region diagrams are shown in Figures 6(a) and 7(a). The two colour orientation-grid region diagrams for T-shirt Ironing at front right sleeve are shown in Figure 6(b) and at front left region in Figure 7(b). The differences between the two are that the ironing surfaces are defined into equal sized grid rather than just a boundary and the orientation is colour-coded.
7. 3D representation of the iron orientation Representing in a 3D orientation image, Figures 8 and 9 are shown for a better visualisation. The same MatLAB M-File that contains three array of matrix X, Y and Z (Theta), which is used for each region under investigation to create the colour orientation-grid region diagram, is used to create the 3D image presentation. The orientation workspace is plotted for each garment by interpolated surface plot. The M-File was written with the use of the “surf” command together with “shading interp”. Also the file was written so that the orientation can be shown in both degree and radian. But in the following graphical analysis, the orientation workspaces for different garments are shown in degree. Figures 8 and 9 show two orientation workspaces for T-shirt ironing at the front right sleeve region and the front left region.
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Figure 6. (a) Orientation region diagram for T-shirt ironing at front right sleeve region; and (b) colour orientation-grid region diagram for T-shirt ironing at front right sleeve region
Figure 7. (a) Orientation region diagram for T-shirt ironing at front left region; and (b) colour orientation-grid region diagram for T-shirt ironing at front left region
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Figure 8. Orientation workspace for T-shirt ironing at front right sleeve region
Figure 9. Orientation workspace for T-shirt ironing at front left region
8. Orientation analyses and discussion The graphical representations for each garment region under investigation in Section 7 are discussed in this section. It should always be remembered that the iron orientations obtained in this experiment are only one of the many orientation possibilities of the iron during garments ironing. Nevertheless, it is still an important issue in the preliminary studies of the ironing process. 8.1 Front right sleeve region The two views of the orientation workspace for the front right sleeve region are shown in Figure 8. The iron orientation at the lower half of the sleeve (i.e. where
Y , 0) can be seen to have a range varied from 145 to 1808. The maximum orientation angle from the positive X-axis occurs at the bottom edge (i.e. area shown in brown) with 1808. This edge is also noted to be the area close to the human operator where the operator is right handed and stands parallel to the X-axis (i.e. parallel to the side of the ironing board) with the board in the X negative direction. At one of the side edge the iron orientation and the angle of the edge from the positive X-axis are 145 and 1208, respectively. They are fairly close to each other and it is questionable whether there is any relationship between them. The iron orientation variation from the bottom edge to the side edge is quite large at 358 in comparison with the side edge to the top edge with 108 changes. The iron orientation variations in the main central sections are small with 58 (smallest measurable) in comparison with edge to edge. The largest edge-to-edge variation is from the top edge to the top right corner. 8.2 Front left region For the front left region, the two views of the orientation workspace are shown in Figure 9 for the front left region. The area close to the human operator where the operator is right-handed and stands parallel to the X-axis (i.e. parallel to the side of the ironing board) with the board in the X negative direction. The iron orientation at the bottom area and the bottom right corner are 1608 and 1808, respectively. The bottom right corner is one of the areas with maximum iron orientation angle in ironing this region. The other region with this maximum iron orientation is the area just above the lower half (i.e. Y positive) also shown in brown. And for the area between this and the bottom area mentioned earlier, the iron orientation is 1558. The iron orientation variation among these areas ranges from 15 to 258. If these areas were ironed with the same 1808 orientation, it would resemble the same ironing as the front right region, which is also a possible way to iron. The top area and the top edge show a large variation across the garment in the X-direction. The variation changes from the larger area with 1458 iron orientation to a smaller change of 58 from 135 to 908. This can be seen clearly in the second view of Figure 8. The colour orientation-grid region diagram in Figures 8 and 9 can also be used to view the variation in the iron orientation with a more defined boundary since the colour orientation are not interpolated in this case. This can be considered as simply a top view of the orientation workspace. This experiment can also be used to compare the iron orientation for the small region ironing of the front right sleeve with the large region ironing of the front right region. It can be seen that the iron orientation for both large and small regions demonstrate a similarity where ironing area closes to the human operator to about half way (Y ¼ 0, assuming that garment is placed in the centre) are iron with approximately 1808 iron orientation. And the variation from the X negative direction across towards the top corner with X positive varied from approximately 1458 to 908.
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9. Conclusions In this paper, both qualitative and quantitative models of the ironing process to be implemented for robotic automation have been developed. The ironing process performed has been described in detail and the similarity between ironing processes is identified to produce a desirable ironing process for robotic automation. This proposed ironing process consists of three main tasks, namely handling, shaping and ironing. The paper investigated these tasks by focusing on ironing trajectories and modelled a set of motions in mathematical expressions that the automation can be applied to. These ironing trajectories or paths can be considered to be composed of smaller discrete movements or profiles. In this study, the iron orientation is recognized to be an important parameter where it has influence on how a garment is ironed and on the efficiency of an ironing process. This resulted in an experiment to obtain the iron orientation and position relative to the garment that the quantitative analysis of the ironing process may be possible. Both 2D and 3D orientation representation have been produced from the data obtained in the experiment. The effect of the orientation have been analysed from these graphical representations and a set of guidelines are obtained. Further reading Cugini, U., Denti, P. and Rizzi, C. (1996), “Design and simulation of non-rigid materials handling systems”, Mathematics and Computers in Simulation, Vol. 41, pp. 587-93. Dai, J.S. (2002), “Advances in robotic dexterous manipulation: methodologies for synthesis”, Tutorial to 2002 IEEE International Conference on Intelligent Robots and Systems (IROS), September 2002, Lausanne, Switzerland. Dai, J.S. and Shah, P. (2003), “Orientation capability of planar manipulators using virtual joint angle analysis”, Mechanism and Machine Theory, Vol. 38 No. 3, pp. 241-52. Dai, J.S., Holland, N. and Kerr, D.R. (1995), “Finite twist mapping and its application to planar serial manipulators with revolute joints”, Journal of Mechanical Engineering Science, Proc, IMechE, Part C, Vol. 209 No. C3, pp. 263-72. Dai, J.S., Holland, N. and Kerr, D.R. (1996), “Task-oriented direct synthesis of serial manipulators using moment invariants”, Proceedings of the 24th ASME. Biennial Mechanisms Conference, 19-22 August 1996, Irvine, California. Dai, J.S., Taylor, P.M., Liu, H. and Lin, H. (2004), “Garment handling and corresponding devices – technology in robotic ironing”, 11th World Congress in Mechanism and Machine Science, Tianjing, China. Hamajima, K. and Kakikura, M. (2000), “Planning strategy for task of unfolding clothes”, Robotics and Autonomous Systems, Vol. 32, pp. 145-52. Paraschidis, K. and Fahantidis, N. (1995), “A robotic system for handling textile and non-rigid flat materials”, Computer in Industry, Vol. 26, pp. 303-13. Shah, P. and Dai, J.S. (2002), “Orientation capability representation and application to manipulator analysis and synthesis”, Robotica, Vol. 20 No. 5, pp. 529-35.
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Acquisition, placement, and folding of fabric materials Frank W. Paul Mechanical Engineering Department, Clemson University, Clemson South Carolina, USA
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Keywords Textiles, Modelling, Mechanical systems Abstract This paper discusses the technical issues associated with the acquisition, placement, and folding of fabric materials with mechatronic devices and machines. Earlier work in this area considered the acquisition of fabrics from a stack of materials. Numerous techniques were evaluated and suggested as a satisfactory way to provide “pick and placement” of such materials for various automated processes. Several end-effector devices were developed which used “pinching and stretching” and “multiple roller” approach for handling, placing, and smoothing fabrics on a flat surface. Fabric wrinkles were detected using a feedback laser sensor to assist in the placement and positioning of fabrics. Later work focused on the positioning of fabrics that required issues of alignment, placement and folding for a variety of fabric operations. A two-dimensional process considered precise placement, laying down, and then folding of a fabric material to have matched ends using a robot manipulator using visual feedback sensing. Additionally, three-dimensional diagonal folding of fabric was considered based on knowledge developed from the two-dimensional case. Work was also conducted to mathematically model and measure deformations of limp fabrics and how wrinkling influenced the process of fabric smoothing, alignment, and folding. The results of this work showed that different fabric types (lighter versus heavier) have different sensitivities and hysteritic effects with respect to wrinkling, smoothing, alignment, and folding.
1. Introduction The handling and manipulation of fabrics using automated machines is a complex process due to the limp or compliant nature of the material. Fabrics have a wide variation in their elastic and deformation properties that cause them to drape naturally, wrinkle, and fold in unpredictable ways. Such properties make the automatic handling and manipulation of the materials complicated, requiring a manufacturing process that uses joining, folding, and ironing of fabric to be controlled in a precise way. When human operators handle fabrics they have an ability to adapt to the limp and compliant nature of the materials using their touch, feel, and visual sensors. These fabrics, and their special shapes, take forms that can be twoand three-dimensional in geometry. Human operators who handle fabrics are generally not influenced by the geometric nature of the material. The automated handling and manipulation of fabrics require the use of mechanical The author would like to thank his numerous graduate students who have conducted research over the past years, on the handling of fabric materials. They have been the real contributors to the knowledge base for handling of limp materials. The author thanks his academic colleagues who provided intellectual stimulation and enjoyment when conducting this work. The author also thanks the financial supporters, industry and government.
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devices and electronic sensors to emulate or approximate the human nature of fabric handling. Such devices must consider whether the material will take a two- or three-dimensional shape or drape. The ability to create the devices and sensors needed to handle fabrics requires an understanding of the material’s physical behaviour as they are manipulated. The purpose of this paper is to summarize and share the research results in mechatronic fabric handling conducted at Clemson University in the Mechanical Engineering Department during the past 15 years. This paper discusses mechatronic devices for fabric acquisition and manipulation, sensor integration for “intelligence”, and models for fabric placement, folding, and smoothing. 2. Acquisition and holding of fabric Material handling and manipulation requires the process of fabric acquisition and holding. Early study by Parker et al. (1983) considered the process of acquiring a single fabric ply from a stack of fabrics and moving the ply to a machine process. This requires a sequence of acquisition, holding, and releasing the ply in the correct orientation at the machine process. This study indicated that the use of a mechanical pin-fabric interaction was a feasible approach as shown in Figure 1. The weight of fabric that could be lifted per pin pair was based on a theoretical model given by: W ¼ K E DXðsin Q þ m cos QÞ=ðcos Q 2 m sin QÞ;
ð1Þ
where KE is the apparent material spring stiffness, DX the pin pair spacing, m is the friction coefficient, and Q the pin angle. A minor limitation using this approach may be damage due to pin penetration of the fabric, although pins are used throughout the apparel fabrication industry. Another approach was the use of a temporary adhesive. This adhesive concept must consider the bond strength and forces that acquire and hold the fabric as well as any deposition of adhesive material on the fabric. Adhesive selection is important as the tape loses its “stickiness” with reuse in the sticking and peeling process. The use of a typical “masking tape” showed that the
Figure 1. Mechanical pin-fabric interaction
holding-peeling force decreases by about 50 percent after 25 acquisition cycles, and was approximately proportional to the tape-fabric interface area. The mechanical release of the fabric and refreshing of the adhesive tape are the limitations of this approach. Later research by Torgerson (1986) used vacuum suction with movable holding points to acquire, hold, orient, and place larger fabric pieces on a work surface. Controls activated the vacuum suction for acquisition and release of the fabric at the appropriate location. The movable holding points provided the ability to handle a variety of fabric shapes and sizes. Figure 2 shows the physical implementation of an end-effector used to accomplish this task. An applied research project that addressed the acquisition, handling, and assembly of shirt collars was addressed by Paul and Dixon (1992). This project required a mechatronic end-effector capable of manipulating a fabric assembly. Figure 3 shows the mechatronic device used to handle and present a shirt collar to a machine pressing station. The device has finger like grippers with one-dimensional movement for stretching the fabric material. This research was addressed by Gopalswamy (1990) and resulted in a mechatronic device that had numerous sensors to provide “intelligence” to the robot system that was accomplishing the fabric manipulation. The work required the consideration of fabric drape and wrinkling in order to achieve a successful device. Recent work by Mehta (2001) developed a roller-pinching device for fabric acquisition. This device is shown in Figure 4. One roll is active and has the ability to “roll-up” a fabric while holding it for positioning at a desired location. Figure 5 shows the sequence of acquisition of the fabric, as one roller simultaneously translates and rotates to perform the desired acquisition. This
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Figure 2. Active multi-degree of freedom end-effector
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Figure 3. Active gripper for material handling
Figure 4. Active two-dimensional roller end-effector
device also has the ability to place and smooth the fabric and this feature is discussed later in this paper. 3. Placement and alignment of fabrics Torgerson (1986) considered placing and aligning a two-dimensional piece of fabric in his research work. A vision sensing system was used to kinematically guide a robot for material placement and orientation. This work showed that vision was a practical means of positioning fabric pieces with different geometries, but was limited by the slowness of real time updating of the motion of the robot.
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Figure 5. Roller fabric acquisition
The handling of a fabric shirt collar assembly raised basic research issues of how one places and aligns material in a joining or assembly machine process (Paul and Dixon, 1992). Mast (1997) addressed this basic process of precisely placing and folding a variety of limp and stiff fabrics on a work table surface. The process considered a robot with closed-loop vision feedback to place and fold a two-dimensional fabric piece in half. Figure 6 shows a schematic of placing a fabric having a free end and then creating a desired motion trajectory in such a way that the manipulated end could be aligned on the free positioned end. While this basic process is not
Figure 6. Motion trajectory and way-points
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difficult for a human operator, the process is quite complex for a robot and requires an iterative control scheme for precise fabric positioning. Figure 7 shows four different configurations that can occur when positioning a material to match a free and manipulated end. The four configurations show that there can be a good end match, a short or overlapping end match (push and pull), or an overlap condition. The error measurements from vision sensing are used to create an iterative fabric manipulation scheme. The manipulation trajectory scheme adapts to changing fabric parameters (limp and stiff fabrics), surface friction, and desired folding speeds. Stiff fabrics require more complex manipulation strategies than limp fabrics. 4. Folding and smoothing of fabrics While Mast (1997) addressed the placement of fabrics, his work also considered how these fabrics folded in half and diagonally. This work considered experimentally seven different materials with lengths ranging from 40 to 80 cm. The use of an iterative motion trajectory scheme, as shown in Figure 6, showed that a three-point trajectory provided acceptable folding with errors of approximately 1 mm. Friction between the draping fabric strongly influences the ability to precisely place one end upon the other. Diagonal folding introduced an additional degree of freedom in the fabric trajectory, and responded differently to using the three-point iterative motion trajectory. Experimental diagonal folding showed that it was not as sensitive to the effects of material friction as when folding material in half, since the fabric surfaces were not in contact until the end of the process. Mehta (2001) developed a fabric handling robot end-effector system that could acquire, place, and smooth wrinkled fabric. This system integrates a robot, end-effector, and laser sensor into a system as shown in Figure 8. The end-effector device has two rollers, one active and the other passive. The active roller has both rotational and translational degrees of freedom that are controlled using sensor feedback on the device. A heuristic control algorithm was used to integrate the actions of the end-effector with those of the robot and
Figure 7. Fabric folding configurations
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Figure 8. Integrated Sensor, robot, and end-effector
laser sensor. The algorithm provides for acquisition, movement from place to place, fabric placement, and smoothing with the roller based end-effector. Figure 9 shows a sequence of grasping, lifting, transport, and placing a fabric piece with the system. Fabrics placed on a flat work surface require determination of how to move the robot end-effector in such a way to cause the fabric to remain in a known position, but to remove wrinkles by a “smoothing” process. This can be accomplished by acquiring optical data using a laser sensor that defines the wrinkle location(s) in the fabric with respect to the spatial robot system. These data are used along with a heuristic control algorithm to calculate the position of the wrinkle and initiate control commands to the robot and end-effector for smoothing action. Figure 10 shows a sequence of motions that smooths a length of fabric. These results suggested that a laser sensor can provide data for locating material surface wrinkles and the robot end-effector system can actively place and smooth the fabric in a desired location.
Figure 9. Active acquisition and placement of fabric
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Figure 10. Active fabric smoothing
Figure 11. Wrinkle strip concept
5. Modeling and measurement of fabric deformation and wrinkling As the previous work demonstrates, three-dimensional fabric geometry knowledge is useful for active control of the removal of fabric wrinkles. The use of a laser sensor in the work of Mehta (2001) was enhanced by work completed by Kopp et al. (2000) which addressed the difficulty of knowing the accurate location of fabric geometric characteristics. This work considered an approach for measuring shape and wrinkle location along a length of strip by evaluating five fabric types. This approach used the difference of total fabric length and wrinkled length. This scheme is shown in Figure 11. A model by Clapp and Peng (1990) was used for analysis along with appropriate boundary conditions. The model considers the fabric weight, forces and moments acting on the strip, including friction as shown in Figure 12. The result for a single wrinkle analysis is shown in Figure 13 along with the sensor scanning technique used to measure the experimental wrinkle shape.
A comparison of the analytical and experimental values showed that it is possible to find the shape and range of possible locations for a wrinkle to exist in a strip by measuring the wrinkled length of fabric. This study showed that the method of analysis is more accurate for lighter fabrics rather than heavier fabrics. The heavier fabrics are more sensitive to hysterisis effects of the fabric
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Figure 12. Wrinkle strip model
Figure 13. Analysis and measurement of fabric wrinkle
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Figure 14. Double hump and marginally stable wrinkle
and may account for poorer agreement in this regard. An interesting result of the analysis showed that it was possible to have multiple and quasi-stable wrinkles. Figure 14 shows experimentally the formation of a double hump wrinkle and a single marginally stable wrinkle. 6. Conclusions This paper summarizes a culmination of work that has occurred over a period of the past 20 years. The earlier work focused on acquisition, holding, and placement of fabrics with different types of mechatronic end-effector devices. The work demonstrated that a variety of acquisition methods were applicable to fabric materials, with consideration given to the material weight and drape. Pins, adhesive, pinching, vacuum, and stretching were found to be successful ways to acquire fabric materials along with sensors for determining fabric location in a workspace. Active end-effectors were designed to take several forms depending upon the particular material application for holding and placement of the fabric. Later work raised issues of alignment and folding and how motion requirements of a robot or equivalent mechatronic machine were required for motions in two- and three- dimensions. This work considered algorithmic strategies for movement of fabric pieces to create end matches and folds. The strategies depended upon an iterative scheme for creating motion trajectories using visual feedback information. Work was also initiated on modelling fabric wrinkles and experimentally verifying the model results. This work provides a basis for understanding how different fabric weights behave under ideal conditions of wrinkling. The results showed that models provide a good guide, but were not precise in predicting wrinkle lengths. The general results of this work have shown that the acquisition, handling, placement, smoothing, and folding of limp fabric materials represents a challenging task for the automation of manufacturing processes in the apparel and textile industry.
References Clapp and Peng (1990), “Buckling of woven fabrics, Part I: effect of fabric weight”, Textile Research Journal, Vol. 60, pp. 228-34. Gopalswamy (1990), “Design and control of robot end-effector for three dimensional manipulation of multiple-ply apparel workpieces”, MS thesis, Mechanical Engineering Department, Clemson University. Kopp, Rahn and Paul (2000), “Measuring deformations of limp fabrics for material handling”, Textile Research Journal, Vol. 70 No. 10, pp. 920-32. Mast (1997), “Iterative techniques for control of fabric manipulations”, MS thesis, Mechanical Engineering Department, Clemson University. Mehta (2001), “Robot system for manipulation of flexible materials”, MS thesis, Mechanical Engineering Department, Clemson University. Parker, Dubey, Paul and Becker (1983), “Robotic fabric handling for automated garment manufacturing”, ASME Journal of Engineering for Industry, Vol. 105 No. 1, pp. 21-6. Paul and Dixon (1992), “Advanced automation for shirt-collar manufacturing”, International Journal of Clothing Science and Technology, Vol. 4 No. 2/3, pp. 26-33. Torgerson (1986), “Robotic fabric acquisition and manipulation with machine vision assistance”, MS thesis, Mechanical Engineering Department, Clemson University.
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Study of relationship between fabric elastic potential and garment appearance quality J. Gersˇak Department of Textiles, Faculty of Mechanical Engineering, Institute of Textile and Garment Manufacture Processes, University of Maribor, Smetanova, Maribor, Slovenia Keywords Mechanical properties of materials, Textiles, Elasticity Abstract Garment is presumably the only product where, in the tailoring process, a two-dimensional fabric is converted into a three-dimensional shape without indirect physical remodelling of the material. Such a remodelling is directly associated with the physical behaviour of fabric structure, which can be treated as a very complex system owing to its constructional properties. Fabrics are non-homogeneous and anisotropic materials. Very small stresses on textile materials cause extremely large strains, so that the deformations occurring are highly non-linear. Non-linear properties of textile materials and thus, connected deformations at low stresses are closely related to the elastic potential and influence fabric draping and fitting of the garment manufactured. For this purpose, the relationship between fabric elastic potential, as an important property under lower tensile load, and garment appearance quality, will be investigated. The investigation is subdivided into two parts. The first part presents the study of relationship between the elastic potential and particular mechanical properties of fabrics, whereas the second part of the investigation is concerned with studying the influence of fabric elastic potential on the drapeability, respectively, appearance quality of the garment manufactured.
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1. Introduction A textile fabric is defined as a manufactured assembly of fibres and/or yarns, which has substantial surface area in relation to its thickness and sufficient mechanical strength to give the assembly inherent cohesion. A woven fabric is a fabric produced by the process of weaving, which forms fabric by interlacing warp and weft yarns (Textile Terms and Definitions, 1995). As clothing materials, fabrics must possess the ability to form a three-dimensional shape from their original two-dimensional planar shape, in order to cover human body. Fabric performance as a clothing material can be specified on two levels of precision: performance attributes and performance properties (Hatch, 1993). Performance attributes specify the five major needs or requirements that fabrics generally should meet. They are: (1) functionality/durability – the ability of textiles to retain physical integrity under conditions of mechanical stress for a reasonable period of time; (2) comfort – the ability to provide the body with freedom from pain, discomfort or the ability to maintain a neutral state;
(3) aesthetic appeal – the degree of pleasantness of textiles to the eye, hand, ear, and nose (to the human body sensory mechanisms); (4) maintenance – the ability of textiles to remain in the same state of cleanliness, size, and physical integrity; (5) health/safety/protection – the aspects of textiles that make them potentially hazardous substances or that protect the human body and the environment from a variety of harmful substances. Although performance attributes provide valuable information about the needs that may be fulfilled by textiles, these attributes are difficult to quantify or measure. Each performance attribute can be clarified by considering specific performance properties that are important for engineered planning of high quality textile materials and products that are made of them. So, performance attribute functionality/durability includes strength, flexibility, as well as elongation and elastic recovery, which determine how well a textile product can absorb mechanical stress, while aesthetic appeal includes formability, drapeability and elastic potential, which define how well a textile product can assure aesthetic appearance – visual form of the 3D shape and the quality of the fit. It means that the fabric build-in cloth, which covers the body as a shell, must possess an adequate extensibility and flexibility to fit the motion of the body. In an attempt to clarify this complex problem, fabric elastic properties and their elastic potential are presented in this paper, as well as the relationship between fabric elastic potential and garment appearance quality, respectively, garment aesthetic requirements. 2. Elastic properties of textile materials Conventional theory of elasticity deals with mechanical properties of solid bodies, where, according to Hooke’s law, the strain is proportional to deformation and is independent of deformation velocity, while conventional theory of hydromechanics deals with viscose fluids, where, according to Newton’s law, the strain is proportional to deformation velocity and independent of its size. However, in reality, there are no ideal solid bodies and fluids. In solid bodies, proportionality exists only in the limited areas of deformation. In fluids, proportionality exists only in the limited velocity deformations. Materials that show a combination of mechanical behaviour of fluids and elastic solid bodies are called viscoelastic materials. A body that is not entirely firm does not keep constant deformation at constant tension – in time is first deformed (slipping). If such a body is exposed to constant deformation, the tension that creates resulted deformation is gradually reduced (relaxation). On the contrary, the body that is not entirely fluent keeps some of the energy while running under certain tension. After unloading, a part of deformation is recovered – the so-called elastic recovery occurs.
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Textile materials show the characteristics of fluids and solid bodies; therefore, they are called viscoelastic materials. Because of the double nature of textile materials, we have to deal with the viscoelastic properties of textile materials. Viscoelastic behaviour of textile materials is caused by a complex anisotropic arrangement of molecules, on which macroscopic mechanical deformation acts. Here, mechanical properties of fibres can be explained on the basis of differential network model (Gruber, 1980), composed of molecule chains, arranged in crystalline and amorphous regions, oriented along the fibre axis and joined together by intermolecular bonds. Acting force can cause changes in macromolecular arrangement, while the chemical composition remains unchanged. Their mechanical properties depend on the movement of fibrous molecules, which is unadjusted along the chain. Macromolecular movement and deformation associated with it depend upon the size of the acting force and tend to change with time and temperature. Mechanical properties of the fabrics can be represented in a modified model. By definition, the primary feature of a fabric structure is that it is a fibrous assembly in which two sets of yarns (one set length-wise and the other set crosswise) are interlaced at right angle to each other. Modified fabric model can be designed if we presume that the system of warp and weft threads forms a geometrical formation of fibres, bonded together with cohesion forces into yarns. In addition to fibre strength, structural fibrous assembly prevents crack propagation because of the discontinuous structure and mobility of fibres at the region of stress concentration, giving fabrics strength reliability. Based on the model designed, it can be assumed that similar processes are present in fibres and fabrics when they are exposed to external forces. Certain amount of deformation occurs, which represents a thermodynamic change and is shown as the change of a form or dimension (tensile and shearing load: elongation; compression load: compressibility). Here, a part of the energy applied is kept as potential energy, while the rest is transformed into thermal energy that causes certain structural changes. Deformation energy is reversible to deformational work and is valid only when slow deformation is applied, since at faster rate, molecules offer higher resistance. The faster the deformation in relation to normal velocity of conformal change in the fibre, the greater is the additional deformational resistance. After unloading, potential energy is transformed into kinetic energy. The material tends to recover its original shape and size – equilibrium state. The part of energy that is dissipated in the form of heat is the cause of plastic deformation. The resulting deformation can be more or less reversible, depending on the load intensity and duration of loading, as well as on relaxation time. As is well known, mechanical properties of textile fabrics in general show non-linear behaviour. This nonlinearity is caused by a structural change in the
fabric during deformation. Fabrics are constructed of yarns and initially possess high flexibility. There are two reasons for flexibility (Kawabata, 1989). One is the flexibility of the yarn itself, the structure of which consists of thin parallel fibres, where the movement of individual fibres is restricted only by the friction between the fibres during deformation. The other is that fabric is constructed by interlacing yarns without any rigid bonding at the yarn interlacing points. This means that the displacement of individual yarns and fibres in the structure caused during deformation applied to the fabric is complex and that mechanical properties of the fabric must be considered as a structural body and not as a continuum. The relationship between deformational and reversible energy, respectively, elastic potential of fabrics, should be known in detail for a successful study of fabrics and their behaviour in produced garment. 2.1 Elastic potential Fabric elastic potential represents an important component in garment appearance quality. It is well known that fabrics have a specific non-homogeneous structure that depends on certain construction properties and material of warp/weft threads. Different deformation mechanisms occur when threads are exposed to tensile, bending or shear loads, because of specific tensile properties of yarns that are the result of inner friction between fibres. Compression and friction forces are caused by interlacing points of warp and weft threads and are also important. Because of the complexity of the problem, this paper presents primarily these parameters that influence fabric elastic potential and that are connected with garment appearance quality (Gersˇak, 2003), such as (Nakanishi and Niwa, 2000): . tensile elastic potential EP, . bending elastic potential BP, and . shear elastic potential GP. Tensile elastic potential EP is defined as a relationship between tensile energy WT and tensile resilience RT: EP ¼ WT
RT 100
ð1Þ
where WT is the tensile energy per unit area (deformational work), in gf cm/cm2, respectively, cN cm/cm2 and RT is the tensile resilience, in per cent. Deformational work WT, which represents the energy needed for tensional deformation of the fabric at a particular maximum loading, is closely connected to flexibility, softness, smoothness and compactness of the fabric. On the other hand, tensile resilience RT, depending on recovering and deformation energy, influences garment appearance. Lower values of tensile resilience RT generally
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mean softer fabrics (lower values are often associated with higher elasticity, which influences the softness of the fabric). However, too low a value negatively influences the garment appearance. Bending elastic potential BP, defined by bending rigidity B and moment of hysteresis 2HB, is given in the form of the following expression: 2 K m 2HB 2B BP ¼ B ð2Þ 2 where B is the bending rigidity per unit length, cN cm2/cm; 2HB is the moment of hysteresis per unit length, cN cm/cm; Km is maximal curvature (Km ¼ 2.5 cm2 1). Moment of hysteresis 2HB, closely connected to bending rigidity, can be taken as a measure for energy that the fabric loses during bending deformation. Larger value of the moment of hysteresis 2HB gives a stiffer feeling. Such fabrics are inelastic and have lower elastic recovery. Lower values of moment of hysteresis 2HB beneficially influence fabric draping. Shear elastic potential GP, defined as a relationship between shear rigidity G and shear hysteresis 2HG and 2HG5, is given in the form: 2 um 2 2HG 2GR GP ¼ GR ð3Þ 2 GR ¼ G þ
2HG 2 2HG5 5
ð4Þ
where 2HG is shear hysteresis at shear angle 0.58, in gf/cm, respectively, cN/cm; 2HG5 is shear hysteresis at shear angle 58, in gf/cm respectively, cN/cm; G is shear rigidity, in gf/(cm 8), respectively, u cN (cm 8)2 1; Fm is maximum shear angle (Fm ¼ 88). Shear hysteresis 2HG and 2HG5 represents the energy that the fabric loses during shear deformation. This loss of energy is caused by the friction that appears between the warp and weft thread crossing points and tensional/compression forces, caused by straining/compression of both yarn systems. 3. Methodology On the basis of previous knowledge, comprehensive investigations were carried out on the topic of relationship between the elastic potential and particular parameters of fabric mechanical properties, as well as investigations on the impact of elastic potential upon garment appearance quality. Owing to the wide range of the investigations and specific behaviour of individual fabrics, the investigations dealt only with the results of elastic potential of
woollen fabrics, mass 150-340 g/m2, fabrics of wool/man made fibre blends with no elastane fibres, mass from 100 to 440 g/m2, fabrics of wool/man made fibre blends with elastane fibres added, mass from 150 to 310 g/m2, pure cotton fabrics, mass from 110 to 330 g/m2, and fabrics of cotton/man made fibre blends, mass from 80 to 260 g/m2, all of them intended for the manufacture of ladies’ jackets. Mechanical and physical properties of all the fabrics analysed were evaluated employing the KES-FB measuring system, and the appearance quality of the garment pieces manufactured was assessed. Garment appearance quality was investigated on the example of ladies’ jackets manufactured, considering the following factors (Gersˇak, 2002). . Aesthetic appeal of the appearance – garment drape, with the accent on evaluating the drape on the front and back part and sleeves, on matching the fitting of various garment components, such as collars, armhole, back slit, pockets, jacket length, etc. . The form produced – 3D shape of the garment piece, evaluated on the basis of garment appearance quality, its spatial characteristics, fullness, for example, of the breast dart and the whole of the front part, volume matching, shape of shoulders, 3D shape and fullness of the sleeves. . Quality of fitting – where special attention was paid to the quality of fitting the back part, fitting the front part, sleeves, collars and drape. Correlation between elastic potential of the fabrics analysed and appearance quality i.e. form of ladies’ jackets, was investigated on the basis of the analysis of fabric mechanical properties and the values for elastic potential calculated, as well as on the appearance quality assessment value – visual form of the jackets manufactured. 4. Analysis of the impact of fabric elastic potential on garment appearance quality The investigation of the relationship between the elastic potential of fabrics as an important property under lower tensile load and garment appearance quality is subdivided into two parts. The first part presents the study of correlation between the elastic potential and particular mechanical properties of fabrics, whereas the second part of the investigation is concerned with studying the influence of elastic potential of the fabrics on its drape – garment appearance quality. 4.1 Analysis of the relationship between elastic potential and parameters of individual mechanical properties of the fabrics Comprehensive analysis of the results of investigating the individual mechanical properties of the fabrics analysed and their impact on elastic potential indicates that individual parameters of fabric mechanical properties directly impact elastic potential. Particular fabrics or groups of fabrics, exhibit
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Figure 1. Relationship between elastic potential, EP, deformational work, WT, and tensile resilience RT
specific values for elastic potential, determined by raw material content and construction of the fabrics analysed. Investigations of tensile elastic potential show that most of the fabrics analysed show higher values of elastic potential weft-wise than warp-wise. It is generally true that elastic potential increases with higher deformational work WT and is directly dependent upon tensile resilience RT of the fabric in question and its construction parameters (Figure 1). It is also evident that higher extensibility means higher deformational work, while tensile resilience is reduced. It is especially valid for the group of woollen fabrics, where tensile resilience, RT, falls to the extension value of around 10 per cent warp-wise and 15 per cent weft-wise. When these values are reached, there is no further noticeable drop in tensile resilience with increased extension, while certain variations are present, as a result of specific fabric construction parameters. For example, fabrics with extremely low density of warp and weft yarns and high mass exhibit lower tensile resilience, RT. The variations mentioned impact tensile elastic potential (Figure 2). It is also confirmed by the relationship between the tensile elastic potential, EP, and deformational work, WT, as well as between the tensile elastic potential, EP, and extension, EMT, which exhibits somewhat higher level of scattering individual values at high extension, EMT, values (EMT-1.10 per cent and EMT-2 . 15 per cent). It can also be seen that the values of tensile elastic potential, EP, range for the group of woollen fabrics from 3.31 to 13.15 cN/cm warp-wise, and from 5.23 to 21.10 cN/cm weft-wise. It is interesting to note that the woollen fabrics analysed, which exhibit higher extension, EMT-2, values, and higher tensile elastic potential, EP-2, weft-wise, have considerably lower values of tensile resilience, RT-2, weft-wise, ranging from 44.31 to 83.23 per cent, as compared to warp-wise values, which range from 56.14 to 94.86 per cent. Lower tensile resilience, RT, values weft-wise are connected with higher elasticity and the impact of fabric softness. However, too low values, exhibited by the fabrics analysed weft-wise, can have a detrimental impact on garment appearance. Analysis of fabric tensile elastic potential shows that the blend of wool and man-made fibres have tensile elastic potential, EP, between 3.75 and 23.90 cN/cm warp-wise, and from 2.72 to 31.20 cN/cm weft-wise. The lowest tensile elastic potential, EP, values are recorded for the fabrics in plain weave, of
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Figure 2. Relationship between elongation, EMT, and deformational work, WT, as well as between the deformational work, WT, and tensile elastic potential, WT, for the woollen fabric analysed
low surface mass and high density of warp and weft yarns. The highest values are recorded for the fabrics in leno weave, of low yarn density and high surface mass. These fabrics also exhibit high deformational work, WT, values and high tensile resilience, RT. Interesting results are obtained by the analysis of fabric tensile elastic potential, for the blends of wool and man-made fibres, with elastane fibres added. Tensile elastic potential ranges from 5.51 to 22.95 cN/cm warp-wise and from 1.19 to 31.25 cN/cm weft-wise. Higher level of dissipation of tensile elastic potential is recorded, while the lowest values are obtained for the fabrics of low surface mass, with equally low deformational work, WT. The lowest values of tensile elastic potential are exhibited by cotton fabrics, ranging from 1.50 to 5.16 cN/cm, then follow blends of cotton and man-made fibres with no elastane, with the values from 2.06 to 8.03 cN/cm, and finally blends of cotton and man-made fibres with elastane fibres added, where the values of tensile elastic potential range up to 12.17 cN/cm. It is also interesting to note the relationship between the extension, EMT, and deformational work,
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Figure 3.
WT, as well as between the extension, EMT, and tensile elastic potential, EP, for the group of cotton fabrics analysed, blends of cotton and man-made fibres with no elastane and with elastane fibres added (Figure 3). Analysis of the results obtained indicates that tensile elastic potential increases with increase in extension, uniformly up to the value of 6.5 per cent (here it belongs to cotton fabrics analysed, which have extension to 4.73 per cent and part of the cotton/man-made fibre blend fabrics without elastane and part of fabrics made of the same blends with elastane fibres added), almost linearly. Dissipation of values is rather high, while tensile resilience is more pronounced for the fabrics with higher extension values. Analysis of bending elastic potential, BP, shows that it increases with increase in bending rigidity, B (Figure 4). All fabrics exhibit higher bending elastic potential warp-wise than weft-wise. Studying the impact of bending hysteresis 2HG on bending elastic potential reveals the tendency of bending elastic potential, BP, to increase with increasing values of bending hysteresis, 2HB, while high values of bending hysteresis, 2HB, result in reduced bending elastic potential, BP (Figure 5). Higher bending hysteresis, 2HB, means reduced elastic recovery, which means lower bending elastic potential. Analysis of the results obtained for shear elastic potential, defined by shear rigidity G, shear hystereses 2HG and 2HG5, shows similar tendencies in individual groups of fabrics. Shear elastic potential increases for all groups of fabrics analysed with increasing shear rigidity G (Figure 6). Special attention should be paid to the values of shear hystereses 2HG and 2HG5, which represent the measure of energy lost during shear deformation. This energy loss is caused primarily by friction, occurring at crossing points of the systems of warp and weft threads in moving one through the other and by tensile/compression forces, as the systems of warp and weft yarn stretch/compress mutually, and depend upon construction parameters of particular fabrics in question. The value of shear hysteresis is directly reflected in the value of shear elastic potential. Increasing shear hysteresis 2HG5 means reduced shear elastic potential, because greater recovery force will be required to overcome the internal friction of the fabric.
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Figure 4. Bending elastic potential BP (a, b – woollen fabrics; c, d – blends of wool and man-made fibres, with no elastane; e, f – blends of wool and man-made fibres with elastane fibres added)
Figure 5. Correlation of bending rigidity B, bending hysteresis 2HB and bending elastic potential BP, for woollen fabrics
The study of shear elastic potential indicates that the fabrics analysed possess specific values of shear elastic potential, associated with the type of weave used, density of warp and weft yarns and raw material content. The group of woollen fabrics exhibits lowest values of shear elastic potential (GP-1 ranging from 6.53 to 46.13 cN/cm, GP-2 from 6.11 to 48.40 cN/cm), while for fabrics blended from wool and man-made fibres (Wo/PE) the values range from 5.84 to 68.06 cN/cm warp-wise and from 5.62 to 69.30 cN/cm weft-wise. Higher shear potential can be attributed to smaller contact area of yarn crossing points, which requires lower force to cope with inner friction. It results in lower shear rigidity and shear hysteresis 2HG5, or higher values of shear elastic potential.
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Figure 6. Correlation between shear rigidity G and shear elastic potential GP (a – group of woollen fabrics; and b – blends of wool and man-made fibres)
Similar values of shear elastic potential are also obtained for the group of fabrics made of wool/man-made fibre blends with elastane fibres added. Shear elastic potential for this group of fabrics, GP-1, ranges from 5.84 to 68.06 cN/cm and GP-2 from 5.61 to 69.30 cN/cm. The highest values of shear elastic potential are recorded for fabrics in plain weave, which are characterised by high density of warp and weft threads and low surface mass. The lowest values of shear elastic potential are recorded for cotton fabrics, where GP-1 values range from 7.17 to 32.30 cN/cm. 4.2 Analysis of impact of fabric elastic potential on its drape – garment appearance quality Garment is presumably the only product where, in the tailoring process, a two-dimensional fabric is transformed into a three-dimensional shape without indirect physical remodelling of the material. Such a remodelling is directly associated with the physical behaviour of fabric structure, which can be treated as a very complex system, owing to its constructional properties. Fabrics are non-homogeneous and anisotropic materials. Very small stresses on textile materials cause extremely large strains, so that the deformations occurring are highly non-linear. Non-linear properties of textile materials and thus connected deformations at low stresses are closely related to the elastic potential and influence fabric draping and fitting of the garment manufactured. Investigations of correlation between the fabric elastic potential and degree of appearance quality, form of the ladies’ jackets indicate that elastic potential has a strong impact on the fabric drape and garment form associated with it.
Analysis of the results obtained for the relationship between the tensile elastic potential, EP, and drape coefficient Kd for woollen fabrics shows that increasing tensile elastic potential, EP, means reduced drape coefficient, Kd. From the point of view of practical use, it means that fabrics with higher tensile elastic potential, EP, have lower drape coefficient, Kd, meaning that they can be formed more easily and fit better. Lower drape coefficient, Kd, associated with increasing tensile elastic potential, EP, is more pronounced weft-wise, as fabrics analysed exhibit higher tensile elastic potential in this direction (Figure 7). Interesting conclusions have been reached while studying the relationship between the bending elastic potential, BP, and drape coefficient, Kd. It can be seen that with increasing bending elastic potential, BP, drape coefficient, Kd, also increases (Figure 8), which means that fabrics of this type are more rigid and harder to drape. Fabrics with high bending elastic potential usually exhibit low values of bending hysteresis, 2HB, they are inelastic, and have low elastic recovery, seen in more shallow crease depth, Lg. It is confirmed by the analysis of bending elastic potential, BP, drape coefficient, Kd, and crease depth, Lg, which shows that increasing bending elastic potential, BP, means also higher drape coefficient, Kd, while crease length Kd drops (Figure 8(b)).
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Figure 7. Relationship between the tensile elastic potential, EP, extension, EMT, deformational work, WT, and drape coefficient, Kd
Figure 8. Relationship between the bending elastic potential, BP, and drape coefficient, Kd; as well as between the bending elastic potential, BP, and crease depth, Lg
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Although tensile elastic potential, EP, and bending elastic potential, BP, show direct relationship with fabric drapeability, i.e. drape coefficient, Kd, and crease depth, Lg, this tendency has not been revealed in studying the relationship between the shear elastic potential and drape coefficient, Kd, but only indirectly, through the values of shear hysteresis 2HG5 (Figure 9). Analysis of the results shows a tendency of drape coefficient, Kd, to increase with the increasing values of shear hysteresis, 2HG5. Large values of shear hysteresis 2HG5 usually indicate inelastic, often too stiff fabrics that require higher force to overcome the inner friction between the fibres during deformation, which is represented with shallower creases. The consequence is lower drapeability which is reflected with higher drape coefficient Kd. It means that fabrics with larger values of shear hysteresis, 2HG5, exhibit higher drape coefficient Kd, while creases Lg are shorter. 5. Conclusion Analysis of the results by studying individual mechanical properties of the fabrics in question and their impact on elastic potential shows that individual parameters of fabric mechanical properties directly impact elastic potential. Particular fabrics, or groups of fabrics, exhibit specific values of elastic potential, determined by raw material content and construction parameters of the fabrics in question. Fabric elastic potential expresses fabric ability to recover, after forces have ceased to act on it and with the purpose of transforming potential energy from the deformation into kinetic, into its original shape and size or equilibrium state. It directly influences the fabric drapeability and its behaviour in a cloth made from it. The results obtained from the relationship between the fabric elastic potential and its fit, i.e. drapeability, indicate that elastic potential impacts drape coefficient and crease depth. Tensile elastic coefficient and
Figure 9. Relationship between the shear elastic potential, GP, shear hysteresis, 2GH5 and drape coefficient, Kd
bending elastic coefficient directly impact draping, while the influence of shear elastic potential is reflected indirectly, through shear hysteresis, 2HG5, value. The knowledge of correlation between the individual parameters of mechanical properties, tensile elastic, bending and shear elastic potential, as well as their impact on drapeability, is an essential part of performance properties that should be known in engineered designing of high-quality fabrics, such that it would offer satisfactory garment appearance, as an important performance attribute of aesthetic appeal of garment. References Gersˇak, J. (2002), “Study of the relationship between fabric mechanics and garment appearance quality level”, Book of Proceedings of 1st International Textile, Clothing and Design Conference, Magic World of Textiles, Faculty of Textile Technology, University of Zagreb, Zagreb, pp. 353-8. Gersˇak, J. (2003), “Investigations of the impact of fabric mechanical properties on garment appearance (Istrazˇivanje utjecaja mehanicˇkih svojstava tkanina na izgled odjec´e)”, Tekstil, Vol. 52 No. 8, pp. 368-79. Gruber, E. (1980), Polymerchemie, Dr Dietrich Steinkopff Verlag, Darmstadt. Hatch, K.L. (1993), Textile Science, West Publishing Company, Saint Paul. Kawabata, S. (1989), “Nonlinear mechanics of woven and knitted materials”, in Chou, T-W. and Ko, F.K. (Eds), Textile Structural Composites, Elsevier Science Publishers B.V., Amsterdam, pp. 67-116. Nakanishi, M. and Niwa, M. (2000), “The fabric mechanical-parameters related to the beautiful motion of one-piece dress for ladies”, Proceedings of the 29th Textile Research Symposium, Mt Fuji, Shizuoka, pp. 99-109. Textile Terms and Definitions (1995), The Textile Institute, Manchester.
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Design of the system for prediction of fabric behaviour in garment manufacturing processes D.Z. Pavlinic´ and J. Gersˇak Department of Textiles, Institute of Textile and Garment Manufacture Processes, Faculty of Mechanical Engineering, University of Maribor, Smetanova Maribor, Slovenia Keywords Mechanical properties of materials, Predictive process, Textile manufacturing processes Abstract The study of fabric behaviour during its transformation from a two-dimensional (2D) product into a three-dimensional (3D) article of clothing is presented in this paper. Actual fabric transformation into a 3D article of clothing occurs in sewing processes, where the fabric is exposed to different mechanical loads and behaves accordingly. Fabric behaviour responses as an outcome of the mechanical loads to which it has been exposed, as well as their correlation with the parameters of the analysed fabric mechanical properties are investigated from this point of view. The system was designed for fabric behaviour prediction in garment manufacturing processes, based on wide fabric behaviour study. The ORANGE software tool used incorporates a lot of machine learning methods. On the basis of the input data (the parameters of mechanical properties) and input knowledge (fabric behaviour responses), it offers the prediction of fabric behaviour in garment manufacturing processes for the fabric selected.
International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 252-261 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520522
1. Introduction Contemporary garment industry has no alternative, but to satisfy all the requirements imposed by the customers, and, from quality assurance point of view, fabrics used represent the factor of potential trouble for those who are directly in charge of engineering high-quality garments. Textile materials-fabrics are manufactured employing modern production methods, with the idea that they should correspond with and satisfy a number of end-users. Modern, multi-coloured fabrics are supposed to match perfectly and make a basis for collections of current and coming-up seasons, sometimes disregarding quality and some other properties important for garment appearance. A lot of labour is needed during garment manufacturing processes, where fabrics are exposed to different loads, till the stage of finished garment to be seen in a shop-window on tailor’s dummy or on a coat hanger is reached. Fabrics and their properties become completely obvious in real garment manufacturing processes, meaning that different fabrics behave differently while being transformed from two-dimensional (2D) to three-dimensional (3D) articles of clothing. It is often too late to solve the problem that can emerge
without additional labour and material costs. It is thus essential for the manufacturer to be familiar with fabrics as raw materials before beginning the process of garment manufacturing. Methods of measuring fabric mechanical and physical properties, as well as appropriate measuring systems have been available for some time, and the study of fabric mechanics in this context has become a reality. For some analysed fabrics, numerous numerical values obtained by measuring are easy to study, but a number of different fabrics appear daily and it is not always possible to study the individual fabric properties. One of the aims of contemporary garment industry is engineer-planning high-quality garments, based on the existing knowledge of fabric behaviour in garment manufacturing processes, which, employing convenient software tools, make possible to predict in detail the fabric behaviour in garment manufacturing processes. The method of designing the system for predicting fabric behaviour in garment manufacturing processes is presented in this paper. Background knowledge needed for the operation of the system, based on correlation between monitored fabric behaviour responses in garment manufacturing processes and particular mechanical properties, has been obtained on the analysis of a large number of fabrics. 2. Starting-point of the system for predicting fabric behaviour Properly organised background knowledge, necessary for faultless system operation and overall prediction presentation, is a sound basis of every prediction system. It can be acquired through experiences of experts in garment industries or through numerous analyses of fabric properties. The background knowledge must be well organised and designed, as well as quickly and easily accessible. In the case of fabric behaviour prediction in garment manufacturing processes, the background knowledge necessary includes fabric behaviour studies in garment manufacturing processes on one hand, where fabrics are exposed to various loads, and the studies of fabric mechanical properties on the other, which supplement the background knowledge offering correlation with particular fabric behaviour responses. The parameters of mechanical and physical properties also give valuable information on the fabric analysed. 2.1 Fabric’s behaviour in garment manufacturing processes Because of different mechanical and physical properties, fabrics behave differently in the course of garment manufacturing processes. Fabrics are for the first time exposed to loads in the course of fabric laying, where tensile force and surface friction act upon them. Deformations that occur depend on the tensile properties of fabric, i.e. elasticity, deformation work and its ability to relax and return to previous condition, as well as on surface properties of fabric, i.e. friction coefficient and geometric roughness.
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For quality cutting of layers they should be stabilised first, which is achieved using vacuum. The impact of vacuum depends on the type and properties of the fabric used, its air permeability and compressibility. In the course of cutting fabric is exposed to the compression and tensile load, i.e. the force the cutter acts on the layer to be cut in its vertical and horizontal movements. Fabric behaviour in the process of cutting, together with its resistance to pressure and tensile force caused by the cutter, are defined by its stretch behaviour, bending and shear rigidity, as well as by its surface and compressive properties. These properties determine the cutting layer stability, as does air permeability (which has a serious impact on the quality of working vacuum). If fabric air permeability is too low, deformations occur and result in uneven contours of the cutting patterns produced, or in pulled out warp or weft threads, as well as in varying dimensions of the cutting patterns produced (Blekacˇ and Gersˇak, 1997). Transformation of a 2D fabric into a 3D article of clothing start with the process of sewing. In this, the fabric in the form of workpiece is exposed to forces created by the sewing machine on one hand, and the forces of transforming it from 2D to 3D form on the other. Of the forces created by the machine, the fabric is exposed to the pressure of presser foot, to pressure or tensile force of the feed dog on the one hand and to puncturing force of the needle with the thread in it on the other. Fabric behaviour, its resistance as a workpiece to the loading of the presser foot, sewing needle puncturing force, and feed dog, all of them depend on the fabric elasticity and its surface and longitudinal compressive properties. In transforming a fabric from 2D to 3D form, the workpiece is exposed to certain tensile, bending and shear loads, as well as to compression. Reaction of the fabric to this transformation depends on its elasticity and ability to relax, bending rigidity, formability, compressibility, shear rigidity and the value of shearing hysteresis and geometrical roughness (Zavec and Gersˇak, 2000). Apart from stresses mentioned, workpiece is also exposed to the stresses of thread in the seam produced. Incorporation of the sewing thread into the fabric composition requires certain rearrangement of warp and weft threads in it, which leads to particular tensile and shearing deformation, and which, if shearing properties are not adequate, can easily result in permanent fabric deformation in the area of the seam – seam puckering or wavy seam (Gersˇak, 2002). 2.2 Connection between the parameters of fabric’s mechanical properties and their behaviour in garment manufacturing processes The field of garment engineering includes fabric behaviour and understanding it requires the knowledge of fabric properties. These are defined on the basis of mechanics, i.e. mechanical and physical properties on one hand and remodelling properties of the fabric in question on the other.
Considerable research efforts have been made to correlate the mechanical and physical properties of the fabrics and their behaviour in garment manufacturing processes, with the aim of defining border i.e. critical values of individual parameters of mechanical properties. The amount of research involved describes about the potential problems in garment manufacturing processes (De Boos, 1991; Gong, 1991; Kawabata et al., 1992). Too high, and too low, values of a particular fabric mechanical property parameter can have a deciding (and bad) influence on the fabric behaviour in garment manufacturing processes. Border i.e. critical values of individual parameters are presented in control diagrams and can be used for the purpose of better understanding the mutual impacts of the factors mentioned. Section 2.3 presents the criteria for fabric’s behaviour evaluation in garment manufacturing processes, which are used to design the system for predicting fabric behaviour in garment manufacturing processes, on the basis of the knowledge of fabric mechanical properties. 2.3 Criteria for the evaluation of fabric behaviour The criteria for fabric behaviour evaluation must be well defined, so that real fabric’s behaviour could be assessed in garment manufacturing processes. Special attention is required when evaluating the 3D shape in area of shoulder and sleeve seams in garment manufacturing, as well with long curved line sewing, especially where the sewing components have different shape of the curve. The problems with fabric guiding into position for sewing, from the point of view of continuous movement, are associated with specific properties of the fabric to be analysed, while the amount of problems of fabrics sticking together depend on their surface properties (friction coefficient and geometric roughness). The problems also occur in guiding the sewing components under the sewing foot, with sewing layers difficult to fit together, as more time is needed to flatten them and to assure even width of the seam in whole line of sewing, straight or curved. Fabrics are already deformed in the area of small loadings, and smooth lines without seam puckering are often difficult to achieve. Because of the loads that act on the fabric in sewing processes and irregular movements of both sewing components, the problem of fabric elasticity often rises, and for printed materials it assumes the form of moving patterns or improperly matched ones. There are numerous factors that characterize finished seam smoothness, the appearance of the inserted sleeve, as well as the form and shape of garment after sewing. Therefore, the criteria for the estimation of fabric behaviour in garment manufacturing processes have to be defined in detail. The control system with defined criteria describing the fabric behaviour using five classes, divided according to the degree of trouble or deformations that are imparted, is an important element in designing the system for fabric behaviour prediction. The evaluation of a particular fabric behaviour responses is referred to
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manufacturing quality, keeping in mind the appearance of the garment or difficulties in manufacturing particular garment parts (Table I) (Zavec, 2001). 3. Designing the system for predicting fabric behaviour The starting-point for designing the system for the prediction of fabric behaviour is widely conducted research of correlation between mechanical and physical properties and obtained qualitative evaluated results of fabric behaviour in garment manufacturing processes. Based on this research, border or critical values of individual parameters of mechanical and physical properties are defined in view of problems in garment manufacturing processes. Knowledge base is designed from the factors presented, and used to predict fabric behaviour in garment manufacturing processes for new fabrics, provided their mechanical and physical properties are known. 3.1 Knowledge base as groundwork for presenting the prediction The algorithm used in constructing the knowledge basis, as a starting point for predicting fabric behaviour, is based on the values of the mechanical and physical properties of the fabrics in question, taken as input elements, as well as on the results of changes in fabric behaviour, as output elements. Functional connection between the input and output elements and prediction are designed on three modules (Figure 1) (Zavec, 2001). Each of the modules has a specific role and task for the knowledge base construction, as well as for its functioning. Module I is used to collect and sort the data obtained by the KES-FB measuring system. Module II enables a review of all the data assembled in the knowledge base, for the fabric sample selected and for the mechanical properties of the parameter selected. Module III is used to predict fabric behaviour in garment manufacturing processes. The knowledge base limitations are border or critical values defined, while algorithm resumes functioning in finding the prediction for a new fabric. The prediction will warn the garment manufacturer of potential problems in garment manufacturing processes, as shown for the fabric TK027 (Figure 2). The system designed for predicting the fabric behaviour in garment manufacturing processes is based on defined borders or critical values of individual parameters of mechanical properties, so it is not able to present the
Table I. Criteria for fabric behaviour estimation
Evaluation of responses
Manufacturing quality/appearance of particular parts
Difficulties in manufacturing particular parts
5 4 3 2 1
High quality/very good appearance Quality manufacture/good appearance Satisfying/smaller deformation Under average/visible deformation Bad/deformation cannot be tolerated
No problem Additional guiding and handling Insignificant troubles noted Serious troubles Significant troubles noted
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Figure 1. Scheme of the knowledge base modular design
Figure 2. Prediction of fabric behaviour for fabric TK027
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impact of individual parameters of mechanical properties of the fabric analysis on their behaviour. Because of this limitation, it was necessary to develop a system for predicting fabric behaviour using machine learning methods.
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3.2 Development of the system for predicting fabric behaviour using machine learning methods For designing the appropriate system to predict fabric behaviour in garment manufacturing processes, fabric behaviour under actual in-plant conditions was investigated. For this purpose, tests were performed to evaluate the fabric behaviour in garment manufacturing processes for 400 different fabrics used for ladies’ outerwear. Fabrics were designed for the autumn/winter season and partly also for the spring/summer season. Multi-coloured fabrics were tested of a wide variety of raw material content, manufactured in different weaves. Twill and plain weaves were used for most of the fabrics analysis, and these two groups were selected for designing the knowledge base. Mechanical and physical properties of all the fabrics analysed were evaluated using the KES-FB measuring system. For each fabric analysed, 47 characteristic behaviour responses were monitored. The 13 characteristic behaviour responses were monitored in sewing processes, and evaluated using the criteria presented in Section 2.3. Eight responses were selected for the purpose of designing the system for predicting fabric behaviour, giving specific correlation to the parameters of mechanical properties (Table II). The elements defined for the system for predicting the fabric behaviour in garment manufacturing processes were associated to background knowledge in the process of designing, which is the central and basic component of the system. The key point of the background knowledge is the connection between
Response designation s1 s2 s4 s6 s7 Table II. Characteristic fabric behaviour responses in sewing processes
s8 s12 s13
Description of fabric behaviour responses in sewing processes Seam puckering Fabric feed – continuous movement of sewing layers Fabric extensibility – irregular movement of both sewing layers Finished seam smoothness Difficult adaptation, folding and rolling of one or both components in sewing Poor ability of contour matching in curved lines managing Stickiness between layers Handling: slippage, aligning and positioning of sewing components during sewing processes
particular fabric mechanical properties and its behaviour in garment manufacturing processes. Assembled background knowledge was needed to construct algorithms of learning. They were used to make the prediction of fabric behaviour in such a way to learn first and then, on the basis of the data learned, to produce the prediction for the new fabric. A scheme for designing the system for predicting fabric behaviour in garment manufacturing processes is shown in Figure 3.
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3.3 Software tool for prediction – ORANGE The ORANGE software tool was the most suitable tool for predicting fabric behaviour in garment manufacturing processes. Its components work in PythonWin environment; their scripts are written using the Python program language. The program mentioned was developed at The Faculty for Computer and Information Sciences, Ljubljana Slovenia (Demsˇar and Zupan, n.d.). The background knowledge and learning examples must be well presented; the presentation has to make possible effective generation and usage of the knowledge. Learning algorithm gets the background knowledge as the input and uses different operators to change the temporary data of a possible hypothesis. In the course of designing the system for predicting fabric behaviour in garment manufacturing processes, background knowledge is presented in the form of declaration calculus over classification and decision regression rules, as well as in the form of probability distribution over Bayes classifier, while learning examples are presented as probability distribution with the basic form of K-nearest neighbour (Kononenko, 1997).
Figure 3. Designing the system for predicting fabric behaviour in garment manufacturing processes
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The K-nearest neighbour method proved to be the most successful, meaning it simplifies saving all the learning examples. In the process of classifying the new examples, a sub-group of similar examples was found and was used to predict new examples. The prediction accuracy with the K-nearest neighbour method is presented with root mean square error (RMSE).
260 4. Conclusions Systems for predicting are gradually gaining ground in the area of textiles as well. Adequate data acquisition, in-plant experience (so much needed these days), are principal and deciding tasks that should be solved in predicting and modelling systems, which is a complex task in itself. Border i.e. critical values of individual parameters of mechanical properties are used as an aid in such a system, but they are easy to define only for groups of similar fabrics or for a group of fabrics within a season, when similar properties are most often required. This limitation should be kept in mind when predicting the behaviour of a new fabric, such that it can be used in garment manufacturing no matter when or where. Machine learning methods allow handling considerable amount of data, and the software system of ORANGE proved to be an appropriate software tool for designing the system for predicting fabric behaviour in garment manufacturing processes. The parameters of mechanical properties are input data, the so-called attributes. Using learning algorithms, the output of the system is the prediction of fabric behaviour for all or selected response only, with an appropriate level of manufacturing quality/appearance of particular garment parts. The methods of designing the system for predicting fabric behaviour have been going through its development phase, which means supplementing and upgrading learning examples. The usage of the system in garment industry would help in engineering high-quality garments, making possible to predict fabric behaviour before actual garment manufacture, provided their mechanical properties are known. Manufacture time will be shortened and potential problems associated with using a wide variety of different fabrics solved in advance. References Blekacˇ, R. and Gersˇak, J. (1997), “Influence of mechanical and physical properties of fabrics on cutting process”, 2nd International Conference – Innovation and Modelling of Clothing Engineering Processes IMCEP ’97, 8-10 October 1997, Faculty of Mechanical Engineering, University of Maribor, Maribor, ISBN 86-435-0202-2, pp. 174-83. De Boss, A. (1991), “The FAST system for objective measurement of fabric properties, operation, interpretation and application”, CSIRO Division of Wool Technology, Sydney. Demsˇar, J. and Zupan, B. (n.d.), Available at Web site: http://magix.fri.uni-lj.si/orange/
Gersˇak, J. (2002), “Study of the relationship between fabric mechanics and garment appearance quality level”, 1st International Textile, Clothing and Design Conference – Magic World of Textiles, 6-9 October 2002, Dubrovnik, Croatia. Gong, H. (1991), Interpretation Guidelines for KES-FB Test Results, Department of Textiles, UMIST, Manchester, pp. 1-6. Kawabata, S., Ito, K. and Masako, N. (1992), “Tailoring process control”, Journal of the Textile Institute, Vol. 83 No. 3, ISSN 0400-5000, pp. 361-73. Kononenko, I. (1997), Machine Learning, Faculty of Computer Science and Information, University of Ljubljana, Ljubljana, ISBN 961-6209-11-6 (in Slovene). Zavec, D. (2001), “Prediction of fabric behaviour in garment manufacturing processes”, Master thesis, Univerza v Mariboru, Maribor (in Slovene). Zavec, D. and Gersˇak, J. (2000), “Influence of mechanical and physical properties of fabrics on their behaviour in garment manufacturing processes”, 3rd International Conference – Innovation and Modelling of Clothing Engineering Processes IMCEP 2000, 11-13 October 2000, Fakulteta za strojnisˇtvo, Univerza v Mariboru, Maribor, ISBN 86-435-0349-5, pp. 249-57.
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Design and engineering challenges for digital ink-jet printing on textiles A. Dehghani, F. Jahanshah, D. Borman, K. Dennis and J. Wang School of Design, University of Leeds, Leeds, UK Keywords Ink-jet printers, Quality, Textiles, Research Abstract This paper will review digital ink-jet printing on textiles and the advantages it offers to textile industry and consumers in comparison with conventional printing. The paper also reports on some of the results of a large project, which has been undertaken in the University of Leeds to address a number of issues concerning the problems associated with this technique. One of the important issues associated with digital ink-jet printing on textiles is speed and reliability, as this has commercial implications for the industry. The research carried out in Leeds has addressed this problem and solutions are proposed which will be covered in detail in this paper. Further research has also been carried out to establish the issues surrounding digital ink-jet printing and print quality when different types of designs are being printed. The paper will address the results of this research on quality assessment of digital ink-jet printing on textiles.
International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 262-273 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520531
1. Introduction Advances in recent years, in various areas of science and technology, has made it possible for digital ink-jet printing to perform very high quality printing on paper with very low cost. This technology has already attracted a number of possible areas of applications such as printing on different substrates and even printing electronic components. The application of digital ink-jet printing to textiles is proceeding rapidly and it is foreseen that the traditional flat and rotary screen-printing and roller printing techniques may, in the medium term, be superseded by digital printing technologies. In short term, some of the traditional market for shorter run screen-printing will be eroded by new digital processes and new markets will evolve for mass customisation products. Digital ink-jet printing can have major economical effects on printing on textiles. As an example, existing high-capital investment rotary screen-printing facilities, requiring significant print runs for economic operation, could be replaced by smaller more flexible units capable of delivering very short runs and meeting “just-in-time” manufacturing requirements. Some of the potential benefits include: No stockholding of printed fabric which means all work could be printed to order with very short lead times. Since no setting or washing of tooling such as screens are required the down time should be virtually zero. Support for this project from EPSRC, Marks and Spencer plc., Cha Technologies, Samuel Bradley Ltd, Guilford Europe Ltd, Coats Viyella Home Furnishings, Zephyr Flags and Banners Ltd, Franklins Textiles Ltd, and Brook International Ltd are gratefully acknowledged.
Tooling costs such as engraving the screens and inventory of tooling will be eliminated. Samples can be produced rapidly as required and therefore there will be no need to stock samples for customer enquiries. 2. Background to the project A large research project was carried out in Leeds University. The following four schools were involved in the project. (1) School of Textiles and Design, Mechatronics Research Group; (2) School of Mechanical Engineering; (3) School of Materials; and (4) School of Colour Chemistry. This EPSRC funded project started in 2000 and main objectives of the project were: . to develop an improved understanding of droplet formation, deposition and interaction with textile structures; . to investigate optimal inks/dyestuffs for use in the commercial range of textile constructions and materials; . to develop optimised piezoelectric print-head constructions to exploit the above-mentioned objectives; . to raise printing speed to acceptable levels for commercial production, also to increase reliability to give defect-free production; and . to research the upcoming business process and industrial requirements of textile jet printing to inform machine development to fulfil future needs. Intelligent digital jet printing, where droplets can be fully controlled and printing process can be monitored online with the effect of a feedback system to rectify any possible problems to achieve reliable results, will open a new window to a wide range of applications for jet printing on textiles. 3. High-speed digital ink-jet printing with high reliability Currently, there are several commercial textile ink-jet machines available, most of which are developments from paper printers and use drop on demand technology (where each drop can be specifically controlled). They are inexpensive (compared with rotary screen printers), but slow with a susceptibility to nozzle blockages. As a sampling tool, the digital textile printer is already proving its worth. However, turning this technology into a low maintenance, lights out production tool is still a considerable challenge. Alongside ink development (to provide a colour gamut and colour wash-, lightand rub-fastness to match screen printing inks), the two main hurdles for making textile ink-jet printers into production tools are their low speed and poor reliability.
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The multidisciplinary EPSRC funded project at Leeds was developed with four main technological components. Each of these components has been a focus for one of the four teams within the University. This section of the paper provides an overview of the distinctive work carried out by the Mechatronics Research Group based in the School of Design. A re-configurable printing architecture has been designed and evaluated that uses a combination of “serial-parallel” print heads, each with a CCD scanning element to monitor the printed output. The principle designs have been prototyped on a demonstrator machine with a dynamic architecture and error checking functionality with the potential for high-speed printing with high reliability (Figure 1). 3.1 Methodology The requirements of the textile printing community for a faster and more reliable ink-jet printing system shaped the research into two parallel approaches. The first focused on the development of an image processing-based vision system that is capable of comparing before and after images from two CCD image arrays to determine whether what should have been printed has been printed. The second focused on designing, modelling and evaluating printer topology and architecture to make effective use of information from the vision system. Development followed a number of key stages. . Evaluation of current state-of-the-art ink-jet and other textile printing systems and architectures. . Investigations into machine vision for error detection using standard line-scan and area-scan camera equipment. Implementation of off-the-shelf image processing software for pattern recognition and blob analysis.
Figure 1. The multi-inline head demonstrator rig encompasses a vision system for each set of coloured nozzles
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Design and development of new re-configurable printer architecture to include localised head-monitoring systems. Experimentation and exploitation of low cost linear array hardware and illumination sources for overcoming economic and space limitations. The anticipation is that each head would require its own localised vision and recovery system. Modelling proposed printer construction and operation to evaluate constraints and throughput based on recovery through inclusion of vision system. Formulation of image processing strategy and systematic development and testing of algorithms for individual drop detection. Development of small-scale evaluation x-y rigs incorporating digitally tuneable illumination and drop detection routines. Design and implementation of full-scale demonstrator rig including a vision system, re-configurable print heads, control system and additional developments from small evaluation rigs. Full testing and evaluation on a wide range of substrates.
3.2 The prototype ink-jet printing system The final development of the work has been the printer/imaging test rig that has allowed theoretical solutions to be prototyped and evaluated. The rig is structured around a 3 m linear motor that traverses the heads and monitoring system. The rig uses two sets of CMY print heads that build-up images in parallel. The substrate being printed can be positioned on a precision moving pattern that steps forward allowing an image to be constructed in the x-y plane. The localised vision system allows print from each of the heads to be monitored in real-time during the printing. Software and interfacing hardware have been developed as a main controller. The software runs on a host PC and implements communication between a number of system processors. These include motion controllers, print controllers as well as image processing algorithms. A summary of the development are described in the following sections. 3.2.1 The multiple in-line design. Research concluded that an in-line design would be most effective. Printers for textiles are required to print widths of up to 3 m and a single head traversing back and forth across the substrate will take considerable time. The design uses an increased number of in-line heads to print designs faster. When a head is deemed to have failed, the control system will take the failed head out of the process and redistribute the heads so that they share the work of the faulty head. This process allows continuous printing till the end of prints with a gentle degrading throughput. For example, sharing the work between eight different heads increases the throughput almost eight times.
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Figure 2. Left: three colour design ink-jet printed (interpretation of photo in Figure 1); right: close up of the ink-jet printed textile shown on left
3.2.2 Illumination. Illumination is critical in any machine vision application. It was concluded that it would be most efficient to illuminate the substrate in one specific hue (rather than using the three RGB channels as this would take three times longer). For this reason, it was necessary to design a system that was digitally controlled. A high-speed digital illumination device has been developed that can combine red, green and blue LED light sources. Each colour is pulsed at high-speed with differing on/off times in order to effectively mix differing ratios of the three colours (RGB) together (Figure 2). The resulting combination of digital light pulses will be exposed to the CCD sensor with the resultant effect being of illuminating in a specifically controlled colour. This colour can be tuned digitally to detect specific colour inks. 3.2.3 Machine vision hardware. After prototyping image processing routines using line-scan and area-scan test facilities, experimentation progressed with linear array technology. The aim here was to develop a system that was cost-effective. The linear array technology retails for around one twentieth of the price of a camera equipment meaning that it is a realistic technology for each head on a printer to have a localised monitor. There were a number of technical barriers to overcome when using these components, one such aspect was the increased sophistication of the hardware interfacing and image grabbing equipment. There are restrictions to the sizes of array that were available to us (arrays that were selected would allow realistic implementation time as well as compliance with print head selection). This direction was very successful, although current array densities and data output speeds are below that required values for significant speed increases to the printing process (sampling speed is a limiting factor on the devices currently in use). However, the modules have been key to demonstrating that the approach was viable. The continuous influx of CCD and CMOS technology onto the market would allow the selection of higher speed devices for future commercial products. 3.2.4 Image processing. The image processing for the system has been one of the major undertakings of the project. Stage 1 involved working with high-level image processing software in attempts to pattern match printed images with those stored on file. This was initially successful on very smooth substrate like
coated paper, where work has been published in the past, but was ineffective on textiles where the texture of the substrate is a key part of the image detected by the vision system. This early research work was the impetus for a low level strategy. This next approach used two images taken from the textile substrates, that of before and after printing. These images could then be subtracted from one another removing the background noise of the textile surface. This idea proved considerably more successful, but required both high quality reproducible images and highly tolerant machine design. After low-level processing and image subtraction the image is sampled over short periods and cross-referenced with data from the print head controller input data stream. Comparisons are made and where there significant variations in the two sets of data it is possible to assess if a nozzle has stopped printing. Figure 3 shows photographic images of a substrate printed first with cyan drops then with yellow drops. The overlapping areas are most important as these are most difficult to detect due to the second colour masking by the undercoat. Evaluation experiments include detecting different size of drops, detecting new drops on same colour, detecting new drops on a background of other colour drops and tests on different types of substrate. After each series of checks the history of each nozzle can be checked statistically and where a nozzle is deemed to be failing too frequently, either the head will be taken out of service for cleaning cycle or the other print head takes the responsibility of that and the printing process will continue. 3.2.5 Main control system and rigs. A number of small-scale test rigs were designed and built prior to developing the full-scale 3 m traverse version. These incorporated the linear array technology and the pulse modulated RGB light source into precision x, y tables and allowed the observation and evaluation of hardware and software during development. A sophisticated control system is necessary to control very large volumes of data being transferred around the system. A high performance Pentium 4 with a series of high-speed interface cards and frame grabbers has been used. The control software was developed in Visual Basic and C++ as well as motion control languages such as ACSPL and is responsible for synchronising the system, controlling the position of the print head, sending image information to
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Figure 3. Cyan drops (left), cyan drops over-printed by yellow drops (right)
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the print heads as well as operating, reading and processing the information from the heads. The final system uses the PC host as the primary controller and two additional microcontrollers to control the head motion and drop ejection, respectively. The control system has been designed to communicate between this controller to synchronise relative images, relative drop ejection and relative image and drop ejection. This has been an intricate process with the final system being able to print interlaced images that are desirable for evaluation purposes. 4. Digital ink-jet printing on textiles and print quality Unlike the paper which has a relatively smooth surface, textile substrates have rough surfaces and this makes digital ink-jet printing more difficult to achieve high-quality prints. Textile substrates usually undergo a finishing stage prior to digital ink-jet printing. Nozzle blockages or banding in ink-jet printing technology has the most implication when print quality is visually assessed. This is one of the defects, which still persists and has effects on the appearance of objectionable variations in areas intended to be uniform in colour or optical density. It is generally the result of small mechanical, electrical, or even chemical imperfections in the printer components, which extends across the width and the height of the printed image. Many researches have been carried out to analyse the banding effect objectively. The ISO-13660 standard is the latest print quality standard intended to systematise measurement of 14 key print quality attributes (Briggs et al., 1999). IAS-1000 is an automated image analysis system based on ISO-13660 for objective banding analysis (Briggs et al., 2000). The system is based on two CCD cameras and sophisticated software to produce the banding frequency domain. The results can be compared with the human visual transfer function (VTF) to determine the lowest level of banding perceptible by human eyes. Subjective print quality evaluation has also been considered parallel to objective analysis. In this method, many variables are being involved which makes the analysis of results more complex. Apart from influence of printer type, substrate, and ink, perceived severity of banding depends upon a number of factors such as, spatial frequency of banding, image design (i.e. the contrast between the bands and the surrounding area) and the viewing distance. 4.1 Subjective assessment of print quality A subjective evaluation survey was carried out in a fixed banding frequency (i.e. 1.5 cycles/mm), which was applied to five different design category of images to be viewed in a normal distance for defining the lowest banding level to the human perception. By analysing the result it was possible to predict the quality of the final image in order to accept or reject the print. The idea behind this survey and the analysis was to come up with an algorithm to integrate to the control and rectifying system as discussed earlier.
It was believed that when the issue of speed and reliability in printing are under consideration, in some cases some defects may not be noticeable or important and could be ignored. This will allow the printing process to continue rather than being interrupted for rectification process. This means the inclusion of a clever algorithm to assist the continuation of printing process based on the level of faults can assure the high-speed printing. Three levels of banding width (i.e. two, three, and four-blocked nozzles), on four primary colour inks (i.e. cyan, yellow, magenta and black) as 12 levels of faults were artificially made on five different image categories in Adobe-Photoshop (Table I). The five categories of images (Figure 4) are: (1) Image 1 – a traditional printing design; (2) Image 2 – a simple solid colour pattern design; (3) Image 3 – a photographic design; (4) Image 4 – a new fashion design, and (5) Image 5 – a logo design (see Figure 4).
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The original and faulty images were printed by Amber textile printer (Stork) in 360 resolution on pre-coated cotton fabric. Printed samples were washed and steamed and cut to small samples ð13 £ 13 cmÞ: The samples were mixed and each ten of them were randomly bonded as a single booklet. The booklets were distributed to 217 students in the age range of 20-30 and they were asked to give their responses to a comment related to the quality of every sample by choosing one of the following options: SD – strongly disagree, D – disagree, N – neutral, A – agree, SA – strongly agree. 4.2 Results and analysis The collected data were analysed in Excel to compare the distribution of responses for every sample. Contingency table statistical method was used to calculate the x 2 values of samples within each image category separately. F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12
No blockage Two blockage of cyan Two blockage of yellow Two blockage of magenta Two blockage of black Three blockage of cyan Three blockage of yellow Three blockage of magenta Three blockage of black Four blockage of cyan Four blockage of yellow Four blockage of magenta Four blockage of black
Table I. Look-up-table of blockage
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Figure 4. Five categories of images
The analysis was continued to compare the difference between the image categories. The results showed that within each image category, magenta blockage has the highest difference relative to the expected distribution responses. In addition, cyan, black and yellow gives less impact on the quality evaluation, respectively. Depending on the percentage of the magenta, cyan, black and yellow colour in an image, the image sensitivity to the faults would be different. As Figure 5
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Figure 5. Comparison of distribution responses with the mean or expected distribution for five different images
shows this could not be a general rule, since it depends on a number of factors such as the design, contrast, sharpness, and brightness of an image. Therefore, an image itself may be favourable to an observer disregarded to the applied faults. However, it can be concluded that images similar to Image 5, which has got narrower lines of solid colours are less susceptible to banding defects whereas, images with bigger solid magenta colour such as Image 4 are more detectable. 5. Conclusions The paper reported some of the outcomes of a large project carried out in Leeds University. The project has brought together a range of technologies and has been successful in most aspects. The designs and concepts that were proposed
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have effectively been tested and a number of companies have expressed interest in developing the prototypes further. The work carried out in the school design included: . development of a working multi-head demonstrator facility that can print images with multiple heads; . a sophisticated control system that is able to synchronise information from three controllers, four heads and four scanners; and . a real-time ink-jet monitoring and recovery system for drops over 150 mm Banding effect on print quality varies relative to the print resolution, width of banding and type of substrate. Detailed surveys were undertaken to obtain meaningful data on the way the individuals see faults in an image. This has been a useful source of information for reference data for the system controller. If we know the level of fault that is either unnoticeable in different categories of designs we can determine when heads/nozzles should be cleaned or replaced. Working through simulations of failure patterns made it possible to identify optimum design arrangements for an in-line design of printer. The models developed have made it possible to run simulations for a range of designs of differing size and complexity. The flexibility of the models allows for new technological developments to be incorporated. Work to this stage is encouraging, barriers to increasing print speed are being removed through the research and print speed increases of ten times seems very realistic. The anticipated problems with the in-line design have been evaluated and widely overcome. This includes successful blending of images, simple colour overlaying and solving alignment problems. Prototyping of the vision system has been successful to a large extent with results from working vision system looking very promising. Current restrictions to array density mean that the system is less reliable at detecting drops below 150 mm in diameter. However, these restrictions will be overcome with the anticipated improvements in array technology. There is also work to be done to increase the processing and scanning speeds to competitive rates. Prototyping of the vision system has been done online using paper substrates and tightly woven textiles. Work so far has been very successful in these areas and there is optimism for taking the ideas forward to a wider range of textile substrates. References Briggs, J.C., Murphy, M. and Pan, Y. (2000), “Banding characterization for ink-jet printing”, IS & T’s 2000 PIC Conference, pp. 84-8. Briggs, J.C. and Forrest, D.J. et al. (1999), “Living with ISO-13660: pleasures and perils”, QEA, Inc. IS & T’s NIP 15, pp. 421-5.
Further reading Borman, D., Jahanshah, F., Dehghani, A.A., King, T. and Gaskell, P. (2002), “On-line vision system for ink-jet printed media”, N.I.P.18, San Diego, California. Borman, D.J., Jahanshah, F., King, T., Dehghani, A.A. and Dixon, D.A. (2002), “Mechatronic system topology and control for high-speed, high-reliability textile ink-jet printing”, Mechatronics 2002, Enschede. Farzad, J., Duncan, B., Dehghani, A.A., King, T. and Gaskell, P. (2002), “Real-time detection and rectification for ink-jet printing of specialist wide format surfaces”, ITMA, Finland. Jahanshah, F., Borman, D., Dehghani, A.A., King, T. and Dixon, D. (2002), “Mechatronics and machine vision for online fault detection and rectification in ink-jet printing”, Mechatronics 2002, Enschede.
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The Emerald Research Register for this journal is available at www.emeraldinsight.com/researchregister
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The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Colour specification at the design to production interface David P. Oulton Department of Textiles, UMIST, Manchester, UK
Tara Young Worthington Manufacturing Ltd, Cheshire, UK Keywords Colours technology, Textile manufacturing processes Abstract This paper describes how the communication of colour specifications between designers and technical production personnel has been improved using calibrated colour and digital networking. The electronic colour communication system known as “Imagemaster”e is described in which both colour and texture are quantified by calibrated variables. Colour is calibrated by reference to CIE colour co-ordinates. Imagemaster also uses and if necessary generates a reflectance curve for each object on the screen for use as a production colour specification. A novel colorimetric model of textile textures based on image content is described, which can be used to predict the independent effect of texture as a distinct component of overall colour appearance. Close electronic collaboration between all those contributing to design, product development and production is described. Savings in the complexity, cost and lead-time for achieving correct colour and technical specifications are reported.
International Journal of Clothing Science and Technology Vol. 16 No. 1/2, 2004 pp. 274-284 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410520540
1. Introduction Colour plays a vital part in the development, marketing, and sales success of a wide range of products. In technical terms, it is an accepted practice to work to production colour tolerances of less than delta E 2 (CIE L*a*b*) under three different illuminants, and colour management systems have been developed in textile manufacture and retailing, which enable production processes to be controlled to this level (Berns, 2000). These and other technicalities of Industrial Colour Management are however not normally the concern of the designer. Design inspiration, and design development are essentially visual and creative processes. The design process has its own distinct language and internal communication methods. Designers also have a different perspective from technologists on visual acceptability once the design has been reproduced, perhaps by industrial dyeing or printing. There are thus readily apparent differences of approach to colour specification and colour-match acceptability between designers and production technologists. They often cause extra expense in sampling, time delays, and unnecessary compromises in the final product. In other words, we have an interface problem. The Imagemaster system developed at UMIST (Oulton and Porat, 1997) seeks to bridge the “communication gap” between the two separate worlds of design and production. The designers and technologists must of course be
given the tools to construct suitable messages to resolve the communication problem. On one side, there are tools concerned with manipulating and visualizing colour appearance and texture, and the message developed is primarily visual. On the other side, the tools are concerned with available dyes, dye recipes and production colour specifications. The specifications are then represented by measured and calibrated numbers (including the colour). The first requirement is to make it easy to create dye recipes and also easy to create garment or fabric visualizations that look exactly like the ultimate product. The second is to make them readily inter-convertible. The designer can generate a technical message consisting of numeric specifications accompanied by a visual image of what is needed in terms of colour and texture. The production technologist can visualize and specify the colour and texture that might be produced by his chosen dye recipe (Oulton et al., 1996). 2. Precise colour communication Two key technical developments enable the visualisation and communication of colour specifications. The first is the colour calibration of a computer monitor screen. A link must be established between visual colour appearance and its technical specification by CIE co-ordinates. The system developed at UMIST establishes on-screen colour reproduction of CIE specifications to better than delta E1 (mean) CIE L*a*b* D65 colour difference for all reproducible on-screen colours. The calibration system requires at most 30 calibration points and can be run in under 5 min (Oulton and Porat, 1991). The second major advance in colour communication is the use of both measured and synthetic reflectance curves to communicate full colour specifications digitally (Hawkyard, 1993). This method is now regularly used to transmit production colour specifications electronically to remote production units. At the receiving site, the reflectance curve is used as input to a local colourant recipe formulation computer system, which reproduces the desired colour to delta E1 or better under multiple illuminants (i.e. a close reflectance curve match). 2.1 The accuracy of on-screen colour reproduction Colour calibration by the UMIST “Adaptive Driver” system (Oulton and Porat, 1991) delivers local, device dependent RGB gun-drive values. These are generated by a dynamic non-linear three-dimensional transform, from CIE colour co-ordinate definitions, whose content is derived by establishing the direction, scaling, and non-linearity of the vectors of CRT colour reproduction space. Colour calibration is based on feed-back measurement of screen colour using a Minolta CA100 colour analyser under system control. The CRT analyser is used to feed the CIE co-ordinates of a screen colour back to the calibration software allowing an unique mapping to be built between independent CIE co-ordinates and device RGB co-ordinates. A typical
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calibration process takes approximately 5 min and uses not more than 30 calibration points on the CIE co-ordinate grid of 16.77 million possible on-screen colour specifications. Long term exhaustive trials have shown that across the 16 million plus colours, the system is capable of reproducing the desired CIE colour specifications to within an average of 0.5 delta E (CMC 2:1). Table I shows the mean reproduction errors after sampling at 58 hue intervals. For each hue interval, all possible combinations of Chroma and Lightness based on reproduction of CIE specified colours at five unit intervals of L, C and H8, have been measured and re-measured over varying time periods. Coverage of CRT colour-space included all colour specifications where one or more gun drive values reach the range limits of 0-255. R, G and B gun-drive values are integers in the range 0-255. This produces stepwise colour change on a grid of 16.77 million possible colours. A real number CIE specification may convert exactly into an integer gun-drive value, or it may be rounded to the nearest integer. This rounding process produces quantisation errors which can reach CMC 2:1 delta E values of 0.6. The calibration routine thus appears to be generating gun-drive values which are accurate to the nearest integer value in most cases. The Minolta CA 100 instrument used to measure screen patches in both calibration and testing is a Tristimulus instrument. It therefore gives a potentially inaccurate determination of screen chromaticity. The specific instrument used in the above-mentioned test, has been cross calibrated against a Bentham Tele-radio-spectrophotometer. Relatively minor smooth distortion of chromaticity was found across colour-space. 3. Precision colour imaging Having put in place the essential elements of colour communication, the UMIST Colour Communication Research Group addressed the problem of modelling the complex surface texture of textile materials. This required the development of computer systems to capture, store, process, and analyse CIE specified colour images typically at 3; 000 £ 2; 000 pixel resolution, often derived from 24 bit RGB originals.
Co-ordinate set
Table I. Monitor screen calibration performance
Example hue page (H ¼ 308) Full set of 72 hue pages
Min. error (DE CMC2:1)
Max. error (DE CMC 2:1)
Mean error (DE CMC 2:1)
Mean differences h c I
Number of samples measured
0.025
1.348
0.487
0.658 0.794 0.097
1,908
0.01
1.969
0.484
0.650 0.792 0.148
124,968
The objectives are to: (1) enable early prototyping decisions to be based on colorimetrically accurate photographic images of potential products and product colours; (2) enable “CAD conferencing” in close buyer-supplier partnerships, and across supplier production sites; (3) add surface texture simulation to the colour communication process, without sacrificing any precision in the colour specification. 4. Visualisation of colour in context Visual testing has revealed that a “colour in context” format is required, for a correct visualisation of CIE co-ordinate specified colour. The default display environment used is an image simulating D65 illumination in a standard matching booth. Alternative environments can be constructed on-screen, and the visual effect can be simulated of any alternative illuminant that has a known spectral power distribution (SPD). An important principle in on-screen “virtual product” visualization is the elimination of electronic menus and windowing features from the field of view during colour judgement. Information screens and tools are therefore only displayed and accessed (from pop-up menus) as and when required. The system has been tested both industrially and in the lab (Oulton and Porat, 1991; Oulton et al., 1996; Smith, 1999) for visual match quality between physical samples in the matching booth, and the on-screen simulation of the measured CIE co-ordinates. The quality of visual match is rated high enough to communicate an accurate visualisation of a measured CIE colour specification under a range of alternative illuminants. 5. Design-led colour and appearance modification Single colours, colour ranges and colour libraries can be built up from measured instrumental input, numerical data input, or established visually on the computer screen. The visual colour manipulation tools pay particular attention to the properties of colour, and use intuitive techniques to locate colours in colour space. Internal functions convert 2D mouse input co-ordinates into colour visualizations and vice versa. When new colours are generated on screen, both CIE co-ordinates and a synthetic spectral curve are generated for use as the master colour definitions. Alternatively, a spectrophotometer can be interfaced to the system, and used to generate the spectral data from a physical sample of the colour. 5.1 User interaction with colour definitions An excess of 1 million colours are frequently present in an image. The software logically groups these into on-screen sets, each of which is a distinct object simulation. Each such object can then be manipulated independently, both in colour and position on the screen. The users can therefore build-up complex
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colour judgement environments. Imagemaster is often used as a Colour Library and historical colour database (with no limit on the number or type of objects). Another example is the use of Imagemaster for colour CAD discussions. It can then support the designer with a database of historical colour-popularity data, and future popularity predictions such as those available from the International Colour Council. For all active objects in a screen simulation, a pop-up window providing feedback on the colour data is available, giving both CIE co-ordinate and spectral definitions. The graphical data thus provided make it easy to study the difference between selected objects and colours. If more than one object in the system is selected, the colour difference between each is displayed (using SPD data to define the current illuminant simulation, and a range of colour-difference equations). 6. The advantages of using calibrated colour images There are a number of important consequences following the adoption of CIE specified colour, for image definition and processing. (1) It becomes possible (and often necessary) to define simulated colour with reference to input measured colour specifications, and also to compare the on-screen simulation with the physical samples originally measured. (2) It is possible to visualise remotely generated colour specifications and texture simulations. (3) Intrinsic colour differences and internal colour relationships within images can be captured, analysed and used to simulate and define known textures. (4) When image colour-sets are moved as a body within CIE L*C*H* or CIE L*a*b* colour space, internal colour relationships are preserved to a great extent. It is thus possible to move an entire image colour-set quite a long way inside 3D colour-space, thus re-colouring the object without losing correct texture and reproducible appearance. (5) CIE-based colorimetric analysis is demonstrated as a very powerful method of abstracting logical object hierarchies from images, and also for advanced colour reduction strategies in print design. 7. Characterizing and modelling texture A definition of texture can be established based on the detailed (sub-millimetre level) spatial distribution of coloured areas within an image. The phenomenon of “colour appearance” is then modelled as having two independent variables. They are the “texture” and its intrinsic base-colour (i.e. single colour) specification. The base colour of a texture then becomes an independent variable which can be changed at will, and is a direct analogue of applying a dye to a fabric with the given constant texture.
The independent variable called “texture” has two components. Each colour definition has a frequency of occurrence (by total pixel count), and a set of locations at which this colour is present, distributed spatially across the texture. The first component is a mapping from the base-colour specification into a cluster of closely related colour specifications. The second component establishes the spatial-position of each pixel-member of the cluster, to represent the characteristic visual appearance of the texture. In practice, this two-part definition leads to a simulation of texture as a set of possibly many thousand colour definitions, called a “colour-set”. Colour sets within excess of 100,000 colour definitions, and perhaps millions of spatially related pixel positions, occur frequently in high resolution image analysis. Modern PCs with a Pentium 3 processor or higher and sufficient memory are powerful enough to handle the necessary calculations for creating, storing and processing the required data structures. 7.1 MDD and MVD value quantification of “texture” A mathematical and statistical analysis has been made, of object and texture colour-sets abstracted from images, and the resulting colour-sets have been characterised by a new scalar measure of colour distribution within each colour-set. This has been given the name “mean directional deviation” (MDD), and it relates colour-set members to the base-colour by means of a three-dimensional mathematical function. The MDD in practice is related to the common experience that an identical dye recipe may produce a shade with perhaps lighter or more vibrant colour in certain textures. As the members of a colour-set are distributed in a colour-space to which vector properties can be ascribed, a second powerful measure of the properties of a texture colour-set becomes available. It has been given the name “mean vector displacement” (MVD) value. The adopted “independent texture variable” is thus defined as a function which operates on an base-colour definition to produce a modified colour appearance. The MVD value specifies the result of applying the function, and thus has both diagnostic and predictive power for changes in visual appearance due to changes in texture. 7.2 The derivation of MDD and MVD values The MDD of a colour-set in each of the three dimensions is defined as the mean sum of all the (many thousand) individual point-colour deviations: for example, in the lightness dimension X . MDDL ¼ DL n where n is the number of set members, and DL is an individual point-colour lightness difference from the intrinsic colour L* value indicated by the dye recipe prediction.
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MDDL defines the MDD of all the members of a colour-set from the intrinsic colour in the lightness dimension of difference. It is measured in colour-difference units i.e. CIE L*a*b* units. Identical measures, MDDC, and MDDH are also defined for the hue and chroma dimensions of difference. DDL, the direction of deviation in lightness, is a basis-vector of three-dimensional colour-difference space. The other two basis-vectors are DDC and DDH, respectively, in the dimensions of chroma and hue. Individual set-member deviations, and mean colour-set deviations MDD, are scalar measures in this colour space, which are regarded as having both direction and magnitude. Directional hue difference DHD is a signed scalar variable in this space, defined as DH D ¼ DH * ðDh8=jDh8jÞ where DH is the metric hue difference (which does not have a defined direction of change), Dh8 is the signed hue angle change, and jDh8j is its un-signed absolute value. The effect of the function ðDh8=jDh8jÞ is to assign a direction of change ^ to DH without altering its numeric value. 7.3 MVD The three mean-value scalars are combined to produce a colour appearance-change vector in the three dimensions of colour: lightness chroma and hue (L C and H ). It is denoted by the symbol MVDTexture. MVDTexture ¼ ðMDDL ; MDDC ; MDDH Þ: Because the MVD is regarded as a vector in colour-difference space, it is appropriate to quote a colour difference between two MVDs in this space. This difference is denoted as delta EMVD. It is calculated in the same way as conventional colour difference delta E (i.e. as an RMS value) as follows. 1=2 delta E MVD ¼ MDD2L þ MDD2C þ MDD2H The difference expressed in delta EMVD (and also in a single MVD value), is defined in terms of CIE L*a*b* colour difference units. In effect, delta EMVD establishes the overall size of the effect produced by the texture relative to the base colour, and the MVD establishes the direction of difference. The MVD is in principle constant over a large range of intrinsic colours for a given texture. The colour-set, from whose colour definitions MVD values are calculated, is an analogue of a textured substrate, to which any intrinsic base-colour can be applied. The base colour is then an analogue of a colourant formulation that might be applied to the substrate.
The MVD for a given texture, plus a base-colour defined by a reflectance curve, combine to give a direct simulation and quantification of any colour appearance difference attributable to texture. The validity and independence of MVD values have been demonstrated (Oulton et al., 1998) in a series of multi-observer trials where it successfully predicted the appearance of a dyed textile yarn, when viewed sequentially as a yarn winding, a knitted fabric, and a cut tuft, in 20 different intrinsic colours. MDD and MVD values were used in a different context to test their validity as a constant characteristic of 63 similar instances of a constant texture. The trials established (Oulton and Porat, 1997) that calculated MDD and MVD values are consistent across the 63 instances, to the limits of experimental error (Figure 1). MDD and MVD values encapsulate the vector principle of mapping multi-dimensional variables (in the above case colour-set membership) onto a meaningful three-dimensional definition of their effect (displacement of colour identity in colour-space). The process is analogous to the common experience of colour matches that only work under certain lighting conditions. Only textures with the same MVD will dye to the same shade using the same dye recipe. In the current context, the prediction is for textures that will have the same visual colour appearance when they are dyed with the identical dye recipe.
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Figure 1. Derivation of MDD and MVD values
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Figure 2. Pixel population distributions. A yellowish green medium depth, medium chroma image of a textile yarn winding is analysed that is judged by observers to have a single intrinsic colour
Figure 3. Pixel population distributions. A yellowish green medium depth, medium chroma image of a textile yarn winding is analysed that is judged by observers to have a single intrinsic colour
Figure 4. Pixel population distributions. A yellowish green medium depth, medium chroma image of a textile yarn winding is analysed that is judged by observers to have a single intrinsic colour
7.4 Colour-set populations An example of a colour-set is illustrated later. It has been isolated from a high resolution photograph using a three-dimensional lightness-, chroma- and hue-(L, C, H) based segmentation algorithm. The extracted colour-set, representing a green textile yarn winding, is analysed in Figures 2-4. RGB integer-value quantization in the screen-drive values is evident in the graphs.
The quantization effect is responsible for the evident “high frequency noise” in the otherwise smooth frequency distributions in L, C and H of the individual pixels. The observers rated the image to be a visual match to the physical sample, and also rated its appearance as a texture with a single intrinsic colour. The relevant pixel populations in the colour-set are graphed by pixel count on the Y axis in Figures 2-4 as separate L, C and H distributions. Interestingly, both the hue and chroma distributions are significantly bi-modal. This in fact represents a detailed difference between highlight and shadow colour. It is also the fundamental reason why injecting colour into “black and white” (i.e. grey-scale) images often produces an artificial or flat appearance in the resulting coloured image. The effect is usually identifiable in textures built up from essentially transparent or translucent coloured materials, particularly if they are also glossy. Textile fibrous assemblies are a good example.
8. Imagemaster in an industrial context For the past 2 years, a “Teaching Company” partnership between UMIST and Worthington Manufacturing Ltd has been used, to enable and establish Imagemaster links between the company and its suppliers and customers in the Lingerie Industry (Oulton and Young, 2003). The key tasks included developing an understanding of the opportunities and limitations of the concepts of calibrated colour visualization. They also include introducing both company and customer personnel to the new technology of digital colour communication. Both practical and conceptual familiarization was found to be necessary. An important outcome is a marked reduction of delays and cost associated with the production of physical lab-dye samples and their communication by postal methods. An equally important outcome is the formation of much better supplier/buyer collaborative teams for product development. In the longer term this produces both continuity of orders and a clear competitive edge when the communication link is with design-lead buying teams who specify the lingerie sets and garments containing components supplied by Worthington Manufacturing Ltd. The Colorite Division of Datacolor Inc. (Datacolor, 2003) supply Imagemaster as a commercial system, and they have sold it to about 200 companies in over 40 countries across five continents, working in the cosmetic, automotive, paint, plastic, and retail industries as well as in textiles. It is clear that the problem of “Colour Specification at the Design to Production Interface” is widely encountered, and a solution based on calibrated digital colour imaging has a wide general appeal.
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References Berns, R.S. (2000), Billmeyer and Saltzman’s Principles of Color Technology, 3rd ed., Wiley-Interscience, New York, NY. Datacolor (2003), Datacolor Headquarters: 5 Princess Road Lawrenceville, NJ 08648 USA. Hawkyard, C.J. (1993), “Synthetic reflectance curves by additive mixing”, JSDC, Vol. 109, p. 323. Oulton, D.P. and Porat, I. (1991), “Control of colour using measurement and feedback”, J.Text. Inst., Vol. 83 No. 3, p. 453. Oulton, D.P. and Porat, I. (1997), Final Report EPSRC Project “Colour Systems for Texture in Textile CAD”, No. GR/J91852 1994-96 (The Imagemaster Project), UMIST, Manchester. Oulton, D.P. and Young, T. (2003), “Accurate colour co-ordination for the textile components of lingerie”, Proc. Int. Conf. CESA 2003 “Computational Engineering in Systems Applications”, University of Beaulieu, France. Oulton, P., Boston and Walsby (1996), “Imagemaster: precision colour communication based on CIE calibrated monitor screens”, Proc. 5th Int. Conf. High Technology, Chiba, Japan, p. 290. Oulton, D.P., Peterman, E. and Bowen, A.W. (1998), “Measuring the contribution of texture to colour appearance”, in Nobbs, J. (Ed.), Proc. Int. Conf. Colour 98, April 1998, Harrogate, Department of Colour Chemistry, Leeds Univ., ISBN 0 85316 218 2, pp. 12-21. Smith, K.J. (1999), “A revolution in colour communication”, January International Dyer, p. 12. Further reading Sargeant, C. (1999), “Colour visualization and communication – a personal view”, in Dinsdale, P. (Ed.), Rev. Prog. Coloration, Soc Dyers and Colourists, Vol. 29, pp. 65-70.
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Modular manufacturing: an alternative to improve the competitiveness in the clothing industry William Ariel Sarache Castro, Roberto Cespo´ n Castro, Santiago Ibarra Miro´ n and Pedro U. Alonso Martı´nez
Modular manufacturing
301 Received February 2003 Accepted August 2003
Department of Industrial Engineering, Central University of Las Villas, Villa Clara, Cuba Keywords Cellular manufacturing, Competitive advantage, Job production systems, Textile manufacturing processes Abstract The change that occurred in the last years in the manufacturing environment of the clothing industry has motivated the redesign, in many cases, of its organizational and productive structures. For the companies in this sector, every time it becomes more necessary to reach satisfactory levels of competitiveness, as it is the only way of remaining in the market. For this, the adoption and implementation of different strategies that act on several links of the supply chain are required. One of these key links is the production function. In this paper, the advantages of the “just-in-time” philosophy for the clothing industry are mentioned, and more specifically the ones of modular manufacturing. This is based on the authors experience in relation to its use in the clothing industry, showing its superiority over the traditional in-line manufacturing.
Introduction During the decades of the years 1960s and 1970s the competitive strategies of the industrial companies were guided to mass production, aimed at achieving substantial improvements and differentiation in costs. At the moment, although to reduce cost is a necessary condition to be competitive, this is not enough, given the characteristics and evolution in the contemporary consumers behavior and the growing competition from other countries, derived from the economy globalization process. Inside this context, it is important to differentiate the concepts of strategic and operative competitiveness (Gabin˜a, 1996, p. 184), outlined in expressions (1) and (2). Strategic competitiveness ¼ innovation þ anticipation þ speed
ð1Þ
Operative competitiveness ¼ costs þ quality þ flexibility þ delivery times
ð2Þ
Concerning this last one and in approaching the concept of several authors (Russell and Taylor, 1998, p. 26; Umble and Srikanth, 1995, p. 34), it is possible
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to conclude that, at present, for a company to be considered competitive from the operative point of view, it should design its strategy to complete the following conditions: competitive prices, products of excellent quality and a high level of service to the client (speed and variety). Given the specific characteristics of the clothing industry, it is important to consider the adoption of new strategies to reach the levels of competitiveness that the market is demanding at the moment. The techniques of modular manufacturing, which are based on the principles of the just in time ( JIT) philosophy, constitute one of the possibilities that is presented as a viable alternative for this productive sector. The JIT philosophy – an alternative for the competitiveness increase This production philosophy, developed initially in Japanese companies, pursues a main competitive strategy, the reduction of the production cycles, the increase of the flexibility, the quality and the reduction of costs, through a logistical focus of type “Pull”. The JIT philosophy has a basic principle: “that the clients are served exactly in the precise moment, exactly in the required quantity, with products of maximum quality and by a production process that uses the minimum of possible inventory and that is free of any waste or unnecessary cost” ( Dominguez Machuca et al., 1995, p. 202). In the JIT system, the ideal size of the lot is an item and to reach it, a structured production system is needed, so that the plant distribution facilitates the handling of batches of this size. The point is to approach to zero the accumulations of parts waiting for being processed as well as to achieve the following results: . Invest the minimum in inventories. . Reduce the times of production delivery. . React more quickly in front of demand changes. . Discover any quality problem. The Japanese companies, pioneers in the application of the JIT, recognize the inventory excess (either of raw material, in process and finished product) as “the enemy number one” of productivity, because in general, the tendency in the manufacturing processes has always been to protect or “to cover” using appropriate or excessive levels of inventory against contingencies. Through this way, some problems, such as the index of rejected pieces, are solved producing some more units; the problem of the mishaps (mechanical and/or electric) is prevented with an increase in the productive capacity or with inventories of security in process. The uncertainty in the demand is solved by producing more inventories and the orders to the suppliers are made with a great anticipation and in a bigger quantity than the really necessary one. For the reasons stated earlier, the efforts of improvement to reach better levels of competitiveness should be approached to reduce the level of
inventories and by this way the true problems of the company begin to be visualized; and this, of course, should be made through a gradual process of continuous improvement. This form of managing the productive system, joined to the execution of a series of necessary elements for their successful practical implementation, has been taken by many Japanese companies to become world-class manufacturers. The concept of modular manufacturing In the specific case of the clothing industry, there appear the denominated modular manufacturing systems, which have become a viable alternative for the improvement of this type of companies. The organizations in many countries have been in the necessity of adopting substantial improvements that allow them to a certain extent to adapt to their competitive capacity. According to Rubenfeld (1990, pp. 51-52), the modular manufacturing is defined as a deep change in the technical-philosophical nature in the form of operating a company. It is born in the new necessities of the market and it implies a new attitude to all the members of the company without caring their hierarchical level, where their purpose is to create a mark of continuous improvement and a flexible system guided toward the client’s necessities. From the philosophical point of view, modular manufacturing welcomes the JIT concepts; from the technical point of view, it demands the disintegration of the rigid lines of production and the adoption of a work system in team, under the conformation of multi-functional and autonomous groups of work that work under the approaches of total quality (Castillo, 1993, p. 44). Concept of module and pre-requisites A module is a team of workers assigned to the production of a specific product, organized so that the product flows in a quick and synchronized way according to the order of its operations. To achieve it, it is necessary to estimate the production times for each operation and by the application of mathematical expressions, it can be arrived to a model of distribution of work loads or modular balance, looking for the appropriate use of the human factor, machines and space. One of the fundamental requirements for the success in a module operation is constituted by the integration of its components as a true work team, with a high conscience of quality and attitude of continuous improvement that allows to come closer at levels of zero defects in short times, with high efficiency indicators in the operation. This makes indispensable that the top management is convinced of the necessity of the change, the advantages that this would bring, and the measures to take, to avoid a failure. Next, it is necessary to qualify the middle level of the organization, especially in the modular organization techniques and coordination of work groups, and finally, to inform the participant of the
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change to the plant personnel, that is who determines the success or failure of their operation. The following step consists of designing and conforming each one of the work groups according to the necessities of the production program. It is important to clarify that the change toward an approach of production in groups, generates a reserve reaction in the employees, which needs a prudential time for its assimilation and which depends on the directive effort and on the existent organizational climate in that moment. That is why, it is recommended to begin with the creation of a pilot module that allows to secure the knowledge in the technical application and at the same time defeat the resistance to the change of rest of the employees. Competitive advantages of the modular manufacturing The important contributions that the modular manufacturing systems offer are evidenced in the improvement of the following aspects. . Reduction of production costs, represented in the increase of the efficiency of manpower, reduction of the in process inventory and decrease of the expenses of the concept of materials handling. . Increase in service to the client due to it is possible to reduce the production cycle and to improve notably, the speed and flexibility. . Improvement of the quality, because it is possible to implant self-controlled systems and also, easier and early detection of errors due to the low level of inventories. . Better use of the plant floor, because of the reorganization of the machines and the material flow, as well as for the reduction of the inventory levels with which unnecessary journeys and added worthless spaces are eliminated. . Decrease of the rotation indexes and personnel’s absenteeism creates a better work climate. The modular manufacturing in front of the in-line production system – results of a case of study through the simulation technique With the purpose of checking the competitive advantages that the modular production systems offer, in front of the classic in-line production systems used in the clothing industry, it was taken as a base for the simulation of these two systems, manufacturing a traditional T-shirt, whose sequence of operations and standard times of production per unit are shown in the Table I. For the development of the simulation, in Table II it is presented the design of a line of production, which with an assignment of ten operatives and ten machines, should manufacture according to the balance of work loads, a total of 1,250 T-shirts in a turn of 8 h.
The calculation of the operatives’ theoretical number (NTO) for each operation was carried out by means of the application of expression (3): NTO ¼
P £ Ti TD
ð3Þ
where NTO is the operatives’ theoretical number, P is the planned production per turn, TD is the available time in the turn, in minutes/turn, and Ti is the time per operation, in minutes/unit. The layout corresponding to the design of this line is shown in Figure 1. It is observed that each work center contains an entrance and an exit area for the material in course. The busy area for the shown configuration corresponds to 34.5 m2. In the proposal, the resulting module for the production of the same product was designed to use nine workers (one less than in-line production system) and 11 machines (one more than in-line production system) and it is expected that, according to the assignment of workloads, the total production of the turn is 1,483 units. The balance of workloads and the plant layout proposed are shown in Table III and Figure 2, respectively.
Operation 1 2 3 4 5 6 7
Name To To To To To To To
close shoulders (CH) hem skirt (DF) hem sleeves (DM) close sleeve (CM) paste neck (PC) paste over band (SC) paste sleeves (PM)
1 2 3 4 5 6 7
Operation To To To To To To To
close shoulders (CH) hem skirt (DF) hem sleeves (DM) close sleeve (CM) paste neck (PC) paste over band (SC) paste sleeves (PM)
305
Time per operation (Ti) (min/unit) 0.290 0.306 0.384 0.244 0.442 0.506 0.647
Total
No.
Modular manufacturing
Table I. Standard times for the operations of a T-shirt
2.819
NTO
NRO*
Operative
Expected production
0.75 0.80 1.00 0.63 1.15 1.32 1.68
1 1 1 1 2 2 2
A B C D EþF GþH IþJ
1,655 1,568 1,250 1,967 2,171 1,897 1,483
Table II. Total 7.33 10 Balance of the Notes: NRO*: real number of operatives; efficiency of the balance: (7.33 £ 100)/10 ¼ 73.3 production line for 1,250 units in a turn of 8 h percent; and maximal expected production: 1,250 units per turn.
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From the calculated capacity it can be inferred that the efficiency concerning the utilization of the human resource will be of 96.8 percent in the modular system, in comparison with the 73.44 percent expected for the in-line production system. However, when analyzing the utilization of the machinery, in the modular system the expected value is 79 percent in front of 73.44 percent of the in-line production system, which evidences that although a notorious difference exists in the expected increment of the efficiency of manpower in a modular system, with regard to machinery this difference is not so remarkable.
Figure 1. Plant layout for the line of production of T-shirt (busy area: 34.5 m2)
No.
Table III. Balance of the production module for 1,483 units in a turn of 8 h
Figure 2. Plant layout for the modular manufacturing system (busy area: 20.1 m2)
1 2 3 4 5 6 7
Operation To To To To To To To
close shoulders (CH) hem skirt (DF) hem sleeves (DM) close sleeve (CM) paste neck (PC) paste over band (SC) paste sleeves (PM)
NTO
Operative
Expected production
0.90 0.94 1.19 0.75 1.37 1.57 2.00
A B CþD D EþF GþF HþI
1,655 1,568 1,488 1,495 1,487 1,489 1,483
Total 8.72 9 Notes: Efficiency of the balance: (8.72 £ 100)/9 ¼ 96.9 percent, and maximal expected production: 1,483 units per turn.
With regard to the utilization of the busy space, in the modular manufacturing system it needs 20.1 m2, while the in-line production system needs 34.5 m2, which means a decrease in the space necessity of 14.4 m2 (41.73 percent). Design of the simulation experiment To corroborate the degree of accuracy or certainty of the earlier calculations and to check the kindness of the inventories reduction strategy, a simulation of this process in both production systems evaluated was carried out. For this the following experiments were carried out. (1) In-line production system with emissions of batches of 50 units between operations. (2) In-line production system with emissions of batches of 25 units between operations. (3) In-line production system with emissions of batch of a unit between operations. (4) Modular manufacturing system with emissions of batch of a unit.
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The variables to compare among the different experiments are: . production per week, . productivity of the manpower, . time of loads of the system, and . inventory average in the system. The results of the statistical analysis of the process operations are shown in Table IV. Results of the simulation experiment Once the simulation program was developed five races were carried out in each outlined experiment, which correspond to the optimal number of the statistical calculations, for a time of work of a week of five working days, and the results are summarized in the Table V. To the obtained results, were applied the necessary statistical tests to demonstrate their dependability.
Operation To To To To To To To
close shoulders (CH) hem skirt (DF) hem sleeves (DM) close sleeve (CM) paste neck (PC) paste over band (SC) paste sleeves (PM)
Distribution type Uniform Uniform Uniform Uniform Uniform Uniform Uniform
Parameters 0.216, 0.266, 0.375, 0.200, 0.400, 0.491, 0.633,
0.303 0.322 Table IV. 0.403 0.236 Probability distribution 0.466 of the production line in the operations of the 0.533 T-shirt 0.658
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As the results of the Table V evidence, the competitive advantage of the modular manufacturing systems is demonstrated, regarding the studied variables. While the batch sizes decrease (and the inventory in course) in each simulated system, all the analyzed variables improve. With regard to the busy space and according to the plant layout shown in the Figures 1 and 2, the area needed in the in-line manufacturing system (34.5 m2) is prominent, in comparison with the reduced area of the modular system (only 20.1 m2). This notorious difference is reflected in the fact that, given the high level of inventories that are accumulated in the in-line productive configuration, it is necessary to calculate and foresee space for its temporary storage, which does not occur in the modular manufacturing system, just as it is evidenced in the simulation results. Conclusions In accordance with the results obtained, the competitive advantage that implies the adoption of a modular manufacturing system is demonstrated. This is evidenced in the increase in productivity of the manpower, reduction of process inventories, reduction of the production cycle and the economy in the necessary space for its operation. However, the adoption of this system demands a deep change in the philosophy and in the form of operation of the organization, which should change the old production schemes and individual incentives and to go toward the promotion of the teamwork under a culture of total quality, where the human resource represents an aspect of maximal importance. In all the hierarchical levels should begin training programs that allow them to know the technique and the philosophy that the modular manufacturing implies. Once this production system is implemented, the organization will come closer to better levels of competitive performance, that will allow it to explore and enter into new market potentials with products of excellent quality, cheaper prices and quick deliveries. It should also be considered that the capacities offered by the modular manufacturing in relation to the flexibility of its operations in general, makes that system more adaptive than the in-line production systems.
Table V. Results of the simulation of the modular production system in comparison with the in-line production system for a week of work
Variable Production average (units) Productivity of the manpower (units /person) Inventory in process (units) Time of loads (minutes)
In-line system In-line system In-line system Modular system (Batch of 50) (Batch of 25) (Batch of 1) (Batch of 1) 5,810
5,990
6,159
581 2,610 141.6
599 2,455 70.4
615 2,274 6.8
7,266 807 179 3.8
References Castillo, J. (1993), “The implementation of modular production systems”, La bobina Notivest, Vol. 55, p. 44. Dominguez Machuca, J.A., Garcia, S., Dominguez Machuca, M.A., Ruiz, A. and Alvarez Gil, M.J. (1995), Operations Management: Tactical and Operative Aspects of the Production and the Services, McGraw-Hill, Madrid. Gabin˜a, J. (1996), “The revisited future – the strategic competitiveness”, Apparel Industry International, Vol. 1, p. 179. Rubenfeld, H. (1990), “Application of modular lines”, La bobina Notivest, Vol. 43, pp. 51-2. Russell, R. and Taylor, B. (1998), Operations Management. Focusing on Quality and Competitiveness, Prentice Hall, New Jersey. Umble, M. and Srikanth, M.L. (1995), Synchronous Manufacturing. Principles to achieve an excellence of world-class, CECSA, Mexico. Further reading Fraser, A. (1992), “The setting in practice of the modular system”, Apparel Industry International, Vol. 1, p. 32. Uribe Macı´as, M.E. (1998), “Productividad y competitividad en las organizaciones latinoamericanas”, Revista temas y reflexiones, Vol. 2, p. 45.
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Intrinsic “dry” thermal resistance of dry infant bedding during use Part 2: estimated vs measured
Received February 2003 Accepted August 2003
C.A. Wilson and R.M. Laing University of Otago, Dunedin, New Zealand
T. Tamura Bunka Women’s University, Tokyo, Japan Keywords Thermal insulation, Predictor-corrector methods, Thermal properties of materials Abstract The aim of this work was to validate the Wilson and Laing theoretical mathematical model for estimating the intrinsic “dry” thermal resistance of upper-bedding, and compare the two-dimensional models commonly used to estimate the “dry” thermal resistance of bedding in use, with the actual intrinsic “dry” thermal resistance measured using an infant thermal manikin. The Wilson and Laing model was the only model used adequately to estimate the intrinsic “dry” thermal used resistance of materials arranged over the infant thermal manikin. Estimation of intrinsic “dry” thermal resistance of bedding during use is not adequate using two-dimensional models. Further investigation into the relationship between thermal resistance, conditions of use, and SIDS using the Wilson and Laing model is recommended.
1. Introduction Thermal resistance of, and heat transfer through, materials have been described from the perspective of health (e.g. by physiologists and medical professionals) and/or comfort (e.g. by heating engineers). Irrespective of the perspective, estimating the “dry” thermal resistance using a predictive model incorporating simple to measure variables (e.g. thickness) is an alternative to more complex techniques such as using a sweating guarded hotplate or thermal manikin to measure resistance. Predictive models developed to estimate the “dry” thermal resistance of multiple layers of materials during use include those which: (1) focus on heat transfer or flow (Woo et al., 1994); (2) exploit the relationship between heat transfer (usually “dry”) and a physical variable, such as thickness (Holcombe and Hoschke, 1983; Weatherall, 1983) and “tog” (Clulow, 1986); and/or International Journal of Clothing Science and Technology Vol. 16 No. 3, 2004 pp. 310-323 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410527237
The assistance of Dr T. Koshiba, Dr M. Sato and N. Maruta, Bunka Women’s University, Tokyo, Japan; B. Niven, University of Otago, Dunedin, New Zealand; and the support of the University of Otago through provision of research and study leave, Bunka Women’s University and the New Zealand Japan Exchange Programme is gratefully acknowledged.
(3) use of an integrated “garment” system approach (Mecheels and Umbach, 1977; Wilson and Laing, 2002). Until recently, estimating the “dry” thermal resistance of three-dimensionally arranged bedding has been possible only by using two-dimensional methods. The need for a three-dimensional method for estimating the “dry” thermal resistance of bedding, where emphasis is placed on approximating the effect of the human body (Kamata et al., 1986; Kerslake, 1991; Wilson and Laing, 2002) on materials arranged over it lead to the development of an alternative approach (Wilson and Laing, 2002). The Wilson and Laing (2002) model was developed to estimate the thermal resistance of a three-dimensional bedding system (for infants) during use, using bedding thickness and selected information about the infant, and the conditions of use. Two-dimensional models are based on flat materials only, generally in single layers. The Wilson and Laing (2002) model adjusts for the effect of the “body” (i.e. sleep position) and method of tucking on total thickness of the bedding combination, air space formation within and thickness of the bedding system. The effect of sleep position is particularly important given: . the effect of conditions of use, such as the use of multiple layers, tucking method and infant sleep position, on thermal resistance (Wilson et al., 1999a, b), and . recognition of thermal resistance and sleep position as sudden infant death syndrome (SIDS) risk factors. Researchers investigating the relationships between thermal resistance and SIDS have characterised clothing and textile materials in a number of ways. “Dry” thermal resistance has been estimated: (1) using the relationship between thickness of single layer materials and their thermal resistance (Bolton et al., 1996; Holcombe and Hoschke, 1983; Weatherall, 1983), and (2) by adding together “tog” values measured on single-layer representative rather than the actual specimens (Clulow, 1986; Fleming et al., 1996, 1990; Ponsonby et al., 1992; Williams et al., 1996). Risk associated with specific product types (L’Hoir et al., 1998; Wilson et al., 1994) or product types and behaviours (Scheers et al., 1998) has also been investigated. However, neither the two-dimensional models nor the recently developed three-dimensional Wilson and Laing (2002) model have been validated. The aim of this work was to: (1) validate the Wilson and Laing (2002) three-dimensional theoretical mathematical model for estimating the intrinsic “dry” thermal resistance of upper-bedding; and
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(2) compare the two-dimensional models (Clulow, 1986; Holcombe and Hoschke, 1983; Weatherall, 1983) commonly used to estimate the “dry” thermal resistance of upper-bedding in use, with the actual intrinsic “dry” thermal resistance measured using an infant thermal manikin. 2. Method Four bedding combinations commonly used to cover New Zealand infants (Wilson et al., 1994), two sleep positions (supine and lateral) and two tucking arrangements (firm and loose) were evaluated (Table I). As energy loss from a manikin in the prone and supine sleep positions (Elabbassi et al., 2001) and arrangement of bedding (and air spaces formed) over the supine and prone manikin (Wilson et al., 1999c) do not differ significantly, the supine manikin was used to represent both prone and supine sleep positions. Bedding items, sleep positions and tucking methods have been investigated and described earlier (Wilson et al., 1999a, 2000, 1999c). The Bunka infant thermal manikin was used to measure the “dry” thermal resistance of bedding, sleep position and tucking combinations. The manikin was dressed in a close-fitting cotton jumpsuit for all tests (Figure 1(a)). Variable Experimental variables Bedding S SAA SAAD S+9A Manikin position Lateral Supine Method of tucking Loose Firmly Bedding Sheet (S) Air-cell blanket (A)
Table I. Description of experimental variables and bedding
Duvet (D)
Description
Sheet Sheet, air-cell, air-cell Sheet, air-cell, air-cell, duvet Sheet, plus nine air-cell blankets
Lightest Typical Typical Heaviest
Right side uppermost Ventral surface and face uppermost Bedding draped loosely over manikin Bedding tucked firmly over manikin with bedding clipped in place to hold bedding taut Cotton; plain weave; napped on both sides; sett 18.8 £ 16.6/10 mm; thickness X ¼ 2:5; sd ¼ 0.3 mm Wool; cellular fabric (sometimes termed honey comb or air-cell) Leno weave variety; weft faced; sett 5.2 £ .16.6 mm; thickness ¼ 2.5, sd ¼ 0.3 mm; thickness X ¼ 6:0; sd ¼ 0.3 mm Outer: plain weave, polyester/cotton; Filling: Dacrone; sett upper layer 32.8 £ 19.5/10 mm, sett under layer and flaps 45.7 £ 30.3/10 mm; thickness X ¼ 34:8; sd ¼ 1.8 mm
Experiments were conducted in a climatic chamber at Bunka Women’s University, where the average air temperature and relative humidity were controlled to 20 ^ 0:58C; 65 ^ 0:5 per cent RH (monitored at the height of the “bed”). Air velocity in the chamber was less than 0.1 m/s. Materials were conditioned for no less than 24 h prior to testing and then tested under these conditions. The supine infant manikin covered in loosely tucked bedding is shown in Figure 1(b).
Intrinsic “dry” thermal resistance 313
Figure 1. Bunka “infant” thermal manikin: (a) lateral position showing standardised clothing, and (b) supine position covered in a loosely tucked sheet and nine blankets
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The 16 segment thermal manikin has been described earlier (Kang and Tamura, 2001). The head formed a 17th unheated segment. Surface temperature of each heated segment was controlled independently to 33 ^ 0:58C: After stabilising the “skin” temperature for a minimum of 10 min, the temperature and energy required to maintain each segment at equilibrium was measured over a 60 min test period. Average energy and temperature data from this test period were used to calculate the intrinsic “dry” thermal resistance for each bedding, sleep position and tucking combination as: Rct ¼
ðT s 2 T a Þ 2 Rct0 H
ð1Þ
where Rct is the intrinsic “dry” thermal resistance (m2K/W), Ts is the mean surface temperature (8C), Ta is the mean air temperature (8C), H is the heat supply to the manikin (W), and Rct0 is the nude “dry” thermal resistance of the manikin (m2K/W). Replicates ðn ¼ 3Þ that varied by more than 5 per cent from the mean were repeated. The interval between measurements was sufficient to allow the manikin skin temperature to cool to less than 258C. “Wet” thermal resistance was not determined. A method enabling use of the manikin in a horizontal sweating position is currently being investigated. Intrinsic “dry” thermal resistance (i.e. excluding the boundary air layer) was also estimated using the three-dimensional Wilson and Laing (2002) model according to: n h i o Rct ¼ ðRctover xover Þ þ Rctadjs1 ys1 þ Rctadjs2 ys2 þ Rctadjs3 ys3 xadj ð2Þ where Rctadjsi ¼ Rctadj ¼ 0:278 þ 0:0127d 2 0:0024da1 þ 0:00226d a2 þ 0:0143da3 20:0041da4 2 ð0:344if duvet is present Þ; i
¼ 1, 2 or 3,
Rct over ¼ Rct over ; i.e. minimal air spaces between layers (m2K/W) where Rct over ¼ 0:051 þ 0:023d 2 ð0:469if duvet is present Þ (Wilson et al., 1999a); xover ¼ proportion of the external enclosing surface (i.e. the bedding) over the body with minimal air spaces between i.e. xover ¼ bover =bT ; bover ¼ the surface distance of bedding over the body along the x-axis (mm) and bT is the total distance of bedding over and adjacent to the body; bT
¼ total distance of the external surface along the x-axis;
xadj
¼ proportion of the external enclosing surface (i.e. the bedding) over the body with air spaces between xadj ¼ badj =bT ;
badj
¼ the surface distance of bedding adjacent to the body along the x-axis (mm);
ysi
¼ a constant representing the proportion of surface area attributable to each section of the “body” were i ¼ 1-3 (Wilson and Laing, 2002) ysi ¼ Asi =A; where A ¼ ðAs1 þ As2 þ As3 Þ;
Asi
¼ surface area of each section of the “body” and A is the total surface area covered by the bedding;
d
¼ thickness of the bedding;
dai
¼ thickness of the air spaces, dai, determined according to Wilson et al. (1999c).
Dimensions of the Bunka “infant” thermal manikin used to estimate the proportions of the enclosing surface over and adjacent to the body, and the proportion of surface area attributable to the three sections of the body were based on: chest circumference (0.47 m); recumbent length (0.84 m); foot length (0.13 m); and surface area of the nude “body” (0.29 m2 excluding the head). Calculation of these constants is described in detail in Part I of this series (Wilson and Laing, 2002). The Wilson and Laing (2002) model was modified to accommodate the larger chest circumference of the Bunka infant manikin (diameter 44 per cent greater than the New Zealand manikin). The effect of larger circumference on the air spaces within the bedding arrangement (Wilson et al., 1999c) was considered and thickness of the air space formed under the sheet layer was subsequently increased by 44 per cent. Dimensions, variables and thickness of bedding used to estimate the thermal resistance of bedding over the Bunka manikin are given in Table II. Intrinsic “dry” thermal resistance was estimated using three two-dimensional models (Clulow, 1986; Holcombe and Hoschke, 1983; Weatherall, 1983). Thickness of single layer bedding was used to estimate the intrinsic “dry” thermal resistance as (for equation (3), Weatherall (1983) and for equation (4) Holcombe and Hoschke (1983)): Rct ¼ 0:028d f ;
ð3Þ
Rct ¼ 0:0276df 2 0:0108
ð4Þ
where df is the thickness of flat single layer materials (mm) and “dry” thermal resistance of representative single-layer bedding were added to estimate the resistance of each bedding combination according to the equation (Clulow, 1986): Rct ¼ Sn þ Bn þ Dn
Intrinsic “dry” thermal resistance 315
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Tucking and manikin position
bT
aT
bover
badj
xover
xadj
Surface variables Lateral Loose 1.13 0.57 0.21 0.92 0.19 0.81 Firm 1.06 0.53 0.07 0.99 0.07 0.93 316 Supine Loose 0.99 0.50 0.36 0.63 0.36 0.64 Firm 0.95 0.48 0.15 0.80 0.16 0.84 Section variables Section 1 Section 2 Section 3 Total Diameter (m) D 0.26 0.23 0.16 0.65 Table II. df 0.23 0.16 0.13 0.52 Surface and section Length (m, no head covering) 0.17 0.33 0.17 0.66 variables, and thickness Surface area of frustum (m2, excluding head 0.13 0.20 0.08 0.40 used to estimate the Proportions ( ysi) 0.31 0.50 0.19 1.00 integrated intrinsic Thickness of bedding (mm) X s.d. thermal resistance of the S 1.65 0.23 bedding system over the SAA 10.25 0.25 Bunka “infant” thermal SAAD 60.80 2.43 manikin (m, unless S+9A 41.00 0.46 otherwise stated) Notes: aT ¼ distance across the bedding surface (x-axis) at the “bottom” of the “body”; (Wilson and Laing, D ¼ maximum diameter of the frustum (m); df ¼minimum diameter of the frustum f(m). 2002)
where n is the number of flat single layer items, S is the sheet ¼ 0.02 m2K/W (0.2 tog), B is the Blanket ¼ 0.15 m2K/W (1.5 tog), and D is the synthetic duvet ¼ 0.93 m2K/W (9.25 tog)
2.1 Statistical analysis Intrinsic “dry” thermal resistance estimated using the two-dimensional models (Clulow, 1986; Holcombe and Hoschke, 1983; Weatherall, 1983) and three-dimensional Wilson and Laing (2002) model, and that measured using the Bunka “infant” thermal manikin was first described. Differences between the Holcombe and Hoschke (1983), Weatherall (1983) and Wilson and Laing (2002) models and the Bunka thermal manikin data were investigated using the Wilcoxon signed ranks test (Siegel and Castellan, 1988). Wilcoxon pair-wise significance levels were adjusted for multiple comparisons using Bonferroni adjustments ðp # 0:01Þ (Bland and Altman, 1995). Where no significant difference in intrinsic “dry” thermal resistance between the estimated and actual values was identified, the effect of bedding combination, sleep position and tucking method on “dry” thermal resistance were investigated using univariate analysis of variance (ANOVA) (Mendenhall and Ott, 1985). Prior to conducting the ANOVA, log transformations were applied to improve the normality of the data. Data trends were compared.
The Clulow (1986) model estimated the intrinsic “dry” thermal resistance from standardised values. Statistical comparison of the Clulow ðn ¼ 1Þ and Bunka ðn ¼ 3Þ data sets was not possible due to the nature of the data. To evaluate the relationship between the Clulow and Bunka data, the mean intrinsic “dry” thermal resistance, and where appropriate the associated confidence intervals, was plotted. 3. Results “Dry” thermal resistance of bedding combinations estimated from the measurement of single layer materials ranged from 0.05 to 1.70 m2K/W for the Weatherall (1983) model, 0.04-1.66 m2K/W for the Holcombe and Hoschke (1983) model, and from 0.02 to 1.37 m2K/W for the Clulow (1986) model. Intrinsic “dry” thermal resistance estimated using the Wilson and Laing (2002) model ranged from 0.14 to 0.71 m2K/W. Actual intrinsic “dry” thermal resistance ranged from 0.22 to 0.61 m2K/W. Intrinsic “dry” thermal resistance determined using the selected methods is shown in Figure 2. Of the models examined, only data from the Wilson and Laing (2002) model did not vary significantly from that measured using the Bunka infant manikin (z46 ¼ 20:06; NS). Estimates derived using the Holcombe and Hoschke (1983) and Weatherall (1983) models varied significantly from that measured using the Bunka infant manikin (z46 ¼ 22:89; p # 0:01; z46 ¼ 22:89; p # 0:01; respectively). The Clulow (1986) model underestimated the resistance of the “sheet” (S: 291 per cent) and the “sheet plus two air-cell blanket” combination (SAA: 222 per cent) and overestimated the resistance of the “sheet, two air-cell blankets and duvet” combination (SAAD: 108 per cent) and the “sheet and nine air-cell blanket” combination (S þ 9A : 173 per cent). Estimates derived using the Clulow (1986) model were outside the range of the Bunka data confidence intervals (Figure 3(a)). The relationship between the Wilson and Laing (2002) estimates and Bunka data (means and confidence intervals) are also shown in Figure 3(b). The effect of bedding combination, sleep position and tucking method on intrinsic “dry” thermal resistance were investigated using the Wilson and Laing (2002) estimates and Bunka data. Type of bedding combination (F 3;31 ¼ 5446:56; p # 0:001; F 3;30 ¼ 2:55:40; p # 0:001), sleep position (F 1;31 ¼ 1234:42; p # 0:001; F 1;30 ¼ 17:94; p # 0:001), and tucking arrangement (F 1;31 ¼ 1197:84; p # 0:001; F 1;30 ¼ 33:08; p # 0:001) affected the intrinsic “dry” thermal resistance of both estimated (Wilson and Laing, 2002) and measured data, respectively. While the relative importance of variables estimated using the Wilson and Laing (2002) model and measured using the Bunka manikin differed, conclusions drawn from data trends were generally the same. The supine sleep position was associated with higher mean intrinsic “dry” thermal resistance when bedding was covering the lateral infant. Loosely tucked bedding was more thermally resistant than firmly
Intrinsic “dry” thermal resistance 317
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318
Figure 2. Intrinsic “dry” thermal resistance of bedding according to sleep position, method of tucking and bedding combination estimated according to Holcombe and Hoschke (1983), Weatherall (1983), and Wilson and Laing (2002) and as measured using the Bunka “infant” thermal manikin
Intrinsic “dry” thermal resistance 319
Figure 3. Mean intrinsic “dry” thermal resistance of bedding measured using the Bunka “infant” thermal manikin (and confidence intervals) and that estimated using: (a) the Clulow (1986), and (b) the Wilson and Laing (2002) model
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tucked (Figure 2). As expected, only the sheet was less thermally resistant than multiple layer combinations. Intrinsic “dry” thermal resistance of various bedding combinations generally increased with increasing blanket layers, i.e. as the number of blanket layers increased so did the thermal resistance. However, in contrast to other bedding combinations that were underestimated, intrinsic “dry” thermal resistance of the “sheet and nine air-cell blankets” ðS þ 9AÞ combination was overestimated using the Wilson and Laing (2002) model. 4. Discussion Of the predictive models investigated, only the Wilson and Laing (2002) model adequately estimated and measured the intrinsic “dry” thermal resistance of upper-bedding in use. Intrinsic “dry” thermal resistance of bedding combinations estimated using two-dimensional models differed significantly from the actual data. The difference between the Holcombe and Hoschke (1983) and Weatherall (1983) models was small reflecting the strong similarity in the approach taken by the two methods. Estimates based on intrinsic “dry” thermal resistance of standardised products as proposed by Clulow (1986) were also considerably outside the range of the Bunka data confidence intervals, possibly reflecting the differences in product type used (i.e. English products and not New Zealand products as used in this work), and/or failure to accommodate air spaces formed between the layers. Differences between Bunka and Clulow data were such the model was judged to not adequately estimate the thermal resistance in use. Accommodation of the effect of product type, sleep position, and tucking on air spacing within the bedding combination was a characteristic of the Wilson and Laing (2002) model only. The effect of tucking method and sleep position on the intrinsic “dry” thermal resistance of bedding during use was the same irrespective of whether the data were measured or estimated using the Wilson and Laing (2002) model. Intrinsic “dry” thermal resistance of bedding over the supine (and by association the prone (Elabbassi et al., 2001)) “body” was greater than that of bedding over the lateral “body”. These findings are consistent with the presence of a greater number of smaller air spaces formed between the bedding layers when the “body” is supine (Wilson et al., 1999a). Loose tucking was more thermally resistant than firm tucking, possibly reflecting the effects of the greater number of smaller air spaces that form throughout loosely tucked bedding (Wilson et al., 1999a). Firmly tucked bedding was associated with the formation of larger air space between the first layer (sheet) and “body” which may account for the lower thermal resistance of firmly tucked bedding (Wilson et al., 1999a). Intrinsic “dry” thermal resistance of the bedding combinations also reflected the thickness and type of bedding in the combination. The least thermally resistant bedding was the “sheet” (S) only and the most was the “sheet, two
air-cell blanket and duvet” (SAAD) combination. The “sheet and air-cell blanket” combinations (SAA and S þ 9A) were intermediate between the two. Previous estimates of the thermal resistance of bedding including a duvet (Holcombe and Hoschke, 1983; Weatherall, 1983) suggested that the combinations including a duvet would be more thermally resistant than that actually measured in this study. Differences between the measured and estimated resistances reflect the lack of differentiation among product structures inherent in the two-dimensional models based on thickness (Holcombe and Hoschke, 1983; Weatherall, 1983). Two-dimensional models fail to accommodate the change in the thickness: resistance relationship that occurred when a duvet is included in the bedding combination. Measured intrinsic “dry” thermal resistance reported in this paper confirms that the relationship between the bedding combinations and thickness of multiple layer bedding is not linear (Epps and Song, 1992; Wilson et al., 1999c) and that a product effect exists (Wilson et al., 1999a). Agreement between intrinsic “dry” thermal resistance of bedding combinations estimated using the Wilson and Laing (2002) model and that measured was greater for some combinations of bedding than the others. As expected, the model was most effective at estimating intrinsic “dry” thermal resistance when bedding combinations were restricted to those used in the development of the original predictive equations (i.e. S, SAA and SAAD). The greatest differences were observed between the estimated and measured intrinsic “dry” thermal resistance of the “sheet plus nine air-cell blanket” ðS þ 9AÞ combination. This S þ 9A combination represented the greatest number of blanket layers being used to cover infants as identified by the New Zealand Cot Death Group (Wilson et al., 1994). Intrinsic “dry” thermal resistance of the S þ 9A bedding combination was overestimated using the Wilson and Laing (2002) model possibly due to the compression of underlying layers as the number of blanket layers in the bedding combination increased. In spite of these differences, results suggest that the Wilson and Laing (2002) model is more accurate than the other models used earlier to estimate the intrinsic “dry” thermal resistance of bedding during use. 5. Conclusions The Wilson and Laing (2002) model proved to be an accurate method for estimating the intrinsic “dry” thermal resistance of actual bedding products in use. The Clulow (1986), Holcombe and Hoschke (1983) and Weatherall (1983) models do not adequately estimate the intrinsic “dry” thermal resistance of bedding during use. Nor do they accommodate the effect of sleep position and tucking methods and bedding type on thermal resistance? Hence, the Wilson and Laing (2002) model is an improved method for estimating the intrinsic “dry” thermal resistance. Further investigation into the relationship between the thermal resistance, conditions of use and SIDS is recommended.
Intrinsic “dry” thermal resistance 321
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References Bland, J.M. and Altman, D.G. (1995), “Multiple significance tests: the Bonferroni method”, British Medical Journal, Vol. 310, p. 170. Bolton, D.P.G., Nelson, E.A.S., Taylor, B.J. and Weatherall, I.L. (1996), “A theoretical model of thermal balance. Implications for the sudden infant death syndrome”, Journal of Applied Physiology, Vol. 80 No. 6, pp. 2234-42. Clulow, E.E. (1986), “Extended list of thermal insulation values for infants bedding and clothing-values used to calculate thermal insulation. Figures in Tables I to V in analysis of survey of 100 infants”, Report no. N7012. Shirley Institute. Elabbassi, E.B., Bach, V., Makki, M., Delanaud, S., Telliez, F., Leke, A. and Libert, J-P. (2001), “Assessment of dry heat exchanges in newborns: influence of body position and clothing in SIDS”, Journal of Applied Physiology, Vol. 91 No. 1, pp. 51-6. Epps, H.H. and Song, M.K. (1992), “Thermal transmittance and air permeability of plain weave fabrics”, Clothing and Textiles Research Journal, Vol. 11 No. 1, pp. 10-17. Fleming, P.J., Blair, P.S., Bacon, C., Bensley, D., Smith, I., Taylor, E., Berry, J., Golding, J. and Tripp, J. and confidential enquiry into stillbirths and deaths regional coordinators and researchers (1996), “Environment of infants during sleep and risk of the sudden infant death syndrome: results of 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy”, British Medical Journal, Vol. 313 No. 7051, pp. 191-5. Fleming, P.J., Gilbert, R., Azaz, Y., Berry, P.J., Rudd, P.T., Stewart, A. and Hall, E. (1990), “Interaction between bedding and sleeping position in the sudden infant death syndrome: a population based case control study”, British Medical Journal, Vol. 301 No. 6743, pp. 85-9. Holcombe, B. and Hoschke (1983), “Dry heat transfer characteristics of underwear fabric”, Textile Research Journal, Vol. 53 No. 6, pp. 368-75. Kamata, Y., Kato, T., Azumi, H. and Watanabu, S. (1986), “Convective heat transfer from human body (Part 1. A simulation by vertical cylinder)”, Society of Fibre Science and Technology Journal, Vol. 42 No. 3, pp. T155-61. Kang, I. and Tamura, T. (2001), “A study on the development of an infant-sized movable sweating thermal manikin”, Journal of the Human Environment System, Vol. 5 No. 1, pp. 49-58. Kerslake, D.M. (1991), “The insulation provided by infants bedclothes”, Ergonomics, Vol. 34 No. 7, pp. 893-907. L’Hoir, M.P., Engelberts, A.C., van Wall, G.T.J., McClelland, S., Westers, P., Dandachli, T., Mellenbergh, G.J., Wolters, W.H.G. and Huber, J. (1998), “Risk and preventive factors for cot death in The Netherlands, a low-incidence country”, European Journal of Pediatrics, Vol. 157 No. 8, pp. 681-8. Mecheels, J.H. and Umbach, K.H. (1977), “The psychrometric range of clothing systems”, in Hollies, N.R.S. and Goldman, R.F. (Eds), Clothing Comfort. Interaction of Thermal, Ventilation, Construction and Assessment Factors, Ann Arbor Science Publishers Inc., Ann Arbor, MI, pp. 133-52. Mendenhall, W. and Ott, L. (1985), Understanding Statistics, 4th ed., Duxbury Press, Boston. Ponsonby, A.L., Dwyer, T., Gibbons, L.E., Cochrane, J.A., Jones, M.E. and McCall, M.J. (1992), “Thermal environment and sudden infant death syndrome: case control study”, British Medical Journal, Vol. 304 No. 6822, pp. 277-82. Scheers, N.J., Dayton, C.M. and Kemp, J.S. (1998), “Sudden infant death with external airways covered”, Archives of Pediatrics and Adolescent Medicine, Vol. 152 No. 6, pp. 540-7.
Siegel, S. and Castellan, N.J. (1988), Nonparametric Statistics for the Behavioral Sciences, 2nd ed., McGraw-Hill, Singapore. Weatherall, I.L. (1983), “Thermal properties of bedding”, in Story, L. (Ed.), Measurement, Construction and Performance, Proceedings of the Eleventh Annual Conference of the Textile Institute, Wool Research Organisation of New Zealand Inc., Christchurch, pp. 106-16. Williams, S., Taylor, B.J. and Mitchell, E.A. and other members of the national Cot Death study group (1996), “Sudden infant death syndrome: insulation from bedding and clothing and its effect modifiers”, International Journal of Epidemiology, Vol. 25 No. 2, pp. 366-75. Wilson, C.A. and Laing, R.M. (2002), “Estimating thermal resistance of “dry” infant bedding – Part 1: a theoretical mathematical model”, International Journal of Clothing Science and Technology, Vol. 14 No. 1, pp. 25-40. Wilson, C.A., Laing, R.M. and Niven, B.E. (1999a), “Estimating dry thermal resistance of multiple-layer bedding materials – re-examining the problem”, Journal of the Human-Environment System, Vol. 2 No. 1, pp. 69-85. Wilson, C.A., Laing, R.M. and Niven, B.E. (1999b), “Estimating thermal resistance of multiple-layer bedding materials – re-examining the problem”, Journal of the Human-Environment System, Vol. 2 No. 1, pp. 69-85. Wilson, C.A., Laing, R.M. and Niven, B.E. (2000), “Multiple-layer bedding materials and the effect of air spaces on “wet” thermal resistance of dry materials”, Journal of the Human-Environment System, Vol. 4 No. 1, pp. 23-32. Wilson, C.A., Niven, B.E. and Laing, R.M. (1999c), “Estimating thermal resistance of bedding from thickness of materials”, International Journal of Clothing Science and Technology, Vol. 11 No. 5, pp. 262-76. Wilson, C.A., Taylor, B.J., Laing, R.M. and Williams, S. and the New Zealand Cot Death study group (1994), “Clothing and bedding and its relevance to sudden infant death syndrome: further results of the New Zealand cot death study”, Journal of Paediatrics and Child Health, Vol. 30 No. 6, pp. 506-12. Woo, S.S., Shalev, I. and Barker, R.L. (1994), “Heat and moisture transfer through nonwoven fabrics. Part I: heat transfer”, Textile Research Journal, Vol. 64 No. 3, pp. 149-62.
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The Emerald Research Register for this journal is available at www.emeraldinsight.com/researchregister
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324 Received January 2003 Revised October 2003 Accepted October 2003
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
A new detergent-free dry-cleaning system Kohei Sawa Cleansawa Co., Wakayama-shi, Wakayama, Japan
Carlos Rodriguez, Kenji Aramaki and Hironobu Kunieda Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama, Japan Keywords Detergents, Cleaning, Textiles Abstract The performance of a new detergent-free dry cleaning machine has been investigated and compared to conventional machines. The new machine includes a highly efficient system for solvent purification, and effectively cleans wool, cotton and synthetic fibers without the need of detergent. Its performance is similar or in some cases better than the conventional machines, which contaminate the clothes with detergent. Since detergent is not needed and solvent is efficiently used in the new machine, environmental impacts and operation costs are reduced, and the negative side effects on the properties of clothes are eliminated.
International Journal of Clothing Science and Technology Vol. 16 No. 3, 2004 pp. 324-334 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410527246
Introduction In conventional dry-cleaning, surfactants (detergents) are usually added to the solvent to remove water-soluble soil and to inhibit redeposition of solid soil particles (Aebi and Weibush, 1959), promoted by the rather high interfacial tension between the fibers and solvent (Rosen, 1989). The proposed mechanisms for soil removal in dry-cleaning include, as a first step, the adsorption of surfactants on the substrate/soil interface that seems to be increased by the presence of water, followed by solubilization in reverse micelles in which the polar heads of surfactant molecules are oriented towards the micellar core (Rosen, 1989). However, dry-cleaning is a complex process that depends on many factors, such as the nature and concentration of the surfactants and additives (mixtures of various surfactants and small amounts of middle-chain alcohols might be used), nature of the soil and fabric, hydrodynamic conditions, mechanical action and characteristics of the solvent and temperature (Azemar, 1997). Owing to this complexity, the precise role of surfactants in dry-cleaning has not been completely clarified yet. As a matter of fact, when chlorinated solvents are used instead of petroleum derivatives, good results are often obtained without the need of surfactants (Tsujii, 1996). The use of surfactants imposes several drawbacks to the dry-cleaning process. They can accumulate and eventually obstruct the filters of the The authors thank Dr Conxita Solans (CSIC, Spain) for useful discussions. C.R is grateful to the Japanese Society for the Promotion of Science ( JSPS) for a research grant during his stay at Yokohama National University.
dry-cleaning equipment. On the other hand, they can remain adsorbed in the clothes, affecting odor and appearance. Moreover, most surfactants are not biodegradable, which increase the environmental concerns over the dry-cleaning process, in addition to the use of toxic, volatile, chlorinated solvents (Lohman, 2002). As substitutes for conventional dry cleaning, some alternative methods like the wet cleaning have been proposed, but they present some problems that still remain to be solved (Keoleian et al., 1997). In this paper, we present a report on a new surfactant-free dry-cleaning system operating in a completely closed flow process.
Detergent-free dry-cleaning system 325
Materials and methods Sample preparation Pieces ð10 cm £ 10 cmÞ of cotton and two kinds of wool, Woolmosurin (Nihon Yushi Co.) and EMPA-107 (EMPA Test Materials) were used as samples for the cleaning tests. Before the tests, cotton samples were artificially soiled with mixture A (Japanese Institute of Standards C9606), while Woolmosurin samples were soiled with mixture B. EMPA-107 samples are supplied, soiled with a carbon black/olive oil mixture. The compositions of A and B are shown in Tables I and II. Cleaning tests were also performed with samples of Woolmosurin soiled with a solution of 20 wt percent sugar and 10 wt percent table salt (NaCl). Samples were dried for 1 h at 708C before and after the cleaning tests. Immediately after the tests weight measurements were taken at a controlled
Component Oleic acid Triolein Cholesterol oleate Liquid paraffin Squalane Cholesterol Gelatin Mud Carbon black
Component Fat Liquid paraffin Carbon black Perchloroethylene
Wt percent 28.3 15.6 12.2 2.5 2.5 1.6 7 29.8 0.5
Table I. Composition of soil A
Wt percent 1 3 0.8 95.2
Table II. Composition of soil B
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humidity (60 percent) and appropriate care was also taken to prevent the contamination of the samples.
326
Solvents and surfactants Perchloroethylene (dry-cleaning grade, boiling point ¼ 1218C) and a commercial petroleum derivative were used as solvents without further purification. A commercial surfactant mixture (cationic/non-ionic surfactant aqueous solutions) was used as detergent in the tests. Dry-cleaning devices Two types of dry-cleaning machines, M12-V-6q (designated as the conventional machine) and M12-V/Greendryq (designated as the new machine) with a capacity of 70 l of solvent were used for the cleaning tests. Both machines are made by Mitsubishi Heavy Industries Co. Schematic drawings of the conventional dry-cleaning machine and the newly developed detergent-free dry-cleaning machine are shown in Figures 1 and 2. The new machine is protected by patents (Sawa, 2003). As can be seen in Figure 1, the conventional machine uses a solvent circulating system in which only part of the solvent is distilled and filtered
Figure 1. Schematic diagram of a conventional dry cleaning machine
Detergent-free dry-cleaning system 327
Figure 2. (a) Schematic diagram of the new dry-cleaning machine, and (b) actual view of the new dry-cleaning machine
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to remove impurities (a trap is used to retain big solid particles). Hence, one part of the solvent that re-enters the washing drum is likely to be contaminated. Additionally, a significant amount of solvent goes with the distillation residue and it is not reused, decreasing the efficiency of the process. The new developed machine (Figure 2(a)) uses a completely closed circuit system for the solvent, which is distilled in a high-efficiency distillation device, so that no impurities enter the washing section and very little solvent is lost in the distillation residue. In the distillation device, the soiled solvent is pre-heated to 1008C and then enters a boiler in which it quickly vaporizes. The distillation process is completed within 25 min. Solvent soiling is monitored by colorimetry using a CCD camera, so that the cleaning process is controlled either by changing the rotation velocity of the washing drum or by varying the flow of solvent. Solvent release is minimized, diminishing related health hazards. Since surfactants are not required in the new equipment, the problems associated with surfactant accumulation in the systems and in the clothes are eliminated, and operating costs decrease. Measurement of relative whiteness The relative whiteness of dried sample fabrics was determined by reflectance in a SR-100 reflectometer (Seven Rivers Co., Japan). Green light (coming from a filter) is projected on the surface of the sample, and the reflected light is detected at an angle of 458. A magnesium oxide (MgO) plate was used as the reference for 100 percent relative whiteness, so that the relative whiteness W is given by: W¼
Reflectance of sample £ 100 Reflectance of MgO
The whiteness improvement ratio is defined as R ¼ W t =W 0 ; where Wt is the relative whiteness at a washing time t and W0 is the initial relative whiteness ðt ¼ 0Þ; therefore, it can be considered as a measure of cleaning performance. Surface tension Surface tensions were measured by a Wilhelmy-type automatic surface balance Model K100 (Kru¨ss Co.) at 258C. Microscopy Sample fabrics were observed using a digital zoom microscope (Omron, Japan) with a 3D CCD camera (maximum magnification £3500). Pictures were digitally overlapped to obtain a deep-focusing image. Results and discussion Figure 3 shows the results of cleaning tests for EMPA-107. The whitening ratio R initially increases sharply, and then becomes almost constant. It seems that most of the soil is removed in the first 2 min. The performance of the new
Detergent-free dry-cleaning system 329
Figure 3. Change of whiteness improvement ratio, R, as a function of washing time for EMPA-107
machine is better than the conventional machine using petroleum derivatives although not as good as the conventional machine using perchloroethylene. However, the difference is not very large. The results for cotton (soiled with mixture A) are shown in Figure 4. Again, most of the soil seems to be removed in the first 2 min. However, when compared to EMPA-107, soil removal from cotton seems to be more difficult. Since cotton is a relatively hydrophilic fiber, the interfacial tension between the fabric and the solvent may be higher than for EMPA-107, so that the work needed to remove the soil (work of adhesion) should be higher. Comparing the performance of the three types of machines, again the new machine does better than the conventional machine using petroleum derivatives but not as good as the conventional machine using perchloroethylene. However, the difference is even smaller than for EMPS-107. In Figure 5, corresponding to Woolmosurin samples, it is again observed that the new machine shows similar performance as the conventional machines. In this case, soil removal proceeds more gradually than in the case of EMPA-107 and cotton. It can be attributed to the weaving structure of the fabric, which imposes a barrier to the penetration of the solvent. In order to confirm the previous tendencies, weight measurements were taken on Woolmosurin samples, and the results are shown in Figure 6. The percentage of soil removal is calculated by Soil removal ¼
m0 2 mt £ 100 m0 2 mw
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Figure 4. Change of whiteness improvement ratio, R, as a function of washing time for cotton (soiled with mixture A)
Figure 5. Change of whiteness improvement ratio, R, as a function of washing time for Woolmosurin (soiled with mixture B)
where m0 is the weight of the soiled sample before the test, mt is the weight after a cleaning time t and mw is the weight of the white (nonsoiled) sample. The data for the new machine shows the same trend as in the whiteness measurements namely, the soil removal increases with time at the beginning
Detergent-free dry-cleaning system 331
Figure 6. Percentage of soil removal as a function of washing time for Woolmosurin (soiled with mixture B)
and then tends to become constant. Around 80 percent of the initial soil is removed only after 6 min. On the other hand, for the conventional machines the soil removal first increases and then decreases at long times. This can be attributed mainly to the gradual adsorption of detergent on the surface of the samples, which cannot be detected by whiteness measurements. The detergent then remains on the clothes affecting their properties. The new machine seems to solve this problem. In addition, it should be pointed out that the reproducibility of the tests was far better for the new machine. In order to confirm the presence of adsorbed detergent on the fabric, Woolmosurin samples were washed for 40 min in an ultrasonic bath containing 2 l of distilled water. The surface tension of water after the washing was measured and the results are presented in Table III. All samples show values that are smaller than the surface tension of pure water (72 mN/m at 258C), Sample 1 2 3
Conditions
Original soiled sample (noncleaned) Pre-cleaned in the surfactant-free new machine during 6 min Pre-cleaned in a conventional machine during 6 min (using perchloroethylene+3 percent detergent) 4 Pre-cleaned in a conventional machine during 6 min (using petroleum derivative+3 percent detergent) Note: Fabric – Woolmosurin.
g (mN m21) 49 63 47 40
Table III. Surface tension (g) of washing water after 40 min (ultrasonic bath)
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Figure 7. Percentage of soil removal as a function of washing time for Woolmosurin (soiled with a hydrophilic sugar þ salt mixture)
Figure 8. Change of whiteness improvement ratio, R, as a function of washing time for Woolmosurin (soiled with mixture B) in the new machine using perchloroethylene (surfactant-free)
which can be attributed to the presence of surface-active substances adsorbed on the fabric. For samples 1 and 2 these substances come from soil which contains some fatty acids. However, the surface tension is the highest for sample 2, indicating that little residual, surface-active soil is left on the fabric. On the other hand, in the case of samples 3 and 4, the surface tensions are the
Detergent-free dry-cleaning system 333
Figure 9. Photomicrographs (£350) of Woolmosurin samples
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lowest, which means that an additional surface-active substance, namely detergent, must be present. Figure 7 shows the results of the test performed on Woolmosurin samples soiled with a hydrophilic soil. As expected for a non-polar solvent, the cleaning efficiency decreases when compared to that of hydrophobic soil (Figure 6). It should be pointed out that the presence of detergent does not improve much of the cleaning performance. The effect of the load on the new machine performance is shown in Figure 8. It is evident that as the amount of clothes increases, the cleaning efficiency decreases, due to several factors such as the decrease in contact area, and hydrodynamic restrictions. Nevertheless, the new machine still removes the soil effectively without the need of surfactant. Finally, Figure 9 shows the microscopic appearance of Woolmosurin samples before and after cleaning with the new machine (Figure 9(b)) and a conventional one (Figure 9(c)). It can be observed that there is a deep cleaning of the fibers even if no surfactant is used. On the other hand, residual matter (probably surfactant) is left when a conventional machine is used. The residual surfactant adsorbed on the fibers may cause shrinkage of the clothes or affect their color and texture (touch), as usually claimed by conventional dry-cleaning machine users. Conclusions Under the testing conditions, the new surfactant-free dry-cleaning machine shows similar or better results when compared to conventional ones. As a matter of fact, fabrics are contaminated with detergent in conventional machines. Since detergent is not needed and solvent is efficiently used in the new machine, environmental impacts and operation costs are reduced, and the side effects on the properties of clothes are eliminated. References Aebi, C.M. and Wiebush, J.R. (1959), “Solubility of sodium chloride in organic solvents with aerosol OT in the presence of moisture”, J. Colloid Sci., Vol. 14, pp. 161-7. Azemar, N. (1997), “The role of microemulsions in detergency processes”, in Solans, C. and Kunieda, H. (Eds), Industrial Applications of Microemulsions, Marcel Dekker, New York, NY, pp. 375-6. Keoleian, G.A., Blackler, C.E., Denbow, R. and Polk, R. (1997), “Comparative assessment of wet and dry garment cleaning. Part 1: environmental and human health assessment”, J. of Cleaner Prod., Vol. 5, pp. 279-89. Lohman, J.H. (2002), “A history of dry cleaners and sources of solvent releases from dry cleaning equipment”, Environmental Forensics, Vol. 3, pp. 35-58. Rosen, M.L. (1989), Surfactants and Interfacial Phenomena, Wiley, New York, NY. Sawa, K. (2003), Japanese Patentd No. 3515934, US, German, British, Italian and French Patents (in press). Tsujii, S. (1996), Kougyousenjou no gijutsu, Chijinshoukan, Tokyo, p. 228 (in Japanese).
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Condensation in three-layer waterproof breathable fabrics for clothing
Waterproof breathable fabrics 335
Y.J. Ren and J.E. Ruckman Department of Clothing Design and Technology, Manchester Metropolitan University, Manchester, UK
Received March 2003 Accepted September 2003
Keywords Condensation, Clothing, Physical properties of materials Abstract This paper investigates the behaviour of condensation in three-layer waterproof breathable fabrics for clothing. An attempt has been made to consider water vapour transfer when condensation occurs within the three-layer waterproof breathable fabrics based on the simultaneous heat and mass transfer theory developed by Motakef and El-Maher and diffusion and condensation theory developed by Wijeysundera et al. According to the analysis made of existing theory, it is possible to model condensation within fabrics and laminates using the thermodynamic equations outlined in this paper, which can assist in predicting the performance of textiles and help to understand the comfort of performance clothing. It is noted that the condensation problem may be solved by changing some physical properties of a three-layer waterproof breathable fabric. The water vapour transfer out of the fabric can be improved, and consequently the formation of condensation reduced, by decreasing the thickness of the waterproof membrane and outer layer fabric or by increasing the average diffusion coefficient of the outer layer and membrane. A decrease in the thickness of the lining could increase the water vapour transfer from the hot side to the interface between the dry-wet regions, but this would also increase the condensation. Increasing the diffusion coefficient of the lining will also increase both water vapour transfer from the hot side and condensation.
Nomenclature a B c C C1 C2 Cc1 Cc2 C(T)
¼ constant in Clausius-Clapeyron relationship (K21) ¼ constant in Clausius-Clapeyron relationship (kg/m3) ¼ mean specific heat capacity of fabric (kJ/kg/K) ¼ water vapour concentration (kg/m3) ¼ water vapour concentration on the human skin (kg/m3) ¼ water vapour concentration in the environmental air (kg/m3) ¼ water vapour concentration at the dry-wet interface (kg/m3) ¼ water vapour concentration at the wet-dry interface (kg/m3) ¼ saturation concentration at temperature T in the wet region (kg/m3)
¼ diffusion constant (m2/s) ¼ diffusion constant in the lining or normal fabric (m2/s) D2 ¼ average diffusion constant in the film and outer-layer fabric (m2/s) g(T ) ¼ function in the Clausius-Clapeyron relationship (kg/m3) 0 g (T) ¼ derivative of function g(T ) (kg/K/m3) 0 g (Tc1) ¼ derivative of function g(T ) at z ¼ Lc ðkg=K=m3 Þ g 0 (Tc2) ¼ derivative of function g(T ) at z ¼ L3 ðkg=K=m3 Þ hfg ¼ heat of vapourisation during change of phase (kJ/kg) K ¼ thermal conductivity of fabric (W/m/K) L ¼ thickness of fabric (m) D D1
International Journal of Clothing Science and Technology Vol. 16 No. 3, 2004 pp. 335-347 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410527255
IJCST 16,3
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336
Ldl Ld2 Lw t
¼ thickness of inner fabric (m) ¼ thickness of film plus out-layer fabric (m) ¼ position of the warm boundary of the condensation, when z ¼ Lc ðmÞ ¼ position of the cold boundary of the condensation, when z ¼ L3 ðmÞ ¼ length of the dry zone between the inner surface of the fabric and wet zone (m) ¼ length of the dry zone between the wet zone and outer surface of the fabric (m) ¼ length of the wet zone in the fabric (m) ¼ time (s)
T T0 T1 T2 Tc1 Tc2 T(z) z
¼ temperature (K) ¼ reference temperature in the Clausius-Clapeyron relationship (K) ¼ temperature of human skin (K) ¼ air temperature of the environment (K) ¼ temperature at the dry-wet interface (K) ¼ temperature at the wet-dry interface (K) ¼ temperature distribution in the fabric (K) ¼ thickness (m)
Greek symbols r G G1
¼ mean local density of fabric (kg/m3) ¼ condensation rate in the fabric (kg/m3/s) ¼ condensation rate in the normal fabric (kg/m2/s)
G2
¼ condensation rate in the lining (kg/m2/s)
1. Introduction When a waterproof breathable fabric is worn as a part of a performance clothing system, the transfer of water vapour from the human body through the waterproof breathable fabric to the outer air is regarded to be the most important element for clothing comfort. However, if condensation occurs within a performance clothing system and especially on the inner side of the waterproof breathable fabric, it seriously affects the comfort of the wearer. The study of water vapour transfer through waterproof breathable fabrics and clothing systems and condensation occurring within the layers of clothing systems has received attention in recent years (Gibson, 1993; Gretton et al., 1998; Pause, 1996; Ruckman, 1997a). These studies concentrated on the performance of waterproof breathable fabrics based on the types of waterproof membranes, such as PTFE or hydrophilic, laminated or coated onto the outer layer. Most of the waterproof breathable fabrics considered in these studies are those consisting of two layers in cross section: a waterproof layer and an outer-layer fabric. In recent years, however, various fabrics with different thicknesses, layers and types of constructions have appeared in the market place. At present, it is common to produce either two-layer or three-layer waterproof breathable fabric using the same membrane type. Waterproof breathable fabrics consisting of three layers (lining, waterproof layer and outer-layer fabric) can be considered as a special form of waterproof breathable fabrics. There are several papers particularly concerned with the condensation problem in waterproof breathable fabrics for clothing and some of the papers
deal with the modelling of the water vapour transfer through a clothing system, when condensation occurs (Farnworth et al., 1990; Ren and Ruckman, 1999; Ruckman, 1997b). However, none of the previous studies paid attention to the condensation occurring in three-layer waterproof breathable fabrics. The aim of this paper is therefore to explain the behaviour of condensation in three-layer waterproof breathable fabrics. In this paper an attempt is also made to consider the water vapour transfer when condensation occurs within the three-layer waterproof breathable fabrics based on the simultaneous heat and mass transfer theory developed by Motakef and El-Maher (1986) and diffusion and condensation theory developed by Wijeysundera et al. (1989).
Waterproof breathable fabrics 337
2. Theoretical background Water vapour transfer is governed by the vapour pressure difference between the two sides of a fabric (Ruckman, 1997a). Once the vapour pressure within a fabric reaches the saturation pressure for the local temperature, condensation will occur in the fabric and the diffusion of the water vapour will be subject to phase change (Motakef and El-Maher, 1986; Ruckman, 1997b). When the vapour concentrations at the two faces of the fabric are at saturation level, condensation occurs throughout the entire thickness of the fabric. When the vapour concentration at the boundaries is less than the saturation level for the local temperature, condensation can occur over some region within the fabric. Thus, condensation occurring in the fabric forms a wet zone separated by two dry zones, or “dry-wet-dry”. Ren and Ruckman (1999) observed that, in contrast to a normal fabric (for which the temperature and vapour concentration profiles are shown in Figure 1), in a three-layer waterproof breathable fabric, one boundary of the dry-wet zones is located within the lining layer and the other boundary of the wet-dry zones is located at the interface between the lining layer and waterproof layer, as shown in Figure 2. According to Motakef and El-Maher (1986) when condensation occurs, liquid diffusion is characterized by two stages. There is an initial transient period
Figure 1. Profiles of temperature and vapour concentration in normal fabrics
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338 Figure 2. Profiles of temperature and vapour concentration in three-layer waterproof breathable fabrics
when condensation occurs. After that the water vapour concentration and temperature profiles are at a steady-state and remain invariant with time. Water vapour continuously condenses in the fabric and the liquid content in the wet zone increases linearly with time. There is no condensation motion. This stage is called the first regime. When the liquid content accumulating in the fabric reaches a certain proportion, the liquid starts to diffuse and causes the condensation occurring in the wet zone to diffuse towards the wet zone boundaries. The region of condensation is expanded. After some time, a new steady-state is reached. The water vapour condenses in the dry-wet boundary on the side of high vapour pressure and re-evaporates at another wet-dry boundary on the side of low vapour pressure. The liquid content in the fabric is invariant with time and the transfer rate of water vapour diffusing into the fabric is equal to that of the water vapour diffusing out. This stage is called the second regime. Motakef and El-Maher (1986) have shown that the location of condensation region and the profiles of water vapour concentration and temperature can be obtained by the simultaneous solution of two coupled conservation equations of heat transfer and water vapour diffusion and by applying the continuity of heat flux and water vapour diffusion at the boundaries of the “dry-wet-dry” zones. Wijeysundera et al. (1989) have given the governing conservation equations of heat and water vapour transfer based on Fourier’s law and Fick’s law: K
›2 T ›T þ Ghfg ¼ rc ›z 2 ›t
ð1Þ
›2 C ›C 2G¼ 2 ›z ›t
ð2Þ
D
They then used the Clausius-Clapeyron equation (Kenneth, 1989) to set up a relationship between temperature and concentration: CðTÞ ¼ Be
aðT1 2T1 Þ 0
¼ gðT Þ
ð3Þ
The constant in the above equation is obtained for the mean temperature (20-338C) T 0 ¼ 299:5 K B ¼ 0:025026 kg=m3
a ¼ 4;988:12=K
The combination of equations (1)-(3) for the quasi-steady-state condition gives: d dT 0 ½K þ hfg Dg ðT Þ ¼0 ð4Þ dz dz where g 0 ðTÞ ¼ dg=dT: The temperature and liquid concentration profiles in the condensation region depend on the width and temperature boundary conditions of the wet zone during the first regime (Motakef and El-Maher, 1986). In the dry region, the governing equations (1)-(3) are uncoupled because the condensation rate is equal to zero. The vapour concentration and temperature vary in a linear relationship with position. At the dry-wet and wet-dry interfaces, the boundary parameters of the vapour concentration and temperature are obtained by considering the Clausius-Clapeyron relationship and the vapour and heat transfer continuity equations. The boundary conditions at the two faces of a fabric, that is in saturation condition are: at z ¼ 0; at z ¼ L2 ;
Tð0Þ ¼ T 1 and Cð0Þ ¼ C 1
ð5Þ
TðL2 Þ ¼ T 2 and CðL2 Þ ¼ C 2
ð6Þ
When z ¼ Lc1 ; for normal and three-layer waterproof breathable fabrics: T 1 2 T c1 dT ¼2 dz Ld1
ð7Þ
C 1 2 C c1 dC ¼2 dz Ld1
ð8Þ
When z ¼ Lc2 ; for normal fabrics: T c2 2 T 2 dT ¼2 dz Ld2
ð9Þ
Waterproof breathable fabrics 339
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C c2 2 C 2 dC ¼2 dz Ld2
ð10Þ
For three-layer waterproof breathable fabrics, the liquid produced by condensation cannot penetrate the waterproof film and therefore the width of the dry region between the wet region and outer air is equal to the thickness of the waterproof film plus the outer-layer fabric, Ld2 ¼ L2 ; and is a constant: K2
T c2 2 T 2 dT ¼ 2K 1 dz L2
ð11Þ
D2
C c2 2 C 2 dC ¼ 2D1 dz L2
ð12Þ
3. Analysis and calculation The following analysis considers the behaviour of condensation in a three-layer waterproof breathable fabric when the fabric is placed between a sweating human skin and the environment. Although in real life, a three-layer waterproof breathable fabric is never worn next to a human skin, nevertheless, this situation simulates a similar microclimate in which a three-layer waterproof breathable fabric is worn as part of a performance clothing system. An analysis for a normal fabric is also given for comparison. Before the suitable parameters are chosen for the analysis, the following assumptions have been made. (1) There are no convective contributions to heat and water vapour transfer. (2) Gravitational effects are negligible. (3) The waterproof membrane and the outer-layer fabric in a three-layer waterproof breathable fabric are regarded to be the same medium in having a mean thermal conductivity and water vapour diffusion coefficient. (4) The thermal conductivity and water vapour diffusion coefficient are taken to be spatially uniform and constant. For the calculation, the environmental condition is set to be a standard condition of 208C and 65 per cent RH. The temperature of the human body is set at 338C (Hardy, 1968). The relative humidity is set to vary between 88 and 100 per cent to investigate the changes of the water vapour transfer rate and condensation in relation to humidity changes on the human body. The thermal conductivity is set at 0.0263 W/m/K for both normal fabric and three-layer waterproof breathable fabric as given by Farnworth (1986). The diffusion constant was calculated using a formula given by Wijeysundera et al. (1989). The diffusion constant for the lining in the three-layer waterproof breathable
fabric was 2:5 £ 1025 m2 =s: The diffusion constants of the film and outer-layer fabric of three-layer waterproof breathable fabric were decided to be an average diffusion constant, 2:15 £ 1026 m2 =s; for the sake of simplifying the calculation. The typical thickness of a three-layer waterproof breathable fabric, 0:73 £ 1023 m; where the thickness of the lining is 0:7 £ 1023 m and thickness of the film plus the outer-layer fabric is 0:03 £ 1023 m; was selected as measured during the preliminary experiments for calculation. The thickness of the normal fabric was also selected at 0:73 £ 1023 m so that the results obtained from the normal fabric could be compared with those of three-layer waterproof breathable fabric. The heat of vapourisation during changes of phase for the temperature range from 20 to 338C is calculated to be 1;000 £ ð22:3621 £ T þ 3164:4Þ kJ=kg: 3.1 The lengths of dry and wet regions For a normal fabric, there are four unknown parameters in equations (7)-(10). These are Tc1, Tc2, Ld1 and Ld2. The temperature values at the interfaces of the dry-wet zone where z ¼ Lc1 and z ¼ Lc2 ; are obtained by eliminating the length scales between the vapour and heat continuity equations (7)-(10). Then the vapour concentrations, Cc1 and Cc2, at the interfaces of the wet zone, where z ¼ Lc1 and Lc2, are obtained using the Clausius-Clapeyron equation (3). Integrating equation (4) and applying the boundary conditions at the dry-wet and wet-dry interfaces, the temperature distribution in the fabric is obtained using the following conservation equations:
¼
½K 1 þ hfg D1 g 0 ðT c1 ÞðT 1 2 T c1 Þ Ld1
ð13Þ
K 1 ðT c2 2 T 2 Þ þ hfg D1 ðC c2 2 C 2 Þ Lw
ð14Þ
½K 1 þ hfg D1 g 0 ðT c2 ÞðT c2 2 T 2 Þ Ld2
ð15Þ
¼
The widths of dry and wet regions, Ld1, Lw and Ld2, are obtained by solving equations (13)-(15) as: Ld1 ¼
L 1þ
Lw ¼
½K 1 ðT c1 2T c2 Þ þ hfg D1 ðC c1 2 C c2 Þ þ ½K 1 þ hfg D1 g 0 ðT c2 ÞðT c2 2 T 2 Þ ½K 1 þ hfg D1 g 0 ðT c1 ÞðT 1 2 T c1 Þ
L 1þ
½K 1 þ hfg D1 g 0 ðT c1 ÞðT 1 2 T c1 Þ þ ½K 1 þ hfg D1 g 0 ðT c2 ÞðT c2 2 T 2 Þ ½K 1 ðT c1 2 T c2 Þ þ hfg D1 ðC c1 2 C c2 Þ
ð16Þ
ð17Þ
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Ld2 ¼
L 1þ
½K 1 þ hfg D1 g 0 ðT c1 ÞðT 1 2 T c1 Þ þ ½K 1 ðT c1 2 T c2 Þ þ hfg D1 ðC c1 2 C c2 Þ ½K 1 þ hfg D1 g 0 ðT c2 ÞðT c2 2 T 2 Þ
ð18Þ
For a three-layer waterproof breathable fabric, there are also four unknown parameters in equations (7), (8), (11) and (12). These are Tc1, Tc2, Ld1 and Lw. However, the method of obtaining these parameters is a little different from that of normal fabrics because the width of the waterproof film and outer-layer fabric is a constant. First, the temperature, Tc1, at the dry-wet interface of z ¼ Lc1 is obtained by eliminating the length scales between the vapour and heat transfer continuity equations (7) and (8). Then, the vapour concentration Cc1 is obtained by the Clausius-Clapeyron equation (3). Secondly, integrating equation (4) and applying the boundary conditions at the dry-wet and wet-dry interfaces of z ¼ Lc1 and Lc2, the temperature distribution in the waterproof breathable fabric is obtained by the conservation equations as: ½K 1 þ hfg D1 g 0 ðT c1 ÞðT 1 2 T c1 Þ Ld1
ð19Þ
¼
K 1 ðT c1 2 T c2 Þ þ hfg D1 ðC c1 2 C c2 Þ Lw
ð20Þ
¼
½K 1 þ hfg D1 g 0 ðT c2 ÞðT c2 2 T 2 ÞK 2 K 1 L2
ð21Þ
The temperature Tc2 at the wet-dry interface, where z ¼ Lc2 ; is obtained by combining the conservation equations (19)-(21) in the following form: ½K 1 þ hfg D1 g 0 ðT c1 ÞðT 1 2 T c1 Þ þ ½K 1 ðT c1 2 T c2 Þ þ hfg D1 ðC c1 2 C c2 Þ ½K 1 þ hfg D1 g 0 ðT c2 ÞðT c2 2 T 2 Þ ¼
K 2 L1 K 1 L2
ð22Þ
The widths of the dry and wet regions, Ld1, Lw, are obtained by solving equations (19)-(21) as: ½K 1 þ hfg D1 g 0 ðT c1 ÞðT 1 2 T c1 ÞK 1 L2 ½K 1 þ hfg D1 g 0 ðT c2 ÞðT c2 2 T 2 ÞK 2
ð23Þ
½K 1 ðT c1 2 T c2 Þ þ hfg D1 ðT c1 2 T c2 ÞK 1 L2 ½K 1 þ hfg D1 g 0 ðT c2 ÞðT c2 2 T 2 ÞK 2
ð24Þ
Ld1 ¼
Lw ¼
3.2 The condensation rate The condensation rate within the fabric, G, can be obtained as follows using equation (2). For normal fabrics: C 1 2 C c1 C c2 2 C 2 G1 ¼ D1 ð25Þ 2 Ld1 Ld2
Waterproof breathable fabrics 343
For three-layer waterproof breathable fabrics: G2 ¼ D1
C 1 2 C c1 C c2 2 C 2 2 D2 Ld1 L2
ð26Þ
4. Results and discussion The changes in the length of dry and wet regions in normal fabrics and three-layer waterproof breathable fabrics are shown in Figures 3 and 4, respectively. The most obvious phenomenon noted from these figures is that in both fabrics the length of the wet region increases with the increased relative humidity at the human skin surface. The other phenomenon noted for both fabrics is that whilst the extent of the dry region near the external air remains constant regardless of the relative humidity changes the extent of dry region near the skin decreases with increasing relative humidity of the human skin surface. This implies that the wet region expansion into the dry region near the skin was faster and easier than that near the external air. This also implies that the liquid produced by the condensation in the fabric expanded more easily towards the hot side at unsaturated vapour pressure than the cold side at saturated vapour pressure.
Figure 3. Extent of the dry-wet-dry region in normal fabrics
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Figure 4. Extent of the dry-wet-dry region in three-layer waterproof breathable fabrics
Figures 3 and 4 also show that the length of the dry region near the external air in the three-layer waterproof breathable fabric is greater than that in the normal fabric. When the relative humidity was low, the length of the dry region near the skin in the three-layer waterproof breathable fabric was slightly greater than that in the normal fabric. However, the length of the wet region in the three-layer waterproof breathable fabric was slightly smaller than that in the normal fabric. With the increase in the relative humidity, the lengths of the dry region and wet region in the three-layer waterproof breathable fabric were close to those in the normal fabric. This reflects the rate of condensation within the three-layer waterproof breathable fabric being faster than that within the normal fabric. Figures 5 and 6 show the changes in the water vapour transfer rates and condensation, when the relative humidity on the human body varies. These figures demonstrate that the water vapour transfer from human skin to fabric increases with increasing relative humidity at the skin surface. They also demonstrate that the water vapour transfer from fabric to external air is slow in three-layer waterproof breathable fabrics resulting in a high condensation rate when compared to that in normal fabrics, especially when the relative humidity at the human skin surface is high. There are two apparent differences between the normal fabric and three-layer waterproof breathable fabric in Figures 5 and 6, when the relative humidity is increased. First, the changes in the rate of water vapour transfer from the three-layer waterproof breathable fabric were far smaller than that of the normal fabric. The former had a linear but only very slight rise with the relative humidity. Second, the increase in the rate of condensation occurring in the three-layer waterproof breathable fabric was greater than the normal fabric. The reason for the two apparent differences was attributed to three factors.
Waterproof breathable fabrics 345
Figure 5. Condensation rate and water vapour transfer in normal fabrics
Figure 6. Condensation rate and water vapour transfer in waterproof breathable fabrics
First, the outside dry region of the three-layer waterproof breathable fabric has a smaller diffusion constant than that of the normal fabric and, therefore, the resistance to water vapour molecules diffusing out of the dry region was greater for the three-layer waterproof breathable fabric than for the normal fabric. Second, the length of the dry region near the external air was a constant. The rate of water vapour transfer through the fabric depended on the changes in the vapour concentration at the interface of the wet-dry region. Third, water vapour could not diffuse into the dry region of the three-layer waterproof breathable fabric but could diffuse into the dry region of the normal fabric.
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One interesting behaviour to note is that, although the change is minimal, the water vapour transfer rate from the three-layer waterproof breathable fabric to the environment increases even though the extent of the dry region near the external air does not change due to the fact that liquid cannot penetrate into the waterproof film. This shows that the vapour pressure at the wet-dry interface played a very important role in the rate of water vapour transfer out of the wet region of the fabric. This is because under quasi-steady-state conditions, the vapour concentration at the interface of wet-dry regions increased with relative humidity, but the extent of the outer dry region and diffusion coefficient did not change. 5. Conclusions This paper has investigated the behaviour of condensation in three-layer waterproof breathable fabrics and considered the changes in water vapour transfer when condensation occurs within the three-layer waterproof breathable fabrics based on the analysis made of existing theory. From the analysis and subsequent calculation, the following conclusions were drawn. The changes in the extent of dry-wet-dry regions show that the extent of the wet region increases with condensation. The extent of the dry region decreases with condensation. However, the changes in the extent of dry region near the external air show a slight decrease (for normal fabrics) or are constant (for three-layer waterproof breathable fabrics). This implies that the extension of the condensation mainly develops towards the direction of the hot side rather than the cold side. The expansion of wet region, i.e. condensation, depends on the difference in the rate of water vapour transfer between the two dry regions adjacent to the wet region. The temperature and vapour concentration at the inside and outside surfaces of the fabric determine the values of the temperatures and saturated vapour pressures at both interfaces of the dry-wet and wet-dry regions. These in turn determine the extent of the dry and wet regions. According to the above conclusions drawn from the analysis of existing theory, the condensation problem may be solved by changing some physical properties of a three-layer waterproof breathable fabric. The water vapour transfer out of the fabric can be improved, and consequently the formation of condensation reduced, by decreasing the thickness of the waterproof membrane and outer layer fabric or by increasing the average diffusion coefficient of the outer layer and membrane. A decrease in the thickness of the lining could increase the water vapour transfer from the hot side to the interface between the dry-wet regions, but this would also increase the condensation. Increasing the diffusion coefficient of the lining will also increase both water vapour transfer from the hot side and condensation.
References Farnworth, B. (1986), “A numerical model of the combined diffusion of heat and water vapour through clothing”, Textiles Research Journal, Vol. 56, pp. 653-65. Farnworth, B., Lotens, W.A. and Wittgen, P. (1990), “Variation of water vapour resistence of microporous and hydrophilic films with relative humidity”, Textiles Research Journal, Vol. 60, pp. 50-3. Gibson, P.W. (1993), “Factors influencing steady state heat transfer and water vapour transfer measurements for clothing materials”, Textile Research Journal, Vol. 63, pp. 749-64. Gretton, J.C., Brook, D.B., Dyson, H.M. and Harlock, S.C. (1998), “Moisture vapour transport through waterproof breathable fabrics and clothing systems under a temperature gradient”, Textile Research Journal, Vol. 68, pp. 936-41. Hardy, J.D. (1968), “Heat Transfer”, in Newburgh, L.H. (Ed.), Physiology of Heat Regulation and the Science of Clothing, Hafner, London. Kenneth, W. Jr. (1989), Thermodynamics, 5th ed., McGraw-Hill, New York. Motakef, S. and El-Maher, M.A. (1986), “Simultaneous heat and mass transfer with phase change in a porous slab”, International Journal of Heat and Mass Transfer, Vol. 29 No. 10, pp. 1503-12. Pause, B. (1996), “Measuring the water vapour permeability of coated fabrics and laminates”, Journal of Coated Fabrics, Vol. 25, pp. 311-20. Ren, Y.J. and Ruckman, J.E. (1999), “Effect of condensation on water vapour transfer through waterproof breathable fabrics”, Journal of Coated Fabrics, Vol. 29, pp. 20-36. Ruckman, J.E. (1997a), “Water vapour transfer in waterproof breathable fabrics. Part I – under steady state conditions”, International Journal of Clothing Science and Technology, Vol. 9 No. 1, pp. 10-22. Ruckman, J.E. (1997b), “Analysis of simultaneous heat and water vapour transfer through waterproof breathable fabrics”, Journal of Coated Fabrics, Vol. 26, pp. 293-307. Wijeysundera, N.E., Hawlader, M.N. and Tan, Y.T. (1989), “Water vapour diffusion and condensation in fibrous insulation”, International Journal of Heat and Mass Transfer, Vol. 32 No. 10, pp. 1865-78.
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Effectiveness of Proban flame retardant in used clothing James R. House Institute of Naval Medicine (Royal Navy), Hampshire, UK
James D. Squire Ministry of Defence, London, UK Keywords Fire, Protective clothing, Armed forces
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361 Received 27 November 2003 Accepted 18 January 2004
Abstract During conflict, Royal Navy personnel wear a two-ply flame-retardant (FR) “action coverall” (AC) and “anti-flash” (AF) hood and gloves, made from Proban (Albright & Wilson’s registered trademark) treated cotton. It is a widely held belief that extended wear, and repeated washing damages the Probanw FR finish making the garments more susceptible to ignition if exposed to flame. To examine this, new and used AC and AF were exposed up to 10 s on a flame manikin. The examples of used AC and AF had been worn for approximately 56 days and washed 20 times over a 12 week period at sea. For flame challenges up to 10 s, much greater than expected in a fuel explosion, the protection afforded by the used clothing was as good as for the new clothing, with some evidence that protection had improved. It is concluded that the Probanw FR treatment was not damaged by wear or washing.
Introduction Because of the ever present risk of fire on warships, even during peacetime, Royal Navy (RN) normal working clothing is made from Probanw treated flame retardant (FR) cotton or polycotton. During military operations, when the risk from weapons flashes, explosions and fire is increased RN personnel wear a two-layered Probanw FR cotton “action coverall” (AC) and “anti-flash” (AF) hood and gloves. This ensemble, described as “action dress” (AD), gives good protection from burns when exposed to short duration flame exposures (House, 1997). In use, RN clothing is exposed to fuels, oils or flammable lubricants, all of which will increase the risk of the garment igniting on exposure to fire or flash, probably causing more significant injury. Most serious burns involve the ignition of clothing and often result in more serious burn injuries than if no clothing had been worn, particularly when the initial fire event was small or of very short duration (Colver and Colver, 1991; Crown and Dale, 1992). Of course, this type of contamination could occur in all types of clothing and there is no q British Crown Copyright 2004/MOD The authors thank Lt Cdr Rees, RN and CPOSA Mote, both from HMS Iron Duke for supplying 20 sets of used “action dress”, Professor Mike Tipton and Dr Adrian Allsopp for their critical review. They also thank the Medical Officer-in-Charge INM, Surgeon Commodore NE Baldock, Royal Navy for permission to publish.
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evidence that inherently FR materials such as aramids, etc. would be any less susceptible. If such contamination were shown to be problematic then the only solution would be to change clothing as soon as is practical after significant contamination, with the soiled clothing being laundered. Fortunately, the AC and AF are white and it is easy to determine if contamination has occurred. For simplicity, hereafter the contaminants are described as POL ( petrol, oils and lubricants); taking petrol to mean any liquid fuels. The Probanw finishes which give the cotton or polycotton materials, their FR properties require that specific washing programmes and synthetic detergents are used. If the garments are washed with natural soaps or boiled it is possible to damage the FR finish. Consequently, it is a common perception in the Fleet that the FR finishes are fragile and are damaged by the ship’s laundry. Furthermore, despite assurances in the scientific literature that Probanw and other FR finishes are durable (Harper and Beninate, 1988; Horrocks, 1983; Lund, 1975) no references have been found which describe studies where fire protection has been evaluated in clothing which has undergone a period of wear and washing. There is a second concern with POL contamination; it may accumulate within garments if the washing programmes and/or the synthetic detergents used are insufficient. If this were the case, and significant contamination of garments were common, the only solution would be to adopt inherently FR materials that could be washed at greater temperatures and with more powerful detergents without the risk of damaging the FR properties. This study was undertaken to assess these concerns. Aim To assess the protection from flame provided by RN AD when new, and to compare this with the protection afforded by garments that had been worn and washed over a prolonged period during real operations. Hypotheses H1. FR finishes would remain intact in used garments and that the level of protection against fire would be unaffected. H2. Washing is sufficient to avoid the accumulation of POL and protection from fire and flash would be unaffected. Methods Twenty sets of AD (AC and AF) were obtained from the RN’s Type 22 Frigate HMS Iron Duke after operations in the Adriatic Sea in 1999. These had been worn for at least 12 h per day for approximately 56 days over a 12 week period, and had been washed approximately 20 times. Testing was conducted on a flame manikin at the UK’s Defence Clothing and Textiles Agencies Research and Technology Group in Colchester, UK [1].
The manikin was developed to enable testing of military clothing ensembles during full flame engulfment of different durations. The manikin is a male size 40R (height 180 cm, chest 100 cm) made from fibreglass and instrumented with 120 thermocouples over the entire surface excluding the feet. Of these, one thermocouple is on each hand and 18 are on the head. The manikin was exposed to flame engulfment for specified periods using 30 propane cup burners producing a mean (SD) heat flux at the surface of the manikin of 77.4 (2.3) kW/m2 (Staples, 1996). The data from the thermocouples were recorded electronically every second during, and for up to 60 s following, the flame engulfment. Heat flux incident upon the manikin surface (skin) was calculated from these data. From this information, predictions of pain and tissue damage could be made using a model developed from human experiments (Stoll and Chianta, 1971; Stoll and Greene, 1959). Further details about the development of this manikin, the method of use and the prediction of burn injury are available (Staples, 1996). The garments were placed on the manikin and challenged with flame for 2, 4, 6, 8 or 10 s. Three sets of AC and AF were tested at each flame challenge, and all of these tests were repeated using new garments, making 30 tests in all. The results are expressed in terms of the level of burn injury predicted as first, second and third degree. This classification describes the depth of damage to the skin. In simple terms: . first degree burn is superficial reddening of the skin, which is painful but does not cause blistering; . second degree burn damages some of the skin layers with resultant blistering but does not cause scarring; and . third is a full thickness burn, through the skin to the tissues below and results in scarring. Results The 20 sets of AC and AF received from HMS Iron Duke had been washed prior to despatch and it was not possible to assess the level of contamination prior to washing. There were patches of light staining which had not been completely removed by laundering, with the gloves being the most badly affected as might be expected. It was not possible to determine if the contamination had been POL. As expected, the char damage to the outer layer of the AC was greater with longer flame challenge durations. There was no evidence of significant garment ignition as all flames quickly receded on cessation of the gas burners. The mean predicted total degree burn injuries (first, second and third) for the whole body including the head are shown in Figure 1. Although first degree burns are painful they are not serious and recover quickly without lasting damage to the skin (sunburn is typically first degree).
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Figure 1. Mean body surface area including the head with a predicted first, second or third degree burn when new and used clothing was exposed to flame (n ¼ 3)
Figure 2. Mean body surface area excluding the head with a predicted second or third degree burn when new and used “action coveralls” were exposed to flame (n ¼ 3)
In addition, it is important to distinguish between the level of protection afforded to the head (single layer FR cotton) and the rest of the body (double layer FR cotton). Consequently, the results have been reconsidered with respect to only second and third degree injuries, and separate graphs of the predicted injuries for the body and the head are shown in Figures 2 and 3, respectively. As the hands of the manikin have only one sensor each, the results of testing are not presented graphically. No evidence was found that the used and greatly soiled gloves had ignited as there was no significant “after burn” on cessation of the flame challenge, or that the level of injury or protection afforded was different between the new and used gloves.
Probanw flame retardant
365 Figure 3. Mean head surface area with a predicted second or third degree burn when new and used “anti flash” hoods were exposed to flame (n ¼ 3)
Discussion The predicted burn injury results demonstrate that the AC and AF provide good protection against short duration flame exposures, as might occur during fuel explosions secondary to enemy action, primarily weapons detonations (Boffard and MacFarlane, 1993; House, 1997; Saxl, 1942; Shafir et al., 1984). For flame engulfment of 3 s or less there are unlikely to be any second or third degree burn injuries under the AC, and less than 30 per cent of the head injured. In real exposures, head injuries might be less than predicted here as a victim may cover the face or head with the hands and arms, and may possibly turn away from the fire or drop to the deck. Although not assured in all situations it seems likely that victims of flame engulfment of two or more seconds would be able to take some protective or avoiding action. The results support our hypotheses that continued wear and washing does not affect the FR finish of RN AC or AF, and that there was no evidence that there was sufficient (if any) long-term POL accumulation that could have significantly increased the risk of garment ignition. The level of protection under the used AC was better than for new garments with up to 15 per cent less body surface with predicted second or third degree burns after 10 s of flame. However, the small sample size (n ¼3) for each condition did not allow us to test this statistically. The predicted burn injury to the head was 8 per cent more (of the head surface) after 10 s of flame for the used compared to the new hoods. However, this equates to less than 1 per cent of the body surface, and occurred as a result of only one head sensor indicating an increased burn. This difference is too small to be considered significant with such a small sample size of only three garments at each flame challenge. It is likely that the used garments provided better protection due to physical changes to the materials during wear, as there is no known mechanism by
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which the Probanw FR finish might be improved chemically during laundering. When garments are worn the material layers and the fibres within rub-together which increases both the thickness of the layers and the air-trapped within them. The material layers are then described as having an increased “loft”. This air provides increased thermal insulation and, provided the garments do not ignite (as demonstrated), gives enhanced protection against fire. How soon new garments start to acquire the increased “loft” is not known. It is proposed that the majority of the changes occur after the first few washes, as it is after this point that greatest changes in other garment properties related to “loft” (appearance and comfort) are commonly noticed. Conclusions Both the AC and AF provide significant and good protection from burns and are appropriate to the expected threat of fire and flash. The level of protection against burns afforded by worn and used AC was at least as good, and possibly better, than when the garments were new. The level of protection against burns afforded by worn and used AF was similar to that provided by new hoods. There is some evidence that protection is slightly reduced for used hoods, but only at levels of challenge at which head injuries are likely to prove fatal, irrespective of whether the hood was new or used. Wearing the AC and AF provides good protection from the expected risks of fire and flash exposure. Probanw treated cotton remains a suitable material for current RN AD. The effect of POL contamination between washes on the flammability of clothing should be assessed. Note 1. DCTA/R&PSG has since moved to Bicester, as part of the Defence Logistics Organisation. References Boffard, K.D. and MacFarlane, C. (1993), “Urban bomb blast injuries: patterns of injury and treatment”, Surgery Annual, Vol. 25 No. 1, pp. 29-47. Colver, C.P. and Colver, J.C. (1991), “Managers, workers must realize need for flame-retardant clothing”, Occupational Health and Safety, Vol. 60 No. 1, pp. 20-3. Crown, E.M. and Dale, J.D. (1992), “Flammability of clothing”, Final Project Report: Bibliography, University of Alberta, Edmonton, Canada, Vol. 2, N94-13819. Harper, R.J. and Beninate, J.V. (1988), “Heat cure flame retardant cotton via precondensate and buffering salts”, Textile Chemist and Colourist, Vol. 20 No. 5, pp. 29-35. Horrocks, A.R. (1983), “An introduction to the burning behaviour of cellulosic fibres”, Journal of Society of Dyers and Colourists, Vol. 99, pp. 191-7. House, J.R. (1997), “The effectiveness of RN protective clothing against burns”, Journal of Defence Science, Vol. 2 No. 2, pp. 205-12. Lund, G. (1975), “Durable flame-retardant finishes – the current situation”, Shirley Institute Bulletin, Vol. 3, pp. 65-9. Saxl, N.T. (1942), “Burns en masse”, US Naval Medical Bulletin, Vol. 40, pp. 570-6.
Shafir, R., Nili, E. and Kedekm, R. (1984), “Burn injury and prevention in the Lebanon War, 1982”, Israel Journal of Medical Sciences, Vol. 20, pp. 311-3. Staples, R. (1996), “Development of a thermal manikin to test the protection offered by clothing assemblies from flame and heat”, Defence Clothing and Textiles Agency, Science and Technology, Ministry of Defence, UK, Research report 96/10. Stoll, A.M. and Chianta, M.A. (1971), “Heat transfer through fabrics as related to thermal injury”, Transactions of New York Academy of Sciences, pp. 649-70. Stoll, A.M. and Greene, L.C. (1959), “Relationship between pain and tissue damage due to thermal radiation”, Journal of Applied Physiology, Vol. 14 No. 3, pp. 373-82.
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368 Received 27 November 2003 Accepted 6 January 2004
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Fire hood retains fire protective qualities after wear and washing The effect of wear and washing on the protection afforded by the new Royal Navy fire fighters’ protective hood James R. House Institute of Naval Medicine (Royal Navy), Hampshire, UK
James D. Squire Ministry of Defence, London, UK Keywords Fire, Protective clothing, Armed forces Abstract Royal Navy (RN) fire fighters have recently been provided with a new two-ply hood made from 20 per cent polybenzimidizole/80 per cent permanent flame retardant Rayon ( fibre made from regenerated cellulose). After 15-20 days of use during live-fire training (and regular washing) the new type hood appeared to be suffering from excessive wear and there was concern that the level of protection might have decreased. To examine this, 25 new and 25 used hoods (worn and washed approximately 15-20 times) were exposed to flame, five each at 2, 4, 6, 8 and 10 s using a flame manikin head to ascertain the predicted burn injuries. The new hood was shown to provide excellent protection against the most severe flame engulfment to which RN personnel might accidentally be exposed. There was no evidence that the protection afforded by the hoods was reduced by prolonged use and washing and therefore it was safe for the “new-type” hood to remain in-service.
Introduction Following an evaluation of the effectiveness of in-service fire fighting clothing (House, 1997), the Royal Navy introduced a new fire fighting hood. The hood has a two-ply “head” and a one-ply yoke, and is made from a blend of FR materials (20 per cent polybenzimidizole (PBI) / 80 per cent permanent flame retardant (PFR) Rayon). The hood provides enhanced protection to the head compared to the previous one-ply Proban (Albright & Wilson’s registered trademark) cotton FR fire fighting hood (House et al., 2000). Importantly, the hood was also thin enough to allow the skull conduction microphone of the fire fighter’s helmet communications system to operate. International Journal of Clothing Science and Technology Vol. 16 No. 4, 2004 pp. 368-373 Emerald Group Publishing Limited 0955-6222
q British Crown Copyright 2004/MOD The authors thank WO(MEM) N Aldridge, 2IC RN Fire Fighting School, Horsea Island for providing the used fire hoods, Professor Mike Tipton and Dr Adrian Allsopp for their critical review. The authors also thank the Medical Officer-in-Charge INM, Surgeon Commodore NE Baldock, Royal Navy for permission to publish.
The new fire fighting hoods were initially well accepted. However, at the RN Fire hood retains fire schools, where the hoods suffer heavy use and soiling during training, and fire protective only 3 months after their introduction it was noted that the hoods appeared to qualities have lost their shape, felt slightly thinner and exhibited material pilling (surface “bobbles”). The concern was that this apparent “damage” would decrease the protection afforded by the hoods and may increase the risk of 369 injury to staff and trainees at the fire school. It might also reasonably be assumed that this type of “damage” would occur to hoods stored in ships’ fire fighting lockers if they are used regularly for training. This study was undertaken to assess if the protection afforded by the hoods was degraded by the apparent “damage”. Aim To assess if the protection from flame provided by the new RN fire fighting hood was compromised by the “damage” apparent after heavy soiling, use and washing. Hypothesis It was hypothesised that the “damage” incurred by the hoods after prolonged use at the fire school reduced the level of protection, thereby exposing personnel to a greater risk of injury if exposed to flame. Methods Twenty-five used fire hoods were obtained from the fire fighting school at Horsea Island, Portsmouth. Each hood is used for only 1 day and is then collected at the end of the week for laundering and returned at the end of the following week. Thus, each hood undergoes one day use and one wash every 2 weeks. Accordingly, the used hoods collected from the fire school are estimated to have undergone between 15 and 20 days use and washes. Twenty-five new hoods were also obtained. This study was undertaken using a free-standing flame manikin head that had previously been developed (Squire, 2000) so that the protection from fire afforded by hoods and helmets, etc. could be tested easily and accurately (House et al., 1999). The head has 30 thermocouples from which the surface temperature can be measured and predicted burn injury calculated after exposure to flame (see below). To test a hood, it is placed on the manikin and engulfed in flame for specified periods of between 1 and 10 s. Thirty propane cup burners provide the flame, and the heat flux incident upon the manikin head when exposed to flame was determined by testing to be an average of 53 kW/m over the surface of the head, peaking at 85 kW/m. The data from the thermocouples were recorded electronically every second during, and for up to 60 s following, the flame engulfment. Heat flux incident
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upon the manikin surface (skin) was calculated from these data. Predictions of pain and tissue damage were made from the heat flux data using a model developed from human experiments (Stoll and Chianta, 1971; Stoll and Greene, 1959). The results are expressed in terms of the percentage of burn injury predicted as first degree (18), second degree (28) and third degree (38) burn injuries. This classification of burn injuries describes the depth of damage to the skin. In simple terms: . 18 – superficial reddening of the skin, which is painful but does not cause blistering. . 28 – damages the outer layers of skin with resultant blistering but without scarring. . 38 – full thickness burn, through the skin to the tissues below and results in scarring. Five examples of the new and the used hoods were tested at 2, 4, 6, 8 and 10 s of flame challenge, making 50 tests in total. The hoods were tested without a breathing apparatus (BA) mask or helmet and thus simulated the head protection available to the RN’s initial response fire fighting team (termed the “Attack Party”) who wear FR coveralls, fire fighting hoods and Probanw FR cotton gloves. To simulate the protection worn by the second initial fire fighting team (the “Attack BA Party”) the hoods should have been tested with a BA mask in situ, and for the full fire fighting team (the “Support Party”) with the further addition of the fire fighting helmet. However, an earlier study demonstrated that the level of protection afforded to the skin underneath the BA mask or the helmet was absolute and unaffected by any hood type up to the maximum 10 s flame challenge (House et al., 2000). Thus, the effect of wearing the BA mask or helmet could be predicted from the results of flame testing the hoods alone. This also avoided the requirement to undertake further testing that would have destroyed many expensive helmets and BA masks. Results The used fire fighting hoods appeared to be slightly “thinner” than the new samples. Also there was some evidence of staining of the used hoods, and they did seem to have lost some of their elasticity and shape. Following the flame testing, there was no evidence of significant shrinkage or “breakthrough” of the hoods. Breakthrough is the process by which the garment either shrinks and rips, or has holes burned through, exposing the underlying “skin”. The mean predicted total burn injuries (18, 28 and, 38) for the head is shown in Figure 1. Although 18 burns are painful they are not serious and recover quickly without lasting damage to the skin (sunburn is typically 18). The results for 28 and 38 injuries are shown in Figure 2.
As the hoods are often worn with a BA mask (Attack BA Party) or a BA Fire hood retains mask and helmet (Support Party) the 28 and 38 burn results have been fire protective recalculated by considering the protective effects of the mask and helmet. qualities The results are shown in Figures 3 and 4. Discussion There was no evidence of significant increase in the level of burn injury predicted, and hence the protection afforded by used compared to new hoods. There was no evidence that the used hoods charred more than new hoods, and no hood exhibited significant shrinkage or breakthrough. When significant shrinkage occurs, the air trapped between the hood and the head is squeezed out, the insulation is reduced, and the severity of burn injury increases. The fact that these hoods suffered neither of these effects demonstrates the effectiveness of the material at protecting against flame.
371
Figure 1. Mean (SD) head surface area with a predicted 18, 28 or 38 burn when new or used fire fighting hoods were exposed to flame (n ¼ 5)
Figure 2. Mean (SD) head surface area with a predicted 28 or 38 burn when new or used fire fighting hoods were exposed to flame (n ¼ 5)
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Figure 3. Mean (SD) head surface area with a predicted 28 or 38 burn when new or used fire fighting hoods and BA mask were exposed to flame (n ¼ 5)
Figure 4. Mean (SD) head surface area with a predicted 28 or 38 burn when new or used fire fighting hoods, BA mask and helmet were exposed to flame (n ¼ 5)
As expected, the level of total burn injury increased in proportion to the flame duration, with almost 100 per cent injury at the most severe flame challenge. When painful but non-serious 18 burn injuries are ignored, it can be seen that the more severe 28 and 38 injuries were restricted to approximately 50 per cent of the head surface area, after 10 s of flame. Fuel explosions have been assessed as lasting between 2 and 5 s with heat exposures ranging from 80 to 135 kW/m (Behnke, 1984). For a flame duration of 5 s, 28 and 38 injuries for those wearing the hood (without BA or helmet) would be restricted to around 15 per cent of the surface of the head. Most of the 15 per cent injury would be to the face around the nose and eyes, as this section is open and unprotected. In a real event (unlike a manikin) it is likely that the victim turning away, falling to the deck and/or covering the face with the hands would shield the face for at least part of the exposure.
When the protective effects of the BA mask are considered in the predicted Fire hood retains burn results, it can be seen that the level of expected 28 and 38 burn injuries falls fire protective to less than 10 per cent of the head surface area. This is decreased further to 5 qualities per cent when the effects of the helmet are also considered. The longest flame duration used in this study (10 s) is unlikely to occur in a fuel explosion (Behnke, 1984). However, personnel trapped within a compartment that has 373 just suffered a “flashover”, and is currently “fully involved”, may experience such an event. In this case, the protection afforded by the hoods, and the increasingly important protective effect of the BA mask and helmet was apparent. Even at this most severe challenge, the level of 28 and 38 injuries was restricted to only 10 per cent of the head surface area, which is considered easily survivable. It is likely that more prolonged flame duration would also be survivable, as the most vulnerable parts of the head (the face and the respiratory airways) are well protected by the BA mask. In no case was there any evidence that the protection afforded by the used hood was significantly less than the new hood. Conclusions The new-type RN fire fighting hood was again (House et al., 2000) shown to provide excellent protection against the most severe flame engulfment to which RN personnel might be exposed. There was no evidence that hoods that had undergone prolonged use and washing provided less protection than new hoods, despite appearing to be degraded. It was recommended that the new fire fighting hood could safely remain in-service. References Behnke, W.P. (1984), “Predicting flash fire protection of clothing from laboratory tests using second degree burn to rate performance”, Fire and Materials, Vol. 8 No. 2, pp. 57-63. House, J.R. (1997), “The effectiveness of RN protective clothing against burns”, Journal of Defence Science, Vol. 2 No. 2, pp. 205-12. House, J.R., Squire, J.D. and Staples, R. (2000), “Assessing fire protection afforded by a variety of fire-fighters hoods”, Proceedings of NOKOBETEF 6 and the 1st European Conference on Protective Clothing, 7-10 May, National Institute for Working Life, Stockholm, Sweden, pp. 296-9. Squire, J.D. (2000), “Development of a head flame testing system”, Proceedings of NOKOBETEF 6 and the 1st European Conference on Protective Clothing, 7-10 May, National Institute for Working Life, Stockholm, Sweden, pp. 296-9. Stoll, A.M. and Chianta, M.A. (1971), “Heat transfer through fabrics as related to thermal injury”, Transactions of New York Academy of Sciences, pp. 649-70. Stoll, A.M. and Greene, L.C. (1959), “Relationship between pain and tissue damage due to thermal radiation”, Journal of Applied Physiology, Vol. 14 No. 3, pp. 373-82.
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Modelling the indentation of fabric by differently shaped pinch grippers
374
H. Lin RIFLEX, School of Textiles and Design, Heriot-Watt University, Galashiels, UK
Received September 2003 Accepted January 2004
P.M. Taylor School of Mechanical and Systems Engineering, The University of Newcastle upon Tyne, Newcastle upon Tyne, UK
S.J. Bull School of Chemical and Advanced Materials, The University of Newcastle upon Tyne, Newcastle upon Tyne, UK Keywords Mathematical modelling, Textiles, Automation, Materials handling equipment Abstract Several pick-up devices have been proposed and invented for automated garment handling but a scientific understanding of picking up operation is incomplete. This paper is an extension of earlier studies into modelling the interaction of the performance of pinch gripper and the properties of flexible material (foam). Here, the relationship between the performance of pinch gripper (size and shape), external load, deformation and the properties fabric is investigated. The distributions of stress and strain within a fabric under differently shaped grippers (flat and curved) are revealed. The main factors affecting the first step of picking up action-two pegs pushing down on the top of fabric are identified. Experiments have been carried out on single- and multi-layer fabrics, and the accuracy of the models is demonstrated through comparison of the predicted results with the experimental data. This study is aimed towards optimisation of design of a gripper and providing knowledge for an intelligent grasping system of fabric handling.
Notation ¼ Young’s modulus ¼ height of sample ¼ half width of a rectangular indenter sx, sy ¼ normal components of stress parallel to x-, y- axes, respectively txy ¼ shear stress in the xy plane N ¼ external load
E h a
International Journal of Clothing Science and Technology Vol. 16 No. 4, 2004 pp. 374-393 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410538956
q v a0-a7 b
a, b R
¼ distributed load (N/2a) for a rectangular indenter ¼ displacement in y-direction ¼ integrating constants ¼ the contact half-length between a sample and a table ¼ experimental constants ¼ the radius of a cylindrical indenter
1. Introduction Industry wants to automate the manufacture of clothing and other textile-based products, which is extremely labour-intensive. Integration of robotics into the manufacturing process is expected to save significant time and money. While robot manipulation of rigid objects, such as auto parts, has
been thoroughly studied and is well understood. The automated manipulation of a highly flexible and complex material such as cloth still presents great challenges to robotics. Controlling a robot to properly handle and place a limp object has been still a difficult task and tremendous efforts have been made towards achieving this target. In this field, people are more interested in design grippers rather than in the fundamental research. For example, a variety of grippers such as pinching grippers (Dlaboha, 1981; Taylor et al., 1996), clamping grippers (Taylor, 1985), pin grippers (Parker et al., 1983), suction grippers (Kolluru et al., 2002; Taylor and Koudis, 1987), adhesive grippers (Monkman and Shimmin, 1991), and electrostatic grippers (Taylor et al., 1988; Zhang et al., 2000) have been researched and developed. However, the successes of every kind of gripper are very limited in some kinds of fabric. Recently, sensing technique has been used in gripper design for the grasping of fabric appeared to be successful and shown some potential (Ono et al., 1992; Paraschidis et al., 1995). But it can be seen, from their reports, that they have still long way to go for practical use in garment handling. It was realised that the deformable behaviour of textile materials would play a very important role in garment assembly. Programmable control system is incapable of dealing with the flexible material owing to its unpredictable, non-linear and complex mechanics behaviour. Consequently, effort is needed in exploring a new control algorithm. The new control algorithm will require the detailed knowledge about flexible material being manipulated that only simulation can provide. Modelling a cloth’s dynamic properties and predicting its motion in reaction to applied forces are critical to solve general control problem (Breen, 1996). However, this modelling work is a difficult task. One of the difficulties is due to the complex mechanics of textile materials, which appear non-linear, visco-elastic, history dependent and have large deformations, large strain and changes in boundary conditions. Another one is complex interaction between fabric properties, handling devices and environment. These difficulties have slowed down the progress in automation of garment assembly. The major task is to find an analytical model to enable control system to change grasping forces according to the properties of materials being handled. Recently, we have proposed two mathematical models for simulating the interaction of the performance of rectangular pinch gripper and cylindrical pinch gripper and the properties of flexible material (foam) using the elasticity theory for the first step of picking up action-peg pushing down onto a sample (Bull et al., 2003; Lin et al., 2003). The studies revealed that when the peg of the gripper pushes down on the top of sample, the pressure of the peg is divided into three stress components within the material, i.e. the normal stress along the height of the sample, the normal stress along the length of the sample and the shear stress. These stress components result in complex deformations, comprising compression, shearing, bending and tension. The deformations depend on the geometry of indenter, external load and the behaviour of material. In our another
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paper, an experimental study of the factors affecting indentation of fabric under a pinch gripper has shown that the structure of fabric is important for the interaction at the fabric/gripper interface. However, more important factor is the shape of indenter (Lin et al., 2004). These investigations (Bull et al., 2003; Lin et al., 2003, 2004) have provided a fundamental understanding of the first step of picking up operation by a pinch gripper for non-rigid materials, making it possible to simulate the whole fabric grasping operation. This study is to extend the model developed for simulating the relationship between the parameters of differently shaped gripper (flat and curved) and the properties of foam (Bull et al., 2003; Lin et al., 2003) to fabrics. The aim is to provide a theory foundation for a model-based control strategy that is used to pickup of fabric panels. In this paper, the first step of picking up of fabric (the peg pushing down onto the top of fabric) is researched, two mathematical models, describing the fields of stresses and displacements within fabrics under a flat and a curved pinch gripper, are presented to relate the performance of grippers to the behaviour of fabric being handled. The accuracy of the prediction is shown through comparing the theoretical results with experimental data. It is expected that the models may be used for providing a prediction of grasping forces of pinching gripper by means of inputting fabric mechanical parameters to the models and that the grasping forces will vary with any changes of those fabric mechanical parameters. 2. Charateristics of the problem The structure analysed is shown in Figure 1, a rectangular piece of fabric is compressed using a much smaller indenter (Figure 1(a), a rectangular indenter and Figure 1(b), a cylindrical indenter). From the viewpoint of mechanics, this problem studied has two main characteristics: (1) Complex deformations (compression, tension, shearing and bending) take place at different areas in the sample and have different changing trends (Bull et al., 2003; Lin et al., 2003) as a result of response to the area beneath the indenter is compressed and two ends are free to move. (2) Complex boundary conditions (changeable compressed region, changeable interfaces of indenter/sample and indenter/rigid support table) as another result of response to the size of the intenter is much smaller than that of the sample. In addition, the problem investigated involves some difficulties in mechanics analysis such as material non-linearities, contact non-linearities, large deformations and large strains. The most important difference between the present study and earlier studies (Bull et al., 2003; Lin et al., 2003) is that foam and fabric has different properties under a pinch gripper owing to different structures. The foam approximately follows bilinear behaviour (Bull et al., 2003), but fabrics show
Modelling the indentation of fabric 377
Figure 1. A schematic of the problem investigated
a strong non-linear behaviour. Typical stress-strain curves for single-layer and multi-layer fabrics are shown in Figures 2-5. They have similar shape, but behave different deformation mechanisms which have been analysed by de Jong et al. (1986) and Saunders et al. (1997), respectively.
3. Theoretical analysis 3.1 Assumptions A basic assumption to solve this kind of problem is that the material is assumed to be elastic, isotropic and homogeneous although there exists some
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Figure 2. A comparison between the modelled results and the test results for single-layer fabric compression by the rectangular indenter
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Figure 2.
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Figure 3. A comparison between the modelled results and the test results for multi-layer fabric compression by the rectangular indenter
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Figure 3.
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Figure 4. A comparison between the modelled results and the test data for single-layer fabrics by the cylindrical indenter
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Figure 4.
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Figure 5. A comparison between the modelled results and the test data for multi-layer fabrics by the cylindrical indenter
degree of anisotropy and inhomogeneity. Fabric assembly is continuous even though after two ends could lift as the indenter pushes down. 3.2 Development of models 3.2.1 Rectangular gripper case. 3.2.1.1 Stress distributions under a rectangular gripper. The functions of stress components of the foam compression by a rectangular gripper have been derived and their visual distribution fields have been displayed in our earlier developed model (Bull et al., 2003). Since these stress functions are independent of the detailed behaviour of materials, the loading and the boundary conditions of fabric compression are completely identical to the developed model. Hence, the functions of stress components developed can be used here to describe the stress distributions within the fabric pressed by the rectangular gripper. They are:
sx ¼
a0 3 a0 2 7a0 h h 2 a0 Nb N y þ y þ y þ 2 þ x 3hb 2 b2 10b 2 h 2 h 2 10b 2
sy ¼ a 0 þ
txy ¼
ða0 2 qÞ a0 a0 y 2 2 x 2 2 2 x 2y h b hb
a0 3 ða0 2 qÞ N x2 2y x 2 2 h h 3hb
ð1Þ
ð2Þ
ð3Þ
where a0 ¼ 3qa=2b: 3.2.1.2 The function of displacement. According to the results of experiment (Figures 2-5), the relationship between the stress and strain of fabric in compression is suggested for both single and multi-layer fabric: 1y ¼ al n sy þ b
ð4Þ
a and b are experimental constants which can be obtained by regression of the experimental compression data, their physical meaning will be discussed later. Using the following equation for sy (Bull et al., 2003): sy ¼ ða0 þ a2 xÞ þ ða1 þ a3 x 2 Þy
ð5Þ
For convenience, let A ¼ a0 þ a2 x 2 ; B ¼ a1 þ a3 x 2 Equation (5) can then be rewritten as:
sy ¼ A þ By According to the basic relationship between stress and strain proposed above and the elasticity theory (Timoshenko and Goodier, 1970):
Modelling the indentation of fabric 385
›v ¼ 1y ¼ a ln sy þ b ¼ a lnðA þ ByÞ þ b ›y
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ð6Þ
Employing the fact that the displacements of the sample in y-direction are zero at the bottom of the sample, i.e. y ¼ 0; 2b # x # b (Figure 1(a)), the function of displacement in the y-direction can be obtained by integrating equation (6) in the y-direction. Z y Z y ›v v¼ dy ¼ a ðlnðA þ ByÞ þ bÞdy 0 ›y 0 a ðA þ ByÞðlnðA þ ByÞ 2 1Þjy0 þ byjy0 B a A þ By A ¼ 2 A ln þ by ðA þ ByÞln e e B ¼
that is v¼
a a1 þ a2 x 2 þ ða1 þ a3 x 2 Þy 2 2 þ a x þ ða þ a x Þy ln a 0 2 1 3 a1 þ a3 x 2 e ð7Þ
a1 þ a2 x 2 2ða1 þ a2 x 2 Þln þ by e
The boundary conditions here are completely identical to the developed model (Bull et al., 2003), hence, the integrating constants in equation (7) are a0 ¼
3qa ; 2b
a1 ¼
a0 2 q ; h
a2 ¼ 2
a0 ; b2
a3 ¼ 2
a0 hb 2
3.2.2 Cylindrical gripper case. 3.2.2.1 Stress distributions under a cylindrical gripper. In the case of fabric compression by the cylindrical indenter, the boundary conditions are the same as the developed model (Lin et al., 2003) which was derived for a cylindrical indenter pressing a much larger foam block. Therefore, the stress fields of fabric compression by the cylindrical indenter can be described by the following equations (Lin et al., 2003) N 2Rha0 þ E 3 3N 3 3a0 R þ 3E 3Nh Nb sx ¼ 2 x 2 y þ 3y þ þ 3 y2 2 h 6Rh 2 4b 20R 4b h ð8Þ 2Rh 2 a0 þ hE Nh 2 þ þ 3 30R 8b
sy ¼
3N a0 Ea 2 3N 2 a0 E y 2 x 2y x þ þ 2 þ 4b 4b 3 h 2Rh 2 h 2Rh 2
txy ¼
Ea 2 a0 1 a0 E N þ 2 x3 2 2 y x2 3 h 2Rh 2 h 2Rh 2 h
ð9Þ
ð10Þ
where a0 ¼ 3N =4b: 3.2.2.2 The function of displacement. For fabric compression under the cylindrical indenter, the stress-strain relationship still follows equation (4) (Figures 4 and 5). The boundary conditions are the same as the developed model (Lin et al., 2003). Therefore, the functions of displacement for fabric compression can be obtained by substituting the integration constants which were derived in the developed model for foam compression by a cylindrical indenter into equation (7): a a1 þ a2 x 2 þ ða1 þ a3 x 2 Þy 2 2 V¼ ða0 þ a2 x þ ða1 þ a3 x ÞyÞln e a1 þ a3 x 2 ð11Þ 2 a1 þ a2 x 2ða1 þ a2 x 2 Þln þ by e where a0 ¼
3N ; 4b
a1 ¼
a0 Ea 2 ; 2 h 2Rh 2
a2 ¼ 2
3N ; 4b 3
a3 ¼
a0 E þ h 2Rh 2
3.3 Contact problem The contact problem for a sample, resting on a rigid base, onto which an external load is applied through the rigid rectangular indenter with sharp corners or the cylindrical indenter have been analysed by our earlier studies (Bull et al., 2003; Lin et al., 2003). Here, the solutions derived for the specific compression are extended to fabric compression for the rectangular indenter and the cylindrical indenter. They are given below. (1) The contact width “a” between a sample and a cylindrical indenter (Figure 1(b)) can be given by the Hertz elastic contact equation ( Johnson, 1987) rffiffiffiffiffiffiffiffiffiffiffi 4 4PhR a¼ ð12Þ pE and contact pressure is also given by the Hertz equation ( Johnson, 1987)
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pðxÞ ¼
E ða 2 2 x 2 Þ 2Rh
ð13Þ
(2) The contact width “b” between a sample and a table for the rectangular indenter (Figure 1(a)) can be determined from the following equation (Bull et al., 2003) 221h 2 a 2 50ab 2 þ 40b 3 ¼ 0
ð14Þ
(3) The contact width “b” between a sample and a table for the cylindrical indenter (Figure 1(b)) can be determined using the equation (Lin et al., 2003) 1 1 2 a3 b 2 2 a7 2 a1 ¼ 0 6 2
ð15Þ
where a0 ¼
3N ; 4b
a7 ¼
3a3 h 2 2 a2 h 10
a1 ¼
a0 Ea 2 2 ; h 2Rh 2
a2 ¼ 2
3N ; 4b 3
a3 ¼
a0 E þ ; h 2Rh 2
Comparing equation (14) with equation (15), the following conclusions can be drawn. The width of the contact area between the sample and the rigid substrate is independent of the magnitude of the compressive load applied to the sample for the rectangular indenter. It is only a function of the width of an indenter and the thickness of a sample. In the cylindrical indenter problem, however, the size of this contact region is not only a function of radius of the indenter and the thickness of the sample, but is also a function of the magnitude of the external load. This is in agreement with the contact studies of Ratwani and Erdogan (1973). 3.4 The physical meaning of a and b Equations (7) and (11) contain two important constants a and b, their physical meaning is discussed as follows. Figure 6 shows that b only affects the amount of displacement of a 15-layer stack of wool twill fabric in compression. Similar curves are obtained for different fabrics investigated. The shape of the compression curves is unaffected by b, which means b is independent of the properties of the material.
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Figure 6. Relation between constant b and curve of compression for 15-layer wool twill cloth
a, controls the shapes of compression curves of fabric as shown in Figure 7, indicating it is dependent on the fabric properties. If the value of a becomes small (Figure 7(a)), the radius of curvature becomes large, then the amount of inter-yarn and/or inter-fibre slippage becomes large. As a result, the fabric becomes soft in compression. If the value of a is large (Figure 7(c)), vice versa. So, a is concerned with hardness in compression because of the friction between fibres. It indicates the nature of the compression of fabrics and it is an important characteristic value for understanding fabric compressional property. 4. Experimental 4.1 Experimental procedure The experiments were performed on a purpose-built compression tester. The rectangular indenter has dimensions of 60 £ 15 £ 10 mm (length, width, height) and the cylindrical indenter has sizes of 60 £ 15 mm (length and radius). The indenter is driven downwards by a stepper motor to apply pressure on a fabric specimen with a size of 60 £ 40 mm. The displacements of the indenter compressing a sample can be measured using an inductive sensor, corresponding loads are recorded with a load cell (the measuring range is 0.05-200 N) within 5 s each increase in displacement to minimize the effects of creep. Each test was repeated five times with a new sample. All the experiments were conducted at standard laboratory air conditions, i.e. the temperature is 20^18C, and the relative humidity is 65 ^ 3 per cent. 4.2 Sample Three different types of weave: plain, twill and satin, and three different kinds of fibre: cotton, polyester and wool were used in the present study. Their
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Figure 7. Experimental compression curves for different structures of single-layer polyester fabrics
specifications are given in Table I. All the samples have a size of 60 £ 40 mm. During the lay-up stage for multi-layer fabric testing, fabric samples were laid up by aligning warp-to-warp and weft-to-weft matched as best as possible from one layer to the next by eye (Figure 8). All the fabrics used for the study are commercially produced and widely used in garments.
5. Results and discussion 5.1 Rectangular gripper case Figure 2 shows a comparison of the data from equation (7) with the results determined by experimental measurement for single layer fabrics. Figure 3 is for multi-layer fabrics. From the two figures, the following conclusions can be drawn. . The results from the model are quite close to the measured data at the first stage and second stage of fabric compression for both single-layer and multi-layer fabrics. There are some divergences between the model and the experiment results at the last stage of compression, which may be explained that model cannot characterize the “incompressible inner core” compression (de Jong et al., 1986). The gaps could be reduced if the inner core is subtracted from the total thickness of the sample. . When a comparison of the results of same fabric with different layers is made, it can be observed that the predicted results for several layers are closer to the test data than that of single layer. This is due to the fact
Material 100 100 100 100 100 100
per cent per cent per cent per cent per cent per cent
Structure cotton cotton polyester polyester polyester wool
Plain Twill Plain Twill Satin Twill
Area density (g/m2)
Thickness at 0.5 cN/cm2 (mm)
Fabric count warp/weft (Thread/cm)
173 517 59 199 130 208
0.63 1.034 0.11 0.68 0.38 0.52
16/13 19/17 15/15 12/11 26/22 14/13
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Table I. Specifications of sample
Figure 8. A schematic of fabric compression by the rectangular indenter
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that the more the layers, the softer the clothes will be. As a result, the proportion of deformation in the first stage and second stage of compression will be larger. 5.2 Cylindrical gripper case An acceptable predictive accuracy has been obtained for most fabrics especially in the first stage of compression. Similar to the rectangular indenter case, the “incompressible inner core” causes the bigger gaps between the analytical results and the measurement data at the last stage of compression. Better results seem to be achieved on smooth surface fabrics such as cotton twill or polyester fabrics. Again, relatively speaking, a smaller deviation can be observed between the modelled results and the measured data on multiple fabric layers (Figure 5). 6. Conclusions Two 2D models have been established for not only solving the stress-strain relationship of fabric pressed by differently shaped pinch gripper, but also linking this to the parameters of grippers. The downward pressure of pegs can be adjusted systematically to the properties of material being grasped based on this model in an intelligent grasping system. On the other hand, the models have predicted some kind of scientific values, for example, what is happening within the fabrics when an indenter pressing them has been revealed, which are useful in understanding the gripping operation and creating a more desired gripper. The important relationship of variables in the first stage of picking up action has been found to be material properties, a, indenter geometry and external load. Further investigation of picking-up of fabric panels can be possible based on this modelling work. The distributions of stress and strain under the gripper are crucial to the success of the subsequent picking operation. The models developed have analysed stress and strain states of fabric panels before buckling – the second stage of picking up action, which makes it possible to deal with the boundary conditions of buckling. Furthermore, although the mathematical models have been developed for static grasping analysis, they could be suitable for dynamic grasping operation at high speed too since viscose effects are minimal in the measurements performed in the study (Lin et al., 2004), but this needs to be confirmed by further experiments. References Breen, D.E. (1996), “Computer graphics in textiles and apparel modelling”, IEEE Computer Graphics and Applications, pp. 26-7. Bull, S.J., Taylor, P.M. and Lin, H. (2003), “Modelling of contact deformation for pinch gripper in automated material handling”, Journal of Materials Design and Applications, Proc. IMECHE, Part L.
Dlaboha, I. (1981), “Cluett’s clupicker enhances robot’s ability to handle limp fabric”, Apparel Word, Knitting Times. Johnson, K. L. (1987), Contact Mechanics, Cambridge University Press, London, p. 105. de Jong, S., Snaith, J.W. and Michie, N.A. (1986), “A mechanical model for the lateral compression of woven fabrics”, Textile Research Journal, Vol. 56 No. 12, pp. 759-67. Kolluru, R., Valavanis, K.P., Smith, S. and Tsourveloudis, N. (2002), “An overview of the University of Louisiana robotic gripper system project”, Transaction of the Institute of Measurement and Control, Vol. 24 No. 1, pp. 65-84. Lin, H., Taylor, P.M. and Bull, S.J. (2003), “A mathematical model for grasping analysis of flexible materials”, Modelling and Simulation in Materials Science and Engineering. Lin, H., Taylor, P.M. and Bull, S.J. (2004), “An experimental study of the factors affecting the indentation of fabric under a pinch gripper”, International Journal of Clothing Science and Technology. Monkman, G.J. and Shimmin, C. (1991), “Use of permanently pressure-sensitive chemical adhesive in robot gripping devices”, International Journal of Clothing Science and Technology, Vol. 1 No. 3, pp. 14-20. Ono, E., Ichijo, H. and Aisaka, N. (1992), “Flexible robotic hand for handling fabric pieces in garment manufacture”, International Journal of Clothing Science and Technology, Vol. 4 No. 5, pp. 16-23. Paraschidis, F., Fahantidis, N., Petridis, V., Doulgeri, Z., Petrou, L. and Hasapis, G. (1995), “A robotic system for handling textile and non rigid materials”, Computer in Industry, Vol. 26, pp. 303-13. Parker, J.K., Dubey, R., Paul, F.W. and Becker, R.J. (1983), “Robotic fabric handling for automating garment manufacturing”, Journal of Engineering for Industry, Vol. 105 No. 21. Ratwani, M. and Erdogan, F. (1973), “On the plane contact problem for a frictionless elastic layer”, International Journal of Solids Structures, Vol. 9, pp. 921-36. Saunders, R.A., Lekakou, C. and Bader, M.G. (1997), “Compression and microstructure of fibre plain woven cloths in the processing of polymer composites”, Composites Part A, Vol. 29A, pp. 443-54. Taylor, P.M. (1985), “Hull automated fabric handling project”, Knitting International, pp. 88-9. Taylor, P.M. and Koudis, S.G. (1987), “Automated handling of fabrics”, Sci. Pro. Oxf., Vol. 71, pp. 351-63. Taylor, P.M., Mokman, G.J. and Taylor, G.E. (1988), “Electrostatic grippers for fabric handling”, Proc. IEEE Conf. on Robotics and Automation, Philadelphia, pp. 431-3. Taylor, P.M., Pollet, D.M. and Grießer, M.T. (1996), “Pinching grippers for secure handling of fabric panels”, Assembly Automaton, Vol. 16 No. 3, pp. 16-21. Timoshenko, S.P. and Goodier, J.N. (1970), Theory of Elasticity, 3rd ed., McGraw-Hill, New York, NY, p. 32. Zhang, Z.W., Chestney, J.A. and Sarhadi, M. (2000), “Characterizing an electrostatic gripping device for the automated handling of non-rigid materials”, Proc. Inst. Mech. Eng., Vol. 215, Part B, pp. 21-36.
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Impact of laundering on the seam tensile properties of suiting fabric A. Mukhopadhyay and M. Sikka
Received 11 November 2003 Accepted 24 February 2004
Department of Textile Technology, National Institute of Technology, Jalandhar, India
A.K. Karmakar Mahavir Spinning Mills Limited, Hosiarpur, India Keywords Fabric testing, Thread, Tensile strength, Laundry equipment Abstract This paper reports an experimental investigation into the effect of laundering on seam tensile properties with the variation of stitch density, linear density of sewing threads and composition of base material. Tensile properties such as initial modulus, secant modulus, seam strength, strain at fracture and work up to fracture increase with stitch and linear density of sewing threads. The impact of coarser yarn is greater on seam properties of polyester-cotton fabric than cotton fabric. The tensile properties except seam strain are reduced due to laundering. Reduction in initial modulus and secant modulus due to laundering is higher for polyester-cotton fabric whereas decrease in seam strength, seam efficiency and strain at break is greater for coarser sewing thread.
International Journal of Clothing Science and Technology Vol. 16 No. 4, 2004 pp. 394-403 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410538965
Introduction Seam quality is an important parameter deciding the performance of garment. The development and selection of sewing threads to give better seam performance requires understanding of the effects of the physical and mechanical properties of sewing threads (Ukponmwan et al., 2000). The quality and performance of a sewn garment depends on various factors such as seam strength, slippage, puckering, appearance and yarn severance (Carr and Latham, 1994; Dorkin and Chamberlain, 1961). A number of studies reveal the interaction of various factors on seam performance (Ukponmwan et al., 2000). Mechanical performance of the seam can be judged by seam modulus, strength, elongation and work of rupture. Failure of a seam makes a garment unusable even though the fabric may be in good condition. Further, seam modulus influences the ease of deformation of the fabric at the place of seam. Since in the lifetime of a garment, both cloth and seam undergo repeated laundering, quality and performance of sewn product might change. Seam performance after laundering is important to adjudge the suitability of a sewn product. This particular study is therefore, aimed at understanding the impact of laundering on seam tensile properties influencing its mechanical performance with the variation of stitch density and the type of fabric sewn.
Experimental Three different three-plied polyester sewing threads are used for making seam. The physical and mechanical properties of the threads are presented in Table I. Since warp seams are more important to overall garment performance, only warp seams are investigated. Two types of suiting fabric differing in material composition (cotton and polyester-cotton blend), but same in construction (three up one down twill) with similar end and pick density are used for making seam with three types of threads. An industrial lockstitch machine is used for joining the fabric. The tensile properties of seam and fabrics are evaluated using ZWICK universal tester (model 1441) following ASTM standard (D 1683-90a). Load on the test specimen is applied at right angles to the direction of stitching. During loading at constant rate of extension, jaw speed up to the preload of 200 cN is set at 50 mm/min and thereafter speed of 300 mm/min is kept up to the breaking point. The following parameters are evaluated: . initial modulus (up to 3 per cent strain), . secant modulus (3-5 per cent strain), . seam strength, . per cent extension at fracture, . seam efficiency (per cent seam strength over fabric strength), and . work up to fracture.
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The above properties are measured before and after laundering of test specimen. The fabrics with and without seam are subjected to laundering process in a domestic twin-tub washing machine as per the ASTM standard (D 13-1950) using 0.5 g/l solution of non-ionic detergent Vaptex 1535 (96 per cent). All the specimen are given six laundering cycles in normal temperature which is followed by drying in the open space during day light. The properties of fabric before and after laundering are given in the Table II. Results and discussion Seam properties of fabric made from cotton and polyester-cotton are measured and the results are presented in the Tables III and IV. The changes that
Thread linear density (tex) 26.5 32.5 39.5
Twist factor (turns/cm £ tex1/2)
Modulus at 1 per cent elongation (N/tex)
Load at 1 per cent elongation (cN)
46.8 46.3 47.1
2.61 2.72 2.78
69.2 88.4 109.8
Extension Breaking Tenacity at break load (N) (cN/tex) (per cent) 0.906 1.212 1.505
34.2 37.3 38.1
14.8 15.1 15.4
Table I. Physical and mechanical properties of sewing threads
Table II. Fabric specification for 3/1 twill weave of different constituents
Cotton before wash Cotton after wash Polyester – cotton (65 : 35) before wash Polyester – cotton (65 : 35) after wash
Fabric type
396
21.2 22.4 22.0 22.4
47.2
48.0
48.0
48.8
29.5/2
29.5/2
29.5/2
29.5/2
59.1/2
59.1/2
59.1/2
59.1/2
9.5
9.2
5.0
4.9
13.5
13.2
13.0
12.8
307
298
290
281
11.62
20.73
3.26
3.54
20.74
32.32
7.90
8.49
35.8
36.2
25.6
26.2
34.8
32.8
23.5
22.9
Yarn count Crimp Strain at Fabric Initial modulus Secant modulus Thread density (tex) (per cent) weight at 0-3 per cent at 3-5 per cent Strength fracture 2 Ends/cm Picks/cm Warp Weft Warp Weft (g/m ) strain (cN/tex) strain (cN/tex) (kN/m) (per cent)
22.91
23.92
7.44
8.95
Work up to fracture (Nm)
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Cotton fabric unwashed
Fabric
39.5
32.5
26.5
39.5
32.5
26.5
Fineness (tex)
29.5 33.5 37.5 29.5 33.5 37.5 29.5 33.5 37.5
29.5 33.5 37.5 29.5 33.5 37.5 29.5 33.5 37.5
Stitch density (stitches/ 10 cm)
2.00 2.39 2.45 2.20 2.89 3.01 2.31 3.01 3.22
2.27 3.04 3.18 2.32 3.25 3.40 2.54 3.51 3.61 4.01 4.56 4.70 4.51 4.89 4.99 4.88 5.14 5.23
4.16 5.08 5.19 4.89 4.97 5.90 5.10 5.26 6.30 1.18 1.40 1.62 1.48 1.71 2.15 1.89 2.16 2.32
1.50 1.93 2.29 2.32 2.71 2.91 2.98 3.20 3.54
Seam modulus at 0-3 Secant modulus at 3-5 Strength per cent strain (cN/tex) per cent strain (cN/tex) (kN/m)
4.61 5.47 6.33 5.78 6.68 8.40 7.38 8.44 9.06
5.73 7.37 8.74 8.85 10.34 11.11 11.37 12.21 13.51
Seam efficiency (h) (per cent)
8.51 9.72 10.13 9.51 11.53 12.12 12.24 13.11 14.22
7.82 8.91 9.32 8.92 10.54 11.61 11.15 12.32 13.21
Strain at fracture (per cent)
0.33 0.38 0.48 0.41 0.49 0.58 0.50 0.59 0.67
0.44 0.49 0.61 0.54 0.60 0.69 0.66 0.71 0.78
Work up to fracture (Nm)
Impact of laundering
397
Table III. Seam properties of cotton fabrics before and after laundering
Table IV. Seam properties of polyester-cotton fabrics before and after laundering
Polyester-cotton fabric laundered
Polyster-cotton fabric unwashed
39.5
32.5
26.5
39.5
32.5
26.5
29.5 33.5 37.5 29.5 33.5 37.5 29.5 33.5 37.5
29.5 33.5 37.5 29.5 33.5 37.5 29.5 33.5 37.5 3.81 5.01 5.55 4.24 5.88 6.12 5.91 6.72 7.13
5.80 6.54 6.62 6.24 7.13 7.44 6.48 7.83 8.12 7.24 9.21 10.81 8.61 10.21 12.80 9.61 10.90 13.90
10.98 11.89 12.53 12.28 13.28 14.80 13.12 14.63 15.33 1.39 1.54 2.04 1.54 1.94 2.42 1.81 2.02 2.51
2.02 2.23 2.67 2.81 3.12 3.88 3.23 3.66 4.65 3.88 4.30 5.70 4.30 5.42 6.76 5.06 5.64 7.01
5.58 6.16 7.38 7.76 8.62 10.72 8.92 10.11 12.85
13.01 14.92 16.33 14.61 16.21 17.32 15.52 16.82 17.83
12.52 14.23 15.75 13.45 15.11 16.21 14.22 15.91 16.90
0.38 0.45 0.55 0.42 0.51 0.62 0.56 0.62 0.71
0.48 0.51 0.66 0.58 0.63 0.71 0.72 0.79 0.81
Strain at Secant modulus at 3-5 Strength Seam efficiency fracture Work up to per cent strain (cN/tex) (kN/m) (h) (per cent) (per cent) fracture (Nm)
398
Fabric
Fineness Stitch density Seam modulus at 0-3 (tex) (stitches/10 cm) per cent strain (cN/tex)
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occurred in the seam properties with the change in the stitch density for different counts of sewing thread and for the two types of fabric before and after laundering are reflected in the tables. Figures 1-6 show the effect of stitch density, fabric type and laundering on seam properties of fabric sewn with 26.7 tex sewing thread. Effect of stitch density It is observed that the effect of stitch density on the tensile properties of seam is very significant. Initial and secant moduli increase with the increase in stitch density (Figures 1 and 2). Since higher stitch density provides better gripping of the two specimens, the stitched specimen shows higher modulus during loading. It is also seen that both seam strength and seam efficiency increase with the increase in stitch density (Figures 3 and 4). It is noted that seam failure occurs significantly at much lower tenacity and strain at fracture of fabric
Impact of laundering
399
Figure 1. Effect of stitch density on seam initial modulus
Figure 2. Effect of stitch density on seam secant modulus
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Figure 3. Effect of stitch density on seam strength
Figure 4. Effect of stitch density on seam efficiency
Figure 5. Effect of stitch density on seam strain at fracture
Impact of laundering
401 Figure 6. Effect of stitch density on seam work up to fracture
(Tables II-IV). This indicate greater role of sewing threads and stitching parameter towards failure of seam. At higher stitch density, modular length (length of yarn between the two stitches) decreases which leads to higher value of seam strength. Further in all the cases, the strain at fracture increases with the increase in stitch density (Figure 5). This can be explained as fabric extension becomes higher at higher breaking load for the seam stitched with higher stitch density. Since both strength and strain at fracture of seam increase with the increase in stitch density, work up to fracture, which measures the energy required to break the specimen, follows an increasing trend with the increase in stitch density (Figure 6). Effect of count of sewing thread It has been observed from Tables III and IV that initial and secant moduli of fabric sewn with finer yarn is lower as compared to the fabric sewn with coarser yarn. This can be explained since coarser yarn possesses higher moduli than finer yarn (Table I). In fact, the load at 1 per cent strain is a more relevant parameter, which is much higher in case of coarser yarn than finer yarn. It is also seen that the seam strength and seam efficiency of the fabric stitched with coarser yarn is higher than the fabric stitched with finer yarn. This is attributed to higher breaking load of coarser yarn than finer yarn (Table I). The above observation is valid for both unwashed and laundered fabrics. Higher value of seam strain at fracture in case of seam stitched with coarser yarn can be explained in a similar way as earlier describing the effect of stitch density. It is noted that marginal difference exists among the extension at break of sewing threads indicating the significant role of fabric extension on the above characteristics. Further, since both seam strength and elongation increase with yarn thickness, work of rupture of seam is higher for coarser yarn than that of finer yarn (Tables III and IV).
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Effect of fabric composition It is found that in all cases initial properties of seam such as initial and secant moduli are higher for polyester-cotton fabric than 100 per cent cotton fabric (Tables III and IV). This indicates that apart from the sewing thread quality, fabric properties play an important role. Since polyester-cotton fabric possesses higher modulus, seam modulus also gets affected. In general, the difference of initial modulus between cotton and polyester-cotton is higher for fabric sewn with coarser yarn. The above observation also holds good in case of secant modulus, seam strength and strain at fracture. This indicates that the coarser yarn has greater impact on polyester-cotton fabric than cotton fabric. The above findings may be attributed to bulkier and resilient polyester fibre component in the fabric leading to better gripping of coarser yarn with polyester-cotton fabric. However, seam efficiency of cotton fabric is higher than polyester-cotton fabric. In the present context, since fabric strength is much higher than seam strength, comparison of two different seams in terms of seam performance does not have much relevance. Higher seam efficiency in case of cotton fabric is merely due to lower strength of the said fabric than polyester fabric. In case of two different types of fabrics stitched with same sewing thread, the impact on seam strength is small as compared to the effect on seam initial modulus. However, seam strain at fracture gets affected substantially, indicating the contribution of fabric. This is due to the difference in extension of two fabrics at the load at which failure of seam occurring. For the same fabric stitched with different sewing threads, the effect on seam strength is greater. Effect of laundering It has been observed from Tables III and IV and Figure 1 that the initial modulus of sewn fabrics is reduced after laundering. However, reduction is more in case of polyester-cotton blended fabrics. Same has been observed in the case of secant modulus (Figure 2). The above observation is true for all count of sewing thread. The above result is influenced by the initial modulus of fabric which reduces substantially particularly for polyester-cotton fabric (Table II). Seam strength and seam efficiency decrease after laundering (Figures 3 and 4). This reduction is more for coarser yarn. This can be explained as coarser yarn due to its greater surface is susceptible to greater damage than finer yarn. However, even after laundering strength of seam stitched with coarser yarn is higher than the seam stitched with finer yarn. Further, no common trend in reduction is observed with the change in stitch density. It has been observed that although seam strength reduces, but seam strain at fracture of seam is increased marginally after laundering the specimen at all stitch densities. Here, it reflects the predominant role of fabric extensibility, which increases after wash. Lower value of initial and secant modulus of fabric
after laundering is indicative of higher extensibility (Table II). Further, it is seen that work up to fracture is reduced after laundering. However, the increase in strain at fracture and decrease in work of rupture do not follow any specific trend with the change in count, stitch density and type of fabric sewn.
Impact of laundering
Conclusions Effect of stitch density, count of sewing threads, fabric composition and laundering on seam tensile properties of suiting fabric are very significant. All the seam tensile properties such as initial modulus, secant modulus, seam strength, strain at fracture and work up to fracture increase with the increase in stitch density and linear density of sewing threads. Coarser yarn has greater impact on seam properties of polyester-cotton fabric than cotton fabric. Both initial and secant moduli are reduced after laundering; the reduction being greater in polyester-cotton blended fabric. Decrease in seam strength and seam efficiency due to laundering is greater for coarser sewing threads. The observation indicates greater role of fabric composition influencing initial and secant moduli of seam, whereas impact of linear density of sewing threads on fabric ultimate behaviour is large. Further, seam strain at fracture is increased marginally, but work of rupture reduces after laundering.
403
References Carr, H. and Latham, B. (1994), The Technology of Clothing Manufacture, 2nd ed., Blackwell Science, Oxford, pp. 113-35. Dorkin, C.M.C. and Chamberlain, N.H. (1961), Clothing Institute Technical Report No. 11. Ukponmwan, J.O., Mukhopadhyay, A. and Chatterjee, K.N. (2000), Sewing Threads, Textile Progress, Vol. 30 Nos 3/4, The Textile Institute, UK.
The Emerald Research Register for this journal is available at www.emeraldinsight.com/researchregister
IJCST 16,5
418 Received November 2003 Revised March 2004 Accepted March 2004
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Contributions of in-plane fabric tensile properties in woven fabric bagging behaviour using a new developed test method R. Abghari Department of Textiles, Science and Research Campus of Azad University, Tehran, Iran
S. Shaikhzadeh Najar Department of Textile Engineering, AmirKabir University of Technology, Tehran, Iran
M. Haghpanahi Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
M. Latifi Department of Textile Engineering, AmirKabir University of Technology, Tehran, Iran Keywords Force, Fabric testing, Tensile strength Abstract To investigate the relation of in-plane fabric tensile properties with woven fabrics bagging behavior, a new test method was developed and a real time data acquisition and strain gauge technique were used. The bagging procedure was carried out while the woven fabric tensile deformations along warp and weft directions were measured. The fabric bagging behavior was characterized by bagging resistance, bagging fatigue, residual bagging height and residual bagging hysteresis. The experimental results show that the bagging load, work, hysteresis, residual hysteresis and fatigue are highly linearly correlated with corresponding parameters in warp and weft directions. An empirical relationship obtained between residual bagging height and bagging fatigue and resistance (R2 ¼ 0.83) suggests that the proposed new test method is able to evaluate bagging behavior of fabrics.
International Journal of Clothing Science and Technology Vol. 16 No. 5, 2004 pp. 418-433 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410554615
1. Introduction Garment-bagging concept is a type of residual deformation that usually occurs in knee, elbow and backside under the influence of a normal force perpendicular to fabric surface. In order to evaluate garment bagging performance, several research works have been investigated and several test methods have been developed (Gurnewald and Zoll, 1973; Kirk and Ibrahim, 1966; Ucar et al., 2002; Yokura et al., 1986; Zhang et al., 1997a, b, 1999a, b, 2000a, b, c; Kisiliak, 1999). Gurnewald and Zoll (1973) attempted to investigate the fabric bagging mechanism and a good correlation between The authors wish to express their gratitude to Department of Textiles, Science and Research Campus of Azad University for providing experimental facilities and financial supporting for this research.
the experimental results and those observed in practice was obtained. Yokura et al. (1986) proposed a system to predict the objective evaluation of bagging propensity of woven fabric. The authors used the volume of the bagged fabric as a measure of the bagging propensity. Zhang et al. (1997b) reported the factors influencing bagging behavior of fabrics by analyzing statistically the bagging characteristics of different woven fabrics. In their research, fabric bagging behavior was characterized by bagging resistance, bagging fatigue and residual bagging height. To measure the bagging properties, a test method using Instron 4466 was developed by the authors. Zhang et al. (1997a, 1999a, b) also studied the fabric bagging mechanism. They developed a test method to subjectively evaluate fabric bagging perception by using a series of photographs taken from bagged fabric samples and compared the results with residual bagging height. In other research, they described the physical mechanism of fabric bagging by developing an equation to describe the fatigue process in terms of fabric internal energy decay. Kisiliak (1999) developed a new modified apparatus for testing the spherical deformation of fabric in elbow and knee. Zhang et al. (2000a) simulated the bagging deformation through the rheological behavior of fabric bagging. Kisiliak (1999), Ucar et al. (2002) and Zhang et al. (2000b, c) also continued their studies and described bagging properties of fabric according to the bagging test method reported earlier. It is reasonable to conclude that the above-mentioned methods are limited because they can only measure the fabric bagging load while a constant tension is applied to the fabric sample. Kawabata et al. (1973) pointed out that fabric deformation on the knees may consist of biaxial tension and shearing. Zhang et al. (2000c) theoretically investigated the stress distribution in isotropic and anisotropic fabrics and related the bagging force to internal stresses in fabric section. They showed that for an anisotropic fabric the internal stresses were distributed non-uniformly between the warp and weft yarns. However, there is no published work to experimentally investigate the contributions of in-plane fabric tensile properties in bagging behavior of woven fabrics. Therefore, the aim of this work is to investigate the bagging behavior of woven fabrics while in-plane fabric tensile stresses two main warp and weft directions are measured using a new developed test method. 2. Experimental 2.1 Fabric bagging tester To investigate the relation of in-plane fabric tensile properties with woven fabric bagging behavior, a new test method different from that of Zhang et al. (Denton, 1972; Ucar et al., 2002) is developed. A photograph of the bagging tester is shown in Figure 1. It can be seen that the fabric-bagging tester has three load cells. One load cell (BSA S-beam, 10 kg) stands in vertical direction and the other two load cells (FAK single point, 10 kg) stand horizontally in plane of fabric. The load cell in vertical direction measures the compression force of fabric same as normal force of knee inserting to fabric. Other two-load cells measure in-plane fabric tensile forces similar to those of forces developed in sides of fabric in knee zone. In this work, in order to simulate the actual conditions of garment bagging formation in different clothing positions a rectangular clamp with four jaws is developed which differs in shape and size from that of Zhang et al.(Denton, 1972; Ucar et al., 2002). In earlier works (Denton, 1972; Ucar et al., 2002), the fabric sample
In-plane fabric tensile properties in woven fabric 419
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Figure 1. A typical picture of fabric bagging tester
with a diameter of 135 mm is placed in a circular clamp with an inner diameter of 56 mm. The fabric is then deformed by a steel ball with a diameter of 48 mm. It may be considered that the size of the circular clamp used by workers (Ucar et al., 2002; Denton, 1972), is too closed to that of steel ball leading to a high bagging load and consequently, a high bagging pressure much higher than the discomfort level of clothing pressure was found (Kirk and Ibrahim, 1966) to be between 60 and 100 g/cm2. As shown in Figure 1, it can be seen that two jaws are connected to load cells and other two jaws can be moved in plane of fabric under a screw control system. A sphere (steel ball) is fixed to the crosshead of the bagging tester, which can be moved downwards in vertical direction. The size of sphere can be changed corresponding to different size of knee and elbow. The speed and motion direction of the crosshead can be controlled so that it is possible to have the cyclic loading. When the sphere contacts the fabric sample, it exerts pressure on the fabric clamped by jaws. In this way, the vertical load cell measures the compression force developed due to the contact of fabric and sphere. The output data in real time are transferred to a PC using the data acquisition system. To store and analyze the data, special software is developed using DELPHI programming language. Some typical figures of the program menu are shown in Figures 2 and 3. In Figure 2, fabric bagging force together with tensile forces in plane of fabric are plotted against time in a five cyclic loading. The hysteresis curves diagram for fabric bagging deformation is shown in Figure 3. 2.2 Experimental procedure In this research, 18 different woven twill worsted and plain cotton/polyester shirt fabrics as listed in Table I were used. To investigate the bagging behavior of woven fabrics, a fabric sample was placed in a rectangular clamp with inner dimensions of 24 £ 17 cm: The fabric sample is clamped by four jaws with a precise pretension. using
In-plane fabric tensile properties in woven fabric 421
Figure 2. A typical diagram of force – time for five cyclic loading
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Figure 3. A typical diagram of force – traverse for five cyclic loading
Fabric A B C D E F G H I J K L M N O P Q R
Construction
Fibers content
Twill Twill Twill Twill Twill Twill Plain Twill Twill Plain Plain Plain Plain Plain Plain Plain Plain Plain
W45 P55 W45 P55 W45 P55 W45 P55 W45 P55 W45 P55 W45 P55 W45 P55 W45 P55 P65 V35 P65 V35 P65 V35 P65 V35 P65 V35 P65 V35 P65 V35 P65 V35 P65 V35
Yarn count (Tex) Warp Weft 41.67 30.49 40.00 41.67 45.45 40.82 28.57 55.56 45.45 39.38 39.38 39.38 39.38 39.38 39.38 39.38 39.38 39.38
45.45 43.48 43.48 43.48 40.82 41.67 34.48 51.28 40.82 11.11 16.67 33.33 11.11 16.67 33.33 11.11 16.67 33.33
Weight (g/m2) 250 249 230 241 239 247 202 269 234 136. 149 176 153 165 170 154 162 190
Yarn density Ends/cm Picks/cm 31.50 29.00 31.00 26.00 25.00 32.00 35.00 27.00 29.00 22.00 22.00 22.00 22.00 22.00 22.00 22.00 22.00 22.00
20.00 25.00 20.50 23.00 19.00 21.00 22.00 21.00 21.00 17.40 17.40 17.40 20.60 20.60 20.60 23.60 23.60 23.60
Notes: W ¼ Wool, P ¼ Polyester, V ¼ viscose
two horizontal load cells. A steel ball (sphere) with a diameter of 48 mm was used. The crosshead speed was regulated at 4 mm/min (^ 0.02 mm/min). The bagging height was set at predetermined value of 30 mm. The time of sphere contact with fabric under maximum pressure at each cycle was 5 min. The recovery time under zero loads between two successive cycles was 2 min. For each fabric sample, the cyclic loading was performed five times. This process was repeated five times and in total, each fabric sample was subjected to 25 cyclic loading. For each fabric type, five samples were used. All experiments were carried out under conditions of 65 ^ 2 percent rh., 208 ^ 28C. Referring to Figures 2 and 3, the maximum load, work of loads and hysteresis percentage at first and last cycles for weft, warp and normal (bagging) directions are measured and then bagging resistance, bagging fatigue and residual bagging height are calculated according to Zhang et al. (1999a, b). A new parameter named as the residual hysteresis for warp, weft and normal (bagging) directions defined as: Residual hysteresis ¼
hysteresis ðpercentÞ in first cycle 2 hystersis ðpercentÞ in last cycle hystersis ðpercentÞ in first cycle £ 100 are calculated:
It is suggested that this new parameter indicates the percentage of residual internal energy of the fabric during bagging deformation. The experimental results of fabric bagging test are shown in Tables II and III.
In-plane fabric tensile properties in woven fabric 423
Table I. Fabric specifications
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Fabric A B C D E F G H I J K L M N O P Q R
Weft (X) 87.00 94.06 99.79 98.84 97.75 97.43 79.38 97.63 97.41 80.67 86.00 92.81 84.79 91.52 97.87 86.00 98.36 105.0
Max force in first cycle (N) Warp (Y) Normal (Z)
(0.87) (1.86) (3.35) (1.55) (1.93) (0.73) (3.55) (1.74) (1.22) (1.05) (2.58) (2.29) (4.2) (1.44) (1.12) (1.57) (1.22) (2.03)
64.00 67.34 70.00 71.00 65.00 70.00 51.95 65.00 69.00 60.00 83.00 80.00 63.43 84.33 88.00 87.83 94.00 97.00
(1.65) (0.96) (2.73) (0.81) (2.46) (2.7) (1.07) (1.17) (2.04) (5.05) (2.20) (2.42) (1.22) (0.84) (3.19) (4.38) (1.29) (2.92)
75.00 80.81 85.05 85.12 84.94 85.21 69.48 85.20 85.40 72.00 74.99 78.94 75.61 81.79 85.17 77.00 85.25 92.00
(1.41) (0.98) (1.60) (0.86) (10.1) (5.7) (2.27) (4.78) (2.44) (2.47) (2.75) (2.19) (2.49) (3.5) (2.16) (2.36) (1.5) (1.81)
Work in first cycle (N mm)
Table II. The experimental results of the bagging tester (mean values)
Fabric A B C D E F G H I J K L M N O P Q R
Weft (X) 756.49 (7.50) 776.35 (4.75) 717.16 (6.16) 891.86 (3.78) 830.43 (4.30) 955.38 (6.69) 646.33 (5.14) 1065 (9.15) 1130.0 (5.54) 759.59 (3.92) 790.00 (10.1) 843.26 (6.61) 758.48 (3.99) 848.54 (4.63) 991.03 (12.3) 737.31 (7.49) 1009.7 (7.94) 1100.0 (10.49)
Warp (Y) 450.30 (13.4) 592.27 (22.5) 530.00 (11.3) 557.39 (5.35) 470.00 (4.80) 560.00 (5.72) 411.40 (6.16) 670.00 (3.70) 790.00 (5.96) 610.00 (2.91) 700.00 (7.71) 681.17 (5.24) 569.06 (6.08) 734.00 (16.3) 769.00 (6.12) 690.00 (4.18) 810.00 (3.39) 845.00 (7.41)
Normal (Z) 477.99 (13.8) 522.40 (9.52) 491.52 (18.1) 605.67 (5.19) 515.27 (7.76) 674.72 (9.26) 462.93 (5.49) 715.24 (3.63) 802.69 (6.62) 523.00 (11.46) 532.64 (16.5) 547.98 (4.52) 513.78 (7.24) 583.96 (7.21) 617.11 (5.45) 556.22 (4.85) 630.24 (4.51) 712.60 (4.49)
Weft (X) 43.43 56.14 94.87 55.70 50.71 77.21 53.34 67.74 86.73 45.53 47.04 52.28 57.22 40.85 65.47 63.31 55.68 70.00
Max force in last cycle (N) Warp (Y) Normal (Z)
(2.45) (1.65) (0.93) (1.47) (1.39) (2.3) (1.72) (2.5) (1.3) (1.74) (0.94) (0.86) (3.4) (1.39) (1.22) (4.84) (2.9) (0.93)
35.00 51.09 60.00 34.38 29.02 50.00 39.68 40.00 36.26 42.00 48.00 39.47 39.98 38.57 41.00 40.00 44.31 50.00
(0.92) (2.58) (3.38) (1.58) (1.86) (4.51) (1.66) (3.18) (2.26) (1.82) (1.13) (1.94) (1.06) (2.81) (1.15) (2.0) (0.84) (1.93)
30.23 53.53 79.78 44.58 40.49 62.01 50.04 53.78 71.18 46.00 48.43 46.81 54.18 38.99 54.72 42.00 44.23 51.00
(1.48) (1.29) (1.83) (2.67) (1.97) (1.11) (1.92) (2.72) (1.78) (1.26) (1.1) (0.88) (2.25) (1.46) (2.34) (0.80) (3.08) (1.31)
Work in last cycle (N mm) Weft (X) 240.00 (4.34) 337.55 (4.86) 442.70 (9.05) 243.81 (6.10) 169.94 (4.21) 309.02 (6.44) 228.71 (9.52) 294.05 (11.8) 381.96 (14.24) 181.58 (5.46) 187.02 (9.98) 217.91 (6.70) 224.83 (4.39) 131.04 (5.85) 268.85 (6.35) 438.49 (4.21) 244.29 (3.63) 304.80 (5.95)
Warp (Y) 140.00 (2.30) 285.63 (3.93) 370.00 (5.74) 166.44 (5.88) 141.09 (3.53) 146.22 (6.44) 218.82 (2.99) 212.42 (8.21) 204.63 (12.4) 250.00 (6.93) 251.62 (4.74) 188.93 (2.63) 162.62 (6.98) 131.23 (7.03) 198.00 (6.33) 396.73 (4.23) 225.46 (3.84) 274.74 (3.54)
Normal (Z) 210.00 (2.10) 281.69 (4.06) 357.04 (5.82) 198.64 (2.62) 161.04 (6.75) 237.13 (2.67) 230.28 (4.75) 235.37 (6.42) 320.87 (5.07) 191.04 (6.09) 203.04 (8.01) 207.80 (5.96) 226.26 (4.61) 147.28 (12.1) 235.85 (3.95) 286.00 (5.13) 193.25 (5.98) 205.00 (6.21)
Note: The data in brackets are SD values
3. Results and discussion 3.1 Relationship between bagging parameters and those of in fabric plane directions 3.1.1 Relation of bagging force and tensile forces in warp and weft directions. As shown in Figures 4 and 5, the maximum bagging force in the first and last cycle correlates linearly with maximum force in weft (x), warp ( y) directions for all fabrics with correlation coefficient (R 2) of 0.97 and 0.83, respectively. This result indicates that the
59.33 46.67 30.00 52.50 58.00 57.67 47.00 60.00 47.33 57.33 54.67 55.33 62.00 48.00 57.00 42.00 58.10 61.00
(4.46) (1.55) (1.09) (1.35) (1.95) (1.59) (1.22) (2.58) (0.93) (1.42) (1.24) (0.80) (0.47) (1.32) (1.77) (1.86) (1.05) (1.03)
Residual bagging height (Percent) 64.34 53.66 43.35 65.09 69.36 69.86 58.61 82.77 70.79 83.60 83.57 87.59 97.62 79.64 92.84 79.92 99.19 95.92
(1.85) (0.97) (1.59) (0.55) (1.04) (0.95) (0.69) (0.42) (0.58) (1.83) (2.58) (0.72) (1.21) (1.12) (0.82) (0.69) (0.71) (0.61)
Bagging resistance (N mm/g)
Note: The data in brackets are SD values
A B C D E F G H I J K L M N O P Q R
Fabric 68.27 56.52 38.27 72.66 79.54 67.65 64.61 72.39 66.20 76.10 76.33 74.16 84.56 70.36 72.87 40.53 75.81 72.29
(0.39) (0.83) (0.86) (0.58) (0.51) (0.8) (1.65) (0.89) (1.39) (0.77) (0.99) (0.63) (0.64) (0.68) (0.54) (0.45) (0.3) (4.39)
Weft (X) 68.91 51.77 30.19 70.14 69.98 73.89 46.81 68.29 74.10 59.02 64.05 72.26 82.12 71.42 74.25 42.50 72.17 67.49
(0.99) (2.37) (0.87) (0.83) (0.52) (1.36) (0.89) (1.09) (1.73) (1.07) (0.61) (0.34) (1.28) (1.27) (0.69) (0.39) (0.45) (0.49)
56.07 46.08 27.36 67.20 68.75 64.86 50.26 67.09 60.03 63.47 61.88 62.08 74.78 55.96 61.78 48.58 69.34 71.23
(1.48) (1.18) (1.67) (0.52) (1.37) (0.51) (0.96) (0.95) (0.39) (0.99) (0.65) (0.88) (1.24) (2.26) (0.83) (0.99) (0.92) (0.85)
Fatigue (Percent) Warp (Y) Normal (Z) 35.73 46.56 25.33 52.57 57.12 25.18 15.27 42.77 44.20 28.38 19.00 10.63 18.00 25.93 30.59 64.08 34.10 34.28
(4.81) (1.63) (2.74) (1.09) (2.97) (4.29) (2.07) (3.73) (0.85) (2.14) (1.18) (0.77) (0.42) (1.13) (1.95) (2.14) (1.41) (1.33)
86.61 95.51 48.38 98.08 92.46 61.07 39.65 90.91 79.66 85.34 51.69 49.76 38.80 57.79 89.78 76.95 93.76 58.74
(8.22) (3.3) (5.98) (4.48) (5.85) (5.46) (2.58) (6.62) (2.96) (5.43) (3.42) (4.68) (1.5) (4.39) (8.18) (8.31) (4.97) (1.83)
80.33 74.93 50.14 87.10 90.39 42.10 39.28 71.19 67.79 61.36 39.71 29.83 35.36 48.58 59.96 72.77 65.57 58.24
(3.34) (5.01) (3.23) (6.1) (3.84) (3.61) (1.84) (7.02) (3.55) (2.73) (4.75) (1.6) (1.86) (1.96) (2.83) (3.33) (2.69) (1.80)
Residual hysteresis (Percent) Weft (X) Warp (Y) Normal (Z)
In-plane fabric tensile properties in woven fabric 425
Table III. Basic parameters of the bagging tester results
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426 Figure 4. Correlation between forces in three directions for all fabrics in first cycle
Figure 5. Correlation between forces in three directions for all fabrics in last cycle
maximum bagging force in fabric distributes between warp and weft yarns which is in agreement with theoretical investigation of Zhang et al. (2000c). The lower correlation coefficient for last cycle indicates that bagging deformation is non-uniformly distributed between the warp and weft directions and to some extent anisotropic fabric properties are involved during bagging deformation. 3.1.2 Relation of bagging work and tensile works in warp and weft directions. As shown in Figures 6 and 7 the work of bagging load in the first and last cycle correlates linearly with work of loads in weft and warp directions for all fabrics with correlation coefficient (R 2) of 0.9 and 0.83, respectively. The lower correlation coefficient for last cycle indicates that non-linearity of fabric deformation in different normal, warp and weft directions is involved. 3.1.3 Relation of bagging hysteresis and tensile hysteresis in warp and weft directions. As shown in Figures 8 and 9 the bagging hysteresis in the first and last cycles correlates linearly with corresponding parameters in weft and warp directions for all fabrics with correlation coefficient 0.78 and 0.93, respectively. The higher value of correlation
In-plane fabric tensile properties in woven fabric 427
Figure 6. Correlation between works in three directions for all fabrics in first cycle
Figure 7. Correlation between works in three directions for all fabrics in last cycle
coefficient for last cycles indicate that all fabrics are well deformed and the residual energy of bagging deformation is well distributed along the warp and weft directions. This result indicates that the shear deformation is occurred particularly in the last cycle and to some extent stress relaxation is created in the warp and weft yarns. 3.1.4 Relation of residual bagging hysteresis and residual hysteresis in warp and weft directions. Figure 10 shows that the residual bagging hysteresis is linearly correlated with corresponding parameters in the warp and weft directions with correlation coefficient of (R 2) 0.9. This result indicates that this new parameter of bagging deformation that demonstrates the non-recovered stored fabric energy is highly correlated with the corresponding parameter along the warp and weft yarn directions. It is suggested that the non-recovered work of loads or in other words the frictional and viscoelastic components of fabric during bagging deformation are decayed in the last cycle.
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Figure 8. Correlation between hysteresis in three directions for all fabrics in first cycle
Figure 9. Correlation between hysteresis in three directions for all fabrics in last cycle
3.1.5 Relation of bagging fatigue and corresponding fatigue in warp and weft directions. The relationships between the fabric bagging fatigue and tensile fatigue in the warp and weft directions are shown in Figure 11. This results shows that the fabric bagging fatigue and corresponding tensile fatigue during bagging formation is linearly correlated with each other ðR 2 ¼ 0:83Þ: It is implicated that the residual elastic stored energy in the fabric due to the fatigue process of fabric bagging is distributed in two principal warp and weft directions. 3.2 Relation of bagging parameters 3.2.1 Relation of bagging fatigue and residual bagging height. The residual bagging height correlate linearly with the bagging fatigue for worsted, shirts and all fabrics with correlation coefficient (R 2) of 0.98, 0.99 and 0.99, respectively, as shown in Figure 12. It is shown that the correlation coefficient for shirt fabrics, which have
In-plane fabric tensile properties in woven fabric 429
Figure 10. Correlation between residual hysteresis in three directions for all fabrics
Figure 11. Correlation between fatigue in three directions for all fabrics
a plain structure, is higher than of worsted twill fabrics. These results indicate that the residual bagging deformation in twill structure is more sensitive to fatigue performance than the plain structure (Zhang et al., 1999b). In addition, the viscoelastic behavior and the frictional effect of worsted fabrics may have influence on fatigue performance of worsted fabrics. In general, it may be deduced that the correlation coefficient of the experimental results are more than those found by Zhang et al. (1999b). 3.2.2 Relation of bagging resistance and residual bagging height. Figure 13 shows the relationships between the residual bagging height and bagging resistance. It is shown that these parameters are non-linearly correlated with each other for worsted,
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Figure 12. Relation between bagging fatigue and residual bagging height
Figure 13. Relation between bagging resistance and residual bagging height
shirts and all fabrics with correlation coefficient (R 2 ) of 0.99, 0.99 and 0.97, respectively. It is implicated that the bagging resistance is mainly related to work of load at first cycle and hence, it represents the ability of fabric to resist bagging deformation at the initial stage (Zhang et al., 1999b). Therefore, the residual bagging height and bagging resistance are highly non-linearly correlated with each other as also found by Zhang et al. (1999b) for worsted fabrics. 3.2.3 Relation of bagging resistance and bagging fatigue. As shown in Figure 14, bagging fatigue and resistance are non-linearly positively correlated with each other for worsted, shirts and all fabric with correlation coefficient (R 2) of 0.99, 0.98 and 0.99, respectively. These results indicate that as the initial energy of the fabric, which reflects both elastic and initial viscoelastic, frictional energy (Zhang et al., 1999b) increases as the fabric bagging fatigue increases. It may be considered that correlation
In-plane fabric tensile properties in woven fabric 431
Figure 14. Relation between bagging resistance and bagging fatigue
coefficient of bagging fatigue and resistance for shirt fabrics, are much higher than those of worsted fabrics. This result shows that the viscoelastic-frictional component of wool component and twill structure of worsted fabrics may have influence on the experimental results. 3.2.4 Relation of residual bagging height, bagging fatigue and bagging resistance. Since the residual bagging height is correlated with bagging fatigue and resistance as described in Sections 3.2.2 and 3.2.3, the multiple regression analysis of this parameters is investigated. The multiple regression equation for predicting residual bagging height for all the fabrics samples is shown in Figure 15 with the following equation:
Figure 15. Correlation between bagging fatigue, bagging resistance and bagging height
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Residual bagging height ¼ 0:61 £ bagging fatigue þ 3:83 £ Lnðbagging resistanceÞ ðR 2 ¼ 0:83; p , 0:001Þ It is shown that the correlation is highly significant with R 2 ¼ 0:83 ðp , 0:001Þ: It may be considered that the residual bagging height is affected by combined influence of bagging fatigue and resistance. When these results are compared with those of Zhang et al. (1999b), it may be deduced that the empirical equation found by proposed new test method to investigate fabric bagging behavior is similar to that in Zhang et al. (1999b). 4. Conclusion In this work, to investigate the relation of in-plane fabric tensile properties with fabric bagging behavior, a new test method is developed and a real time data acquisition and strain gauge technique are used. The bagging procedure was carried out while the woven fabric tensile deformations along the warp and weft directions are measured. By analyzing the experimental results, different parameters including load, work, hysteresis at the first and last cycles for three different normal, warp and weft directions are calculated. In addition to characterize bagging behavior of woven fabrics, bagging resistance, bagging fatigue, residual bagging height and residual bagging hysteresis are also measured. The experimental results show that the bagging load values, for worsted and shirt (Ucar et al., 2002; Zhang et al., 1997a, b, 1999a, b, 2000a, b) fabrics in comparison with the earlier experimental works are much lower and in the range 50-100 N. It was also found that the bagging load, work, residual hysteresis and fatigue are highly linearly correlated with corresponding parameters in the warp and weft directions. The experimental results of bagging performance woven fabrics indicate that the residual bagging height is linearly correlated with bagging fatigue (R 2 ¼ 0:99 shirt, R 2 ¼ 0:98 worsted and R 2 ¼ 0:99 all fabrics). However, the residual bagging height is non-linearly correlated (R 2 ¼ 0:99 shirt, R 2 ¼ 0:98 worsted and R 2 ¼ 0:98 all fabrics) with bagging resistance. An empirical relationship obtained between the residual bagging height and fatigue and resistance (R 2 ¼ 0:83 all fabrics) suggests that the proposed new test method is able to evaluate the bagging behavior of fabrics. The experimental results of this work suggest that the bagging behavior of woven fabrics are predictable in terms of fabric biaxial tensile properties under low stress fabric mechanical conditions. Further studies are needed to theoretically investigate the dynamic analysis of fabric during bagging procedure. References Denton, M.J. (1972), “Fit, stretch and comfort”, Textiles, pp. 12-17. Grunewald, K.N. and Zoll, W. (1973), In Textile Bull, No. 3, pp. 273-5. Kawabata, S., Niwa, M. and Kawai, H. (1973), J. Text Inst., Vol. 64, pp. 62-85. Kirk, Wm. and Ibrahim, S. (1966), Textile Res. J., pp. 37-47. Kisiliak, D. (1999), Textile Res. J., Vol. 69, pp. 908-13. Ucar, N., Realff, M.L., Radhakrishnaiah, P. and Ucar, M. (2002), Textile Res. J., Vol. 72, pp. 977-82.
Youkura, H., Nagae, S. and Niwa, M. (1986), Textile Res. J., Vol. 56, pp. 748-54. Zhang, X., Dhingra, R.C. and Miao, M. (1997a), Textile Asia, No. 1, pp. 50-2. Zhang, X., Li, Y. and Yeung, K.W. (1999a), Textile Res. J., Vol. 69, pp. 511-8. Zhang, X., Li, Y. and Yeung, K.W. (1999b), Textile Res. J., Vol. 69, pp. 598-606. Zhang, X., Li, Y. and Yeung, K.W. (2000a), Textile Res. J., Vol. 70, pp. 18-28. Zhang, X., Li, Y. and Yeung, K.W. (2000b), Textile Res. J., Vol. 70, pp. 751-7. Zhang, X., Li, Y., Yeung, K.W., Miao, M. and Yao, M. (2000c), J. Text Inst., Vol. 91 No. 4. Zhang, X., Yeung, K.W., Yao, M. and Li, Y. (1997b), “Factors influencing bagging behavior of woven fabrics”, Proc. the 4th Asian Textile Conference, 24-26 June, pp. 512-17.
In-plane fabric tensile properties in woven fabric 433
The Emerald Research Register for this journal is available at www.emeraldinsight.com/researchregister
IJCST 16,5
434 Received January 2004 Revised May 2004 Accepted May 2004
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
On the performance of the geometrical models of fabrics for use in computational mechanical analysis Christopher G. Provatidis Faculty of Mechanical Engineering, National Technical University of Athens, Athens, Greece
Savvas G. Vassiliadis Department of Electronics, Technological Education Institute of Piraeus, Athens, Greece Keywords Textile fibres, Modelling, Computer aided design Abstract The computer aided engineering and the respective computer aided design tools compose a modern mechanical modelling environment for the textile materials. The numerical mechanical models of the textile structures are a strong tool for the in-depth study of the mechanical properties and the behaviour of the textiles. The precision of these models in terms of their accuracy in representing the exact geometry of the real textile structures is the fundamental factor affecting the overall success of the idealisation. This paper discusses older traditional analytical models (Peirce, Saw-tooth, Kemp) as well as some variations of these fundamental models. Their numerical solutions are successfully compared to the experimental measurements of the yarn longitudinal deformation parameters using microscopic and digital image processing techniques. The results of the analytical models are compared with the actual measurements and the more precise models are indicated.
International Journal of Clothing Science and Technology Vol. 16 No. 5, 2004 pp. 434-444 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410554624
Introduction The computer technology in the recent years offers to the users increased availability of computing power under lower cost. The engineering tools like computer aided engineering (CAE) and computer aided design (CAD) use the maximum of the available computing resources. The higher the computing power available, the complete and precise are the engineering tools. For example, computing methods as the finite element method (FEM) or boundary element method (BEM) become more and more spread and widely used, solving mechanical problems and supporting the analysis of mechanical structures. The textile products, like the fabric structures, are of complex construction and they are suitable to mechanical analysis using numerical or computational methods. The analysis provides the necessary data for the estimation of the behaviour of the fabric during its end use (Hu and Teng, 1996). The modelling i.e. the representation of the real structure in the computer environment is the first stage of the numerical mechanical analysis (Tarfaoui and Akesbi, 2001). The precise description of the topology of the fabric microstructure, i.e. the geometrical details of the structure, is the main premise for efficient modelling. The determination of the coordinates of the geometrically important elements of the
fabric microstructure is almost impossible mainly because of the deformability of the fabric. A local measurement of the fabric cross-section does not represent the real one, since it is usual to meet local deformations. Even if this kind of geometrical data are acceptable, the procedure to collect them is time-consuming and difficult. The fabric cell is of small dimensions and the use of a microscope is necessary. The fabric cross-section can be observed and a digital image is captured using a digital camera mounted on the microscope. The image is processed to obtain the required forms and shapes of the yarns involved in the fabric construction. Using the above described procedure, it is possible to retrieve the geometrical data of a fabric structure only if a fabric sample is available, i.e. only if the fabric is already constructed. For a fabric in the design stage, before its real construction it is impossible to use such an analytical laboratory technique. However, often it is necessary to determine the mechanical behaviour of the fabric, before its construction. This latter case is very useful in the design procedure of the textile products because it helps to ensure that the fabric meets the requirements and the specifications (Hearl, 1994). If the fabric is not yet constructed, it is necessary to obtain the geometrical data of its structure based on the major structural characteristics like the warp and weft density as well as the warp and weft crimp. In the present work the comparative study of the most popular models is presented and their accuracy is demonstrated. The most precise model is suggested for use in the modelling of the textile mictrostructure. Similar work has already been presented although it was based on limited samples and models examined (Provatidis et al., 2003). Model of Peirce The model introduced by Peirce (1937) in his pioneering work is often used as a reference for the representation of the fabric structure. However, its computational complexity is a serious difficulty. The formulation of the model of Pierce results in a system of seven equations with 11 unknowns. Its solution is only possible if four of them get a specific value. It is usual to choose the warp and weft density and the warp and weft crimp as the four design characteristics determined by the designer and thus, having a given value in the model. These constants will reduce the number of the unknowns from 11 to 7 and the solution of the system will be possible. The determination of the exact value of the rest seven unknown quantities will provide the full data necessary for the representation and modelling of the particular fabric structure (Figure 1). The algebraic system of the seven equations of the Peirce model is non-linear and it has a complex form. There is not a closed, analytical solution. The numerical solution of the system is made by a computer program based on the Newton-Raphson technique and the source code is realised in Fortran. The iterative algorithm converges and approaches the solution of the system with a very good precision. The value of the angle u between the warp u1 and weft u2 yarns axis of the straight part of the cell and the neutral level of the fabric are calculated. This is a critical parameter, since all the rest can be derived from it. The system of equations of the Peirce model is as follows: p1 ¼ ðl 2 2 Du2 Þcos u2 þ D sin u2
ð1Þ
p2 ¼ ðl 1 2 Du1 Þcos u1 þ D sin u1
ð2Þ
h1 ¼ ðl 1 2 Du1 Þsin u1 þ Dð1 2 cos u1 Þ
ð3Þ
Performance of the geometrical models of fabrics 435
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436 Figure 1. Model of Peirce
h2 ¼ ðl 2 2 Du2 Þsin u2 þ Dð1 2 cos u2 Þ
ð4Þ
c1 ¼
l1 21 p2
ð5Þ
c2 ¼
l2 21 p1
ð6Þ
D ¼ h 1 þ h2
ð7Þ
where c is the crimp; p the threads spacing; l the length of the yarn in the unit cell; u the angle between the yarn and plane of cloth; h the maximum displacement of the yarn axis from the plane of cloth; and D the maximum distance between the warp and weft yarn axis, and the indices 1 and 2 are for warp and weft yarns. The Peirce model is of limited practical use unless a computer supports its numerical solution. Peirce has tried to introduce either nomograms or simplified aproximating expressions in order to give a practical perspective to this fundamental work. Saw-tooth model The so-called “saw-tooth” representation of the fabric is the simplest and widely used model. The yarns constituting the fabric cell are considered to have partially straight shape only. The adjacent parts have an alternate slope about the neutral level of the fabric. The yarns are not curved even in the parts where they pass over and under the yarns of the opposite direction. Many authors have based their work on the saw-tooth model of fabrics. Figure 2 shows the approach of Kawabata (1989) and Figure 3 shows the respective approach of Leaf (1979). The saw-tooth model gave a solution to the problem of the increased computational complexity of the Peirce model. Since it is of less precision in its concept, it is expected that its results will be more far from the real structural characteristics of the fabric. In both cases, the slope of the yarns, which is represented by the angle f in the model of Kawabata and by the angle u in the model of Leaf, is calculated using the values of the spacing and the crimp of the yarns: cos u1 ¼
1 p2 ¼ c1 þ 1 l 1
cos u2 ¼
1 p1 ¼ c2 þ 1 l 2
ð8Þ
The angle u2 is defined accordingly. In the above equation c denotes the crimp of the yarns, p the spacing of the yarns and l the length of the unit cell (l is a function of
Performance of the geometrical models of fabrics 437
Figure 2. Model of Kawabata
Figure 3. Model of Leaf
the crimp and spacing of the yarns). The index “1” refers to the warp yarns and the index “2” the weft yarns. Peirce approximation Peirce introduced an approximating version of the model after the presentation of the complete fabric cell model. The simplification was based on a higher number of assumptions making the solution of the system much more easier and the calculation
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of the model parameters very fast (Peirce, 1937). The approximant model will be analyzed in terms of the precision of its results. The following equations give the values of the angle u in degrees in both warp and weft directions: 12 12 pffiffiffiffi pffiffiffiffi l1 l2 ð9Þ u1 ð8Þ ¼ 106 2 1 ¼ 106 c1 u2 ð8Þ ¼ 106 2 1 ¼ 106 c2 p2 p1 Kemp model All the previous models are based on the assumption that the yarns are incompressible, i.e. the shape of their circular cross-section does not change by the application of the load. However, in the real fabrics the yarns are compressed and the shape of their cross-section becomes flattened. Kemp (1958) introduced a transformation of the crimp and yarns density expressions by considering the deformation of the yarns. If the vertical and horizontal dimensions of the flattened cross-section of the yarn are known, the model of Kemp produces the modified c 0 (crimp) and p0 (yarn spacing) quantities, which have to be used in the Peirce’s model, instead of the initial values of c and p. The measurement of the deformation of the yarns cross-section is a difficult task involving precise laboratory work and microscopy. If a is the length of the yarn cross-section along the major axis and b the respective length along the minor axis, then: p01 ¼ p1 ða1 2 b1 Þ
ð10Þ
p02
ð11Þ
¼ p2 ða2 2 b2 Þ
c 01 ¼
c1 p2 p2 2 ða2 2 b2 Þ
ð12Þ
c 02 ¼
c2 p1 p1 2 ða1 2 b1 Þ
ð13Þ
equations (10)-(13) show the transformations of c and p foreseen by the Kemp model. Using the new values of the crimp and yarn spacing parameters, c 0 and p0 , and solving again the Peirce’s system of equations, a new set of the values of angle u is derived. Modified model of Peirce If a decision has been made for measuring the characteristics of the deformed cross-sections of the yarns, then it is possible to estimate the apparent diameter of the warp and weft yarns. It is obvious that such a measurement can take place only if a fabric sample exists. If the fabric is still in the design stage, before its real production, the last Kemp and modified Peirce model are not applicable. In that case only the first three models are available (Peirce, Saw-tooth, Peirce approximation models). The current model presupposes the measurement of the deformation of the cross-sections of the yarns. Equations (1)-(7) describe the relationships between the variables of the Peirce model. If the mean diameters of the yarns are known, the quantity D ¼ h1 þ h 2 ¼
d1 þ d2 2
ð14Þ
has a fixed value per sample. After the value of D has been determined, it can be used to decrease the complexity of the system of equations, resulting in a more precise numerical solution. Experimental work The experimental work has been focused on the preparation of fabric samples and the microscopic measurement of the angles u1 and u2. The measured angles after the statistical process are used for the evaluation of the various models described earlier. Six different plain weave fabrics have been selected and they were used for the experimental work. The selection was made such that different structural cases were to be included in the group of samples. Samples of fabrics of symmetric as well as of non-symmetric construction, help the thorough study in a wider construction range. An index of constructional symmetry of the fabrics is the ratio of the crimps c1 =c2 . If the value of the ratio c1 =c2 is equal to 1, then the fabric in terms of crimp (and thus, usually in terms of general appearance) is considered as symmetrical. If the ratio has a different value, it denotes less symmetrical structure of the fabric. The crimp tests of the warp and weft yarns were performed according to the ISO Standard 7211/3. The warp and weft yarns density, i.e. number of threads per unit length was determined using the ISO Standard 7211/2. That structural information is extremely useful, since it serves among others the determination of the scale of the microscopic images and thus, the measurement of the diameter of the cross-sections of the yarns. The results of the crimp and yarns density measurements are given in Table I. The conditioned samples were processed to achieve increased hardness, which is necessary for easier cut without any deformation of the specimens. The samples were immersed in a hardened resin solution. After the polymerisation and hardening of the glue, the sample was hard enough, so that the yarns could not move or change their shape during the cutting procedure. A disk cutter was used to obtain several thin stripes of fabric per sample in the warp and weft direction. Several specimens were prepared, so that after a screening the ones in best condition were to be selected. The specimens were observed using a stereo-microscope under low magnification (10-20X). The objects were lightened symmetrically from both sides for the elimination of undesirable shadows. The electronic camera attached to the stereo-microscope provided the microscopic images in an electronic format, ready for further processing (Figure 4). The images were transferred to a computer and the files of the pictures were stored on the hard disk, ready for use in the next processing stage. Density (yarns/cm) Sample 1 2 3 4 5 6
Crimp (per cent) c1/c2
p1
p2
c1
c2
21.5 21.0 25.0 28.5 22.0 25.0
17.5 16.0 21.5 26.5 14.5 12.0
5.76 9.46 8.06 5.78 11.32 4.56
0.93 6.44 5.98 5.53 12.38 13.55
6.19 1.47 1.35 1.05 0.91 0.34
Performance of the geometrical models of fabrics 439
Log (c1/c2) 1.79 1.17 1.13 1.02 0.96 0.53
Table I. Crimp and yarns density measurements
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440 Figure 4. Fabric cross-section
The raw images were processed in order to enhance the quality of the images. Very often it was necessary to increase the contrast and to detect the edges for the contour definition of the objects on the image. In parallel, the image processing supported the technical homogeneity of the final images. The already filtered, balanced and processed image is brought into the next step. It is now subjected to a manual marking of the slopes of the yarns, in order to measure the angle u between the straight parts of the crimped yarn and the neutral level of the fabric. The procedure of the measurement of the angle u took place in about 20 points in each direction of every sample. Figure 5 shows the steps of the image processing. On the straight part of the particular segment of a yarn a line was drawn, approaching the local slope of that yarn. Using the facilities of a commercial image processing software, it is possible to measure the length of the sides of the right triangle, which hypotenuse is the first drawn line indicating the yarn slope. As shown in Figure 5, by measuring the relative lengths of H and P the angle u was calculated using the formula:
u ¼ arctan
H P
ð15Þ
After the processing of the microscopic images, the experimental work resulted in a large number of measurements of the angle u. The measurements were taken following the same procedure and their variation was within acceptable limits. Few extreme values due to local unexpected deformation of the yarns were eliminated. The average of the measured values of the angle u for both warp and weft directions are given in Table III. In parallel to the angle u measurements, the dimensions of the deformed yarns cross-sections have been measured. In every cross-section of the warp and weft yarns, the two axes in the horizontal and vertical direction of the almost elliptic cross-section have been precisely marked, as in shown Figure 6. For every sample and in each of the warp and weft directions the ai and bi of 20-30 yarn cross-sections were measured. The lengths ai and bi were measured on the digital image in relative units (e.g in pixels). Their ratio is an index of the deformation of the yarns. Their absolute dimensions can be derived, since the yarns cross-sections are in known distance. That known distance between two adjacent yarns compared
Performance of the geometrical models of fabrics 441
Figure 5. Cross-section image processing
Figure 6. Measurement of the yarns flattening
to the relative distance on the picture gives the scale of the picture. This scale is used for the specification of the yarn cross-section dimensions. From the ai and bi an approximation of the mean diameter of the yarn can be calculated. Although the value of the mean diameter has no real meaning, it can be used in the modified Peirce model. Table II contains the values of a and b (horizontal and vertical dimension) of the deformed yarns cross-sections.
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Results The actual measurements of the angles u in the warp and weft direction of the six different samples are shown in the Table III. The angle estimations according to the Peirce, Saw-tooth and Peirce-approximation models are given in the same table. The three models require only macro-mechanical characteristics (yarns crimp and density) for the estimation of the angles u. Saw-tooth model provides results characterized by a strong underestimation of the angles u when compared to the actual data. The results of the Peirce model give less underestimated results, while the results of the Peirce-approximation model are better fitted. In Table IV the estimations of the Kemp and the modified Peirce model are given. Both models require micro-mechanical data of the deformation of the cross-sections of the yarns.
Warp Sample
Table II. Horizontal (a) and vertical (b) length of the deformed yarns cross-sections
Table III. Actual measurements and model data
Table IV. Kemp and the modified Peirce models data
1 2 3 4 5 6
Weft
a
b
a
b
0.0446 0.0427 0.0074 0.0315 0.0321 0.0298
0.0193 0.0302 0.0052 0.0203 0.0275 0.0210
0.0441 0.0513 0.0287 0.0264 0.0418 0.0347
0.0246 0.0362 0.0202 0.0149 0.0275 0.0202
Peirce’s appr. u1(8) u2(8) 25.44 32.60 30.09 25.47 35.66 22.64
Sample
Actual measurements u1(8) u2(8)
u1(8)
u2(8)
Models Saw-tooth u1(8) u2(8)
1 2 3 4 5 6
33.22 34.21 38.50 32.47 32.41 29.06
20.01 26.79 24.61 20.56 30.65 18.44
7.99 22.77 21.45 20.23 33.74 33.53
19.00 24.00 22.27 19.02 26.06 16.98
27.36 32.53 35.02 32.20 38.75 35.71
Peirce
7.78 20.03 19.34 18.62 27.15 28.28
10.22 26.90 25.92 24.92 37.30 39.02
Sample
Actual measurements u1(8) u1(8)
Peirce modified u1(8) u2(8)
u1(8)
u2(8)
1 2 3 4 5 6
33.22 34.21 38.50 32.47 32.41 29.06
22.53 31.16 27.60 22.96 33.01 27.34
24.95 31.57 27.99 25.35 41.07 24.03
12.31 27.92 26.31 25.42 35.92 39.91
27.36 32.53 35.02 32.20 38.75 35.71
Models
8.38 30.17 24.25 22.86 39.50 37.59
Kemp
The results of the Kemp and Peirce-modified model are close to each other and they have a better approximation to the actual measurements when compared to the other three models. An error estimator is defined as: ua 2 um ð16Þ e ðper centÞ ¼ 100 ua
Performance of the geometrical models of fabrics 443
The error estimator can be calculated for every sample belonging to each model group. Further, the mean error index (MEI) can be defined as follows: k X ei ðper centÞ i¼1 MEIn ¼ ð17Þ k n¼1;2;...;5
where k is the total number of the samples and n is the number of the models used. Figure 7 shows the MEI of the five models used in the comparative study. From the chart in Figure 7, it is obvious that the Peirce-approximation, Kemp and Peirce-modified models are much better fitted to the actual results than the Peirce and Saw-tooth models. Kemp model seems to be most balanced within the three better models. If the deformation of the yarn cross-sections is not available the recommended model is the Peirce approximation model. It is worth to mention that even the best models of geometrical representation of the fabrics give a significant error of about 15 per cent. Conclusions The accurate geometrical modeling of the textile fabrics is necessary for the micro-mechanical study of the woven structures using modern CAE tools. A long experimental procedure on defining the angles u of the samples has been performed. The geometrical models available were compared over six different samples in warp and weft directions and the best have been indicated. Even the best models appear in
Figure 7. MEI
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a considerable deviation from the actual measurements. This last fact enables the future planning of the work in the field of a better geometrical representation, either by using the statistical data or by defining correction procedures. References Hearl, J.W.S. (1994), “Fabric mechanics as a design tool”, Textile Horizons, Vol. 14 No. 5, pp. 12-16. Hu, J.L and Teng, J.G (1996), “Computational fabric mechanics: present status and future trends”, Finite Elements in Analysis and Design, Vol. 21, pp. 225-37. Kawabata, S. (1989), “Nonlinear mechanics of woven and knitted materials, in textile structural composites”, Composite Materials Series, 3, Elsevier Science Publishers, Amsterdam, ISBN 0-444-42992-1. Kemp, A. (1958), “An extension of Peirce’s cloth geometry to the treatment of non-circular threads”, Journal of the Textile Institute, Vol. 49, pp. T44-8. Leaf, G.A.V. (1979), “Woven fabric tensile mechanics”, Proceedings of the NATO Advanced Study Institute on Mechanics of Flexible Fibre Assemblies, Killini, Greece, pp. 143-57. Peirce, F.T. (1937), “The geometry of cloth structure”, Journal of the Textile Institute, Vol. 28 No. T45, pp. 43-77. Provatidis, Ch.G., Vassiliadis, S.G. and Livaditi, M.A. (2003), “Estimation of the geometrical characteristics of the fabrics for use in numerical mechanical modelling”, Proceedings of the 4th International Conference: Innovation and Modelling of Clothing Engineering Processes – IMCEP 2003, pp. 17-23. Tarfaoui, M. and Akesbi, S. (2001), “Numerical study of the mechanical behaviour of textile structures”, International Journal of Clothing Science and Technology, Vol. 13 Nos 3/4, pp. 166-75.
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Structural characterization of textile fabrics using surface roughness data Savvas G. Vassiliadis Department of Electronics, Technological Education Institute of Piraeus, Athens, Greece
Christopher G. Provatidis
Structural characterization of textile fabrics 445 Received January 2004 Revised April 2004 Accepted April 2004
School of Mechanical Engineering, National Technical University of Athens, Athens, Greece Keywords Textile fibres, Surface texture, Numerical analysis Abstract The surface of the textile fabrics is not absolutely flat and smooth. Its geometrical roughness within certain extents is considerable. The surface roughness influences the fabric hand and it plays a significant role in the end use of the fabric. In parallel, the periodic variations of the fabric surface level due to the regular interlaced patterns of the yarns cause a respective variation of the geometrical roughness measurement. Thus, the fabric roughness data measured using the Kawabata Evaluation System for Fabrics and imposed to a certain process of numerical calculations result into the retrieval of the structural parameters of the fabric. The principle of the method has a non-destructive character and can be applied to woven or knitted fabrics.
Introduction The measurement of the micromechanical properties of the textile fabrics can take place using various methods and equipment. The most commonly used is the one based on the Kawabata Evaluation System for Fabrics (KES-F), establishing an almost global reference method. It provides precise low stress mechanical measurements. It is mainly used for the objective measurement of the fabric hand parameters and it supports the determination of complex properties of the textile fabrics like sewability, seam puckering, etc. (Kawabata and Niwa, 1998). In addition to the low stress mechanical tests, the KES-F provides facilities for the measurement of the coefficient of friction and the geometrical roughness of the fabric. The surface characteristics contribute to the formation of the total hand value (THV) of the fabric. Earlier work has been done using the friction measuring data obtained from the KES-F system for the tribological investigation of the textile fabrics (Bueno et al., 1996). On the other hand, surface data obtained using optical methods and subjected to signal processing techniques have been used for the identification of the fabric structures (Xu, 1996). Surface data of a fabric, captured by an optical CCD sensor and processed later, leaded to the detection of structural defects (Castellini et al., 1996). The present paper discusses the use of the surface data obtained by the KES-F system, for the structural characterisation of the textile fabrics, substituting other analytical testing and maximising the utilization of the information available from the KES-F measurements.
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Method of measurements The surface roughness of a fabric can be measured using either optical or mechanical principles. One instrument already in use for measuring of the surface roughness based on a mechanical sensor in the textile laboratories is the KES-FB4. It is a part of the KES-F system, which consists of four individual measuring instruments connected to a central computer. The particular KES-FB4 can conduct simultaneously the measurements of the geometrical roughness and the coefficient of friction (m) of the fabric. The sensing element consists of a metallic rod equipped in its free end with a thin wire in a U form (Figure 1). The sensor touches the surface of the fabric under a constant normal force. A linear differential transformer is used for the generation of an electrical signal proportional to the vertical movement of the sensor. The width of the sensor is about 6 mm. If the density of the yarns is n threads/cm, the sensor scans simultaneously a part (w) of the fabric equal to: w ¼ 0:6n ðthreadsÞ Considering that the density of the yarns in the majority of the fabrics is 10-30 threads/cm, the sensing wire scans simultaneously a certain width corresponding to 5-15 threads. Thus, the surface roughness data are not exactly derived from a punctual scanning of the fabric surface. That data represent the global roughness of that stripe containing many interlaced yarns. Structure of the surface The textile fabrics are rare balanced in terms of appearance of warp and weft on their surface. Very often, even in the case of the plain weave fabrics, there is a domination of one group of threads. They appear more intense on the surface resulting in hiding the other group of threads. This is introducing a certain difficulty in obtaining structural information from the surface roughness data. Usually it is possible to obtain structural data for one direction of the fabric whereas the results on the other direction do not give
Figure 1. Sensing element of KES-FB4
clear information about the respective structural parameters. Under certain conditions it is possible to obtain information about the large scale relief data of the surface as it happens in the case of the twill fabrics. Figure 2 shows the cross-section of an ideal plain weave fabric. If the mechanical scanning device was able to follow exactly the upper surface of the fabric, it should detect a repeated pattern of wavelength l. This wavelength corresponds to the double yarn spacing p.
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l ¼ 2p Since the sensing element covers a wider region (more than one thread), it will scan the upper surface of the structure shown in Figure 3. The signal produced will contain a repeat of the pattern of wavelength l equal to the yarn spacing p. An interesting point is that the theoretical amplitude (DH) of the variation of the surface level is restricted to the half if compared with the previous case.
l¼p A factor having an important role in the configuration of the surface characteristics of the fabric is the crimp of the yarns, under the consideration that the yarn densities of warp and weft are of the same class. If the crimp values of the weft and warp yarns are close to each other, the fabric produced is more or less balanced in terms of appearance.
Figure 2. Cross-section of a plain weave fabric
Figure 3. Side view of a plain weave fabric
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If the values of the crimp are far from each other, the result is an unbalanced surface with one dominating direction in the surface structure of the fabric (Figure 4). The real structure of the fabrics differs from the ideal one, mainly because of the flattening of the yarns cross-sections. The flattened yarns lead to a compressed profile of the fabric, and to a minimised amplitude of the variation of the surface level (Figure 5). In the case of the knitted fabrics the situation is more complex. It is very difficult to correlate the structural characteristics of the fabric to their surface roughness data. The sequence of the variations of the fabric surface is not that clear and well defined as it happens in the case of the woven fabrics. Each structural unit consists of the various parts of a loop and usually these parts are in a non-orthogonal arrangement. Although it is very difficult to obtain precise structural information from the surface roughness data of the knitted fabric, it is possible to obtain information about the design of the fabric. There is a way to define the knit of the fabric: single jersey, double jersey or interlaced. Measurement In order to obtain the surface roughness measurements, the samples are mounted on the KES-FB4 instrument and the procedure starts when the sensors of friction and geometrical roughness are scanning a certain part of the fabric surface under constant speed (KES, 1991). The sensors transform the measurements of the coefficient of friction and the thickness variation (geometrical roughness) into an electrical signal. The signal is amplified within the KESF-FB4 electronic unit and it is transferred to the
Figure 4. Unbalanced surface structure
Figure 5. Flattened cross-sections of the yarns
computer connected to the system. The analog to digital converter (ADC) module in the personal computer converts the analog signal into a digital one. The digital signal can be stored on the magnetic media of the computer or it can be processed in a further stage. The geometrical roughness measurement is a part of the global objective measurements of the fabrics, which include the full set of the micromechanical parameters of the fabric (Kawabata, 1989). If a fabric is subjected to the objective measurements procedure, there are raw data available from the geometrical roughness measurement on the KESF-FB4, i.e. there is no need for a specific measurement. The availability of the surface roughness data, strengthens the interest on the use of these surface data for the determination of the structural parameters of the fabrics under test (Figure 6). The geometrical roughness signal is almost useless in its raw form. In that stage the signal indicates only the upper and lower limits of the thickness variation of the fabric. In order to get a better idea about the variation characteristics of the signal, an integrator is used. The integration is either analog (if there is no computer connected to the system) or numerical (if the signal is transferred to a computer for further processing). The calculated value gives an indication about the variation mode of the signal. If Lmax is the scanning length, z is the displacement of the sensor from an arbitrary standard position, ¯z the mean roughness, the mean deviation of the surface roughness is calculated as follows: Z Lmax 1 jz 2 zj dL SMD ¼ Lmax 0
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The next step involved in the processing of the roughness signal is the examination of its frequency contents. The frequency contents may provide useful information about the fabric structure in a convenient form. Signal discrimination The specimen is mounted under a constant mechanical tension on a special scanning table. Scanning take place by moving the table and consequently, the fabric is mounted on it at constant speed (1 mm/s). The sensor is in contact to the fabric surface and it is mounted on a fixed positioned beam. The final digital signal is stored in the memory of the computer and then in the storage devices. Let the scanning length be Lmax expressed in millimeters, and the total number of the samples within that scanning length is N. The sampling frequency can be defined as:
Figure 6. Fabric surface roughness measurement
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fs ¼
N ðsamples=mmÞ Lmax
Based on the Nyquist theorem of sampling, the minimum sampling frequency to resolve a feature from a digital signal is fmax. On the opposite, if the sampling frequency is given, the maximum frequency content of a digital signal can be assumed: fs ¼ 2fmax , fmax ¼
fs N ¼ 2 2Lmax
Hence, for the KES-FB4 the maximum frequency content or by inversion the minimum discriminating length is: lmin ¼
1 1 2 2Lmax ðmmÞ ¼ ¼ ¼ f max f2s fs N
This is the minimum length of a surface variation (minimum wavelength) detectable by the specific KES-FB4 system. The sampling frequency is a technical characteristic of the A/D converter module defining its performance. If the density of the threads of the fabric is less than 1/lmin, all the embossed details of its surface can be detected and recorded. Of course, the majority of the fabrics in use do not exceed that upper limit imposed by the technical characteristics of KES-FB4. Fourier transform of the data The driving software of our KES-F system exports the data in a hexadecimal format. It is necessary to convert the raw data in the standard ASCII format. A Fortran code has been developed for the automatic conversion of the data. The geometrical roughness signal in the time domain gives a first approach to its morphological characteristics. It provides the amplitude of the variation and after a short process it is possible to obtain the statistical characteristic of the mean deviation of the signal. Information about the frequency components is almost impossible to be obtained from the time domain raw signal. The rare exception is when the main frequency existing in the signal is of high power and the rest frequency components are of much less power. Fourier transform is a powerful engineering tool widely used in many applications and of course, in many textile fields. The specific use of the Fourier transform, as an analysis tool of the geometrical roughness signal, is very successful since it detects and quantifies its frequency components. The data of the geometrical roughness signal are given in the discrete form: zðnÞ ¼ {zð0Þ; zð1Þ; zð2Þ; . . .; zðN 2 1Þ} where N is the total number of the samples of the raw digital signal. Every component of the signal is represented by a numerical value, thus the signal z(n) is considered as a digital signal. Considering the discrete character of the signal the discrete Fourier transform (DFT) of the initial signal can be considered (Papoulis, 1962).
Z ðkÞ ¼
N 21 X
zðnÞe2jð N Þnk ; 2p
0#k#N 21
n¼0
If the number of the samples chosen is equal to 2n, then the DFT can be replaced by a usual fast Fourier transform (FFT) of the geometrical roughness signal. The main property of the FFT is the fast calculation of the frequency components of the signal. The Fourier transform as a result gives a discrete spectrum of N components. Of course, that output spectrum has a symmetric form and practically the information contained in the spectral output is restricted to the N/2 components. In the current application, for every test 260 samples are available in forward and another 260 in the backward relative motion of the sensor. In the analysis following, the forward data are considered only in the processing to avoid any misuse of the backward motion data. Using the 260 samples of the signal the outmost close N values for the FFT are either 128 or 256. The higher the samples number the better the discrimination of the output spectrum components. However, the length of 128 has been chosen because the first few samples are not of valid value due to the settling period of the electronic system. Considering an FFT of a signal of length 128, the output spectrogram will contain 128=2 ¼ 64 components. The approach used in the current work is to calculate the FFT of a signal consisting of the first 128 samples. The next stage is to calculate the FFT of a signal consisting of 128 samples, but starting from the tenth sample, then the FFT of the 128 samples starting from the twentieth sample, etc. The main idea is to calculate the FFT within a window of length 128 sliding on the initial signal. The distance between the two successive windows is constant and has been selected equal to ten. The S resulting sequences of the transformed data are then averaged in the frequency domain, to obtain a reliable estimate of the data spectrum: Z ave ðkÞ ¼
S 1X Z ðsÞ ðkÞ; S s¼1
k ¼ 0; 1; . . .; K 2 1:
The averaged Fourier transform estimates the data spectrum at K discrete equispaced frequency points of the form {2p k=K; k ¼ 0; 1; . . .; K 2 1}. This expression is more precise than the single FFT transform and the variation between the different spectrums gives a good approach of the uniformity of the signal in terms of frequency contents. The spectral contents of the signal provided by the averaged FFT transform are presented on the spectrogram. Each column of the spectrogram corresponds to a frequency component contained in the initial signal. Its amplitude corresponds to the power of the specific component and its position on the frequency axis indicates the specific frequency it corresponds to. One point of interest is the calibration of the horizontal axis in order to indicate the exact values of frequencies or the equivalent wavelength.
lmin ¼ 2l ¼ 2
L N
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where lmin is the minimum wavelength appearing on the spectrogram, l is the sampling interval, L is the mean scanned length and N is the total samples number. Results Plain weave The numerous FFT’s were calculated for each position of the “sliding” window on the initial signal. Since the window has a length of 128 samples and the total samples number is 260 it is possible to calculate up to 13 partial FFT of the signal corresponding to the various positions of the “sliding” window. The FFT of the warp direction of the samples used is shown in Figure 7. The strongest frequency components of the 13 successive spectrograms are located in the same position. It is an indication that the information is distributed equally on the total length of the 260 samples of the signal and it does not depend on the position of the sliding window. A further result of this observation is that it is safe to use the averaged FFT of the initial signal without any loss or distortion of the information contained. In the weft direction the relationship between the various FFT spectrograms of the sliding window is the same as it happens in the warp direction, i.e. the averaged FFT is absolutely the representative concerning the frequency contents of the geometrical roughness signal. The sample of the plain weave fabric has the following structural characteristics: . Warp: Ne 30/2, 25 threads/cm . Weft: Ne 20/1, 22 threads/cm . Weight per unit area: 230 g/m2 In the spectrogram of Figure 8, the strongest frequency component corresponds to the wavelength of 0.451 mm. As it is already given, the threads density of the weft of the sample is 22 threads/cm or their spacing is 0.454 mm. The surface scanning in the warp direction detects the periodic variation of the surface due to the weft threads. The error
Figure 7. FFT’s of surface roughness signal (sliding window)
Structural characterization of textile fabrics 453
Figure 8. Averaged FFT of warp direction
between the real threads spacing and the one detected by the FFT of the geometrical roughness signal is less than 0.7 per cent. The scanning in the weft direction due to the more intense presence of the warp threads gives more than one main peak of comparable power. There is a first peak on the wavelength of 0.43 mm, when the real distance between the yarns of the sample is 0.42 mm. The error is about 2.5 per cent. It is interesting to observe that a next peak is detected on the wavelength of 0.82 mm corresponding practically to the first harmonic wavelength (corresponding to the subharmonic frequency) of the basic one. It is obvious that in the weft direction the method of obtaining structural data based on the surface roughness of the fabric provides less reliable results due to the domination of a set of the yarns over the surface of the fabric (Provatidis et al., 2003) (Figure 9).
Figure 9. Averaged FFT of weft direction
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Twill weave The surface of the twill fabric is characterised by the successive diagonal ribs. The slope of the ribs depends on the specific twill weave as well as on the structural characteristics of the fabric (warp and weft density etc.). A twill fabric 2/2 has been used with the following characteristics: . Warp: Ne 24/2, 21 . Weft: Ne 40/2, 25 threads/cm . Weight per unit area: 245 g/m2 A specimen was subjected to geometrical roughness measurement in the warp and weft directions as well as additionally in another three equispaced directions in between the initial ones, i.e. 22.58, 458, 67.58. This procedure establishes the multidirectional scanning of the fabric. The geometrical roughness signals obtained have been processed in the same way as in the case of the plain weave fabrics. Using the sliding window principle the FFT of the particular signals have been calculated. For every measuring direction the averaged FFT has been defined. The spectra of the averaged FFT are shown in Figure 10. It is obvious that a strong frequency component appears when the scanning angle approaches the vertical direction to the ribs of the fabric. It is the dominating wavelength component characterizing the geometrical roughness of the twill fabric. This wavelength is characteristic of the twill fabric during its use. The users of the twill fabrics very often feel the characteristic vibration caused by the rubbing of two parts of the fabric. Thus, this main wavelength component is a sensorial characteristic of the fabric. Knitted fabrics A set of 19 knitted fabrics has been subjected to surface roughness testing. The fabrics belong to three structural categories: single jersey, double jersey and interlock. The three kinds of knitted fabrics were constructed using conventional
Figure 10. FFT in multiple directions (twill fabric)
and compact cotton yarns. In many cases each category of the fabrics was available in their raw form, after the dyeing procedure and after the application of a softening agent. The density of the courses and wales has been kept constant within the three categories of knit. The linear density and the twist multiplier of the yarns were the same for all the specimens. There will be various samples deriving from the combination of the main parameters: Knit, yarn technology, dyeing stage. The specimens will be subjected to laboratory surface roughness tests. The surface roughness data have been processed using the sliding window averaged FFT method and the final results are given in the Table I. The wavelengths of the main spectral components were detected and they become an instrument for the evaluation of the surface roughness structure. The results show a very good stability on the geometrical roughness characteristics of the various samples belonging to the same knit group. The coefficient of variation between the wavelengths of the main spectral components within each group is very low between 0.7 and 2.3 per cent. The low values of the CV per cent indicate that the different yarn production technologies and the different finishing stages do not influence significantly the wavelength of the main spectral component of the geometrical roughness signal. Table II contains the CV per cent of the three main categories of the fabrics grouped depending on their knit. A further interesting result derived from the processed data is the correlation between the normalized wavelength of the main spectral components in the courses
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
KNa
Fb
SPc
pd1 (mm)
pe2 (mm)
X1f
Yg1
X2h
Y2i
SJ SJ SJ SJ SJ SJ SJ DJ DJ DJ DJ DJ DJ IL IL IL IL IL IL
D D S S G G G D D S G G G D D S G G G
K K K C C K K C K K K K C K C C C K K
0.714 0.714 0.714 0.714 0.714 0.714 0.714 0.909 0.909 0.909 0.909 0.909 0.909 0.769 0.769 0.769 0.769 0.769 0.769
0.526 0.526 0.526 0.526 0.526 0.526 0.526 0.625 0.625 0.625 0.625 0.625 0.625 0.769 0.769 0.769 0.769 0.769 0.769
0.269 0.279 0.281 0.292 0.278 0.273 0.274 0.257 0.294 0.298 0.326 0.308 0.289 0.341 0.337 0.334 0.356 0.336 0.323
0.353 0.353 0.339 0.357 0.338 0.335 0.323 0.300 0.303 0.306 0.274 0.276 0.279 0.319 0.344 0.337 0.304 0.313 0.322
0.377 0.391 0.393 0.409 0.389 0.382 0.384 0.283 0.323 0.328 0.359 0.339 0.318 0.443 0.438 0.434 0.463 0.437 0.420
0.671 0.671 0.644 0.678 0.642 0.636 0.614 0.480 0.485 0.490 0.438 0.442 0.446 0.415 0.447 0.438 0.395 0.407 0.419
Notes: aKnit: single jersey (SJ), double jersey (DJ), interlock (IL). bFinishing: gray(G), dyed (D), softened (S). cSpinning technology: conventional (C), Compact (K). dCourse spacing ( p1). eWale spacing ( p2).fWavelength of the main spectral component in the course direction (X1). gWavelength of the main spectral component in the wale direction (Y1). hNormalised wavelength of the main spectral component in the course direction (X2). iNormalised wavelength of the main spectral component in the wale direction (Y2)
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Table I. Knitted fabric surface roughness data
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and wales direction. As shown in Figure 11, the points on the graph are grouped in certain areas, which are the characteristic of the knit of the fabric. All the specimens of the knitted fabrics give correlation points of their main wavelength, which belong to an area essentially different from the rest ones.
456
Conclusions The geometrical roughness characteristics of the fabrics provide information on their structural characteristics. The data obtained from the KES-FB4 instrument were subjected to digital signal processing techniques in order to get the spectral characteristics of the geometrical roughness measurements. The components of higher power and thus dominating in the resulting spectrum give useful information about the structure of the fabric and they influence the final behaviour of the fabric in terms of hand or other sensory characteristics. The principle and the results are encouraging although the method has to be verified on a bigger variety of fabrics of different properties and structural characteristics to strengthen the correlation between the spectral results to the structure of the fabric and the effects of its geometrical roughness.
Table II. CV per cent of the positions of the main wavelength components
Figure 11. Correlation of the normalised main frequency components position (X2 vs Y2)
Single jersey Double jersey Interlock
CVcourse (per cent)
CVwale (per cent)
0.74 2.29 1.08
1.22 1.48 1.49
References Bueno, M.A., Lamy, B., Renner, M. and Viallier, P. (1996), “Tribological investigation of textile fabrics”, Wear, Vol. 195, pp. 192-200. Castellini, C., Francini, F., Longobardi, G. and Tiribilli, B. (1996), “Online textile quality control using optical fourier transforms”, Optics and Laser in Engineering, Vol. 26, pp. 19-32. Kawabata, S. (1989), “Nonlinear mechanics of woven and knitted materials, in textile structural composites”, Composite Materials Series, Vol. 3, Elsevier Science, Amsterdam, ISBN 0-444-42992-1. Kawabata, S. and Niwa, M. (1998), “Clothing engineering based on objective measurement technology”, International Journal of Clothing Science and Technology, Vol. 10 Nos 3/4, pp. 263-72. KES (1991), Manual for Surface Tester KES-FB4, Kato Tech Co. Ltd, Japan. Papoulis, A. (1962), The Fourier Integral and its Applications, Mc-Graw Hill, New York, NY. Provatidis, C., Vassiliadis, S., Rangussi, M. and Prekas, K. (2003), “Retrieval of structural parameters of textile fabrics from surface roughness data obtained from KES-F measurements”, Proceedings of the 4th International Conference: Innovation and Modelling of Clothing Engineering Processes – IMCEP 2003, ISBN 86-435-0575-7, pp. 149-56. Xu, B. (1996), “Identifying fabric structures with fast Fourier transform techniques”, Textile Research Journal, Vol. 66 No. 8, pp. 496-506.
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458 Received October 2003 Revised June 2004 Accepted June 2004
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COMMUNICATIONS
A statistical model for developing body size charts for garments D. Gupta and B.R. Gangadhar Department of Textile Technology, Indian Institute of Technology Delhi, New Delhi, India Keywords Clothing, Human anatomy, Statistical analysis, Charts Abstract A simple easy to follow statistical approach has been proposed for developing body size charts from anthropometric data. It has been possible to cover 95 percent of the population using 11 size charts. Multivariate analysis was carried out to detect relationships between variables. Principal component analysis was carried out to identify the key body measurements which can form the basis for classifying the population. Bust for the upper body and hip for the lower body were identified as the critical dimensions affecting garment fit. Body shapes and their distribution within the population have been identified. Validation of size charts was done by calculating the aggregate loss of fit.
Introduction The process of developing body size charts involves taking anthropometric body measurements of the target population and its division into homogeneous groups for the purpose of garment manufacture. Indian men and women have always worn traditional Indian dresses which are mostly draped, such as the dhoti, sari, angavastram, dupatta, or lungi. These garments are not stitched hence there was not any need for sizes. The few structured garments (such as salwar-kameez) which have evolved and are being sold as RTW are based on the concept of “One size fits all”. No attempt has been made to measure up the population at the national level and so till date no body size charts are available for the Indian population. Currently, India is poised on the brink of a major retail revolution. The younger generation is fast changing its dressing habits and western clothes are becoming more and more popular in the cities as well as suburbs. It is at this stage that an acute need is felt for an efficient garment sizing system. RTW for men is based mostly on the sizes prevalent in the international market. As the fit is less critical in that category, the market could exist and mature without any size charts. But as the women adopt formal western wear and demand more fashionable and better fit – the survival of the manufacturer or retailer will depend on the “goodness of fit” provided by his garments. A detail review was undertaken to study the various sizing systems reported in literature. It was found that statistical methods ranging from simple percentiles to complex combinations of multivariate and regression analyses have been employed for distribution of population into subgroups. More recently, it has been possible to International Journal of Clothing Science and Technology Vol. 16 No. 5, 2004 pp. 458-469 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220410555641
The authors are extremely thankful to ITC Limited, Lifestyle Retailing Business Division, India for allowing the use of the anthropometric data set for this study. Help provided by Dr Lipika Dey, Assistant Professor, Department of Mathematics at IIT Delhi with the mathematical analysis is gratefully acknowledged.
employ powerful mathematical techniques with much better results. Some of the important approaches listed in the literature are briefly discussed below. In a study by Salusso (1982), the principal component sizing system (PCSS) has been used for classifying adult female body form with respect to the US Standard for apparel sizing. This approach is useful in identifying the critical body or the fit affecting dimensions which can form the basis of size chart development. Researchers found that 15 principal components can be used to summarize trends in body form variation. Principal components 1 and 2, i.e. laterality (fullness) and linearity (length), respectively, were selected to describe body size and type. In another study, Tryfos (1986) suggested an integer programming approach to optimize the number of sizes so as to maximize expected sales or minimize an index of aggregate discomfort. He divides the space of body dimensions artificially into a set of discrete possible sizes. The problem is formulated as a “p median” or “Facility Location problem”. Another novel approach for the construction of apparel sizing systems has been proposed by McCulloch et al. (1998) based on the goodness of fit that an individual experiences when wearing a garment of a particular size. Using this measure known as aggregate loss, various existing US sizing systems were compared (Ashdown, 1998). Non-linear optimization techniques were used to derive a set of possible sizing systems from anthropometric data. Results showed that size assignment as well as the ability to identify non-accommodated individuals results in substantial improvements in fit over existing sizing systems. Most techniques used so far are rather complicated and based on complex mathematical calculations. The current study was undertaken with the aim of developing an easy to follow statistical model for developing body size charts for garment manufacture. The model has been demonstrated using a recent anthropometric data set available for young Indian females. Material and methods Anthropometric data for 2,095 Indian women from six metro cities in India were used. A total of 21 measurements were recorded for each subject. These included 9 linear and 12 girth measurements as shown below: Linear measurements: (1) height, (2) waist length from center front, (3) cervical to natural waist, (4) cervical back to natural waist, (5) cervical height, (6) outside leg length, (7) inside leg length, (8) arm length, and (9) shoulder width Girth measurements: (1) neck girth at midway level, (2) neck girth at neck base,
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(3) (4) (5) (6) (7) (8) (9) (10) (11) (12)
round bust, natural waist, intended/artificial waist, hip 4 (hip measured at 4 inch below the natural waist), hip 6 (hip measured at 6 inch below the natural waist), thigh, ankle, knee, upper arm, and wrist
Methodology Statistical analysis of anthropometric data All analyses were conducted using statistica Ver 6.0 and Microsoftw Excel 2000. Mean, median, range, skew and SD for the important measurements were calculated. Multivariate analysis of the dataset were carried out with a view to reduce the number of variables (which would form key dimensions) and to detect structure in the relationships between variables. Principal component analysis (StatSoft, Inc., 2002) The aim of principal component analysis is the construction of a set of variables “Xi”s ði ¼ 1; 2; . . .kÞ; of a new set of variables (Pi) called principal components, which are linear combinations of the “X”s. These combinations are chosen so that the principal components satisfy two conditions: (1) the principal components are orthogonal to each other, and (2) the first principal component accounts for the highest proportion of total variation in the set of all “X”s, the second principal component accounts for the second highest proportion and so on. Figure 1 shows a two dimensional data set (plotted in the X1-X2 plane) which is divided into two clusters. The variations of the data along the axes are also shown. In the current problem, this technique needs to be applied to a 20 one dimensional data set. This technique was used to identify the key dimensions which can form the basis of a sizing system for garments. Results and discussion Univariate analysis At the outset, the range, mean and median for all the body dimensions were calculated. Results for three measurements are reported in Table I. As expected, data for all measurements showed a near normal distribution. Care was taken to identify the outliers under each parameter so that they could be eliminated during the final analysis. This would help to improve the accuracy of the size charts.
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Figure 1. Principal components
Dimension Height Bust Waist
Maximum
Minimum
Range
SD
Skew
Mean
Median
78.74 53.5 45.31
53.15 20.75 18.69
25.59 32.75 26.62
2.46 3.18 3.29
0.308 0.31 0.83
61.72 32.37 27.01
61.61 32.37 26.57
Table I. Univariate analysis of the height, bust and waist dimensions (in inches)
Height as a critical dimension. The first classification of population data was carried out on the basis of height of subjects. The population was divided into three height categories, namely: (1) Short¼ , Mean 2 SD, (2) Medium ¼ Mean ^ SD, and (3) Tall ¼ . Mean+SD. Results are reported in Table II. The height distribution for Indian women was compared with some data available for western women (Cooklin, 1999) (Table III). An overwhelming percentage of women (73 percent) in the Indian data set is concentrated in the medium height category. Indian women are found to be shorter in all categories. Women in the US are the tallest followed by the European women. Analysis of girth parameters. Population data for bust and waist were also analyzed. Results are compiled in Table I. Majority of the population has a bust measurement between 31 and 33 inch. This is a very narrow range of bust distribution for such
Category
Height (inch)
Count (percent)
Max.
Min.
Avg.
Short Medium Tall
,59 59-64 .64
352 (10.55) 1522 (72.65) 352 (16.80)
58.98 63.98 78.74
53.15 59.06 64.02
57.64 61.45 65.46
Table II. Height categories and their distribution in the sample data
IJCST 16,5
a large data set. It indicates that there is possibly a bias in the data toward the younger women. The frequency distribution for the waist shows a concentration around waist of 25-27 inch and few data entries in the range of 15-20 inch and 40-45 inch. These latter entries may constitute the outliers, which a conventional sizing system cannot cater to. Special size categories would have to be developed to cater these outliers.
462 Multiple correlation analysis Multiple coefficient analysis was carried out to determine the interrelationships between the various body parameters. BS 7231 (BSI, 1990) standard was taken as a guideline for identifying the key parameters from the correlation matrix shown in Table IV. According to this standard:
Country
Table III. The height (in cm) distribution of populations of major nations
Table IV. Correlation co-efficients of key dimensions
USA England West Germany France India
Short 155 150 156 152 146
Medium
(46) (24) (31) (28) (10)
165 160 164 160 156
Tall
(45) (55) (47) (51) (73)
175 170 172 168 166
(9) (19) (22) (16) (17)
Notes: Values in parentheses indicate the percent of total population in each group
Dimension
Height
Nat waist
Hip 6
Bust
Height Cervical height Natural waist Waist length_center front Cervical _natural waist Center back_natural waist Artificial waist Outer leg Inner leg Hip 4 Hip 6 Thigh Knee Ankle Bust Upper arm girth Wrist Neck_mid Neck_neck Arm length Shoulder_shoulder Outer leg-inner leg
1 0.866 0.104 0.172 0.246 0.235 0.139 0.713 0.52 0.185 0.204 0.127 0.205 0.179 0.132 0.073 0.146 0.18 0.138 0.48 0.275 0.116
0.104 0.139 1 0.224 0.33 0.124 0.801 0.08 0.101 0.78 0.752 0.541 0.478 0.201 0.781 0.49 0.279 0.638 0.484 0.109 0.348 2 0.035
0.204 0.224 0.752 0.138 0.277 0.091 0.74 0.185 0.173 0.919 1 0.611 0.55 0.243 0.714 0.472 0.275 0.581 0.435 0.136 0.326 20.013
0.132 0.159 0.781 0.242 0.39 0.167 0.716 0.11 0.07 0.74 0.714 0.562 0.507 0.218 1 0.467 0.252 0.62 0.488 0.125 0.347 0.031
. .
.
if correlation co-efficient is , 0.5 then no relationship; if correlation co-efficient is between 0.5 and 0.75 then there is a mild relationship; and if correlation co-efficient is . 0.76 it indicates a strong relationship.
All length measurements appear to have good correlation among themselves and all girth measurements have good correlation with each other. However, there is poor correlation among the length and girth parameters. This is a significant finding as most empirical size charts are based on a linear increment across all measurement in all sizes. In other words, it is assumed that as the body grows in girth it also grows correspondingly in length or height. It is because of this assumption that the existing sizing systems yield a good fit for only 20 percent of the population they are intended for. Four body dimensions having good correlation with maximum of other dimensions were identified as key dimensions (Table IV). They are as follows. (1) Bust: has mild to strong correlation with seven other body dimensions; (2) Hip: has mild to strong correlation with seven other body dimensions; (3) Natural waist: has mild to strong correlation with six other body dimensions; and (4) Height: has mild to strong correlation with three major linear body dimensions. From these findings it may be concluded that bust measurement for the upper body and hip measurement for the lower body garments are the most critical measurements. Waist is common to both top and lower body garments, but may not be so critical as it is adjustable in most garments. In general, it can be inferred that these four dimensions are the important landmarks on the body and hence should be related closely to the garment measurements. Principal component analysis In the next step, prinicipal component analysis was carried out in order to reduce the number of variables and to detect the structure in the relationships between variables. The first five principal components (factors), accounting for 66.97 percent of the total variability in the data set were identified (StatSoft, Inc., 2002). Results are reported in Table V. They further endorse the results obtained from the multiple correlation analysis. Based on the interrelationships existing in the data set, the body measurements have been classified as follows: (1) Principal component 1 has high loadings (large co-efficients) on all girth related dimensions, i.e. natural waist, artificial waist, hip 4, hip 6 and bust. (2) Principal component 2 has high loadings on all height related dimensions, i.e. height, cervical height, outer leg and inner leg. (3) Principal component 3 has high loadings on upper body dimensions, i.e. waist length from center front, cervical to natural waist and cervical back to natural waist. (4) Principal component 4 has high loadings on lower body dimensions, i.e. inner leg length and crotch length. (5) Principal component 5 has high loadings on girth related dimensions of neck, arm and leg.
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Table V. Principal component analysis (revised)
Dimension
Factor 1
Factor 2
Factor 3
Factor 4
Factor 5
Height Cervical height Natural waist Waist length_center front Cervical _natural waist Center back_natural waist Artificial waist Outer leg Inner leg Hip 4 Hip 6 Thigh Knee Ankle Bust Upper arm girth Wrist Neck_mid Neck_neck Arm length Shoulder_shoulder Outer leg – inner leg
0.02 0.03 0.09 0.02 0.03 0.01 0.09 0.02 0.01 0.10 0.10 0.06 0.06 0.02 0.09 0.05 0.02 0.08 0.05 0.01 0.03 4 £ 102 5
0.20 0.19 0.03 0.01 0.01 0.02 0.02 0.19 0.12 0.02 0.01 0.01 0.00 0.00 0.02 0.01 1 £ 102 5 0.01 0.01 0.10 0.005 0.00
0.01 0.01 0.00 0.29 0.26 0.23 0.00 0.03 0.05 0.01 0.02 0.01 0.01 0.00 0.00 0.00 9 £ 102 5 0.01 0.01 0.01 0.0443 0.01
0.01 0.008 7 £ 102 6 0.01 0.00 0.02 0.00 0.05 0.23 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.02 0 5 £ 102 5 0.00 0.0062 0.61
0 0.00 0.018 0.01 0.02 0.03 0.03 0.00 0.01 0.05 0.04 0.01 0.00 0.14 0.01 0.04 0.31 0.06 0.18 0.01 0.02 0.01
These findings provide the framework for size chart development in this study. Based on these results the first classification of population was done on the basis of height (Principal component 2). This represents all height related parameters. The height categories were subdivided on the basis of ratio of critical girth measurements namely bust and hip (Principal component 2) to arrive at the body shapes. Results are discussed below. Classification of population into body types Classification on the basis of height The population was divided into three height categories as indicated earlier. They are tall: $ 64 inch; short: # 59 inch and medium: 59-64 inch. Drop value Within the height categories, the population was further categorised on the basis of key girth dimensions. Bust for the upper body and hip 6 for the lower body were identified as the most critical dimensions as they show mild to good correlation with maximum number of body dimensions. For identifying the overall body shape, a derived parameter drop value was used, which is the difference between the hip and bust measure (hip 6-bust). Drop values help to identify distinct relationships between key dimensions that determine body shape. Based on drop values, the population under each height group was classified into six categories as shown in Table VI (Cooklin, 1999). Each category corresponds to one of the generally perceived body shapes namely: . triangle or pear shaped (bust much smaller than hip), as in category 1; . inverted triangle (bust much bigger than the hip), as in category 6;
. .
A statistical model
rectangle (bust is equal to hip) as in category 4; and the other categories lie in between these.
Within each bust category identified on the basis of drop value, hip 6 and bust have a linear relationship. This means that either one of these can be used as the basis for generation of body measurement tables or more suitably, bust measurement can be used as the basis of classification for the upper body garments and hip 6 can be used for classifying the lower body garments. A closer look at the various body dimensions after classification of each individual case revealed the outliers having improbable drop values in the range of 8-27 inch. A general size chart cannot cater to these extremes thus a total of 32 individuals (1.53 percent of the sample data) with improbable measurements were eliminated. They mostly belonged to the category of very small bust or extralarge bust. Results obtained for Indian women in various categories are compared in Table VII with figures reported for western women (Cooklin, 1999). It is observed that for the
S. no.
Category
Hip 6-bust (inch)
1 2 3 4 5 6
Very small bust Small bust Medium bust Full bust Large bust Extra large bust Total
.6 4-5 2-3 0 to 2 1 2 1 to 24 . 24
Short 21 77 86 26 9 2 221
(1) (3.68) (4.11) (1.24) (0.43) (0.09) (10.5)
Medium 274 522 508 179 31 8 1522
(13.08) (24.92) (24.25) (8.54) (1.48) (0.38) (72.6)
Tall
Total(percent)
87 133 95 32 5
(4.15) (6.35) (4.53) (1.53) (0.24) – 352 (16.8)
18.23 34.95 32.89 11.31 2.15 0.47 100
Notes: Values in parentheses indicate the percent of total population
Bust type
Height group
V small
Short Medium Tall Short Medium Tall Short Medium Tall Short Medium Tall Short Medium Tall Short Medium Tall
Small Medium Full Large Extra large
USA
England
West Germany
France
India
– – – 10 10 1 21 21 5 14 15 3 – – – – – –
1 3 2 5 12 5 9 20 7 7 14 4 2 5 1
– – – 11 16 7 15 23 10 5 8 5 – – – – – –
– – – 11 19 6 12 23 7 5 9 3 – – – – – –
1 – 4 4 25 6 4 24 5 1 8 2 0.4 2 0.2 0.1 0.4 –
1
465
Table VI. Body types obtained on the basis of drop 2 value (hip 6-bust)
Table VII. Distribution of bust types among population of major nations
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466
Indian sample the data are skewed toward the small and medium bust categories with the least number of subjects in the large bust category. Development of size charts Having classified the population into three height categories and six body shapes, size charts for each category were developed adopting the empirical approach. The range for each body dimension under each category was identified. In order to cater all individuals, the range was spread with constant gradient over the population. A gradient of 2 inch between two consecutive sizes for key dimensions namely bust, waist and hip was maintained. The bust girth size interval of each size chart is used as the basis for all comparative calculations. For other dimensions, suitable grades were empirically determined and spread over the sizes. Some body dimensions like cervical height, center back to natural waist, center front to natural waist, etc., do not change much from one size to another. This can be attributed to the fact that the sizes are being developed from pre classified dimensions. In all, 11 size charts have been proposed covering 96.38 percent of population. The population covered by each category is given in parentheses. . Short height – small bust (3.68 percent), medium bust (4.11 percent) and full bust (1.24 percent). . Medium height – very small bust (13.08 percent), small bust (24.92 percent), medium bust (24.25 percent) and full bust (8.54 percent). . Tall height – very small bust (4.15 percent), small bust (6.35 percent), medium bust (4.53 percent) and full bust (1.53 percent). A representative chart for the short height-small bust category is given in Table VIII.
Bust
Table VIII. Size chart for the short height, small bust category
Hip 6 Natural waist Waist length-Center front Cervical-waist Center back-waist Thigh Knee Ankle Upper arm Wrist Neck mid Neck-neck Shoulder Height Outer leg length Inside leg length Agg. loss
26
28
30
32
34
36
38
40
Grade
30 22 9 11 11 14 11 8 8 5 11 11.5 13 53 36 26 1.84
32 24 9.5 12 11.5 16.25 12.5 9.5 9 5.25 11.5 12 14 54 36.5 26.5 1.19
34 26 10 13 12 18.5 14 11 10 5.5 12 12.5 15 55 37 27 1.89
36 28 10.5 13.5 12.5 20.75 15.5 12.5 11 5.75 12.5 13 15.5 56 37.5 27.5 2.32
38 30 10.5 13.5 13 23 17 14 12 6 13 13.5 16 57 38 28 1.57
40 32 10.5 13.5 13 25.25 18.5 15.5 13 6.25 13.5 14 16.25 58 38.5 28.5 1.23
42 34 10.5 13.5 13 27.5 20 17 14 6.5 14 14.5 16.5 59 39 29 3.79
44 36 10.5 13.5 13 29.7 21.5 18.5 15 6.75 14 14.5 16.5 60 39.5 29.5 2.02
2 2 0.5 – – 2.25 1.5 1.5 1 0.25 0.5 0.5 – 1.0 0.5 0.5
Notes: All measurements are in inches
Validation of the proposed size charts Having proposed the size charts, the final step lies in validating the same. For this purpose, a measure known as the aggregate loss of fit (McCulloch et al., 1998) was employed. An optimal sizing system with a given number of sizes would have the lowest value of aggregate loss where the average distance of individuals from their size is as low as possible. It was calculated as the average of the Euclidean distance in three dimensional space of the individuals from their allocated size using the following formula: X p ðassigned bust 2 actual bustÞ2 þ ðassigned hip 2 actual hipÞ2 Aggregate loss ¼ 2 þ ðassigned waist 2 actual waistÞ ðNumber of individuals in the categoryÞ Validation of the proposed size charts was done based on different criteria because different set of body measurements are relevant while buying different garments. For example, bust may determine the size for an upper body garment such as a shirt, while this measurement is not needed while buying a skirt or a pair of trousers. Hence for each body dimension, various values for the aggregate loss were calculated as follows. (1) Bust, natural waist and hip with bust as the key dimension. (2) Bust, natural waist and hip with natural waist as the key dimension. (3) Bust, cervical to natural waist, center back to natural waist, center front to natural waist, shoulder width, neck girth at midway and neck girth at neck base to validate for the upper body dimensions needed for a shirt. (4) Natural waist, hip, outer and inner leg seam dimensions needed for lower body measurements such as those required for trousers and skirt. Selection of the body dimensions used for validation was based on the principal components obtained earlier. Body dimensions such as arm length, arm scye, wrist, thigh, knee, angle, were not considered during the calculation of the aggregate loss as they are not key areas for fit. However, optimization of these dimensions will be integral to a good size chart. The ideal value for aggregate loss of fit will be a number given by the square root of the number of body dimensions considered – allowing for ^ 1 inch deviation of the body dimension from the assigned size. Thus, for the calculation of the aggregate loss considering p three body dimensions, the allowable aggregate loss of the goodness of fit would be 3, i.e. 1.73 inch Based on this understanding, multiple analyses were carried out using 3, 4, 5 and 7 measurements. . Two analyses were carried out using three body dimensions each. One for the top body using cervical to natural waist, center back to natural waist, center front to natural waist and the second for the lower body using, waist, outer and inner leg. The ideal value for aggregate loss of goodness of fit in each case would be 1.73. . Considering four body dimensions, namely bust, cervical to natural waist, center back to natural waist and center front to natural waist. The ideal value for aggregate loss of goodness of fit would be 2.00.
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467
IJCST 16,5
.
.
468
Considering five body dimensions required for a dress – namely, bust, shoulder width, cervical to natural waist, center back to natural waist and center front to natural waist. The ideal value for aggregate loss of goodness of fit would be 2.23. Considering seven body dimensions required for a formal shirt namely bust, shoulder width, mid neck girth, base neck girth, cervical to natural waist, center back to natural waist and center front to natural waist. The ideal value for aggregate loss of goodness of fit would be 2.65.
The summary of aggregate loss of goodness of fit obtained for short height-small bust category is given in Table IX. The total aggregate loss for this category is 1.84 inch against the benchmark value of 1.73. Results for medium and tall height categories using different sets of measurements are reported in Tables X and XI. The values obtained for proposed tables are quite close to the ideal value for aggregate loss of fit. Thus, it is obvious that the proposed size charts are quite accurate. Since the data has been sorted on the basis of drop value, the contribution of bust and hip measurements to aggregate loss can be expected to be minimum. The difference of actual size of waist from that of assigned sizes will be more. Thus, aggregate loss can be taken as a measure to assess the conformance of the actual waist measurements observed in the population to that of the assigned sizes with respect to bust and hip.
Bust type Very small Small Medium Full Table IX. Aggregate loss for different dimensions in short height category
– 1.84 1.69 2.39
– 4.47 2.18 3.26
– 1.83 2.01 2.05
– 1.94 2.12 2.16
– 2.25 2.42 2.41
– 2.49 2.69 2.71
– 2.3 2.86 3.08
Notes: aCervical to natural waist, center back to natural waist, center front to natural waist; bbust, cervical to natural waist, center back to natural waist and center front to natural waist; cbust, shoulder width, cervical to natural waist, center back to natural waist and center front to natural waist; and d bust, shoulder width, mid neck girth, base neck girth, cervical to natural waist, center back to natural waist and center front to natural waist
Bust type Very small Small Medium Full Table X. Aggregate loss for different dimensions in medium height category
Body type Upper body Based Based Three Four Five Seven a on bust on waist dimensions dimensionsb dimensionsc dimensionsd Lower body
Body type Upper body Based Based Three Four Five Seven a on bust on waist dimensions dimensionsb dimensionsc dimensionsd Lower body 6.54 2.05 3.63 1.93
9.29 4.12 2.93 2.32
2.2 2.72 2.67 2.54
2.31 2.8 2.74 2.77
2.7 3.12 2.98 3.05
3.01 3.35 3.23 3.36
3.03 2.67 2.98 2.59
Notes: aCervical to natural waist, center back to natural waist, center front to natural waist; bbust, cervical to natural waist, center back to natural waist and center front to natural waist; cbust, shoulder width, cervical to natural waist, center back to natural waist and center front to natural waist; and d bust, shoulder width, mid neck girth, base neck girth, cervical to natural waist, center back to natural waist and center front to natural waist
Bust type Very small Small Medium Full
Body type Upper body Based Based Three Four Five Seven on bust on waist dimensionsa dimensionsb dimensionsc dimensionsd Lower body 4.91 2.24 1.99 3.58
6.77 2.95 2.45 4.87
2.57 2.26 2.04 2.72
2.64 2.34 2.15 2.99
2.88 2.71 2.47 3.23
3.36 3.08 2.84 3.61
3.05 2.35 1.76 2.64
Notes: aCervical to natural waist, center back to natural waist, center front to natural waist; bbust, cervical to natural waist, center back to natural waist and center front to natural waist; cbust, shoulder width, cervical to natural waist, center back to natural waist and center front to natural waist; and d bust, shoulder width, mid neck girth, base neck girth, cervical to natural waist, center back to natural waist and center front to natural waist
Conclusions A simple statistical approach has been proposed for developing body size charts for women. Using a linear grading technique, 11 size charts for Indian women have been developed. It could be shown experimentally that bust girth rather than waist girth should be the basis for apparel sizing as this gives lower aggregate losses in most categories. For the lower body hip girth was identified as the most critical dimension The sizing system has been optimized with respect to three key dimensions simultaneously so as to obtain a minimum aggregate loss value. The proposed size charts indicate only body measurements. The actual garment measurements can be derived by incorporating the ease and design allowances. References Ashdown, S.P. (1998), “An investigation of the structure of sizing systems”, International Journal of Clothing Science and Technology, Vol. 10 No. 5, pp. 324-41. BSI (1990), BS 7231, Part 1, Body Measurements of Boys and Girls from Birth to 16.9 Years, British Standards Institution, London. Cooklin, G. (1999), Pattern Grading for Women’s Clothes – the Technology of Sizing, Blackwell Science Ltd, Oxford, UK, pp. 3-18. McCulloch, C.E., Paal, B. and Ashdown, S.P. (1998), “An optimization approach to apparel sizing”, Journal of the Operational Research Society, Vol. 49 No. 5, pp. 492-9. Salusso, C.J. (1982), “A method for classifying adult female body form variation in relation to the US Standard for apparel sizing”, Doctoral Dissertation, University of Minnesota, available at: www.wsu.edu:8080/~salusso/BODY/s.html StatSoft, Inc. (2002), Electronic Statistics Textbook, Tulsa, OK. available at: www.statsoft.com/ textbook/stathome.html. Tryfos, P. (1986), “An integer programming approach to the apparel sizing problem”, Journal of the Operational Research Society, Vol. 37 No. 10, pp. 1001-6. Further reading Ashdown, S.P. and Delong, M. (1995), “Perception testing of apparel ease variation”, Applied Ergonomics, Vol. 26 No. 1, pp. 47-54.
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469 Table XI. Aggregate loss for different dimensions in tall height category
International Journal of Clothing Science and Technology
ISSN 0955-6222 Volume 16 Number 6 2004
International textile and clothing research register Editor-in-Chief Professor George K. Stylios
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EDITORIAL ADVISORY BOARD Professor Mario De Araujo Minho University, Portugal Professor H.J. Barndt Philadelphia College of Textiles & Science, Philadelphia, USA Professor Dexiu Fan China Textile University, Shanghai, China Professor B. Knez University of Zagreb, Croatia
Professor Masako Niwa Nara Women’s University, Nara, Japan Professor Issac Porat School of Textiles, UMIST, UK Professor Ron Postle The University of New South Wales, Australia
Editorial advisory board
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Professor Rosham Shishoo Swedish Institute for Fibre and Polymer Research, Molndal, Sweden
Professor Carl A. Lawrence University of Leeds, Leeds, UK
Professor Paul Taylor University of Newcastle, Newcastle upon Tyne, UK
Professor Trevor J. Little North Carolina State University, USA
Professor Witold Zurek Lodz Technical University, Poland
Professor David Lloyd University of Bradford, Bradford, UK
International Journal of Clothing Science and Technology Vol. 16 No. 6, 2004 p. 3 # Emerald Group Publishing Limited 0955-6222
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International Journal of Clothing Science and Technology Vol. 16 No. 6, 2004 pp. 4-5 Emerald Group Publishing Limited 0955-6222
Editorial The International Textile and Clothing Research Register Championing the Research Efforts of the Community The International Textile and Clothing Research Register (ITCRR) is in its tenth year of publishing the research efforts of our community. It provides a breadth of activity in the field of textile and clothing research and it encourages participation and dissemination to those working in this discipline and further afield. Again as you will see in this new edition, textile and clothing research is increasing in volume, in quality and in diversity, all good news for all of us involved in it. Research, development and innovation can, without doubt, give us more wisdom, enable our industries to become more competitive, and contribute to our quality of life. I believe that registering research projects will provide the due credit to originators of the research and contribute much more to the future development of this field. Groups of expertise can be identified in this manner, repetition and reinvention can be avoided, leading to best utilisation of time and funding for faster and better directed research in the international arena, since globalisation is on everybody’s agenda. The ITCRR has been set-up with all these things in mind. Textiles and clothing originate from the physiological need to protect ourselves from the environment. This has made necessary the art of hand knitting and weaving, and cut and sew processes, which have been evolving for many centuries. Although the original need for clothing has somewhat changed, mechanisation of this process started after the industrial revolution and has continued this century, with automation developments on a massive scale. Considering the upstream part of the whole textile and clothing production chain, yarn-making is the most highly automated area, followed by fabric, with high speed knitting and weaving machines. The downstream part of garment making, however, still remains probably the less developed connection in this chain; one that no doubt many of us have our eyes on as the candidate for development into the new century. With massive computerisation over the last 20 years, logistics and sales have also changed dramatically from pen and paper to electronic data interchange and electronic point of sale. New challenges are already upon us with nanotextiles; nanofibres nanocoatings, with multifunctional and smart textiles and clothing, and with wearable electronics. Consistent and extensive research and development in textile and clothing science and technology underpin all these developments by the international research community, whether in educational establishments, in research trade organisations, or in companies. IJCST has been set-up 15 year ago as a platform for the promotion of scientific and technical research at an international level. With the statement that the manufacture of clothing in particular needs to change to more technologically advanced forms of manufacturing and retailing, IJCST continues to support the community in these and other efforts. q Professor George Stylios
The journal continues with its authoritative style to accredit original technical research. The refereeing process will continue and will try to reduce waiting time during the refereeing process as much as possible. IJCST will be instrumental in supporting conferences and meetings from around the world in its effort to promote the science and technology of clothing. I praise the enthusiasm of our research community and those authors that have made IJCST an invaluable resource to all involved with textiles and clothing. I thank our editorial board for their continuous support and our colleagues who have acted in a refereeing capacity, with commitment to progress our research efforts. I take the liberty to list some of those names below (apologies in advance if anyone has accidentally been omitted from this list): . Professor Paul Taylor, University of Newcastle . Professor Haruki Imaoka, Nara Women’s University . Professor Mario De Araujo, University of Minho . Professor H.J. Barndt, Philadelphia College of Textiles and Science . Professor Masako Niwa, Nara Women’s University . Professor Jachym Novak, Vysoka Skola Sronjni a Tectilffi . Professor Isaac Porat, UMIST . Professor Roy R. Leitch, Heriot-Watt University . Professor Ron Postle, The University of New South Wales . Professor Gordon Wray, Loughborough University of Technology . Dr Taoruan Wan, University of Bradford . Professor David Lloyd, University of Bradford . Professor G.A.V. Leaf, Heriot-Watt University . Dr David Brook, University of Leeds . Dr C. Iype, University of Leeds . Dr Jaffer Amirbayat, UMIST . Dr Norman Powell, Leeds Metropolitan University . Dr David Tyler, Manchester Metropolitan University . Dr Jintu Fan, Hong Kong Polytechnic University . Dr Lubas Hes, University of Minho . Dr Jelka Gersak, University of Maribor . Dr Han Fan, Heriot Watt University Thank you all subscribers, authors, editorial board members, referees, publishing team, colleagues and students for your support and note that my address for correspondence is: Heriot-Watt University, School of Textiles, Netherdale, Galashiels, Selkirkshire, TD1 3HF, Scotland. E-mail:
[email protected] George K. Stylios Editor-in-chief
Editorial
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Alcoy-Alicante, Spain 6
Aitex, Asociacion de la Investigacion de la Industria Textil, P1, Emilio Sala, 103801 Alcoy-Alicante Tel: +0034 965 5442200; Fax: +0034 9655442200; E-mail:
[email protected] Chemical Laboratory Reyes Botı´
Near infrared analyzing method for properties of feathers and down: Feathers and Down Craf-1999-71488 Other partners: De Vries Holland Feathers and Down B.V. (Coordinator) Interplume, Ducky Dons Netherlan B.V. A. Molina and C. Spa Finnish Feather Naturtex TNO
Academic
Industrial
None Project started: 1 September 2002 Finance/support: 331.150e Source of support: European Commission Keywords: NIRA, Feathers and down
None Project ended: 31 August 2004
A fast and objective measurement technique has been identified that can help the European down and feather industry to reduce costs by decreasing the testing time and increase productivity. The implementation of this new testing method (NIRA) will represent technology transfer from the NIR industry to a more traditional testing environment. Thereby, its use will help to improve the working conditions in test laboratories in the down and feather industry and will lead to a marked reduction in chemical use. The net prospective cost savings to the European down and feather industry will be about 45 million euros. European down and feather products can be put in a competitive position and therefore imports from Far East countries can be blocked. The new testing method is expected to be commercially implemented 12 months after the completion of the project.
Project aims and objectives Industrial objectives and targets
(1) To provide a reliable, fast and easy to operate method for determining the most important quality aspects of feather and down at the same time: .
content of feather and down (percentage), species of the material.
.
fat content (percentage).
(2) To be able to determine the quality aspects before production starts and during the production, with a method robust enough and suitable to apply in the typical conditions in feather and down plants. (3) To better control our own production quality. (4) To develop an analysing method that can be commercially available for other feather and down companies, and will be paid back in 1 or 2 years at most. (5) To implement the developed technique into the existing labelling standards (e.g. EN 12934). Technical objectives (1) A quick availability of the results less than a few minutes. (2) Determination of the feather and down ratio with a deviation of less than 5 per cent. (3) Undoubtedly distinguish the species of the feather and down material. (4) Determination of the fat content with a deviation of less than 0.1 per cent. (5) A procedure for carrying out the measurements, including a working description. (6) The libraries of NIR-spectra and data of samples with known content of feather and down, species and fat content. These libraries are the essential part of the technique to be able to measure the desired parameters. (7) The feather and down samples can be used as reference material for future work in improving or adapting the technique or for other purposes. This can save time and money involved with the preparation of the samples. (8) A draft proposal for incorporating the technique into the existing standard methods will be set up and that may be evaluated by concerning parties like the companies and the European Down and Feather Association (EDFA). Economic objectives (1) Reduction in production losses because of poor quality. (2) Reduction of the time and cost needed to carry out testing. (3) New European suppliers of high quality feather and down can be established, because the import from Asian countries will be reduced. This will generate an extra turnover of e 10 million. (4) Increase of the competitiveness of the European feather and down industries as a whole.
Research deliverables (academic and industrial) .
Report on latest developments;
.
Samples of feather and down material to build up the library;
.
Measuring techniques (feather and down content, species, fat content);
.
Spectra library;
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Measuring procedure and pilot demonstration;
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Technical evaluation and cost-benefit analysis; Progress report about draft proposal;
. .
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Business plan.
Publications None
Alcoy-Alicante, Spain Aitex, Asociacion de la Investigacion de la Industria Textil, Pl, Emilio Sala, 103801 Alcoy-Alicante Tel: +0034 965 5442200; Fax: +0034 9655442200; E-mail:
[email protected] Chemical Laboratory Ana Carbonell
Optimization of cotton fabric processing for a flame retardant finish: G1ST-CT-2002-50270 Other partners: THOMOGLOU (Coordinator), ASTIR, LOUFAKIS, CLOTEFI, HABO, IFP, MOLTO, PYMAG, AITEX, LICOLOR, INOTEX, TECHNA
Academic
Industrial
None None Project started: 1 March 2003 Project ends: 28 February 2005 Finance/support: 661.460e Source of support: European Commission Keywords: Flame retardant, Added value textiles, Safety The flammability of textile fibers is a setback to many end-use applications of textile materials. Textile fibers when subjected to sources of ignition can ignite and burn, creating risk for the consumer. Most textile fibers are flammable in air unless they have been modified chemically during fiber production or processing to render them flame retardant (FR). The end-uses for fibers span an enormous range of products and activities and in many of these flame retardancy is an important aspect of the product performance: flame retardancy is required to protect life and property. The need for FR textiles is clearly demonstrated by the statistical analysis of fire deaths and fatalities, related costs and loss of property. In the UK, each year, while 20 per cent of dwelling fires are caused by textiles – being the first material to be ignited – the percentage of deaths associated with these fires is increased up to 50 per cent. This
disproportionate fatality emphasizes the need to develop successful FR systems for textile materials. The current range of available chemicals, which are used to impart FR properties to textiles, is mainly based on scientific developments during the 1950s and 1960s, when the emphasis laid mainly on providing durable ignition resistance at an affordable cost. More recently and alongside with the need for improved safety, issues such as environmental sustainability and toxicological properties of FR materials and handle and comfort properties of FR fabrics, have to be compromised.
Project aims and objectives (1) Textile industry goals: .
innovate and produce new added value products environmental friendliness and non-toxicity of FR chemicals, advanced fabric performance and quality and reengineered FR systems towards end use requirements;
.
enlarge current markets; and
.
anticipate niche markets.
(2) Social goals: . improvement of health and safety; .
protection of the environment; and
.
improvement of quality of life.
Research deliverables (academic and industrial) .
Technological, economic and environmental assessment of the existing FR products and processes.
.
Data on the evaluation of the quality performance of typical FR fabrics.
.
Guidelines for the development of new FR formulations.
.
Optimal operational finger prints on FR processes.
.
Detailed description of the new sequence of mechanical treatments to follow FR process.
.
Data on FR behaviour of treated fabrics.
.
Data on mechanical and comfort performance of FR fabrics.
.
FR formulations.
.
Environmental and economic assessment of FR formulations proposed.
.
Guidelines for the full scale production.
.
Technical training on the new systems proposed.
.
Implementation reports.
.
FR fabrics produced covering various end uses.
.
Performance criteria according to various end uses.
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Specification profiles of FR fabrics according to various end uses and operational guidelines for their production.
.
Financial statements.
.
Exploitation policy.
Publications None
Athens, Greece National Technical University of Athens, Iroon Polytechniou 9, Zografos Campus, GR-15773 Athens, Greece Tel: +302107721520; Fax: +302107722347; E-mail:
[email protected] Prof. Christopher Provatidis and Lect. Savvas Vassiliadis, School of Mechanical Engineering Research staff: Dipl. Eng. Dimitris Venetsanos, Lect. Kleanthis Prekas, Dipl. Eng. Ioannis Koukoulis
Numerical modelling and simulation of textile materials Other Partners: Academic
Industrial
None University of Maribor, Faculty of Mechanical Engineering Project started:1 July 2003 Project ends:1 July 2005 Finance/support: 11.740 Euro Source of support: General Secretariat of Research and Technology-GR Keywords: Objective measurements, Mechanical model, Textile fabrics The textile materials have a complex structure. The structural complexity of the fabrics imposes relevant complexity in the study of their mechanical properties. The proposed project deals with the low-stress analysis and simulation of the mechanical behavior of the fabrics. The special loading conditions refer to the characteristic ‘‘handle’’ of the fabrics, as well as to other properties like sewability of fabrics, etc. In order to create the suitable micromechanical models of the fabrics, it is necessary to analyze the structural characteristics of the fabrics and to study their microstructure from the geometrical point of view. Based on that, the parametric micromechanical computational models will be compared and cross-correlated. A series of special tensile, shearing, compression, bending, geometrical roughness, etc., laboratory tests will be performed in both standard Kawabata Evaluation System for Fabrics as well as in the automated version of it. The measurements obtained will be compared and they will be used for the evaluation of the performance of the computational models. Finally, the model correction
actions are foreseen, so that the maximum possible convergence between the experimental and the computational results will be achieved.
Research register
Project aims and objectives Textile fabrics will be tested using the Kawabata Evaluation System for fabrics in both standard and automated versions. The results will be compared and correlated. The mechanical data will be used for the evaluation of the performance of numerical models of fabrics created using finite elements.
Research deliverables (academic and industrial) .
Correlation of the measurements of the standard and automated versions of the KES-F.
.
Evaluation of FEM models of textile fabrics.
Publications Contact mechanics in the two-dimensional finite element modelling of fabrics, IJCST (in press).
Athens, Greece Technological Education Institute of Piraeus, P. Ralli & Thivon 250, GR-12244, Athens, Greece Tel: +302105381224; Fax: +302105450965; E-mail:
[email protected] Prof. Maria Rangoussi, Prof. Christopher Provatidis and Lect. Savvas Vassiliadis, Department of Electronics Research staff: Lect. Kleanthis Prekas, Prof. Thanos Peppas, Ass. Prof. Anastasios Delopoulos
Electrically conductive textiles Other partners: Academic Industrial None National Technical University of Athens, Aristoteles University of Thessaloniki Project started: 1 January 2004 Project ends: 30 June 2006 Finance/support: 60.000 Euro Source of support: Ministry of Education GR Keyword: Electrically conductive textiles The project focuses on the properties of the textile electrically conductive materials. In principle, the textile fibres made from natural or man-made polymers are electrical isolators. The electrically conductive fibres are made through adding metallic materials in the man-made polymer structures. They Finally combine the character of the textile fibres with the specific electrical conductivity. The
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electrical and mechanical properties of textile yarns made of man-made electrically conductive fibres will be studied taking in to account the influence of the mixing and spinning parameters. The electrically conductive yarns will be used for the production of textile fabrics with special characteristics in terms of joule effects, as well as of their shielding behaviour in electromagnetic fields. The deformation of the yarns in the fabric structure, which is expected to change the initial electrical properties of the yarns, will be studied and it will be modeled. In parallel the weaving parameters will be correlated to the final electrical characteristics of the fabrics. Electrical and mechanical tests are planned to prove the suitability of the end products in various applications.
Project aims and objectives The aim of the project is to define the parameters for the production of electrically conductive fabrics dedicated for specific uses under controlled conditions to meet the specific needs and standards. The objectives are the thorough study of the textile and electrical properties of the fibres, yarns and fabrics taking in to account the changes of the behavior of the materials occurring when complex structures are developed.
Research deliverables (academic and industrial) .
.
A thorough study of the influence of the textile structures and the deformations on the electrical properties of the conductive textiles. Production of sample fabrics for the investigation of the suitability in specific enduses.
Publications None
Bolton, UK Bolton Institute, Deane Road, Bolton, BL3 5AB, UK Tel: 01204 903108; Fax: 01204 399074; E-mail:
[email protected] Leah Higgins, Advanced Materials Research Center Research staff: Prof. S. C. Anand (Director of Studies), Dr D. A. Holmes (Supervisor), Dr M. E. Hall (Supervisor)
Effect of laundering on dimensional stability, distortion and other properties of cotton fabrics (Ph.D. Project) Other partners: Academic
Industrial
None
Whirlpool Corporation, USA
Project started: March 2000 Project ended: February 2003 Finance/support: $16,000 per annum Source of support: Whirlpool corporation Keywords: Cotton, Laundering, Dimensional stability, Wrinkling New cotton garments tend to shrink and distort when first laundered, particularly if they are tumble dried. Although this behaviour is often an inevitable consequence of the manufacturing and finishing process consumers tend to blame their laundering equipment. This project is the second Ph.D. project in an ongoing collaboration between Bolton Institute and Whirlpool Corporation. The underlying aim of this research is to gain a better understanding of how different laundering factors effect the levels of shrinkage, distortion and also wrinkling observed in new cotton fabrics on initial laundering. This knowledge will allow the project sponsors to develop laundering equipment that is less damaging to the appearance and dimensional stability of cotton fabrics. Publications Higgins, Anand, S. C., Hall, M. E. and Holmes, D. A. (2002a), ‘‘Factors during tumble drying that influence dimensional stability and distortion of cotton knitted fabrics’’, International Journal of Clothing Science and Technology (in preparation). Higgins, L., Anand, S. C., Hall, M.E., Holmes, D.A. and Brown, K. (2001), ‘‘Effect of repeated laundering of dimensional stability and distoration of weft knitted cotton fabrics’’, IAT Conference Proceedings March 2001. Higgins, L., Anand, S.C., Holmes, D.A., Hall, M. E. and Underly, K. (2002b), ‘‘Rinse cycle softener and drying method and the effect of tumble sheet softener and tumble drying time’’, Textile Research Journal (in preparation).
Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: 004 021 340 4921; Fax: 004 021 340 5515; E-mail:
[email protected] Testing, experienting of technologie, equipment, products Research staff: Nicula Gheorghe (Eng.)
Filtering products meant for reducing the impact of the industrial processes over the environment Other partners: Academic None Project started: 1 June 2000 Finance/support: 5,500 EUR
Industrial None Project ended: 15 November 2002
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Source of support: Ministry of Education, Research and Youth Keywords: Environment protection, Polluting phenomena, Man protection
14
The filtering products considered in this paper aim at solving the problems connected to the negative effect of the industrial processes over the environment. The industrial fields for which the filtering products have been mainly accomplished are: food, chemical, metallurgical, mining, as well as the fields connected to these, where there take place physico-chemical processes accompanied by state transformations or structural modifications, which generate polluting phenomena. There have been accomplished and experimented, for the first time in Romania, the following: .
polyphenylsulphuric fibres,
.
PP filament yarns, and
.
spun and filament polyester yarns.
As a consequence of the experiments, the following products have been tested and introduced into production: .
Filter for waste waters – accomplished of PA6 yarns, 940 dtex count/140 f/70Z, meant for the mining industry and the concrete mixing plants.
.
Galvanic bath filter – accomplished of PP yarns, 640 dtex count, 124 f/120 Z, meant for the electrotechnical, metallurgical, chemical industry.
.
Filters meant for cooling emulsions for the ball bearing industry, accomplished of polyester yarns of the count 76/32 f 4 dtex in the warp and Nm 70/3 or Nm 40/4 in the weft.
.
Hot gas filters for the ferro – alloy industry, accomplished of polyester yarns of the count 76/32 f 4 dtex.
Project aims and objectives .
Designing, accomplishing, experimenting, and certifying of the filtering materials with special structures obtained by spinning, weaving, and special treatments by using fibres having special characteristics.
.
Ensuring the technical and qualitative level of the products in accordance with the requirements imposed by the European norms.
.
Employing the experience belonging to the specialists working with the organizations which are partners in the field of accomplishing and IPE testing new fabrics by means of performant technologies.
.
Developing the collaboration relationships with the potential end-users.
Research deliverables (academic and industrial) None Publication The periodical Industria Textila (2001), No. 3, pp. 164-6.
Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: 004 021 340 4921; Fax: 004 021 340 5515; E-mail:
[email protected] Textile mechanical processing Research staff: Doina Toma (Eng.), Professor Dr Eftalea Carpus (Eng.), Ileana Iorga (Eng.), Claudia Niculescu (Eng.)
Cold protection equipment Other partners: Academic
Industrial
None None Project started: 1 June 2000 Project ended: 15 October 2002 Finance/support: 17,500 EUR Source of support: Ministry of Education and Research Keywords: Heat insulation, Risk factor, Performance level, Protection individual equipment Working in low temperature environments and the contact with cold objects implies the beginning of energy transfer from the body towards the environment. During longer time period, transfer is affected by cooling the body and by overstraining of the physiological functions, possibly by reaching severe illness states: getting cold, freezing of the body extremities, and coma. The prevention of the above-mentioned symptoms makes the interdepositing of an insulating layer between the body and the environment necessary by using IPE that is used against cold. Based on the protection requirements and the minimum specified needed performance parameters, the following IPE types used against cold have been accomplished. For working indoors (1) Quilted costume made up of a blouse and trousers, containing three layers of material: .
Outer layer. Woven fabric of 80 per cent cotton/20 per cent PA.
.
Intermediate layer. Non-woven of 80 per cent PES/20 per cent thermoadhesive fibres.
.
Interior layer. 100 per cent cotton woven fabric.
(2) IPE used against cold, made up of two layers: . Exterior layer. Costume made up of a blouse and trousers, accomplished of 99 per cent Rhovyl/1 per cent Bekinox;
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Interior layer. Heatinsulating undergarment, containing a quilted blouse and quilted trousers, manufactured of 100 per cent cotton woven fabric, face – back and non-woven 100 per cent Rhovyl.
For working outdoors (1) Quilted costume made up of a blouse and breastplated trousers, manufactured of three layers of material: .
Exterior layer. Woven fabric of 100 per cent cotton/20 per cent PA.
.
Intermediate layer. Non-woven of 80 per cent PES/20 per cent thermoadhesive fibres. Interior layer. 100 per cent woven fabric.
.
The accomplished products, which were tested and certified according to the European Normatives, satisfy the essential requirements of safety and health corresponding to the envisaged utilization fields.
Project aims and objectives .
Designing, accomplishing, experimenting and certifying the IPE made up of functional and intelligent textile materials, having special structures obtained by spinning, weaving, needlepunching, manufacturing, by using fibres having special characteristics.
.
Ensuring the technical and qualitative level of the products according to the requirements imposed by the European Normatives.
.
Utilization of the experience of the specialists belonging to the partner organizations in the field of accomplishing and testing IPE, as well as the material basis, with a view to accomplishing new products by means of performant technologies. Developing the collaboration relationships established with the potential beneficiaries.
.
Research deliverables (academic and industrial) None Publication Toma, D., Carpus, E., Iorga, I. and Niculescu, C. (2003), ‘‘ Individual protection equipment used against cold ’’, Industria Textila, No. 2, p. 75, ISSN 1222-5347.
Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: 004 021 340 4921; Fax: 004 021 340 5515; E-mail:
[email protected]
The Department of Textile Product Testing, Control and Notification The Romanian enterprises manufacturing textile soil coverings, wishing to import and export, as well as producers from abroad having markets in Romania Research staff: Ramona Buriceanu (Eng.)
The developing of the methodologies for testing the textile soil coverings according to the European Norms EN 1307 and EN 1470 Academic
Industrial
None
Industrial partners manufacturing fibres, yarns, woven fabrics, knits, textile soil coverings, technical articles, etc. Project ended: 15 December 2001
Project started: 21 January 2000 Finance/support: 20312,5 EURO Source of support: 96.08 per cent Budget 3.92 per cent cofinancing Keywords: Textile soil coverings, European norms, EN 1307, EN 1470, Quality As part of the project, there has been effected the complex studying and analysing of all the quality parameters that characterize the textile soil coverings based on the standards EN 1307 and EN 1470, which can be applied to the textile soil coverings which are needle punched in flat form, knitted, conventional, woven and raised. The project has achieved the classifying of the textile soil covering utilizations by comfort, the aspect preserving and wear resistance, by way of establishing the significant technical parameters that arise in classifying the textile soil coverings. Fifty six normative references (national and international standards) have been evaluated and studied, the textile soil covering characteristics have been studied, and the results have been obtained based on the effected tests also have been implemented at the industrial partner. The activity carried out as part of the project allowed the tackling and the clarifying of the following technico-scientific aspects: .
the description of the categories of textile soil coverings (depending on mass and pile thickness);
.
establishing the identifying requirements and integrating tolerances of the characteristics;
.
establishing the basic and supplimentary requirements with a view to the classification of the textile soil covering by wear (integrating into 1, 2, 3, 4 classes);
.
establishing the classification requirements of the textile soil coverings by aspect; and
.
establishing the classification requirements and classification categories LC1, LC2, LC3, LC4, LC5 of the textile soil coverings by comfort.
The results of the tests have been presented and analysed with the specialists of the partner for the purpose of finding out the technological solutions of integrating into the imposed quality classes, of improving the technical performances of the products and of increasing the enterprise competitiveness at the European level.
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Project aims and objectives .
Creating a coherent system of qualitative evaluation of the textile soil coverings, based on the European Standards EN 1307 and EN 1470.
.
Classifying the textile soil coverings utilization by comfort, aspect and depending on wear resistance.
.
Creating the technico-scientific basis that is needed for certifying the products belonging to the range of textile soil coverings.
.
Facilitating the textile soil covering exportation on the EU market by way of creating the conditions for mutual acknowledging of the INCDTP laboratory tests with the similar EU organisms.
Research deliverables (academic and industrial) .
Strengthening the position on the internal and international market of the enterprises manufacturing textile soil coverings will lead to the increase in the competitional capacity of the textile products, having in view the forming of the unique European market.
.
Increasing the product quality and competitiveness. Aligning to the normative European requirements regarding the classification of the textile soil coverings.
.
.
Increasing the qualification degree by acquiring new knowledge concerning the covering classification.
Publications None
Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th, Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: +40-021-340.49.28; Fax: +40-021-340.55.15; E-mail:
[email protected] The Department of Laboratory Equipment and Apparatus Meant for the Textile Industry Romanian Research and Education Ministry Research staff: Daniela Isar (Senior Researcher), Virgil Motocu (Senior Researcher), Cristian Jipa (Senior Researcher)
Ecological textile technical articles as asbestos substitutes for the industry; equipment for accomplishing these Other partners: Academic
Industrial
None
Fermit SA – Ramnicu Sarat Enterprise
Project started: 20 December 1999 Project ended: 29 January 2003 Finance/support: 33,000 EUR Source of support: Governmental budget, The Research-Development, National Institute for Textile and Leather Keywords: Asbestos – free yarns, Asbestos substitute yarns, Technical textiles, Composite materials, Eco-technologies, Environmental health, Quality of life The asbestos extensive use is the cause of severe damages both for the human health and the environment. The cancerous character of this mineral, under whose generic title there are included many silicates, is a worldwide acknowledged fact. During the past 15 years, laws have been enacted to prohibit the use of asbestos. In recent years, sustained efforts have been made to find substitutes for asbestos. The present project aimed at accomplishing of the technology and a specialized machine meant for obtaining a composite cord as an asbestos substitute, meant for producing the automotive clutch disks. This technical article is made up of versions of three components: textile yarns, glass yarns and metal yarns. The machine does the twisting – cabling of the three yarn components with variations of the winding parameters, so that it would allow obtaining of the characteristics needed for the respective technical norms imposed to the clutch disks. The stages applied as part of the project were the following: .
establishing the working conditions specific for the automotive friction elements;
.
textile and non-textile raw material selection based on which asbestos substitute composite structures can be produced;
.
technology for accomplishing versions of asbestos substitute composite structures;
.
design and accomplishing the necessary machines meant to obtain these composite structures; and
.
instrumental techniques for investigating and characterizing the obtained products.
Project aims and objectives The project refers to the obtaining of the technology and the machine necessary to achieve the asbestos substitute composite yarn, meant to accomplish the friction elements in the automotive industry.
Research deliverables (academic and industrial) .
Technology of accomplishing the asbestos substitute composite yarn meant for producing automotive clutch disks.
.
Project and equipment meant for accomplishing the asbestos substitute composite yarn.
.
The production of textile technical articles: asbestos substitute composite yarn meant for producing automotive clutch disks.
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Publications Industria Textila (2000), No. 2, p. 83 (Romania). Industria Textila (2003), No. 2, p. 145 (Romania).
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Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, 3rd Sector, Bucharest, Romania Tel: +40(021)340.49.28; Fax: +40(021)340.55.15; E-mail:
[email protected] Special Products Romanian Research Ministry Research staff: Claudia Niculescu (Senior Researcher), Florica Ionescu (Senior Researcher)
Procedure to obtain Neoprene microcellular backed plates. The design and the achieving of the technology of making-up the professional suit for independent divers Other partners: Academic None
Industrial ARECA S.A. Enterprise – Bucharest ARGOS S.A. Enterprise – Cluj-Napoca
Project started: 1992 Finance/support: 13,000 e Source of support: Governmental Budget Keywords: Composite materials, Safety life, Procedure microcellular plates, No conventional technology The project consisted in achieving of a procedure to obtain Neoprene backed microcellular plates on textile support destined for making the professional suits for independent divers and designing the suit. The stages of project were: .
achieving of a procedure to obtain Neoprene microcellular plates covering both sides with Lycra knit;
.
.
designing the suit according to the anthropometric sizes of the male population of Romania; testing the performances: thickness and mass, comfort at wear, handle at dressing and undressing, thermal isolation degree at diving under water of depth of 3-51 m and temperatures between 4 and 25 C;
.
homologation of the prototype.
The obtained results shall be applied for obtaining the other new products such as: life saving suits, mountings for cars, splits for emergency hospitals and rescue centers, thermal isolations for pipes, phonon – absorbent upholstery, suits for surfing, professional suits for ski.
Research register
Project aims and objectives The projects aim was to design and develop a professional wet suit for divers with high characteristics of thermal isolation, resistance and elasticity. The project objectives were as follows: .
designing and achieving of a procedure to obtain Neoprene microcellular plates on textile support destined for making the professional suits for independent divers;
.
designing and manufacturing the prototype of suit according to the anthropometric sizes of the male population in Romania; and
.
homologation of the suit.
Research deliverables (academic and industrial) . .
. .
Technical documentation and blue prints. Technology of obtaining Neoprene microcellular plates coating on both sides with Lycra knit. Establishing the making-up technology of suit. Prototype of suit.
Publications None
Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, 3rd Sector, Bucharest, Romania Tel: +40(021)340.49.28; Fax: +40(021)340.55.15; E-mail:
[email protected] Special Products Romanian Research and Education Ministry Research staff: Claudia Niculescu (Senior Researcher)
Parachutists’ Life Preserver Other partners: Academic None
Project started: 1997
Industrial ARECA S.A. Enterprise – Bucharest STINGO – SOMET S.A. Enterprise – Buzau
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Finance/support: 16.300 e Source of support: Governmental Budget Keywords: Composite materials, Textile materials, Life safety, No conventional technology, Inflatable equipment The projects intend to design and develop a technology for manufacturing a parachutists’ life preserver to be worn when the parachutist is undertaking a descent over or near the sea. The life preserver, in one size, consisting in a waistcoat with inflatable stole, inflation equipment and survival equipment. The life preserver was conceited to be worn over the parachutists’ normal clothing and equipping before the parachute harness, the reserve parachute and any suspended load. The life preserver was manufactured of a cotton gabardine and a polyester webbing harness. The stole is inflatable from manually operated CO2 cylinder or an oral inflation tube and valve. The survival equipment consists of whistle and a life line. The stages of project were: .
research, selection and achievement of the materials,
.
selection of the survival equipment,
.
design of the waistcoat, design of the inflatable stole,
. .
design of the inflatable equipment,
.
achievement of the life preserver, and testing the performances of the life preserver.
.
Project aims and objectives The projects aim was to design and develop a technological process for a Parachtists’ Life Preserver. The project objectives are as follows: .
designing the parachutists’ life preserver,
.
designing the CO2 cylinder and the operating head,
.
achievement of the parachutists’ life preserver, and salvage the life of parachutists.
.
Research deliverables (academic and industrial) Technical documentation and blue prints for waistcoat, CO2 cylinder, operating head and inflatable stole. Manufacturing technological process. Prototype of parachutists’ life preserver. Publications None
Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, 3rd Sector, Bucharest, Romania Tel: +40(021)340.49.28; Fax: +40(021)340.55.15; E-mail:
[email protected] Special Products Romanian Research and Education Ministry Research staff: Claudia Niculescu (Senior Researcher)
The flying and survival suit on the sea Other partners: Academic None
Industrial ARECA S.A. Enterprise STINGO-SOMET S.A. Buzau Enterprise
Project started: 1997 Finance/support: 38.700 e Source of support: Governmental budget Keywords: Sea rescue equipments, Composite materials, No conventional technology, Hypothermia protection, Inflatable equipment The projects intend to design and develop a technology for manufacturing an individual equipment for helicopter aircrew that fly over or near the sea. The equipment consists of a waterproof suit, a thermal insulated suit and a survival west. The stages of project were: .
research, selection and manufacturing the materials;
.
designing the waterproof suit, thermal insulated suit, survival west, inflatable stole, CO2 cylinder and the operating head;
.
manufacturing the suit;
.
testing the performances of the suit: waterproof at a pressure of 2,000 mm water column, physiological comfort, resistant at high temperature, thermal isolation, buoyancy for 80 daN, time of filling of pneumatic cushion pillow with liquefied CO2, possibility to localize the shipwrecked person with light and acoustic signals, possibility to recover the shipwrecked person with the force system.
Project aims and objectives The projects aim was to design and develop a technological process for an individual equipment for helicopter aircrew. The project objectives are as follows:
Research register
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.
designing of a suit with a view to protect the life of helicopter aircrew in situation of a flay accident over the sea;
.
development and manufacturing the suit; and
.
homologation of the suit.
Research deliverables (academic and industrial) .
Technical documentation and blue prints.
.
Manufacturing technological process. The flying and survival suit for helicopter aircrew
.
Publication Hight Performance Textile (2001), ‘‘Flaying and survival suit for marine use’’, p. 151-7.
Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, 3rd Sector, Bucharest, Romania Tel: +40(021)340.49.28; Fax: +40(021)340.55.15; E-mail:
[email protected] Special Products Romanian Research Ministry Research staff: Doina Grecu (Senior Researcher), Claudia Niculescu (Senior Researcher), Radu Radulescu (Senior Researcher)
Personnel parachute system for paratroopers with backward attachment Other partners: Academic
Industrial
None AEROSTAR S.A. Bacau Enterprise Project started: 1992 Finance/support: 50.000 e Source of support: Governmental budget Keywords: Aeronautic accessories, Aerodynamic studies, Parachute systems, Paratroopers deployment The projects consisted in designing and achieving of the parachute system (main and the reserve parachute) has dorsal attachment. It is conceived for paratroopers launching at low altitude and with forced opening for the main parachute. The system was conceited for low altitude launching, with forced opening for the main parachute and hand opening for the reserve parachute.
The stages of project were: . aerodynamic calculation of the main parachute and the reserve parachute, .
designing of the parachutes, riser system, parachutes’ pack and harness assembly,
.
manufacturing of the parachute system, manufacturing technological process,
. .
.
testing and evaluation of the performances: deployment and inflation, stability, rates of descent and minimum deployment altitude for main and reserve parachute, maximum horizontal rate and maximum horizontal rate for main parachute and homologation of the prototype.
Project aims and objectives The aim of the projects was to design and manufacture of a back attached parachute system assembly for preparing, training and delivering into battle the parachute troopers and their specific weaponry. The objective was: . designing of a parachute system for equipping the paratroopers, .
manufacturing the parachute system, and
.
homologation of the system.
Research deliverables (academic and industrial) Parachute documentation and blue prints. .
Manufacturing technological process.
.
Manufacturing of a parachute system (main parachute, reserve parachute, riser system, parachute pack and harness assembly).
Publications None
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: 004 021 340 4921; Fax: 004 021 340 5515; E-mail:
[email protected] Departament of Medical Article Research Alexandra ENE (Eng.) Research staff: Carmen Mihai, (Eng.) Adriana Petrescu, Maria Bulearca (Techn.)
Research register
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Technologies for accomplishing a new generation of textile structures meant for implantable medical articles having utilization in cardiovascular surgery Other partners: Academic
Industrial
The Research-Development None National Institute for Chemicals and Pharmaceuticals, Ministry of Health and Family Project started: 30 September 2000 Project ended: 30 September 2002 Finance/support: 23, 000 EUR Source of support: 70 per cent governamental, 30 per cent own Keywords: Implantable products, Weaving technologies, Cardiovascular surgery The identification of the biological requirements of the most complicated mechanism, that is the human body, correlated with the possibilities of the current technique, has enabled the successful achievement, in Romania, for the first time, by a team of specialists from The Research-Development National Institute for Textile and Leather, of a new generation of surgical implants meant for the cardiovascular surgery. The accomplishing of new vascular prosthesis types has imposed a high precision degree in the making of a tube with diameter included, so as to coincide with that of the blood vessel with which it is to be coupled. In this respect, for the accomplishing of these products, the following aspects were aimed at: .
choosing the weaving model,
.
adequate choice of the yarn length density,
.
exact establishing of the textile backing density, establishing of the yarn number in weft, and
. .
establishing of the internal diameter.
To design the fabrics destined for the vascular prostheses, the minimal requirements have been considered for the biofunctional characteristics imposed by the clinical usage field as a consequence of which there resulted the following: .
.
the product geometry imposes the use of the tubular structure and the maximal work-width, and the impermeability imposes main parameters of fabric designing (achieving of a structure for which untwisted yarns are used, the densities of the two systems and the product mass, etc.)
Project aims and objectives .
Accomplishing of a new generation of products based on textile materials having special structures, achieved through weaving technologies, meant for cardiovascular surgery as vascular prostheses and textile patches.
.
.
Assurance of the technical and qualitative level, having in view the physicochemical, physico-mechanical, biological and microbiological characteristics in accordance with the European norms in force. Implementation of the GMP procedures in the manufacturing of the products.
Research deliverables (academic and industrial) The research results are meant for the following fields: .
as sterile products in sanitary network (hospitals and clinics),
.
as didactic material (teaching aids) for universities having chemical, pharmaceutical, biological and medical profiles, and as technical documentation for final producers.
.
Publications New generation of vascular prostheses obtained through weaving technologies (2003), Medtex’ 03 International Conference, Bolton, UK. The diagnosis of the implantable product sector meant for cardiovascular surgery (2002), Revista Industria Textila, No. 3, pp. 14-8.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: 004 021 340 4921; Fax: 004 021 340 5515; E-mail:
[email protected] Information – Automation Research staff: Dr Emilia Visileanu (Eng.), Carmen Ghituleasa (Eng.), Mihai Stan (Math.)
Informatic system of simulating the textile industry processes (spinning and weaving) Other partners: Dr Tudor Sireteanu (Math.), Virgil Mitre (Eng.), Gheorghe Ghita (Eng.)
Academic
Industrial S.C.
The Institute for the Mecha-Nics of Solids POSTAVARIA Bucharest ROMANA S.A. Project started: January 2000 Project ended: December 2002 Finance/support: 25.000 EURO Source of support: MEC program Relansin Keywords: Informatic system, Simulation, Spinning, Weaving
Research register
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The informatic product can be applied to the promotion of the new products and it eliminates the preliminary experimental stages of establishing the technological parameters and the characteristics of these. The achieved informatic product (one for the spinning process, and the other for the weaving process, respectively) is made up of a main menu having five options: data bases, price simulation, help, exit. The data base contains the elements associated with a previous experience that included data regarding the raw material, equipment and the characteristics of the already accomplished products. The ‘‘simulation’’ component. In the case of spinning, there is a calculated spinnability index that allows the selection of a spinning plan based on the technological parameters necessary to accomplish the new product. As part of this option, too, there is the calculated break resistance of the yarn that is going to be produced (the Ning Pan algorithm). Within the weaving process, the activation of the ‘‘simulation’’ option allows the establishment of the creation elements, colour range, the warp and weft yarn number, when previously, by a selection procedure, the technological parameters corresponding to the new woven fabric, etc. have been established. The price option achieves the calculations of an economic nature concerning the accomplishing of the new product (yarn or woven fabric). The help option helps the utilizer in using the informatic product.
Project aims and objectives .
Accomplishing an informatic product having a technological applicability.
.
Modernizing of the designing systems in the spinning and weaving mills. Reducing of the costs of promoting the new products (time and labour force).
.
Research deliverables (academic and industrial) Informatic product that can be used for establishing the spinning plans from the wool and wool type spinning mills. Informatic programme of establishing the characteristics of designing the woven fabrics (structure and colour). Publication The Periodical Magazine (2002), Industria Textila, No. 3, pp. 153-6.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, 3rd Sector, Bucharest, Romania Tel: +40(021)340.49.28; Fax: +40(021)340.55.15 ; E-mail:
[email protected] Special Products Romanian Research and Education Ministry
Research staff: Claudia Niculescu (Senior Researcher), Doina Grecu (Senior Researcher), Alexandra Ene (Senior Researcher)
Research register
Developing of manufacturing technologies for new types of textile and plastic medical articles for emergency purposes Other partners: Academic None
Industrial IZOLATORU S.A. Enterprise ARECA S.A. Enterprise Project ended: 2002
Project started: 2000 Finance/support: 26.000 e Source of support: Governmental budget Keywords: Medical articles, Emergency service, Human health, Manufacturing technology
The projects intend to develop a technology for manufacturing the emergency medical articles such as: splints for arm and leg, arm and forearm holder, extrication spine splint, vacuum mattress and transfer sheet. These products are intended for the use of emergency hospitals, mountain rescue services, civil protection, extrication services and ambulance services. These products were manufactured with textile materials (polyamide, polyesters), plastic materials (PVC) and rubber (neoprene). Each of these medical articles is conceived with a precise destination such as: arms and legs immobilization, spine immobilization, arms sustain, injured people transport etc. The stages of project were: .
research, selection and achievement of the materials,
.
design of the emergency articles, elaboration of the manufacturing technology for the emergency articles,
. .
manufacturing of the prototypes,
.
testing the performances: physical-chemical, biological, functional and clinical, and homologation of the products.
.
Project aims and objectives The projects aim is to develop a technology for manufacturing the emergency medical articles. The project objectives are as follows: .
.
.
development of non-conventional assembly technologies for the subassembly of the medical articles with textile structures, development of technology to manufacture the pellicle fabric for the joints through HF welding, development of manufacturing technologies of the medical articles for external use depending on the quality and technical requirements,
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. .
. .
30
design of medical articles for external use, manufacture of medical articles for external use (splints for arm and leg, arm and forearm holder, extrication spine splint, vacuum mattress, transfer sheet), developing technical specification papers, and physical-chemical, biological, functional and clinical testing.
Research deliverables (academic and industrial) (1) Technical documentation and blue prints. (2) Manufacturing technological process. (3) Prototypes: .
splints for arm and leg,
.
arm and forearm holder, extrication spine splint,
. . .
vacuumed mattress, and transfer sheet.
Publication Textile Industry Magazine (2002), ‘‘ Medical emergency articles for external use ’’, No. 2, pp. 88-93.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Str., Sector 3, Bucharest, Romania Tel: 0040-21-340 49 28; Fax: 0040-21-340 55 15; E-mail:
[email protected] The Research-Development National Institute for Textile and Leather, Research Medical Articles Department Research staff: Ene Alexandra, Mihai Carmen, Visileanu Emilia, Petrescu Adriana, Bulearca Maria
Non-resorbable surgical thread Other partners: The Chemical-Pharmaceutical National Research-Development Institute
Academic
Industrial
None
The Research-Development National Institute for Textile and Leather-unique Romanian producer in this field Project ended: 2002
Project started: 2001 Finance/support: 25.000 EUR
Source of support: Governmental Budget Keywords: Surgical thread, Biocompatibility, Braiding, Textile structures The accomplishment of non-resorbable surgical thread imposed high precision degree in the making of a braided textile structure from 4, 6, or 8 biomedical polyester yarns in order to obtain products with biomedical and biofunctional characteristics specific to various surgical field (orthopaedic, gastroeneterology, cardiovascular, etc.) In this respect, for the accomplishment of these products, the determinate were: choosing of the braiding model; adequate choice of length density of the yarn that is to be mechanically processed; the exact establishing of the textile structure density; establishing of the yarn number in the structure; and establishing of the proper apparent diameter of the final product. A special attention has been given to the raw material selection, no bleached optically characterized by good tolerance in human body, inertia from the chemical point of view, maintaining for a while the functional properties; very good dimensional stability; no allergic states or hyposensitivity; not cancerous; very high mechanical resistance. At the design, the structure have been considered the minimal requirements for the biofunctional characteristics, imposed by clinical usage field, respectively, to assure the physical and mechanical characteristics, physical and chemical parameters as well as the microbiological level of performances in accordance with the European norms in force.
Project aims and objectives The project was focused on accomplishing through braiding technology the textile structures destined to obtain nonresorbable surgical thread used in various surgical fields. The microbiological characteristics are assured through nonconventional technology based upon gamma Co60 irradiation and the biological characteristics through complex finishing technologies. It was also the aim of the project to obtain products having the aspect of the external surfaces compatible with the natural tissue so that to be assured of the development of the neo-tissue adjacent to the wound as well as the performing of special finishing and thermo stabilization procedures.
Research deliverables (academic and industrial) Consist in: technologies and products destined to different surgical fields. The production is certified in accordance with the norms imposed by the international guide, named Good Manufacturing Practice. The products are accomplished in collaboration with universities and industrial partners from Romania, Poland and Italy and the distribution is in Romania and Turkey. For realizing the objectives of this project the institute has special machines and devices afferent for each phase of the technological process. Publications Ene, A. (n.d.), ‘‘Surgical reinforced mesh destined to rebuild the thoracic wall’’. Ene, A. (n.d.), ‘‘Accessories for textile industry’’. Ene, A. and Mihai, C. (n.d.), ‘‘New generation of vascular prostheses performed through weaving technology’’. Ene, A. and Mihai, C. (n.d.), ‘‘New resorbable materials having textile structures, based upon copolyesteric blends’’.
Research register
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Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu str., Sector 3, Bucharest, Romania Tel: 0040-21-340 49 28; Fax: 0040-21-340 55 15; E-mail:
[email protected] The Research-Development National Institute for Textile and Leather, Research Medical Articles Department Research staff: Ene Alexandra, Mihai Carmen, Visileanu Emilia, Petrescu Adriana, Bulearca Maria
Surgical reinforced mesh Other partners: The Chemical-Pharmaceutical National Research-Development Institute
Academic
Industrial
‘‘Victor Babes’ University of Medicine –Timisoara
The Research-Development National Institute for Textile and Leather-unique Romanian producer in this field Project ends: 2004
Project started: 2003 Finance/support: 35.000 EUR Source of support: 20.000 EUR governmental budget; 15.000 EUR other sources Keywords: Reinforced mesh, Biocompatibility, Knitting, Textile structures
The research in the field of biomaterials and prosthetic products has resulted in the elaboration of a new technological solution to achieve a new medical product on the basis of a knitted textile equipped with support elements that assure the functional and biomedical performances required in the clinical usage field, respectively, biocompatibility with the human tissue, chemical un-reactivness correlated with maintenance of functional properties, very good dimensional stability, non-cancerous, maximum resistance and life time, surgical adaptability, adequate for the development of the neotissue, flexibility, and the possibility of intrasurgery cutting. Product assures strong support for the wound and increased sustaining degree for the thoracic cavity during the accomplishment of post surgery physiotherapeutic; maintaining of the breathing function; protection of the endothoracic structures; preserving a certain degree of the parietal extension; eliminating the possibility of fluid retention or of blood separation and accumulation within the thoracic cavity; the option to collagenate the reinforced textile support so that the product could be used in other surgical fields. A special attention has been given to the raw material selection, no bleached is optically characterized by good tolerance in human body, inertia from the chemical point of view, maintaining for a while the functional properties, very good dimensional stability, no allergic states or hyposensitivity, not cancerous, and very high mechanical resistance.
Project aims and objectives The project was focused on accomplishing through knitting technology the textile structures destined to obtain an implantable product used in order to assure the rebuilding of the thoracic wall. The structure meets the biofunctional and biomedical characteristics imposed by the clinical usage field, respectively, the physical and mechanical characteristics, and the physical and chemical parameters in accordance with the European norms in force. The microbiological characteristics are assured through nonconventional technology based upon gamma Co60 irradiation and the biological characteristics through complex finishing technologies. It was also the aim of the project to obtain products having the aspect of the external surfaces compatible with the natural tissue so that to be assured of the development of the neotissue as well as performing special finishing and thermo stabilization procedures.
Research deliverables (academic and industrial) Consist in: technology and products for rebuilding of the thoracic wall. The production is certified in accordance with the norms imposed by the international guide, named Good Manufacturing Practice. The products are accomplished in collaboration with universities and industrial partners from Romania, Poland and Italy and the distribution is in Romania and Turkey. For realizing the objectives of this project the institute has special machines and devices afferent for each phase of the technological process. Publications Ene, A. (n.d.), ‘‘Surgical reinforced mesh destined to rebuild the thoracic wall’’. Ene, A. (n.d.), ‘‘Accessories for textile industry’’. Ene, A. and Mihai, C. (n.d.), ‘‘New generation of vascular prostheses performed through weaving technology’’. Ene, A. and Mihai, C. (n.d.), ‘‘New resorbable materials having textile structures, based upon copolyesteric blends’’.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu str., Sector 3, Bucharest, Romania Tel: 0040-21-340.49 28; Fax: 0040-21-340 55 15; E-mail:
[email protected] Research Medical Articles Department, The Research-Development National Institute for Textile and Leather Research staff: Ene Alexandra, Mihai Carmen, Visileanu Emilia, Petrescu Adriana, Bulearca Maria
Knitted mesh for haernia and eventration Other partners: The Chemical-Pharmaceutical National Research-Development Institute
Research register
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Academic
Industrial
‘‘Victor Babes’ University of Medicine –Timisoara
34
The Research-Development National Institute for Textile and Leather-unique Romanian producer in this field Project ends: 2004
Project started: 2003 Finance/support: 35.000 EUR Source of support: 25.000 EUR governmental budget; 10.000 EUR other sources Keywords: Eventration, Biocompatibility, Knitting, Textile structures
The research in the field of biomaterials and prosthetic products has resulted in the elaboration of a new technological solution to achieve a new medical product on the basis of a knitted textile that assure the functional and biomedical performances, required in the clinical usage field, respectively, biocompatibility with the human tissue, chemical unreactivness correlated with maintanance of functional properties, very good dimensional stability, non-cancerous, maximum resistance and life time, surgical adaptability, adequate for the development of the neotissue, flexibility, and the possibility of intrasurgery cutting. The knitted mesh of the type PLASTEX is used in surgical operations for the tightening of the abdominal muscles. The product is made from 100 per cent biomedical polyester. A special attention has been given to the raw material selection, no bleached is optically characterized by good tolerance in human body, inertia from the chemical point of view, maintaining for a while the functional properties, very good dimensional stability, no allergic states or hyposensitivity, not cancerous, and very high mechanical resistance.
Project aims and objectives The project focuses on accomplishing through knitting technology the textile structures destined to obtain an implantable product used in order to assure the support of the abdominal muscles. The structure meets the biofunctional and biomedical characteristics imposed by the clinical usage field, respectively, the physical and mechanical characteristics: high resistance for an unlimited period of time, to cyclical stress of different nature it is subject to after implant; stable configuration of the mesh; not frying at the edges, thus it can be cut in all shapes and sizes, intraoperationally; not kinking; easily modelling during the surgical operation, as well as the physical and chemical parameters in accordance with the European norms in force. The microbiological characteristics are assured through nonconventional technology based upon gamma Co60 irradiation and the biological characteristics through complex finishing technologies. It was also the aim of the project to obtain products having the aspect of the external surfaces compatible with the natural tissue so that to be assured of the development of neotissue as well as performing special finishing and thermo stabilization procedures.
Research deliverables (academic and industrial) Consist in: technologies and products destined to gastroenterology. The production is certified in accordance with the norms imposed by the international guide, named Good Manufacturing Practice. The products are accomplished in collaboration with
universities and industrial partners from Romania, Poland and Italy and the distribution is in Romania and Turkey. For realizing the objectives of this project the institute has special machines and devices afferent for each phase of the technological process.
Research register
Publications Ene, A. (n.d.), ‘‘Surgical reinforced mesh destined to rebuild the thoracic wall’’. Ene, A. (n.d.), ‘‘Accessories for textile industry’’. Ene, A. and Mihai, C. (n.d.), ‘‘New generation of vascular prostheses performed through weaving technology’’. Ene, A. and Mihai, C. (n.d.), ‘‘New resorbable materials having textile structures, based upon copolyesteric blends’’.
35
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu str., Sector 3, Bucharest, Romania Tel: 0040-21-340 49 28; Fax: 0040-21-340 55 15; E-mail:
[email protected] Research Medical Articles Department, The Research-Development National Institute for Textile and Leather Research staff: Ene Alexandra, Mihai Carmen, Visileanu Emilia, Petrescu Adriana, Bulearca Maria
Accomplishing of a new generation of vascular prostheses through weaving technology Other partners: The Chemical-Pharmaceutical National Research-Development Institute
Academic
Industrial
None
The Research-Development National Institute for Textile and Leather-unique Romanian producer in this field Project ended: 2003
Project started: 2000 Finance/support: 30.000 EUR Source of support: 20.000 EUR governmental budget; 10.000 EUR other sources Keywords: Cardiovascular surgery, Biocompatibility, Weaving, Bifurcated structures The accomplishment of new vascular prostheses types imposed high precision degree in the making of a tube with diameter included, so as to coincide with that of the blood vessel with which it is to be coupled. In this respect, for the accomplishment of these products, the determinate were: choosing of the weaving model; adequate choice of length density of the yarn that is to be mechanically processed; the exact establishing of the textile support density; establishing of the yarn number in weft; establishing of the internal diameter (D) of the graft and counting of the total number of weft yarns necessary for obtaining by weaving of the tube with internal diameter (D).
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A special attention has been given to the raw material selection, no bleached is optically characterized by: good tolerance in human body, inertia from the chemical point of view, maintaining for a while the functional properties, very good dimensional stability, no allergic states or hyposensitivity, not cancerous, and very high mechanical resistance. To design the fabrics destined for the vascular prostheses, consider the minimal requirements for the biofunctional characteristics, imposed by clinical usage field, respectively, the product geometry imposes the use of the tubular structure and the maximal work-width; impermeability imposes main parameters of fabric designing (achievement of a structure for which there are used untwisted yarns, the densities of the two systems and the product mass, etc.).
Project aims and objectives The project was focused on accomplishing through weaving technology the linear textile structures destined to obtain vascular prostheses used in arterial surgery or bypass in aneurismal or occlusive illness of aorta, peripheral arteries with the exception of the coronaries. The microbiological characteristics are assured through nonconventional technology based upon gamma Co60 irradiation and the biological characteristics through complex finishing technologies. It was also the aim of the project to obtain products having the aspect of the external and internal surfaces comparable with the natural ones performing special goffrage and thermo stabilization procedures as well as the anti-thrombogenical treatments.
Research deliverables (academic and industrial) Consist in: weaving technology for accomplishing vascular prostheses. The production is certified in accordance with the norms imposed by the international guide, named Good Manufacturing Practice. The products are accomplished in collaboration with universities and industrial partners from Romania, Poland and Italy and the distribution is in Romania and Turkey. For realizing the objectives of this project the institute has a weaving machine unique in Europe, designed and performed in collaboration with the most important producer, named Jakob Mueller – Switzerland. Publications Ene, A. (n.d.), ‘‘Surgical reinforced mesh destined to rebuild the thoracic wall’’. Ene, A. (n.d.), ‘‘Accessories for textile industry’’. Ene, A. and Mihai, C. (n.d.), ‘‘New generation of vascular prostheses performed through weaving technology’’. Ene, A. and Mihai, C. (n.d.), ‘‘New resorbable materials having textile structures, based upon copolyesteric blends’’.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: (0040) 21-340 49 28; 340 42 00; Fax: (0040)-21-340 55 15; E-mail:
[email protected]
Eng. E. Anghel, Textile Mechanic Department Research staff: Eng. E. Anghel, Dr. Eng. Emilia Visileanu, Eng. C. Mihai
Research register
Terrestrial air filling system (SGT) Other partners: Academic None
37 Industrial SC Condor SA – Bucharest – Society of Special clothing and Parachutes SC MUNPLAST SA – Bucharest Project ended: November 2001
Project started: March 1999 Finance/support: None Source of support: Budget Keywords: Technical textiles, Air filling structures, UV resistance, Air and water proofing, Extreme meteorological conditions resistance
Development of some woven technical textile supports covered with polymer meant for the manufacturing of low weight systems, mechanically resistant, balanced regarding weft and warp, air and water proved, UV resistant. Performance structures designed by correlating raw materials characteristics with usage conditions.
Project aims and objectives Accomplishment of the following objectives. .
special esthetic level;
.
visual impact over public; and
.
easy mounting-demounting.
Research deliverables (academic and industrial) Academic: The Research-Development National Institute for Textile and Leather (INCDTP) – development and testing of woven structure. Industrial: SC Munplast SA – Bucharest – polymer covering (INCDTP – testing) Society of Special clothing and Parachutes – CONDOR SA – manufacture and testing of terrestrial air filling system. Publications Invention patent: Polymer covered woven structure meant especially for terrestrial air filling systems (Gold medal – Brussels EUREKA 2001). Composite with textile component for terrestrial air filling system, Aquadepol Colloquium, Constanta, 2001. Polymer covered woven structure meant especially for terrestrial air filling systems, innovation and development in the textile field, INCDTP Symposium 2004.
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Bucharest, Romania The Research-Development National Institute for Textile and Leather (INCDTP), 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: (0040) 21-340 49 28; 340 42 00; Fax: (0040)-21-340 55 15; E-mail:
[email protected] Eng. E. Anghel, Textile Mechanic Department Research staff: Eng. E. Anghel, Dr. Eng. Emilia Visileanu, Prof. Dr. Eng. E Carpus, Eng. C. Mihai
Textile anti-oil barriers (B.T.A.P.) Other partners: Academic
Industrial
Navy Research-Development SC Rolast SA – Pitesti National Institute – Constanta Project started: October 1996 Project ended: October 1998 Finance/support: None Source of support: Budget Keywords: Technical textiles, Elastomer covering, UV resistance, Floats, De-polluting, Environment protection, Air and water proofing .
Development and testing of a woven structure covered with elastomer that will present the following characteristics: UV radiations resistance, abrasion cutting, perforation and impact strength, flexibility, stretching and aging resistance.
.
Efficiency establishing for anti-oil barrier, formed of floats in open sea conditions (waves and wind action, day-night temperature variations, UV radiations, repeated mechanical stress, surface marine micro-organisms action).
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Restriction of areas for accidental oil froths-over into the sea and their annihilation through de-polluting activities.
Project aims and objectives The project aims at. .
restricting oil accidental froths-over into the sea;
.
oil recovery and valorization; and
.
easy mounting-demounting.
Research deliverables (academic and industrial) Academic: INCDTP – woven structure development and testing. Navy R&D National Institute – Constanta – floats manufacture, forming and assembling anti-oil barrier, and its testing. Industrial: SC ROLAST SA – Pitesti – elastomer covering and testing.
Publications Association between technical fabric/elastomer in the fight against black ebb-tide, Symposium – Textiles Universe Bucharest, 1999. Performance structures meant for sea environment protection, 12th Papers Session, Navy Academy, 2001. Technical support meant for usage in sea medium and internal waters in the activities of research and environment protection, Symposium/Bucharest, 2000. Woven support covered with elastomer – a success in the de-polluting activity, Session of scientific papers, CCS Navy Technique 2000, Constanta.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: (0040) 21-340 49 28; 340 42 00; Fax: (0040)-21-340 55 15; E-mail:
[email protected] Prof. Dr Eng. Eftalea Carpus, Textile Mechanical Processing Department Research staff: Prof. Dr Eng. Eftalea Carpus, Eng. Doina Toma, Eng. Claudia Niculescu, Eng. Ileana Iorga, Eng. Ramona Buriceanu
Individual protection equipment made of fireproofing Other partners: Academic
Industrial
‘‘Aurel Vlaicu’’ University – S.C. ALEXROMCOM S.R.L. Arad Technique University – ‘‘Gh. Asachi’’–Iasi Project started: 4 October 2001 Project ended: 30 May 2004 Finance/support: 75.000 Euro Source of support: 70 per cent lei budget, 30 per cent industrial sector co-financing Keywords: Protection, Garment, Component layers, Fibers with performance characteristics, Specific analyses In order to assure the protection function, garments should be designed and developed in conformity with health and security essential requests, transposed in technical rules applicable for the garment types destined to a certain field of activity. Protection garment development, through correlating functional, ergonomic and comfort requests, is a synthesis stage resulted after. .
delimitating the fundamental, specific and additional characteristics of textile supports;
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establishing the raw material;
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designing the textile supports; and
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designing the protection equipment constitutive elements.
Starting from the idea of realizing multifunctional textiles, capable of responding to certain performances, there have been chosen, as raw materials base, fibers with performance characteristics, respectively, meta-copper fibers type Kermel and viscose fibers FR. As mentioned above, the fireproofing, designed and used for developing individual protection equipments (EIP), has the following components. .
external layer – fabric of classically spinned yarns (50 per cent kermel/50 per cent viscose FR);
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internal layer – non-woven material (100 per cent kermel fibers) lining – fabric of classically spinned yarns (100 per cent viscose FR)
.
Materials selection on scientific and esthetic criteria occupies a special place in EIP development and has as its main component the activity of determining basic and specific characteristics. For the textile material component layers, specific physicalmechanical analyses were conducted in conformity with EN ISO norms, while for the layered fireproofing, functional characteristics were determined in conformity with I.N.C.D. methods for work protection, adapted to the specific SR EN, namely. . entrainment heat resistance; . radiation heat resistance; .
resistance to projection of molten metal quantity; and
.
resistance to molten metal spatters.
Project aims and objectives The aim of the project consists of developing a thermal protection equipment by using performance characteristics fibers. The projects objectives had as target the thermal EIP development through. . .
usage of new fibrous blends of fibers with performance characteristics; designing and development of EIP experimental model;
.
experimentation and assessment of experimental model;
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highlighting of experimental model performances in conformity with European Norms;
.
thermal EIP development of layered fireproofing – prototype; and
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thermal EIP experimentation and certification.
Research deliverables (academic and industrial) Academic: conception, thermal EIP designing, results dissemination. Industrial: thermal EIP manufacturing. Publications Carpus, E. and Iorga, I. (2004), ‘‘Layered fireproofing meant for EIP’’, paper presented at the Symposium INCDTP, Bucharest, 18 March 2004. Carpus, E., Toma, D., Niculescu, C. and Florentina P. (2003), ‘‘Individual thermal protection equipment’’, Industria Textila, Bucharest, No. 4. pp. 222-4.
Bucharest, Romania The Research–Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: 0040 21 340 42 00; Fax: 0040 21 340 55 15; E-mail:
[email protected] Dr Eng. Petronela Drambei, Mechanical and Chemical Processing Department Research staff: Dipl. Eng. Carmen Mihai, Dipl. Eng. Alina Popescu
Ecological textiles and flexible technologies of accomplishing Other partners: Academic
Industrial
Technical University ‘‘Gh. Asachi’’ S.C. VASTEX S.A., S.C.PRODIN Iasi-Faculty of Textiles/Romania S.A./Romania Project started: 1 October 2002 Project ended: 30 April 2004 Finance/support: 47,000 Euro Source of support: 65 per cent budget and 35 per cent from textiles factories: S.C. VASTEX S.A., S.C.PRODIN Keywords: Ecological fibres, Lyocell fibers, Clean technologies, Enzymatic treatments, Fibrillation Ecological and toxicological properties of textile materials and garments are decisive criterions for their quality appreciation. That is why in up to date designing and textile materials processing, it is indicated to use ecological raw materials and to apply ‘‘clean technologies’’. These can assure the prevention of the environment pollution and protect the human health. Lyocell fibers marked a special impact on the textile worldwide market from their appearance. The trends in the field of textile fibers and the necessity of increasing the textile articles competitiveness determined analyzing of the lyocell fibers potential for garment sector and especially for fashion. In this order some different finishing experiments on lyocell weaves have been done. The technological experiments had in view the primary fibrillation effect-enzymatic defibrillation-secondary fibrillation. For obtaining these effects, there have been accomplished rope finishing with/without weaves causticizing, followed by defibrillation (biopolish treatment) before or after dyeing, using different cellulasic enzymes, as: Bactosol CA (Clariant), Perizym 2000 and Perizym LYO (Textil Chemie GmbH Dr. Petry). The experiments had in view also, to emphasize the influence of these technological stages to the surface modifications that appear in finishing the lyocell textile materials.
Project aims and objectives The project had as aim and objectives the accomplishing of new textile ecological products by.
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using new ecological raw materials;
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using flexible, mechanical and chemical technologies for ecological fibers, in function of the technical requirements imposed by the utilization field: articles with classic, ‘‘peach-skin’’, or ‘‘denim’’ aspect; and
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establishing and optimization of the technical parameters and technological solutions of chemical processing, having low impact on environment and human health.
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Research deliverables (academic and industrial) Academic: optimization programme for accomplishing yarns containing lyocell fibers. Industrial: new ecological textile articles (yarns, woven fabrics) for garments and home textiles and their technologies of accomplishing. Publications Aspects regarding woven fabrics finishing made of lyocell fibers, Autex Research Journal, No. 1, 2003. Considerations regarding mechanical and chemical processing of the blends containing lyocell fibers, Industria Textil, No. 1, 2003, pp. 3-7. Contributions to the study of structural properties of lyocell fibers, Industria Textil, No. 3, 2003, pp. 147-50. Lyocell ecological fibers – potential raw material for Romanian textile industry, Ecology and Textiles, I.N.C.D.T.P. Symposium, Bucharest, 7 November 2003. Lyocell fibers processing technologies in Romania, MC meeting of Cost 628 Action, Zurich/Switzerland, 11 December 2003. New performant destined for garment textile fibers, Machines and apparatus for the textiles of the 3rd millennium, paper presented at the INCDTP Symposium, Bucharest, 25 September 2003.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: (0040) 21-340.49.28; 340.42.00; Fax: (0040)-21-340.55.15; E-mail:
[email protected] Dr Eng. Iuliana Dumitrescu, Products Control and Testing Department Research staff: Dr Eng. Emilia Visileanu, Phys. Marilena Niculescu, Dr Eng. Stefan Manea, Dr Chem. Viorica Tamas, Eng. Vasilica Bercea, Eng. Floarea Pricop, Eng. Paul Vasile
Natural dyes obtained from plants and vegetable wastes Other partners: SC Laceca SA
Academic
Industrial
None
SC Hofigal SA, SC Dacia SA, SC Prodin SA
Project started: 2003 Project ends: 2004 Finance/support: 17,500 Euro Source of support: PNCDI, Biotech Programme(80 per cent) + co-financing from industrial companies(20 per cent) Keywords: Dyes of plants, Technologies, Textiles Because of the climatic diversity and geographic conditions, in Romania, there are numerous plants in the spontaneous flora or cultivated ones, out of which natural dyes can be obtained. Within INCDTP, we tried to elaborate a method of obtaining dyes from plants and wastes resulted from companies that deal with vegetable material, namely greenhouses, juice and preserved food enterprises and timber factories. There have been used tomato and patience roots, locus tree, fir and beech bark, fir needles, and onion leaves. Vegetable dyes were obtained through water extraction, by boiling, water/alcohol distillation, Soxhlet extraction with organic solvents. The efficiency for the extraction of natural dyes is relatively low, i.e. 4.8 per cent for the dye obtained from fir needles. Textile materials dyeing was conducted with and without mordants (copper, aluminum, ferrous, zinc sulphate). Mordants were applied before or after dyeing. It has been observed that obtained shade depends on: dyeing and mordanting time (generally, with increase in time, colour gradually darkens); used mordant quantity and quality; material pre- and post-treatment processes. Obtained colours are pink, cream, yellow, brown, and green. Evaluation of dyeing with natural dyes was carried out through determining wash and light fastness. Depending on the used technological process, there can be obtained light fastnesses of 3-4, wash fastnesses of 4-5. Natural dyes can be used for dyeing cotton, wool and polyamide textile materials, silk and jute, paper, wood toys, reed products, wax, candles, soaps and other cosmetics.
Project aims and objectives .
Obtaining of natural dyes from plants is existent in the spontaneous flora and wastes resulted from companies that deal with vegetable material processing, namely greenhouses, juice and preserved food enterprises, timber factories.
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Researches regarding the dyeing technology, for the purpose of increasing the colour strength, and also the physical-mechanical fastness properties (wash, light, sweat and abrasion fastness).
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Researches regarding the replacement of toxic mordants (containing heavy metals).
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Physical-chemical characterization of dyes obtained and also of treated textile materials.
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Database regarding information necessary to obtain natural dyes needed in the food, pharmaceuticals, cosmetic, textile and leather industries, handicraft shops, kits containing: natural dyes, (cotton, wool, polyamide), fibers dyed with the obtained dyes, and the characteristics of the dyed materials.
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Research deliverables (academic and industrial) (1) Documentation study: listing of tinctorial plants existent in the country, establishment of interest characteristics, technologies for obtaining dyes of plants and vegetable wastes. (2) Technological processes of natural dyes extraction from: tomato roots, patience roots, locus tree bark, beech bark, fir bark, and onion leaves. (3) Technological processes of dyes application on textile materials: cotton, and wool. (4) Physical-chemical analyses characterization methods for the dyes obtained, and also for the textile materials dyed with natural dyes. Publications Dumitrescu, I., Visileanu, E., and Niculescu, M. (2004), ‘‘Natural dyes obtained from plants and vegetable wastes’’, paper presented at Colourage, Annual 2004, pp. 121-9. Dumitrescu, I., Visileanu, E., Niculescu, M., Vasile, P., Cosmin, V., Bercea, V., Manea, S., Tamas, V. and Pricop, F. (2003), ‘‘Natural dyes obtained from plants and vegetable wastes. Part I.’’, Industria Textila, No. 2, pp. 89-96.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: 0213404928; Fax: 0213405515; E-mail:
[email protected] Adriana Gospodariu, Textile Mechanical Processing Department Research staff: Maria Dan, Maria Bulearca
Protection net against hail, thunder showers and solar radiations Other partners: Academic
Industrial
Agronomic SC SIRETUL SA – Pascani, Iasi Research-Development Institute for Vegetable and Flower crops – Vidra, Ilfov Project started: 2000 Project ended: 2002 Finance/support: 300 952 Source of support: Budget Keywords: Knitted textiles, Agriculture, Agricultural crops protection, Hail, Thundershowers, UV radiations The products aim at eliminating or reducing the destructive effects generated by the external climatic phenomena: hail, thunder showers and excessive solar radiations.
Materials are obtained through knitting technology on warp knitting machines, being made of 100 per cent poly-filament polyester yarns. Knittings are unstripping, have maximum stability in linking areas between net cells and are resistant to mechanical stress, chemical products and UV radiation action. By developing this class of knitted protection textiles in the agriculture field, the following socio-economic effects are obtained. . significant production increase; . .
increment of superior quality production volume; decrease of destructive impact for extreme atmospheric factors over crops;
.
reduction of diseases and pests rise risks; and
.
production of ‘‘clean’’ and competitive agricultural products.
Project aims and objectives Aim. Increase of qualitative and quantitative productions in the vegetables and flowers field, by reducing the negative impact of external factors over crops. Objectives. Design, production and experimentation of net type knitted textile structures made of filamentary polyester; demonstration of new realized products utility and functionality; obtained results dissemination through scientific events, participation in expositions for the technical-scientific field. Stage. Finished research
Research deliverables (academic and industrial) Academic: research reports, experimental models designs, experimental models, scientific papers. Industrial: product technical specifications – experimental model, textile technologies for the experimental models development. Agronomical: agro-technologies made efficient by experimental models usage. Publications Advertising (polychrome) publicity on Issue No. 2/2003 of Industria Textila magazine cover. Gospodariu, A. (2002), Posters at TIB’ 2001, Made in Romania Section. Gospodariu, A. (2003), ‘‘Protection net against hail, thunder showers and solar radiations’’, Workshop, Targu Jiu, October 2003.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: (0040) 21-340.49.28; 340.42.00; Fax: (0040)-21-340.55.15; E-mail:
[email protected] Eng. Adriana Gospodariu, Textile Mechanical Processing Department Research staff: Eng. Maria Buzdugan, Dr Eng. Emilia Visileanu, Eng. Constantin Mirea, Eng. Eva Bomher
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Knitted articles of gradual compression and support for persons with different circulatory disorders Other partners: Academic None
Industrial S.C. BELLATEX S.A. S.C. RO-GALU S.A. Project ended: 20 December 2002
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Project started: 16 January 2001 Finance/support: 30.000 Euro Source of support: 80 per cent budget, 20 per cent industrial sector co-financing Keywords: Life quality, Variation law, Knitting, Finishing, Gradual compression Studies globally conducted show that about 20 per cent of the total population suffer of disorders associated to the venous insufficiency (edemas, varicose veins, varicose ulcers, thromboses), localized at the lower limbs level. These considerably alter the physical and psychical potential and performances of the individual. The very high rate of the mentioned disorders and its increasing tendency or, in the most optimist views, the actual level maintaining spotlight the phenomenon amplitude and its impact on life quality. The aim of the research was to develop knitted articles of gradual compression and support for being used in the above-mentioned disorders prophylaxis and therapy. These assure a compression with pre-established values in conformity with a law of preestablished variation. Because the nude elastic yarns impose very severe conditions in the mechanical processing and limit the possibilities regarding the product structure conceiving, there have been used elastan yarns 44 dtex. . .80 dtex, simple or double winded with polyamide, covered in polyamide yarns 44 dtex f34. . .78dtex f23, stretched or textured. Stockings were knitted on circular knitting machines with 4 inches in diameter, four systems and fineness 30E. The finishing phase, especially important for obtaining the desired characteristics, includes the following operations: presetting, scouringdegreasing, dyeing, softening, whizzing. Thus, there have been obtained stockings to which the compression variation law presents a gradual diminution of the compression, from the ankle to calf of the leg in the case of a leg dimension corresponding to the nominal size, respectively, a progressive and balanced increase of the compression in the case of leg dimensions superior to the nominal size of the product.
Project aims and objectives The aim of the project consists in developing knitted articles (stockings) of gradual compression and support for being used in the circulatory disorders prophylaxis and therapy. The project objectives were targeted to manufacturing these groups of products, by. .
.
elaborating a study regarding tendencies and accomplishments at the global level on knitted articles of gradual compression and support; elaborating a preliminary technological scheme for the realization of the product types;
.
designing variants of stockings for gradual compression and support;
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technologically experiencing the development of stocking variants;
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developing experimental model products; establishing the manufacturing technologies for stockings with gradual compression and support, and implementation preparing; and certification, elaboration of standard proposals, patenting, dissemination.
.
.
Research register
47 Research deliverables (academic and industrial) Academic: conception, designing of knitted articles, experimentation, results dissemination. Industrial: manufacture of support stockings with gradual compression. Publications Gospodariu, A. (2003), ‘‘Support stockings with gradual compression’’, Industria Textila, Bucharest, No. 1. pp. 170-3. Scarlat, R. (2004a), ‘‘Support stockings with gradual compression’’, paper presented at the INCDTP Symposium, Bucharest, 18 March 2004. Scarlat, R. (2004b), ‘‘Support stockings with gradual compression’’, paper presented at the RELANSIN Symposium, Bucharest, 6 June 2004.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: (0040) 21-340.49.28; (0040) 21-340.42.00; Fax: (0040)-21-340.55.15; E-mail:
[email protected] Romanian Research and Education Ministry, The Department of Laboratory Apparatus and Equipment Meant for the Textile Industry Research staff: Daniela Isar, Senior Researcher, Emilia Visileanu, Doctor Engineer, Cristian Jipa, Senior Researcher
Studies and researches for accomplishing products meant for filtering processes Other partners: Academic
Industrial
None ICE Felix SA Computers Entreprise Project started: 1 August 2002 Project ends: 10 December 2004 Finance/support: 81000 EUR Source of support: 59 per cent governmental budget; 35 per cent The Research – Development National Institute For Textile and Leather; 6 per cent ICE Felix SA Computers Entreprise Keywords: Technical textiles, Filter cartridges, Processes filters, Cleaner processes, Products and eco-technologies
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The project aims at accomplishing of the technology and the machines needed for obtaining the textile filtering cartridges meant for the process filtering from the following fields: petrochemistry, metallurgical industry, electronics, electrotechnicals, dyes, cosmetics, pharmaceuticals, food industry, etc. It allows the filtering of the following: water, galvanizing solutions, mineral and vegetable oils, petroleum products, chemical solutions, solvents, dyes, inks, various drinks, etc. The filtering cartridge is a textile technical article made up of a textile yarn (roving) deposited in a special geometry on a tubular perforated support, with the respecting of the yarn tension and the cartridge hardness parameters. The shape and dimensions of this item correspond to the international standards. The stages as part of the project are. . .
\establishing of the specific conditions for the mentioned filtering media; elaborating of the accomplishing technology;
.
designing and accomplishing of the necessary machines meant to obtain the textile filtering cartridge; and
.
selection of the textile materials based on which one can accomplish the filtering material of the cartridges, depending on the filtering (working) environment.
Project aims and objectives The project refers to the obtaining of the technology and machine necessary to achieve the textile filtering cartridges meant for the process filtering from the various filtering fluids media.
Research deliverables (academic and industrial) .
Technology of accomplishing the textile filtering cartridges meant for the process filtering.
.
Project and equipment meant for accomplishing the textile filtering cartridges. The production of the textile filtering cartridges.
.
Publications Textile Industry Magazine, (2002), No. 4, p. 289. Textile finishing, dyeing, energy, environment, paper presented at the Scientific Event, Busteni, 12 December 2003.
Bucharest, Romania National Research and Development Institute for Textile and Leather – Division Leather and Footwear Research Institute, 93 Ion Minulescu str., Sector 3, Bucharest, Romania Tel: +4021-323.50.60; Fax: +4021-323.52.80; E-mail:
[email protected] Dsg. Pop Marlen, Footwear Research Department
Research staff: Dr Eng. Gaidau Carmen, Eng. Ivan Magdalena, Chem. Dumitrescu Iulia
Research register
Ecological leather garment Other partners: Academic None
Industrial ‘‘Casa Vili’’ SC Comtex SRL Bucharest Project ended: April 2003
Project started: January 2001 Finance/support: 460.000.000 lei Source of support: State budget and SME’s resources Keywords: Eco-products, Leather garment, Specific characteristics (1) Ecological goods, in this case eco-sanogenetic leather garment or leather ecogarment, are the sum of some constructive, functional and aesthetical views, answering all the human requirements on garment. (2) The above products are made from the best ecological leathers obtained under the research project. (3) Characteristics of leathers intended for the eco-garment comply with the EU regulations as follows. . Council Regulation (CEE) No. 880/92; .
Oko-tex standard 116-leather clothing and textile;
.
commission information on eco-labelling, procedural guidelines for the establishment of product groups and ecological criteria; and decisions 2002/231/EC and 2000/1980/EC.
.
(4) Manufacture of ecological leather and eco-products is characterized by. . lack of toxic chemicals that are replaced by alternative environmentally friendly products; .
leather assortments are made by environmentally friendly processes;
.
eco-products involve a stylistic and functional matrix providing for the design of eco-sanogenetic products as follows.
.
structural-functional characteristics: physico-mechanical, chemical and biochemical characteristics; energy characteristics: energy meridians, and electrical homeostasis; and
. .
stylistic characteristics: human architecture ratios and rhythm, and inner ergonomic space.
(5) These products are the first Romanian generation of ecological leather and garment eco-products.
Project aims and objectives .
Finding out the design characteristics for garment eco-products made from sheepskins with eco-sanogenetic characteristics resulted from specific processing technologies.
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Development of an ecologic product schedule leading to a Romanian modern general concept dealing with eco-products.
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Design, tests, pilot-plant ecological processing of sheepskins intended for garment.
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Manufacture of a sheepskin range for the garment manufacture, enabled by the project stylistic matrix.
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Development, design, pursuance and control of prototype and manufacture technology for a sanogenetic wearing apparel range.
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Design and pursuance of the ‘‘zero’’ series and drawing up the documentation for commencement of ecological garment production.
.
Development of a sanogenetic sheepskin processing plant, making this valuable material available to SMEs.
50
Research deliverables (academic and industrial) .
Leather eco-products were made by ecological technologies.
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Results of tests performed on these products revealed that they comply with the EU standards and are toxic chemicals free.
.
Toxic chemicals were substituted for environmentally friendly materials. Application of the design matrix laid down under this project ensures the manufacture of garment eco-products complying with the EU standards.
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Publications Ecological leather wearing apparel and human ecology – theoretic and constructive characteristics, paper presented at the National Conference on Textile and Garment Design, Cluj-Napoca, 2001. Ecological leather wearing apparel, paper presented at the National Research Salon, Bucharest, 2003. Ecological wearing apparel – aesthetic, technical and economic reference points according to the present EU standards, paper presented at the National Research and Development Institute for Textile and Leather Symposium Research in the Industry, Bucharest 2004.
Bucharest, Romania National Research and Development Institute for Textile and Leather – Division Leather and Footwear Research Institute, 93: Ion Minulescu str., Sector 3, Bucharest, Romania Tel: +4021-323.50.60; Fax: +4021-323.52.80; E-mail:
[email protected] Dr Eng.Gaidau Carmen, Leather Research Department Research staff: Eng. Miu Lucretia, Dsg. Pop Marlen
Ecological sheep garment nappa Other partners: Academic
Industrial
None
S.C. TARO SRL, Bucharest
Project started: January 2001 Project ended: April 2003 Finance/support: 460.000.000 lei Source of support: State budget and SME’s resources Keywords: Ecological sheepskins, Non-toxicity, Clean technology Today fashion trends and those in consumer requirements have imposed development of some ecologic leathers complying with requirements for sanogenetic products. Ecological leathers made from prime wool and long wool breed raw skins of 3-6 class by special processing technologies and making use of selected chemicals as processing aids with the view of obtaining products showing no harmful effects on the end consumers, according to the EU standards in this field. When finishing sheepskin leathers, finishing formulations preserving the natural grain and carcinogen amine-free dyes were employed, aiming to obtain finish colours in line with the garment general eco-design notion. The resulted finished sheepskins, intended for garment, comply with both technical and aesthetical requirements, as well as the functional ones. Research is thus in line with nowadays’ trends, imposed by the fashion requirements, but also the consumer health.
Project aims and objectives . .
.
Development of ecological sheepskin processing technologies. Manufacture of sheepskin garment leathers with the ecological and human health requirements. Enlarging the sheepskin range with the ecological leathers.
Research deliverables (academic and industrial) . . . .
Papers presenting testing results. Result dissemination. Technology transfer to the SMEs processing sheepskins. Manufacture of sheepskin garment nappa complying with the EU quality standards (SG, Oko-Tex, CEE Guide).
Publications None
Bucharest, Romania National Research and Development Institute for Textile and Leather – Division Leather and Footwear Research Institute, 93 Ion Minulescu str., Sector 3, Bucharest, Romania Tel: +4021-323.50.60; Fax: +4021-323.52.80; E-mail:
[email protected]
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Dr Eng. Trandafir Viorica, Collagen Research Department Research staff: Chem. Albu Madalina, Dr Chem.Coara Gheorghe, Biol. Bratulescu Victoria
New composite collagen membrane-based bioactive and bioresorbable systems for tissue prosthetics Other partners: Academic
Industrial
National Institute for S.C. PONETI SRL, Bucharest Chemical-Pharmaceutical Research and Development Project started: 2001 Project ended: 2003 Finance/support: 1.310.000.000 lei Source of support: State budget and SME’s resources Collagen is a protein largely spread within the animal body, which when extracted from the dermis provides a large range of biomaterials for external (dressings, skin grafts, ointments, etc.) and internal (grafting and implants) applications. From our studies have resulted a series of products, which are as follows. .
The first generation of collagen-based biomaterials prepared from type I collagen fibrils obtained from bovine hide dermis and subsequently treated by drying; these biomaterials are employed as resorbable dressings in healing burns and sores, hemostatically acting powders, bioactive ointments and creams, surgical threads.
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The second generation of biomaterials, also based on type I collagen fibrils, are composite prosthetic materials, like as collagen impregnated textile prosthetics, vascular ducts, and implants.
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The third generation of biomaterials, prepared by organogenesis (cell growth) on a collagen support of various isotopes and combined with other natural polymers.
Bioactive and bioabsorbable SCG II skin substitute is a microporous structure made of a three-dimensional collagen fibre and fibril network, highly hydrophilic and with chemotactic action onto the fibroblasts. Biointegrable SCP skin substitute based on a transparent collagen membrane with textile (polyester fibre network) insert.
Project aims and objectives .
Preparation of collagen-based biomaterials intended for human medicine, which are a higher generation of collagen-based products.
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Improving the medical action by ensuring a quicker healing in fully aseptic conditions.
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Substitution of some imported similar products for Romanian products with the same effects and less expensive.
Research register
Research deliverables (academic and industrial) .
A skin substitute was prepared with the same softness and adequate binding capacity for an uniform wound covering.
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Skin substitutes act in wound healing by releasing active constituents contained within the structure (drugs, collagen molecules), thus avoiding contamination risk. Collagen membranes can carry many other bioactive substances, which is the specific characteristic of in vitro and in vivo compatibility and gradual release should be established for.
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SCG II skin substitute can be applied in preparing tissues by organogenesis in cell cultures and as definitively grafted vivid tissues. PLASCOL skin substitute was tested in vivo as abdominal wall with very good results. All the above products have shown high biocompatibility, controlled bioresorbtion, biointegration, characteristics similar to the substituted tissue, reducing the traumatisms caused by repeated dressing.
.
.
Publications Trandafir, V. (2002), ‘‘Improving the textile prosthetic biocompatibility by collagen treatment’’, paper presented at the Symposium, Universe of Medical Implantable Materials for Humans, November 2002. Trandafir, V. (2003a), ‘‘Collagen bioactive products for medical and pharmaceutical use’’, paper presented at the First International Symposium, New Resources in Pharmaceutical Industry, Constanta, June 2003. Trandafir, V. (2003b), ‘‘Characterization of some collagen gels and spongy matrices used as supports in cell growth’’, Academic Days of Iassy, September 2003. Trandafir, V. et al. (2003c), ‘‘Effect of hydration degree on the hydrothermal and thermooxidizing stability of some collagenous matrices’’, Journal of Thermal Analysis and Calorimetry, Vol. 72 pp. 581-5.
Bucharest, Romania National Research and Development Institute for Textile and Leather-Division Leather and Footwear Research Institute, 93 Ion Minulescu str., Sector 3, Bucharest, Romania Tel: +4021-323.50.60; Fax: +4021-323.52.80; E-mail:
[email protected] Dr Eng. Gaidau Carmen, Leather Research Department Research staff: Eng. Miu Lucretia, Eng. Niculescu Olga, Eng. Vidru Maria, Subeng. Bocu Veronica
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New technologies for the manufacture of footwear for professional use and of bovine leather assortments intended for this according to the EU standards
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Other partners: Academic
Industrial
National Institute for Work S.C. FLAROS SA, Bucharest Protection Research and S.C. EUROPLASTIC SRL, Bucharest Development Project started: January 2001 Project ended: January 2003 Finance/support: 1.150.000.000 lei Source of support: State budget and SME’s resources Footwear for professional usage should comply with some minimal requirements, such as providing good working conditions, adequate hygienic conditions, and easy care. Used conditions are determined by risk level, risk exposing frequency, body position during the work, ground characteristics and product performance. According to the EU standards, this kind of footwear is classified into three categories, depending on the scope (corresponding to the three risk levels): (1) protective footwear; (2) working footwear; and (3) safety footwear. To meet the protective requirements, footwear should be made from certain materials, which kind and processing technique could act on the specific footwear character. Some studies for the manufacture of leather semi-finished products for footwear uppers have been finalized with the manufacture of fireproofe and waterproof bovine leather making use of auxiliary materials selected for this purpose. Physical-mechanical characteristics (water and water vapour permeability, flexing endurance, dyeing fastness, etc.) comply with the Romanian standards, in line with the European ones. Following these studies two kinds of footwear have been made by the CR technique: (1) anti-boring semi-high boots, thermally resistant; and (2) safety anti-boring semi-high boots, thermally resistant.
Project aims and objectives .
Manufacture of footwear for professional use and of leather semi-finished products intended for this according to the EU requirements (EN 344/92).
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Development of some auxiliary materials (chemicals) for wet and final finishes of the bovine leathers.
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Alignment of the national requirements on the footwear for professional use with technical specifications of EU standards.
Research deliverables (academic and industrial) .
Manufacture of waterproof and fireproof leather assortments adequate for uppers of footwear for professional use.
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Have patented the technology for the manufacture of leather intended for uppers of footwear for professional use.
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Manufacture of footwear for professional use complying with SR EN 3451 correlated with SR EN 344-1, and SR EN 345-2 correlated with SR EN 344-2 requirements (protection of toes against mechanical aggression, water penetration and absorption, protection against accidental contact with flame and radiant heat, thermal insulation, hydrocarbon resistant soles etc.).
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To the resulted footwear marking the protective symbols SB P WRU HRO HI have been applied, corresponding to the SR EN 345/96 specifications.
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Certification of the new bovine leather assortments and of the two kinds of footwear; drawing up the product standards.
Publications Exhibition Salon SANO SCUT, November 2002, Petrosani – Product sheets for leather and footwear were presented. Exhibition ‘‘Conceived in Romania’’, October 2002, Bucharest – Product sheets for leather and footwear were presented. ‘‘Fabricarea pieilor cu performance nalte pentru echipamente de proteccie’’, la al XXVI-lea Congres al IULTCS, 8-1 Imartie 2001, Africa de Sud, autori: Lucrecia Miu, Carmen Gaidu, Virginia Henculescu, Emilia Dobrescu, Marcel lonescu, Marian Crudu. ‘‘Materials and technologies for high Level Performances Leather for Protective Clothing and Gloves Against Heat and/or Flame’’, la International scientific Conference ‘‘Lighter industry on the turn ofthe century’’, 23-24 November 2001, p. 247, Radom Polonia, autori: ing. Lucrecia Miu, dr.ing. Carmen Gaidu, ing Virginia Henculescu, ing. Emilia Dobrescu, ing. Marcel lonescu, ing. Marian Crudu. ‘‘Procde pour la re´alisation des cuirs hydrophobises et ignifuges’’, Dr.ing. Carmen Gaidau, ing. Lucretia Miu, ing. Virginia Hentulescu, ing. Vasile Lascarov, ing. Marcel lonescu, ing. Marian Crudu, cerere de brevet prezentat la al 31 -lea Salon Intemacional de Invencii, Tehnici _i Produse Noi, Geneva, 2003, medalie de bronz. ‘‘Procede pour la realisation des cuirs hydrophobises et ignifuges’’, Dr.ing. Carmen Gaidau, ing. Lucretia Miu, ing. Virginia Hentulescu, ing. Vasile Lascarov, ing. Marcel lonescu, ing. Marian Crudu, cerere de brevet prezentat la Eureka, 2003, Bruxelles, 2003, medalie de argint. ‘‘Realizarea de piei cu nalt performancaˆ pentru nclcmintea de uz profesional’’, autori: Carmen Gaidu, Lucrecia Miu, Virginia Henculescu, Vasile Lascarov, Ctaˆlin Dumitru, Marcel lonescu, Marian Crudu, Revista de Pielrie-nclcmnte, No. (2003) l3. Revista de Pielrie-Inclcminte (Leather and Footwear Journal) Vol. 2, 2002. ‘‘Technologies, chemical materials and high performance leathers for professional use’’, la al XII-lea Congres Intemacional de Pielrie _i Industrii Conexe, 9-11 octombrie, 2002, Budapesta, Ungaria, autori: Garmen Gaidu, Lucrecia Miu, Virginia Henculescu, Lascarov Vasile, Dumitru Ctlin, lonescu Marcel, Crudu Marian. ‘‘52th Salon Mondial de l’Innovation, de la Recherche et des Nouvelles Technologies’’.
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Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: (0040)21-340.49.28; Fax: (0040)21-340 49 28; E-mail:
[email protected] Romanian Research and Education Ministry, Special Products Department Research staff: Claudia Niculescu, Senior Researcher – INCDTP, Adrian Salistean, Aerospace Engineer – INCDTP
Design and evaluation program of the round parachutes performances – flight simulator Other partners: Academic
Industrial
INCAS None National Research Institute for Aerospace Project started: September 2002 Project ended: February 2004 Finance/support: 80 000 e Source of support: 93.5 per cent governmental budget; 6.5 per cent (The Research – Development National Institute for Textile and Leather and National Research Institute for Aerospace) Keywords: Parachute, Software, Numerical methods The project has developed a software for. .
parachute design and performance evaluation; and
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aerodynamic analysis (parachute descend simulation, pressure and air speed distribution).
In the project there were implemented numerous and various calculus methods, analysis and design to achieve aerodynamic behaviour simulation. Methods of parachute design implementation. Round parachute calculus methods. .
classical methods of calculus;
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opening shock forces;
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shock loading evolution; and
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altitude effect on opening shock forces.
Theoretical study methods. .
round parachute in the axial – symmetric movement;
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parachute surface modelling;
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rear air flow modelling;
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air flow equations around a parachute with no porosity;
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numeric solution of the problem; and
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parachute opening dynamics.
Elaboration of various constructive variants and optimum solution choosing based on. .
drag force;
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canopy shape and riser length effects;
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parachutes opening forces;
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canopy filling time;
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canopy load effect on opening forces;
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opening force calculus methods: W/(CDS)p methods; Pflanz methods, force trajectory computerized method;
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analysis methods concerning the canopy loading;
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altitude and porosity influences; and
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parachute weight evaluation.
Project aims and objectives The aim was to develop a calculus and analysis instrument for the parachute designers to aid them in shortening the design time. The program can be used by laboratories and institutions from the parachute research area, manufacture preparation or existent solution validations. The objectives were to obtain. .
parachute design and performance evaluation software;
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aerodynamic analysis (parachute descend simulation, pressure and air speed distribution); and
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software.
Research deliverables (academic and industrial) .
Parachute design software. It contains all data referring to the design of various round parachute types, calculus methods, decision and optimal solution choosing.
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Aerodynamic analysis and flight behaviour simulation program. It contains analysis for aerodynamics, stability and verification for the proposed solution. As input data there will be used the technical and physical characteristics of parachute obtained with the above design program.
Publication Textile Industry Magazine (2004), ‘‘Design and evaluation program of the round parachutes performances’’, Vol. 1, pp. 7-10.
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Bucharest, Romania The Research – Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Street, Sector 3, Bucharest, Romania Tel: (0040)21-340 49 28; Fax: (0040)21-340 49 28; E-mail:
[email protected] Romanian Research and Education Ministry, Special Products Department
Research staff: Researcher Radulescu Radu, – INCDTP, Mechanical Engineer Doina Grecu – INCDTP
Droppable container for materials landing – CPMU Other partners: Academic
Industrial
None None Project started: 1999 Project ended: 2001 Finance/support: 11 000 e Source of support: Governmental budget Keywords: Military technique, Aerial delivery systems, Parachute cargo The project aim was to develop a droppable container for material to be used with any parachute systems available for parachuting light payload. The container is used for materials landing from any aircraft (airplanes, helicopters, balloons, etc.) with any parachute type (cargo or personnel) in accordance with landing load. The system is composed by damper platform with or without container, suspension, clamping system and parachute. The container is fixed on the pneumatic dumping platform. Technical specifications. .
Maximum suspended load: 150 daN
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Minimum launching altitude: 300 m
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Descend rate: 6-8 m/s
The stages of project were: research and elaboration of achievement documentation stage; prototype design and achievement stage; and prototype testing, on ground and on flight, and homologation stage.
Project aims and objectives The project aim is to develop and homologate a droppable container for light payload to be used; from any aircraft with any parachute systems available for parachuting light payload. The project objectives were developing of the webbing system for container; design and manufacture of the container; and design and manufacture of the pneumatic dumping system.
Research deliverables (academic and industrial). . . .
Technical documentation and blue prints. Manufacturing technological process. Homologated prototype of container for materials landing (CPMU).
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Publications None
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Str., Sector 3, Bucharest, Romania Tel: 0213404928; Fax: 0213405515; E-mail:
[email protected] Eng. Doina Toma, Textile Mechanical Processing Research staff: Prof. Dr Eng. Eftalea Carpus, Eng. Eva Bomher
Protective gloves against mechanical and thermal risks Other partners: Academic
Industrial
None None Project started: 1 June 1996 Project ended: 25 October 1999 Finance/support: 20 000 e Source of support: Research and Education Ministry Keywords: Mechanical risks, Thermal risks, Knitted protection gloves The adequate choosing of the protective gloves depending on the hazard factors of the utilization field and the need of dressing up the workers in IPE are elements that secure personnel safety and health. An important part in the prevention of the various professional diseases and working accidents is played by the protective gloves that should be. .
Research register
perfectly conceived, without any flaws; comfortable in wearing; adaptable to the purpose they are worn for; accomplished of materials that should ensure protection at all parameters involved in the safety field.
The protective gloves accomplished by the specialists from our institute by the technology of two - phase knitting are five - fingered gloves having an elastic cuff obtained from the structure (Plate 1). They are accomplished in two versions: (1) From one layer: glove knitted of Kevlar para-aramidic yarns. (2) From two layers: exterior layer – glove knitted of Kevlar para-aramidic yarns; and interior layer – glove knitted of 100 per cent cotton yarns.
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Plate 1.
The simple protective gloves ensure hand protection against. . occasional contact with the open flame; .
heat when in contact with hot objects at the temperature of maximum 100 C for 8 s; and
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superficial mechanical aggressions: abrasion, cutting, and snagging.
The double-layered protective gloves ensure hand protection against. . occasional contact with the open flame; .
heat when in contact with hot objects at the temperature of maximum 200 C for 10 s; and
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superficial mechanical aggressions: abrasion, cutting, and snagging.
Project aims and objectives .
Protection gloves designing and manufacturing by using performance fibers that confer them the capacity to annihilate the risk factors.
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Performance testing for the produced gloves from the protection characteristics point of view, in conformity with the European Standards for the applying field. Diversification of individual protection equipments able to assure the optimal level of protection for the risk level corresponding to the foreseen applying field.
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Improving of the working conditions for high risk degree environment.
Research deliverables (academic and industrial) Academic: conception, designing of new types of protective gloves against mechanical and thermal risks, results dissemination. Industrial: new types of protective gloves against mechanical and thermal risks. Publications Toma, D. (1997), ‘‘Protection gloves’’, Dialog Textil, pp. 10-11, ISSN 1224-0192. Toma, D. and Carpus, E. (n.d.), ‘‘Protective gloves against mechanical and thermal risks’’, Ergonomics of Protective Clothing, pp. 216-17 ISSN 0346-7821.
Bucharest, Romania The Research-Development National Institute for Textile and Leather, 16th Lucretiu Patrascanu Str., Sector 3, Bucharest, Romania Tel: 0213404928; Fax: 0213405515; E-mail:
[email protected] Eng. Doina Toma, Textile Mechanical Processing Research staff: Phys. Iuliana Cohea, Prof. Dr Eng. Eftalea Carpus
High visibility warning clothing Other partners: Academic
Industrial
None None Project started: 1997 Project ended: 1999 Finance/support: 20 000 Euro Source of support: Research and Education Ministry Keywords: Visual signalling, Protection equipment, Warning clothing On European level, a significant importance is given to the usage of high visibility warning clothing and especially to the awareness of the factors involved in the correct applying of request provisions of ‘‘visual signaling’’ for people who unfold their activity on the routes of road traffic or in other work places (such as building construction, mines, etc.) On the basis of the protection requests and minimally necessary performance parameters specified, there have been developed the following garment types of high visibility. .
suit of high visibility, class 3, model CBV3 made of fluorescent material, 85 per cent PES/15 per cent bbc+retro reflecting tapes; and
suit of high visibility, class 2 model CCV2 made of fluorescent material 85 per cent bbc/15 per cent PES (material surface 0.3 m2) + fabric 100 per cent bbc+retro reflecting tapes The products developed, tested and certified in conformity with the European Normative comply with the essential requests of security and health corresponding to the foreseen applying fields. .
Project aims and objectives Designing and development of fluorescent textile supports which confer to the equipment the capacity to signalize the worker presence in areas of accident risks by striking with high speed moving objects (public roads where motor- or auto-vehicles circulate, railway transports, wood exploitation industry). Development of manufacturing technologies and assembling systems able to assure equilibrium between safety, mobility and dexterity, comfort and costs. Performance testing for the textile supports and the realized protection equipments from the protection characteristics point of view, in conformity with European Standards for the applying field.
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Research deliverables (academic and industrial) Academic: conception, designing of new high visibility warning clothing, results dissemination. Industrial: new high visibility warning clothing. Publications Toma, D., Cohea, I. and Carpus, E. (1999),‘‘High visibility warning clothing’’, Industria Textila, No. 3, ISSN 1222-5347, pp. 152-7. Toma, D., Carpus, E. and Cohea, I. (n.d.) ‘‘High visibility warning clothing’’, Ergonomics of Protective Clothing, ISSN 0346-7821, pp. 88-9.
Budapest, Hungary Budapest University of Technology and Economics, H-1521 Budapest, Hungary Tel: +36-1-463-1376; Fax: +36-1-463-1376; E-mail:
[email protected] Department of Plastics and Rubber Technology Prof. Judit Borsa
Development of special properties on cotton cellulose Other partners: Academic Budapest University of Technology and Economics – Department of Chemical Engineering, Department of Chemical Technology, Department of General and Analytical Chemistry, Department of Organic Chemical Technology, and Department of Physical Chemistry. Hungarian Academy of Sciences, Chemical Research Center – Institute of Chemistry, and Institute of Isotope and Surface Chemistry. Bay Zoltan Institute for Materials Science and Technology, Hungary Johan Bela National Center of Epidemology, Hungary Johannes Kepler University, Linz, Austria Cornell University, Ithaca, NY, USA
Industrial None
Project started: 1 January 2001 Project ends: 31 December 2004 Source of support: OTKA (Hungarian National Science Fund), NKFP (Hungarian National Research and Development Fund) Keywords: Cotton, Cellulose, Swelling, Quaternary ammonium hydroxide, Mercerization, Chemical modification, Carboxymethylation, Soil release, Protective clothing, Hospital infection, Medical textile, Antimicrobial textile New properties of cotton fiber are developed by physical and/or chemical modification. Structure and morphology of modified fiber are studied (1 and 2), furthermore, research on functional textiles is on-going (3). (1) Swelling of cotton cellulose. Quaternary ammonium hydroxides are intracrystalline swelling agents of cellulose, moreover, the large molecules can even dissolve it. Effect of tetramethylammonium hydroxide (TMAH) on the properties of cotton cellulose (degradation, supermolecular structure, morphology, degree of mercerization) and on purification of cellulose (retting of hemp, scouring of cotton) is studied in comparison with sodium hydroxide. (2) Chemical modification of cotton cellulose. 2-3 per cent of hydroxyl groups of cotton cellulose are substituted by bulky carboxymethyl groups. Modified fiber retains its fibrous nature while many of its properties differ from those of the original fiber. Some properties of fiber (in this project mainly accessibility, hydrophyl character, swellability) as a function of reaction parameters are studied. (3) Functional textiles. .
Soil release: in a former project partially carboxymethylated cotton fabric was effectively used to limit the dermal exposure of workers handling pesticide. The modified fabric has dual effect: it entraps large amount of pesticide during contamination and releases its large ratio during washing. In this project partial carboxymethylation as a durable soil release finishing is studied.
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Protective clothes/Antimicrobial textiles: cationic antimicrobial agent is bounded on the anionic groups of cellulose fiber. The survival time of some microorganisms (Candida albicans, Staphylococcus aureus) on this fabric is studied.
Project aims and objectives Cotton is the most commonly used fiber in clothing, moreover, it is an excellent model to study cellulose itself. Cellulose, as a renewable raw material has a special significance in the sustainable development, hence any information on its possible improvement can be interesting for areas outside textiles as well. The aim of the project is to modify cellulose by physical and/or chemical methods to change its properties. It can be important both from the scientific and practical point of view. The project has three main objectives: (1) physical modification by swelling with quaternary ammonium hydroxide, (2) physical and chemical modification by carboxymethylation, and (3) functional textiles.
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Swelling. TMAH seems to be a special activating agent of cellulose: due to its slightly apolar character it can penetrate into the apolar parts of the cellulose structure, too. Scientific literature on its swelling effect is very limited. The aim of the project is to obtain the basic information on the effect of TMAH on the structure and morphology of cellulose and on purification of cellulose sources (hemp and cotton) in comparison with sodium hydroxide.
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Chemical modification. Substitution of hydroxide groups by bulky carboxymethyl groups is a good tool to loosen the ordered structure of cellulose. Carboxymethyl cellulose of high degree of substitution (DS , 0.6) is soluble in water. Introducing some carboxymethyl groups (DS , 0.08. . .0.1) into cotton cellulose can significantly change the properties of fiber. The aim of the project is to characterize the cotton cellulose modified by various technologies, and to study possible applications of modified fiber.
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Functional textiles. New, valuable properties of cotton fabric can be developed by proper modification. The project focuses on two topics: durable soil release finishing and antimicrobial textiles/protective clothes (hospital textiles protect people from infection, but according to international statistical data, they are also carriers of micro-organisms; the aim of the project is to reduce the survival time of the micro-organisms on the fabric as a part of the strategy against nosocomical infection).
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Research deliverables (academic and industrial) Academic deliverables .
Swelling with TMAH: important information can be obtained about the activation of cellulose by a slightly apolar swelling agent. It can be a starting point for further research on special modifications of cellulose.
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Chemical modification: especially, the structure of the amorphous phase might be interesting.
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Functional textiles: study of the soil release from the carboxymethylated cotton fabric can help in the further understanding of fiber swelling and highly anionic fiber surface on the release mechanism.
Industrial deliverables Results might be applied in textile finishing (durable soil release, antimicrobial textile), and possibly in purification (delignification) of cellulose. Publications Borsa, J., Racz, I. and Toth, T. (2002), ‘‘Chemical modification of cotton cellulose for medical textiles’’, 2nd AUTEX Conference, Brugges, Belgium. Borsa, J., Toth, T. and Takacs, E. (2003), ‘‘Radiation modification of swollen and chemically modified cellulose’’, Rad. Phys. Chem., Vol. 67, pp. 509-12. Borsa, J., Toth, T., Racz, I. and Balkan, D. S. (2002a), ‘‘The role of anionic group and improved accessibility of chemically modified cellulose in adsorption and release of cationic molecules’’, 1st International Cellulose Conf., ICC 2002, Kyoto, Japan.
Borsa, J., Tanczos, I., Pokol, Gy., Toth, T. and Schmidt, H. (2002b), ‘‘The effect of tetramethylammonium hydroxide in comparison with the effect of sodium hydroxide on the slow pyrolysis of cellulose’’, Pyrolysis 2002, Leoben, Austria. Borsa, J., Toth, T., Takacs, E., Sajo, I. and Tanczos, I. (2002c), ‘‘Activation of cotton cellulose by tetramethylammonium hydroxide’’, 1st Int. Cellulose Conf., ICC 2002, Kyoto, Japan. Borsa, J., Zala, J., Kiss, K., Lazar, K., Toth, T. and Horvath, E. (2003), ‘‘Antimicrobial cotton fabric for hospital use’’, 2nd European Conf. on Protective Clothes, Montreux, Switzerland. Obendorf, S. K. and Borsa, J. (2001), ‘‘Lipid soil removal from cotton fabric after mercerization and carboxymethylation finishing’’, J. Surfactants and Detergents, Vol. 4, pp. 247-56. Tanczos, I., Borsa, J., Sajo, I., Laszlo, K., Juhasz, Z.A. and Toth, T. (2000), ‘‘Effect of tetramethylammonium hydroxide on cotton cellulose in comparison with sodium hydroxide,’’, Macromolecular Chem. Phys., Vol. 201 No. 17, pp. 2550-6. Tanczos, I., Pokol, Gy., Borsa, J., Toth, T. and Schmidt, H. (2003), ‘‘The effect of tetramethylammonium hydroxide in comparison with the effect of sodium hydroxide on the slow pyrolysis of cellulose’’, J. Analytical and Applied Pyrolysis (in press). Toth, T., Borsa, J. and Tanczos, I. (2002), ‘‘Equilibrium swelling of cotton cellulose in tetramethylammonium hydroxide’’, 10th Oesterreichische Chemietage, Linz, Austria. Toth, T., Borsa, J., Takacs, E. and Sajo, I. (2003), ‘‘Effect of preswelling on radiation of cotton cellulose’’, Rad. Phys. Chem., Vol. 67, pp. 513-15. Toth, T., Borsa, J., Reicher, J., Sallay, P., Sajo, I. and Tanczos, I. (2003), ‘‘Mercerization of cotton cellulose with tetramethylammonium hydroxide’’, Textile Res. J., Vol. 73 No. 3, pp. 273-8.
Budapest, Hungary Budapest University of Technology and Economics (BUTE), Budapest, M} uegyetem rkp. 3., H-1111 Hungary Budapest, H-1521, Hungary Tel: +36-1-463-1376; Fax: +36-1-463-1376; E-mail:
[email protected] Prof. Judit Borsa Department of Plastics and Rubber Technology
Effect of quaternary ammonium compounds on structure and reactivity of cellulose Other partners: Academic
Industrial
Department of Analytical Chemistry, None BUTE Department of Physical Chemistry, BUTE Department of Chemical Technology, BUTE Chem. Research Center of the Hungarian Academy of Sciences Johannes Kepler University, Linz, Austria Dr Habil Ildiko Tanczos
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Project started: 1 January 1999 Project ended: 31 December 2002 1 January 2002 (the project will be continued in 2003) Finance/support: Euro 15,000, Euro 5,000 Source of support: Hungarian National Research Fund and Austrian-Hungarian Scientific Exchange Program Keywords: Cellulose, Cotton, Tetraalkylammonium compounds, Tetramethylammonium hydroxide, Sodium hydroxide, Swelling, Mercerization Quaternary ammonium compounds are intracrystalline swelling agents of cellulose, moreover, they are also its good solvents in the case of sufficiently large size of molecule. Scientific literature on the effect of tetraalkylammonium hydroxides on cellulose is very limited, partly due to the relatively high price of these chemicals. Tetramethylammonium hydroxide has recently been applied in the electronic industry for surface cleaning, hence its price has significantly decreased. Some more information about the interaction of cellulose with these swelling agents, compared to sodium hydroxide, could be interesting both from a scientific and technological point of view.
Project aims and objectives The aim of the work is to study the interaction of tetramethylammonium hydroxide (TMAH), the smallest member of the tetraalkylammonium hydroxide family, with cotton cellulose. Crystallinity, sorption capacity, water retention, dye uptake, effect of high energy irradiation etc. were investigated. Purification of various cellulose sources (wood, hemp, cotton) was also studied.
Research deliverables (academic and industrial) It was found that TMAH is a more effective swelling agent of cellulose than sodium hydroxide. It was explained by its large size, partly apolar character, and extremely high activity. This property of TMAH might be used in various areas including textile industry. Publications Borsa, J., Ta´nczos, I., Sajo´, I., Juha´sz, Z.A. and To´th, T. M. (1999), ‘‘Activation of cellulose with tetramethylammonium hydroxide’’, Advances in Wood Chemistry, International Symposium (Proceedings), Wien, Austria. Taka´cs, E., Wojna´rovits, L., Fo¨ldva´ry, Cs., Borsa, J. and Sajo´, I. (2001), ‘‘Radiation activation of cotton cellulose prior to alkali treatment’’, Res. Chem. Intermediates, Vol. 27, pp. 837-45. Ta´nczos, I., Putz, R. and Borsa, J. (1999), ‘‘Comparative study on the effects and mechanism of the new quatam pulping’’, 10th International Symposium on Wood and Pulping Chemistry, Main Symposium (Proceedings), Yokohama, Japan, Vol. II, pp. 288-91. Ta´nczos, I., Borsa, J., Sajo´, I., La´szlo´, K. and Juha´sz, Z.A. (1998), ‘‘Comparison of the effect of sodium hydroxide and tetramethylammonium hydroxide on cotton cellulose’’, International Symposium in Wakayama on Dyeing and Finishing of Textiles (Proceedings), Wakayama, Japan, pp. 276-7. Tanczos, I., Borsa, J., Sajo, I., Laszlo, K., Juhasz, Z.A. and Toth, T.M. (2000), ‘‘Effect of tetramethylammonium hydroxide on cotton cellulose in comparison with sodium hydroxide’’, Macromolecular Chemistry and Physics, Vol. 201 No. 17, pp. 2550-6. To´th, I., Borsa, J., Reicher, J., Sallay, P., Sajo´, I. and Tanczos, I., ‘‘Mercerization of cotton with tetramethylammonium hydroxide’’, Textile Research Journal (in preparation).
Budapest, Hungary Budapest University of Technology and Economics (BUTE), Budapest, Mu¨egyetem rkp. 3., H-1111, Hungary, Budapest, H-1521, Hungary Tel: +36-1-463-1376; Fax: +36-1-463-1376; E-mail:
[email protected] Prof. Judit Borsa, Department of Plastics and Rubber Technology
Advanced textiles Other partners: Academic
Industrial
Chem. Research Center of the None Hungarian Academy of Sciences Bay Zolta´n Institute for Materials Science and Technology Ilona Ra´cz Ph.D. Cornell University, Ithaca, New York, USA Prof. S. Kay Obendorf, Johan Be´la National Center of Epidemiology Project started: 1 January 2001, Project ends: 31 December 2004, 1 July 2001 31 July 2004 Finance/support: Euro 25,000, Euro 30,000 Source of support: Hungarian National Research Fund, Hungarian National Research and Development Fund Keywords: Cellulose, Cotton, Chemical modification, Carboxymethylation, Pesticide protective clothes, Soil release, Medical textile, Antimicrobial textile Supermolecular structure and morphology of cellulose can significantly be modified by chemical modification. Slight carboxymethylation of cotton cellulose improves the accessibility of the fiber, which can be used for various purposes.
Project aims and objectives The aim of the work is to find useful applications for a fiber with very high accessibility (sorption capacity). Slight carboxymethylation as durable finishing for various aims (pesticide protection, lipid soil release, antimicrobial properties) has been studied.
Research deliverables (academic and industrial) Highly accessible cotton fiber was used for pesticide protective clothes. Durable carboxymethylation finish has been used on cotton fabrics to trap the pesticide on the fabric decreasing the transfer to the skin and also enhancing the removal of the pesticide by laundering. This finish improved also the lipid soil removal from cotton fabric. Studies on antimicrobial fabric are going on.
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Publications Borsa, J., Ra´cz, I., Obendorf, S.K. and Bodor, G. (1999), ‘‘Slight carboxymethylation of cellulose’’, Lenzinger Berichte, Special Symposium Issue, pp. 19-25. Borsa, J., Racz, I., Obendorf, S.K. and Bodor, G. (1999), ‘‘Slight carboxymethylation of cellulose’’, Advances in Wood Chemistry, International Symposium, Wien, Austria. Csisza´r, E., Borsa, J., Ra´cz, I. and Obendorf, S.K. (1998), ‘‘The reduction in human exposure to pesticide through selection of clothing parameters: fabric weight, chemical finishing, and fabric layering’’, Archives of Environmental Contamination and Toxicology, Vol. 35, pp. 129-34. Obendorf, S.K. and Borsa, J. (1999), ‘‘Carboxymethylierung von Baumwollflaeche zur Verbesserung der Trageeigenschaften’’, International Textile Bulletin, Vol. 45, pp. 40-2. Obendorf, S.K. and Borsa, J. (2001), ‘‘Soil removal from chemically modified cotton’’, Detergent and Surfactant, Vol. 4 No. 3, pp. 247-56. Ra´cz, I., Obendorf, S.K. and Borsa, J. (1998), ‘‘Carboxymethylated cotton fabric for pesticide protective work clothes’’, Textile Research Journal, Vol. 68, pp. 69-74.
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] Dr V.S. Moholkar, Textile Technology Research staff: Prof. Dr ir. M.M.C.G. Warmoeskerken
Ultrasound enhanced mass transfer in wet textile processes Other partners: Academic
Industrial
None Project started: 1 July 1998
Stork Brabant, The Netherlands Project ended: 30 June 2002 (the project will be continued in 2003) Source of support: Stork Brabant, The Netherlands Keywords: Ultrasound, Enhanced mass transfer, Sono-process engineering, Cavitation, Process intensification One of the main problems in wet textile processes is the relatively slow transport processes in the porous structure of the textile substrate. Due to the complex geometry of textile materials these processes are mainly diffusion controlled. It is believed that ultrasonic waves can enhance these processes. The current project is aimed at understanding the mechanisms of ultrasound waves and their effect on the enhancement of the transport processes by inducing convective diffusion in the pores of textile materials. The mechanisms of ultrasound waves are being investigated in terms of acoustic cavitation phenomena and acoustic streaming. The theoretical analysis is supported by model experiments.
Project aims and objectives The relatively slow transport processes in the porous structure of the textile substrate form one of the main problems in wet textile processes. Due to the complex geometry of textile materials these processes are mainly diffusion controlled. The aim of the project is to intensify the mass transfer process in the pores of textiles by acoustic cavitation. The focus of the project is on the mechanisms of ultrasound waves and their effect on the enhancement of the transport processes by inducing convective diffusion in the pores of textile materials. Publications Moholkar, V.S. (2002) ‘‘Intensification of textile treatments: sonoprocess engineering’’, PhD thesis, University of Twente, The Netherlands. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2000a), ‘‘Mechanistic studies in ultrasonic textile washing’’. AATCC Annual Book of Papers-2000 (CD-ROM version), Section 18, 1-8. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2000b), ‘‘Scale-up and optimization aspects of an ultrasonic processor’’, Proceedings of 21st Annual European AIChE Colloquium, AIChE NL-BE Section, pp. 59-66. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2001), ‘‘Intensification of mass transfer in textile materials’’, Proceedings of the 1st AUTEX Conference (Technitex), Povoa do Varzim, Portugal, 26-29, June 2001, pp. 204-13. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2002a), ‘‘The mechanism of ultrasonic mass transfer enhancement in textiles’’, Proceedings of the 2nd Autex Conference, Bruges, Belgium, 1-3 July, p. 561. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2002b), ‘‘Mechanistic aspects and optimization of ultrasonic washing’’. AATCC Review, Vol. 2 No. 2, pp. 34-7. Moholkar, V.S., Pandit, A.B., and Warmoeskerken, M.M.C.G. (1999), ‘‘Characterization and optimization aspects of a sonic reactor’’, Proceedings of the International Conference and Exhibition on Ultrasonics (ICEU-99), Ultrasonics Society of India, Vol. 1, pp. 17-22. Moholkar, V.S., Rekveld, S. and Warmoeskerken, M.M.C.G. (2000), ‘‘Modeling of the acoustic pressure fields and the distribution of the cavitation phenomena in a dual frequency sonic processor’’, Ultrasonics, Vol. 38, pp. 666-70. Moholkar, V.S., Huitema, M., Rekveld, S. and Warmoeskerken, M.M.C.G. (2002), ‘‘Characterization of an ultrasonic system using wavelet transforms’’, Chem. Eng. Sci., Vol. 57 No. 4, pp. 617-29.
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] M. Lopez-Lorenzo M.Sc., Textile Technology Research staff: Prof. Dr ir. M.M.C.G. Warmoeskerken, Dr ir. V.A. Nierstrasz
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Enzymatic upgrading of the properties of recycled paper fibers Other partners: Academic
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Technical Univ. Eindhoven, Wageningen Agricultural Univ.,
Industrial Kappa RP Europe, Sappi, So¨dra, Voith Sulzer, Buckman, DSM, Novozymes
ATO-DLO, KCPK, TNO Paper and Board Project started: 1 September 2000 Project ends: 31 August 2004 Finance/support: N/A Source of support: Ecology, Economy and Technology program (EET) from the Dutch Ministry of Economic Affairs Keywords: Cellulase, Enzyme technology, Cellulose, Surface modification It is expected that within 10 years the processes of textile production will be shifted substantially due to increasing governmental and environmental restrictions and the availability of fresh water. Enzyme technology is a promising technology to fulfill expected future requirements. In 1998 the Textile Technology Group has taken the initiative to start research on fundamental aspects on enzyme applications. This project focuses the surface modification of cellulose fibres. Paper is a nonwoven material formed by cellulose fibres. The recycling of cellulose fibres is limited since the tensile strength decreases during this process. Generally, it is assumed that the deterioration of properties of recycled paper is mainly due to structural changes in the fiber cell wall caused by drying. The project aims to improve the tensile strength of recycled paper, for which different concepts for the surface modification of the fibres will be developed. Recycled fibers can be upgraded through enzymatic treatments of these fibers. Enzymatic hydrolysis of cellulose by cellulases can improve fibrillation and flexibility, enabling the formation of a fibre-network, which gives improved strength characteristics to the paper.
Project aims and objectives The overall aim of the project is ‘‘fibre technology for a durable production of paper and board’’. Our task in this project is to minimise the decrease in the tensile strength of paper during the recycling process using enzyme technology. We will establish the connection between bonding and strength properties and how fibres are affected due to the enzymatic modification. Publications Lenting, H.B.M. and Warmoeskerken, M.M.C.G. (2001a), ‘‘Mechanism of interaction between cellulase action and applied shear force, an hypothesis’’, Journal of Biotechnology, Vol. 89 No. 2-3, 217-26. Lenting, H.B.M. and Warmoeskerken, M.M.C.G. (2001b), ‘‘Guidelines to come to minimized tensile strength loss upon cellulase application’’, Journal of Biotechnology, Vol. 89 No. 2-3, pp. 227-32.
Lopez-Lorenzo, M., Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2002a), ‘‘Enzymatic modification of cellulosic fibers: from lyocell to recycled paper’’, Book of abstracts of the 2nd International Symposium on Biotechnology in Textile Industry (INTB conference), Athens, Georgia, USA, 3-6 April, pp. 25-6. Lopez-Lorenzo, M., Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2000b), ‘‘Enzymatic modification of cellulosic fibers: from lyocell to recycled paper’’, Proceedings of the 2nd Autex Conference, Bruges, Belgium, 1-3 July, p. 563.
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] P.B. Agrawal M.Sc., Textile Technology Research staff: Prof. Dr ir. M.M.C.G. Warmoeskerken, Dr ir. V.A. Nierstrasz
Bioscouring of cotton fabrics Other partners: Academic
Industrial
TNO Textiles, TU Graz, Textile Alberto de Sousa (Portugal), UMinho, UPC Terrassa Tinfer (Spain) Project started: 1 December 2000 Project ends: 30 November 2004 Finance/support: N/A Source of support: EU 5th framework Keywords: Bioscouring, Enzyme technology, Cotton, Pectinase The traditional alkaline scouring process can be replaced with an enzymatic scouring process, in which impurities such as protein, wax and ash are efficiently removed prior to further processing of the cotton fabric. Our aim in this project is the development of a new environmentally and industrially viable (enzyme based) continuous process for the scouring of cotton. In order to design a stable enzymatic pre-treatment process, it is necessary to understand the structure of a cotton fiber that will help to make a targeted attack on non-celluloses. Due to the high substrate specificity of most enzymes it is necessary to have sufficient detailed information about the substrate composition and structure to design and introduce a robust pre-treatment process. On the basis of the structure of the cotton fiber an alternative process was proposed.
Project aims and objectives The overall aim of this project is the development of a new environmentally and industrially viable enzymatic continuous and batch processes for the scouring of cotton fabrics.
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Publications Agrawal, P.B., Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2002a), ‘‘Bioscouring of cotton textiles: the structure of cotton in relation to enzymatic scouring processes’’, Book of abstracts of the 2nd International Symposium on Biotechnology in Textile Industry (INTB Conference), Athens, Georgia, USA, 3-6 April, pp. 21-2. Agrawal, P.B., Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2002b), ‘‘Bioscouring of cotton textiles: the structure of cotton in relation to enzymatic scouring processes’’, Proceedings of the 2nd Autex Conference, Bruges, Belgium, 1-3 July, p. 562. Lenting, H.B.M., Zwier, E. and Nierstrasz, V.A. (2002), ‘‘Identifying important parameters for a continuous bioscouring process’’, Textile Research Journal, Vol. 72 No. 9, 825-31.
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] T. Topalovic M.Sc., Textile Technology Research staff: Prof. Dr ir. M.M.C.G. Warmoeskerken, Dr ir. V.A. Nierstrasz
Catalytic bleach processes Other partners: Academic TNO Textiles, TNO Nutrition
Industrial Procede Twente B.V., Boessenkool B.V., TDV B.V., Emiod B.V., Vlisco Helmond B.V. Project ends: 30 October 2006
Project started: 1 November 2002 Finance/support: N/A Source of support: Ecology, Economy and Technology Program (EET) from the Dutch Ministry of Economic Affairs Keywords: Oxidative catalysts, Process intensification, Bleach In the traditional bleaching process high temperatures and high concentrations of peroxide are needed. In this recently honored project innovative bleach processes will be developed for the pre-treatment of textile materials using oxidative catalysts. Processes on the basis of oxidative catalysts can be performed at much lower temperatures (40 C) and with a significant reduction of the concentration of chemicals compared to the traditional process. In this project more environmentally acceptable and more efficient pre-treatment processes for textile materials will be developed on the basis of such oxidative catalysts.
Project aims and objectives The aim of this project is the development and introduction of more environmentally acceptable and more efficient pre-treatment processes for textile materials on the basis of oxidative catalysts.
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] Textile Technology Research staff: Prof. Dr ir. M.M.C.G. Warmoeskerken, Dr ir. V.A. Nierstrasz
Dynamic and advanced wetting of textile materials Other partners: Academic
Industrial
None None Project started: 1 May 1999 Project ended: – Finance/support: W/A Source of support: The Dutch Foundation for Technology of Structured Materials Keywords: Wetting, Dynamic surface tension, Contact angle, Nanotechnology, Surface heterogeneity, Surface roughness Wetting is key in transport processes in wet textile processing, like washing and dyeing. The knowledge of liquid flow through and the wetting of complex materials is often limited and the process conditions are usually chosen on an empirical basis, rather than a fundamental one. Recent advances in the characterization of surface properties of materials make it in principle possible to relate the macro- and meso-scopic properties of the textile to its nanoscopic properties, even under conditions far from equilibrium. In this project the inter relations between wetting properties, surface roughness, surface heterogeneity and adhesion forces will be studied. The Textile Technology Group has advanced facilities available such as an autoporosimeter, equipment to measure the dynamic surface tension and high resolution ADSA equipment to measure dynamic and equilibrium wetting characteristics.
Project aims and objectives The aim of this project is to generate fundamental knowledge about wetting phenomena in textile materials and to develop tools to predict the wetting behavior in wet textile processes.
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Publication Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2002), ‘‘Dynamic wetting of textile materials’’, Proceedings of the 2nd Autex Conference, Bruges, Belgium, 1-3 July, p. 564.
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Ghent, Belgium Ghent University, Department of Textiles, Faculty of Applied Sciences, Technologiepark 907, 9052 zwijnaarde gent Tel: 09/2645411; Fax: 09/2645846; E-mail:
[email protected];
[email protected] Lieva Van Langenhove and Paul Kiekens Research staff: Els Van Nimmen, Kris Gellynck
The use of spider silk for scaffolds in soft tissue engineering Other partners: Peter Verdonk, Fredrik Almqvist, Johan Mertens, Domir De Bakker, August Verbruggen
Academic
Industrial
None None Project started: 1 January 2002 Project ends: 31 December 2005 Source of support: BOF – University Ghent Keywords: Spider, Silk, Cartilage, Tissue engineering, Scaffold Injured cartilage, not accreting by itself, often decreases quality of life. The chondrocytes need an implanted support to bridge and recover the wound with extra-cellular matrix products forming fresh cartilage. Advances in cell biology and biomaterial research have led to new possibilities in tissue engineering. Transplanted scaffolds, holding a 3D cell culture, should copy the cartilage characteristics. Strength and flexibility are important, but even more an adequate porosity, so the chondrocytes can migrate through the matrix, but are not able to float around. Looking for regeneration and not a repair, we want the scaffold material to disappear while real cartilage is healing the wound. In this way, the material and its hydrolysis products that are frequently toxic of synthetic polymers have to be biocompatible and harmless. Spider silk is a promising fibre for many applications. Completely made out of protein, a suspected biocompatibility is already proven. The harmless amino acid hydrolysis products make the silk a good candidate for creating a bioresorbable textile scaffold. The chondrocytes cells adhere quite well on the spider cocoon silk threads. Cocoons that could be obtained each autumn in large numbers from the Araneus diadematus garden spider. The mechanical properties of the silk is more appropriate than polymeric gels, like hyaluronic acid, collagen, alginate, which proved to be successful in 3D immobilisation and maintaining the differentiated phenotype of chondrocytes. The phenotypical products collagen II and aggrecan were also detected around the cells growing on the spider cocoon silk. A silk 3D textile could possibly be applied in
combination with a polymer gel, probably alginate in order to achieve some biomechanical stability. While biodegradation is occurring, the silk textile is overgrown with real cartilage and eventually the wound will be recovered without any definitive synthetic implants.
Research register
Project aims and objectives The project-purpose is to compare the properties of spider silk fibres and the textile fabrics that can be made out of these fibres towards the conditions of a good scaffold for soft tissue engineering. A scaffold has to support the migrating and growing cells and replace the soft tissue while biodegrading during the regeneration. A textile should be engineered with an adequate porosity; porous enough so cells have space to multiply, not too porous so the cells stay attached to the scaffold. The cells should attach on the scaffold so problems due to cytotoxicity are to be excluded and the adhesion of the cells tested. Just as soft tissue the textile scaffold should be strong and flexible. An important condition in tissue regeneration is the biocompatibility of the textile fabric, but also of the hydrolysis-products after biodegradation.
Research deliverables (academic and industrial) .
Some textile fabric prototypes;
.
Proof of biocompatibility: in vitro and in vivo tests; Single fibre properties;
. .
Proof of good adhesion of different cells on the scaffold;
.
Proof of regrowth of soft tissue in the scaffold.
Publications De Bakker, D., Gellynck, K., Van Nimmen, E., Mertens, J. and Kiekens, P. (2002), ‘‘Structural analysis and differences in cocoon structure revealed by means of scanning electron microscopy between several spider species’’, 20th European Colloquium of Arachnology, 22-26 July 2002, Szombathely, Hungary. De Bakker, D., Van Nimmen, E., Baetens, K., Gellynck, K., Mertens, J. and Kiekens, P. (n.d.) ‘‘Structure and use of different silk threads produced by the water spider Argyroneta aquatica’’, Belgian Journal of Zoology (in press). Gellynck, K., De Bakker, D., Van Nimmen, E., Mertens, J., Kiekens, P. and Van Langenhove, L. (2002), ‘‘Research and development of a spider silk textile for cartilage regeneration’’, Poster PhDSymposium, 11 December 2002. Gellynck, K., Verdonk, P., Almqvist, F., Van Nimmen, E., De Bakker, D., Mertens, J., Kiekens, P., Van Langenhove, L. and Verbruggen, A. (2003), ‘‘A spider silk supportive matrix used for cartilage regeneration’’, 2nd Annual Meeting of the European Tissue Engineering Society, 3-6 September 2003, Genova, Italy. Gellynck, K., Verdonk, P., Almqvist, F., Van Nimmen, E., Van Langenhove, L., De Bakker, D., Mertens, J., Verbruggen, A. and Kiekens, P. (2003), ‘‘A spider silk supportive matrix used for cartilage regeneration’’, Healthcare and Medical Textiles ’03, 8-9 July 2003, Bolton, UK. Gellynck, K., Verdonk, P., Almqvist, F., Van Nimmen, E., De Bakker, D., Mertens, J., Kiekens, P., Van Langenhove, L. and Verbruggen, A. (2003), ‘‘Spider silk-based scaffolds for cartilage repair’’, 18th European Conference on Biomaterials, 1-4 October 2003, Stuttgart, Germany. Van Nimmen, E., Kiekens, P. and Mertens, J. (2002), ‘‘Some material characteristics of spider silk’’, International Journal of Materials and Product Technology (in press).
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Van Nimmen, E., Gellynck, K., De Bakker, D., Gheysens, T., Mertens, J., Kiekens, P. and Van Langenhove, L. (2002), ‘‘Research and development of spider silk for biomedical applications’’, Proceedings SEM Annual Conference on Experimental and Applied Mechanics, 10-12, June 2002, Biological Inspired and Multi-Functional Materials and Systems, Milwaukee, Wisconsin, USA.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645409; Fax: +32-9-2645831; E-mail:
[email protected] Carla Hertleer, Department of Textiles Research staff: Prof. Lieva Van Langenhove
Smart textiles for children in hospital environment Other partners: Academic University Hospital Ghent
Industrial User committee consisting of several Flemish companies
Catholic University Louvain Project started: 1 September 2000 Project ended: 31 August 2004 Finance/support: BF 17.984.726,00 Source of support: IWT, STWW (Strategic Technologies for Welfare and Prosperity) Keywords: Smart textiles, Medical applications The field of ‘‘smart textiles’’ is gaining a lot of interest. Worldwide, research is performed contributing to the development of smart textiles. The principles and materials used are very divergent. Many researchers however, focus on the same field of application, i.e. healthcare. Within the project, which is carried out from September 2000 to August 2004, a thorough analysis was made on what is meant by smart textiles, what can lead to smart textiles and what the background mechanisms consist of. On the other hand, it is examined which parameters give important information about the health condition of a patient in a hospital.
Project aims and objectives In the field of textiles, it is investigated what are the possibilities and on which principles they are based. Based on these results, suggestions are given to the University Hospital. The Department of Paediatrics defines the needs and the Department of Textiles will look for new possibilities to meet these needs. By exchanging opinions, new ideas appear for potential applications.
Research deliverables (academic and industrial) In 2001, a prototype is developed focusing on the measurement of two important physiological parameters, i.e. the heart rate and the respiratory rhythm. These
measurements will take place via textiles worn by the patient. The necessary electrodes and their wiring are entirely realized in textile materials. In this way, a garment is created which is not annoying for the patient but still contains all components to perform a good guarding function. In a later stage, the system can be extended to a real multisensor suitable to measure still other parameters. Another part of this project considers the further development of artificial muscles and the use of thermochrome dyes in a hospital environment. In 2001, several exploratory tests have been realized. Within the framework of this project, a monitoring belt has been developed. The belt contains textile sensors for the measurement of two important physiological parameters, i.e. heart rate and respiratory rhythm. The textile sensors are made out of stainless steel. This material was opted for a.o. because of its good electroconductive properties and the fact that it is easy to incorporate in a textile structure. Different kinds of textile structures have been tested, but the stretchability of a knitted structure guarantees an intense contact between the skin and sensor. A test method was developed to simulate this contact. In this way, the influence of the different washing cycles on the electrode’s performances can be objectively investigated. Experiments in a clinical environment are planned to determine how the measurement results of the textile sensors are related to the conventional electrodes. Furthermore, miniaturisation and the packaging of the electrical circuit are treated to integrate the circuit in the monitoring suit. Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645735; Fax: +32-9-2645846 Heidi Regelbrugge, Department of Textiles Research staff: Prof. Lieva Van Langenhove
Biomimetics in textiles Other partners: Academic
Industrial
Department of Biology None Project started: 1 October 2001 Project ended: 30 September 2004 Finance/support: BF 2.400.000 Source of support: Ghent University, BOF-VEO Keyword: Biomimetics A new research topic is biomimetics or biomimicry. Natural selection resulted in mechanisms and structures that are extremely refined and ingenious, since optimal variants become extinct. Some of these natural systems are analysed, copied and
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integrated in materials, enabling an enormous range of new improved products and applications to come into being. This project focuses on the applications in the textile industry, as it is intensively looking for new and improved products. There are three factors hindering the application of natural mechanisms in textiles: (1) there is no systematic list of natural mechanisms that could be used in textiles; (2) the mechanisms of natural properties are often unknown; and (3) it is not always technically possible to integrate the mechanisms in textiles.
Project aims and objectives The main goals of this project are to make a list of mechanisms in nature that could be applied in textiles and to select and evaluate some of these natural mechanisms.
Research deliverables (academic and industrial) A database on biomimetics is completed and is to be consulted on the Internet (by means of a password). Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645417; Fax: +32-9-2645831; E-mail:
[email protected] Marian Ledoux, Department of Textiles Research staff: Prof. Lieva Van Langenhove
Alternative thread preparation mechanisms for air jet weaving looms Other partners: Academic
Industrial
None None Project started: 1 January 2002 Project ends: 31 December 2004 Finance/support: BF 14.912.672 Source of support: IWT Keywords: Air jet, Weaving, Weft insertion, Simulation In this study, a computer programme is being developed to simulate the weft insertion on air jet weaving looms. On an air jet loom, the yarn is first wound on a drum in preparation, then it is accelerated by main blower(s) and additional blowers and finally, at the end of the insertion, the yarn is decelerated and stopped. When
decelerating and stopping the thread at high speed, it is possible that high tensions occur. This results in thread ruptures leading to machine stops and consequently to lower production. After thread deceleration and stopping, the thread will rebound over a certain distance, and when the thread is not stretched during binding, this may lead to fabric defects. The aim of this project is to adequately simulate the weft insertion, to obtain a better insight in the weft process and to produce a means for the study and development of alternative thread preparation mechanisms. This can lead to an accelerated weft insertion and consequently, higher production speeds to lower tensions when decelerating and stopping the thread resulting in fewer thread ruptures and machine stops and fabrics with no defects by stopping the rebound of the thread.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645739; Fax: +32-9-2645846; E-mail:
[email protected] Sybille Storme, Department of Textiles Research staff: Prof. Paul Kiekens
Vocational training in the clothing sector in Turkey Other partners: Academic None Project started: 2 April 2002 Finance/support: 1.404.065,00 e Source of support: European Commission Keywords: Training, Clothing
Industrial None Project ends: 31 May 2005
The clothing industry in Turkey has undergone important changes over the last decade, due to the rapid expansion of this industry, which was coupled with the need for modernization of infrastructures and improvement of the industry’s products. The above changes could never have come smoothly, if the human resources employed in the industry did not acquire the necessary skills to deal with the technical and managerial changes entailed by this modernization.
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In addition, attain and maintain a high competitiveness level, the clothing industries in Turkey have to focus on the use of high technology and proper management structures that will allow them to respond successfully to the consumers’ demands. These changes require primarily the reconstruction of the industrial management of the industries and simultaneously employees’ training to support this change. It is very clear that business schemes like quality management, team-work, implementation of high technology in the production plantations, require well-trained managers and supervisors, as well as appropriately trained workers and technicians.
Project aims and objectives Training in this project will be focused on the following target groups. . . . . .
supervisory training (by local and EU-trainers); middle management training (by local and EU-trainers); sewing machine training (by local trainers); training for computerised pattern preparation and cutting (by local trainers); and training of repair and maintenance of sewing machines (by local trainers).
The trained workers will receive diplomas recognised by the industry. Therefore, the project will effectively help satisfying the industry’s demand for qualified workers, which in turn will improve the quality of production and increase the demand for managers with modern qualifications, able to keep up with the modern managerial and technical changes in the industry. It is anticipated that about 5,900-6,000 employees of the Turkish clothing sector would be trained by the end of the project.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645411; Fax: +32-9-2645831; E-mail:
[email protected] Kris Gellynck, Department of Textiles Research staff: Prof. Paul Kiekens
Spider silk for biomedical applications Other partners: Academic
Industrial
Department of Biology
None
Department of Orthopaedic Surgery Project started: 1 January 2002 Project ends: 31 December 2005 Finance support: BF 11.000.000 Source of support: Ghent University, BOF Keywords: Biomaterials, Spider silk, Biocompatibility This project, which started in January 2002, aims at the development of a textile fabric from spider silk for biomedical purposes. Therefore, all the requirements for a good biomaterial have to be tested. The most important one is the biocompatibility. No matter how the fibres are processed, by weaving, knitting, or needle-punching, the starting material may not induce any severe immunological reactions. Some in vitro tests can be done with immunocells like macrophages, but this only gives a partial answer, in vivo tests are more reliable. The ethical commission of the medical department approved the proposition to implant several kinds of enzymatically treated and untreated spider silk fibres in white rats. After sedation, the rats got a silk sample on the left side and a vicryl sample on the right side of the incision. Vicryl is a widely known biocompatible material, which enabled a good comparison. The fibres were removed from the rats after 1, 4, and 7 weeks and 3 months. The surrounding tissue was microscopically examined on immunocells that represent acute and chronic inflammatory reactions. The acute reaction was much larger on the untreated fibres than on the treated ones. This substantiated the hypothesis that spider cocoon silk fibres are surrounded by a bio-incompatible layer. Considering the fact that some enzymes can harm the fibres and decrease the strength and elasticity, we see that they are useful to increase the usefulness in biomaterials. Biocompatibility is not the only requirement, also the rate of biodegradation, cell adhesion, porosity of the eventual material, etc, are terms that have to be fulfilled.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645407; Fax: +32-9-2645831; E-mail:
[email protected] Philippe Westbroek, Department of Textiles Research staff: Prof. Paul Kiekens
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Development of an electrochemical sensor for the detection of benzene, (chloro)phenols, dioxins and PCBs Other partners: Academic
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Industrial
None None Project started: 1 February 2003 Project ends: 31 January 2005 Finance/support: 122.730,00 e Source of support: IWT Keywords: Electrochemistry, Dioxins, PCB In this project, tetrasulfonated metallophthalocyanines (MTSPcs) are used as catalyst and are immobilized at the surface of an electrode, with M ¼ Co(II); Fe(II) or Ni(II). At this stage of the project, Co(II)TSPc and Fe(II)TSPC were immobilized at the surface of a gold electrode and the deposited layer is fully characterized by electrochemical methods and XPS. Oxidation of chlorophenols at this electrode in aqueous alkaline solution resulted in poisoning of the electrode, but for this effect solutions are sought and will be found in the near future. At present, the electrode is able to detect chlorophenols in a concentration range from 100 ppb to 500 ppm in a reproducible way (standard deviation of less than 1 per cent). Solutions will be found to avoid or circumvent poisoning of the electrode, ultramicroelectrodes will be investigated for their suitability in order to improve on the detection limit (goal is 20 ppb) and to be able to measure in non-aqueous solutions. Finally, the developed electrode will also be tested for its usability in detection of PCBs and dioxins.
Project aims and objectives The aim of the project is to develop an electrochemical sensor system which is able to detect (chloro)phenols, PCBs and dioxins in the ppb concentration range in aqueous (waste water) and non-aqueous (oil, fat, food) medium. These compounds are very toxic and difficult to decompose, a property that explains their danger and difficulty to be detected. However, these compounds can be oxidised electrochemically at the surface of an electrode if a catalyst is used.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645741; Fax: +32-9-2645846; E-mail:
[email protected]
Kathleen Van de Velde, Department of Textiles Research staff: Prof. Paul Kiekens
Research register
Biomedical textiles from dibutyrylchitin and chitin (CHITOMED) Other partners: Academic
Industrial
None None Project started: 1 January 2003 Project ends: 31 December 2005 Finance/support: 363.650,00 e Source of support: European Commission Keywords: Chitosan, Biopolymers, Medical textiles On the European market, there is a lack of innovative biomaterials that aid in regeneration of wound tissue. The project aims at the design and development of optimal textile forms for medical applications made from dibutyrylchitin (DBC) and chitin, from fishery by-products. Recently, a method for the synthesis of DBC is developed. DBC is easily soluble in common recyclable solvents and has film and fibre forming properties. Chitin can be regenerated (RC). This opens the way for the development of novel functional biomaterials made from DBC and RC. The project will generate novel biomaterials and medical items that accelerate the wound healing with no scar formation and undesirable effects, that are easy to handle and could be prepared as self-adhering dressings. This kind of dressing would reduce the pain and suffering of patients. Six industrial companies and three universities from five countries join forces in this project, financed by the European Commission. Ghent University, Department of Textiles is coordinator of the project. The project is oriented and targeted at improving the competitiveness of the European industry and enhancing the quality of life of the EU citizen through the sustainable production and rational utilisation of natural resources with special emphasis on new technologies.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645736; Fax: +32-9-2645846; E-mail:
[email protected] Johanna Louwagie, Department of Textiles Research staff: Prof. Paul Kiekens
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Re´seau de soutien l’innovation scientifique et technologique pour le textile (RESIST) Other partners: Academic
84
Industrial
Fucam None ENSAIT Project Started: 1 January 2002 Project ended: 31 December 2004 Finance/support: 100.000,00 e Source of support: Ministre de la re´gion wallonne Keywords: Technical textiles, Innovation, Management, Training The partners decided to develop a European network, called RESIST, to realize a crossborder support tool bringing together several competences and contributing to the maintenance and creation of employment in the textile sector. To strengthen the competitive position of the textile companies in the border region (Flanders, Wallonia and Northern France), integration of technological and organizational innovations from different domains is aimed for, namely . . .
quality control; information and communication technology (ICT); and strategic process control (MSP) (logistics, etc).
Project aims and objectives Integration of these innovations can only be realised for SMEs when there is consultation and complementarity between all partners of the sector. Therefore, the RESIST project not only aims at sensitisation, education and technical and scientific support, but also at developing joint methods to attain real cross-border exchange/cooperation. The proposed actions need to contribute to a profitability increase of the companies by controlling the different problem areas, such as short-term actions, quality and surveillance, and more in general, by controlling their actions within an extensive and shared environment.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645735, Fax: +32-9-2645846
Johanna Louwagie, Department of Textiles Research staff: Prof. Paul Kiekens
Research register
Quality training in textiles (Poland)+technological quality management in textiles (Lithuania) Other partners: Academic
85 Industrial
None None Project started: 1 January 2003 Project ends: 31 December 2004 Finance/support: 150.000,00 e; 165.000,00 e Source of support: Ministry of the Flemish Community Keywords: Quality, Training In 2003, two projects were started in the framework of the co-operation programme between Flanders and the candidate member states in Central and Eastern Europe (funded by the Flemish authorities). One is with Poland and the other one with Lithuania. These projects aim at providing assistance to SMEs and testing laboratories in their reorganisation to become competitive in the free market economy. In order to achieve this, a new way of leadership and internal management is needed. As a consequence, these projects mainly focus on the introduction and the implementation of quality management systems according to ISO and EN standards in SMEs and testing laboratories. It is also necessary that the local industrials and laboratories are actively involved in the development of new testing methods and the implementation of EN and ISO standards. In both countries, training sessions for personnel will be organised, revealing the basic principles of modern quality management in a free market environment. In order to get a clear view of the local situation, a preparatory visit was paid to the partner countries. During this visit, details concerning the course programme were discussed. In consultation with the partners, training sessions were developed in different modules. Seven modules were taught in English by the Department of Textiles to trainers from Poland and Lithuania (training of trainers). The courses were summarized in local language. Subsequently, the training sessions were repeated for a broader public (training of trainees).
Project aims and objectives These projects aim at providing assistance to SMEs and testing laboratories in their reorganisation to become competitive in the free market economy. In order to achieve this, a new way of leadership and internal management is needed. As a consequence, these projects mainly focus on the introduction and the implementation of quality management systems according to ISO and EN standards in SMEs and testing laboratories. It is also necessary that the local industrials and laboratories are actively involved in the development of new testing methods and the implementation of EN and ISO standards.
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Research deliverables (academic and industrial) None Publications List of publications on demand.
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Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645407; Fax: +32-9-2645831; E-mail:
[email protected] Philippe Westbroek, Department of Textiles Research staff: Prof. Paul Kiekens
Environmentally friendly metallization of synthetic fibres Other partners: Academic
Industrial
None None Project started: 14 October 2002 Project ends: 13 October 2005 Finance/support: 31.250,00 e Source of support: NATO, Science for Peace Sub-programme Keyword: Electro-conductive fibres The aim is to develop electroconductive fibres, yarns and clothing of metallized acrylonitrile fibres. Polyacrylonitrile fibres are treated in NiCl2 baths that contain a reducing agent to reduce Ni(II) to its metallic form after absorption by the fibre. Polyacrylonitrile fibres were treated in solutions of different concentrations of NiCl2 and CoCl2 and with different types and concentrations of reducing agent. It was found that Rongalite as a reducing agent behaved superior over sodium dithionite and a concentration ratio of 3/1 of Rongalite to NiCl2 resulted in the optimal uptake and reduction of Ni(II). Under these circumstances, metallized polyacrylonitrile fibres were obtained with a specific resistance of about 103 /m. With CoCl2, it was not possible to obtain electroconductive fibres. The influence of thermofixation on the properties of the metallized fibre and its mechanical properties will be studied. First, trials will be executed in yarn production and the process of production will be studied and optimised. Finally, clothing and garments will be produced as a function of applications and needs. This project is carried out under NATO’s Science for Peace programme – 978005 – Synthetic Fibres.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645740; Fax: +32-9-2645846; E-mail:
[email protected] Jo Verschuren and Karen De Clerck, Department of Textiles Research staff: Prof. Lieva Van Langenhove
Plasma-colour: the use of plasma treatments to obtain very deep colours Other partners: Academic None Project started: 1 November 2003 Finance/support: 246.900,00 e Source of support: IWT Keywords: Plasma, Dyeing, Colour
Industrial None Project ends: 31 October 2005
The synthetic fibre market is characterised by a trend towards ever-finer fibres. A major problem of fabrics based on these finer fibres is to obtain very deep colours via the common dyeing processes. Especially deep blacks are difficult or sometimes even impossible to be obtained. In this project, the use of plasma treatments is investigated for obtaining deeper shades on dyed fabrics. The objective is to have an understanding of the various causes of the shade deepening effect. This should then allow a more efficient optimisation of the treatments. The reproducibility as well as the durability of the treatments are important aspects in this project. Further the effect of fabrics structure and dye type is taken into consideration.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-2645417; Fax: +32-9-2645831; E-mail:
[email protected]
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Marian Ledoux and Fanny Bossuyt, Department of Textiles Research staff: Prof. Lieva Van Langenhove
Self-learning machine speed for air-jet looms: a concept and feasibility study
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Other partners: Academic None Project started: 1 December 2002 Finance/support: 390.837,00 e Source of support: IWT Keywords: Weaving, Air jet, Speed
Industrial None Project ends: 30 November 2004
The aim of the project is to investigate the possibilities of developing an air-jet loom having a self-learning speed. In practice, it is observed that the loom speed always equals the speed obtained when weaving the weakest yarn. In other words, the weakest link determines the speed of the process. Ideally, the speed should be adjusted to the quality of the yarn. Better quality of the yarn would result in a higher speed and hence on an average, a higher production speed. Series of tests are being done on a large variety of yarn. The yarns are subdivided into two large groups: filament yarns and spun yarns. During the weaving tests, the influence of the speed changes on the weaving parameters, the fabric quality and the weaving return is controlled. To this end, different testing algorithms are being developed and tested as to their influence on the textile technical aspects. The final aim is to obtain an algorithm which enables the loom to automatically find an optimum speed.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University – Department of Textiles, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium Tel: +32-9-26457; Fax: +32-9-2645831 Kathleen Van de Velde, Stefaan Janssens and Stijn Rambour, Department of Textiles Research staff: Prof. Gustaaf Schoukens
Development of a high performance artificial grass for soccer Other partners: Academic None Project started: 1 March 2004 Source of support: IWT Keywords: Extrusion, Artificial grass
Research register
Industrial None Project ends: 1 March 2007
The aim of the project is to develop a high performance artificial grass that meets the requirements of FIFA-UEFA for soccer and that is generally accepted by the market. The main aim is to optimize the composition of the grass itself, as well as the composition of the underlying construction. These optimizations will be based upon the comparison of artificial grass with natural grass. A research stand will be built to follow up important parameters such as wear and climate resistance, interaction with ball and player. A numerical simulation model will be developed. The underlying goal is to utilize this simulation infrastructure to test construction alternatives of the grass and to get a better insight in the complex relation between optimal playability of grass and the mechanical development criteria. The company wants to offer in 2006 a complete new grass for soccer. This product must fulfill the FIFA acceptance criteria and be in accordance with the market needs for ‘‘optimal playability’’ and be able to outperform product of competitors.
Research deliverables (academic and industrial) None Publications List of publications on demand.
Ghent, Belgium Ghent University, Faculty of Engineering, Department of Textiles, Technologiepark 907, B-9052 Ghent, Belgium Tel: +32 9 264 57 40; Fax: +32 9 264 58 46; E-mail:
[email protected] Jo Verschuren, Department of Textiles Research staff: Jo Verschuren, Lieve Van Landuyt
Cold plasma technology for textile products, taking into account their specific properties Other partners: Academic
Industrial
None
None
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Project Started: January 1999 Project ended: Autumn 2004 Finance/support: 100 000 e Source of support: 1999-2001: Bijzonder Onderzoeksfonds, Ghent University Keywords: Cold plasma, Textile structure, Gas flow, Industrial reality, Wicking properties This PhD research can be divided into three parts, which will consider the textile as a porous substrate with specific properties, to be treated in industrial reality. Literature on plasma-for-textiles was scanned and following observations were made: treatment conditions are often not industrially feasible, typical textile properties are not considered, and essential treatment information is missing. A reactor was designed that considers the specific behaviour of a textile during its plasma treatment. A homogeneous column of gas is introduced in the reactor and passes the plasma, perpendicular to the plane of the textile. The reactor enables the study of both free flow around the sample and forced gas flow through the sample. Experiments give an insight in the (lack of) treatment homogenity in the plane of a textile sample as well as perpendicular to it. The techniques and methods for effect characterisation used and developed during this research have in common that they consider the complete textile volume, and that they can be used at STP conditions. Wicking properties were determined to assess the influence of fibre processing chemicals and post-plasma water treatment, and to study the penetration of plasma created reactive species. UV-VIS diffuse reflection spectroscopy is used as an alternative means of characterization of a plasma treatment effect and its atmospheric aging.
Project aims and objectives To show that any plasma-for-textiles application benefits from the consideration of the treated textile substrate as a three-dimensional porous structure with a large total surface, which contains unavoidable impurities at the fibre surface and fibre polymer structure. To produce data that are useful for any potential plasma-for-textile application at both reduced and atmospheric pressures. To show that the introduction of plasma-for-textiles in industry would benefit from a generic, objective and no-nonsense approach of the topic, by all involved. To develop a reactor and plasma effect characterisation methodology that complies with the above.
Research deliverables (academic and industrial) Original experimental reactor set-up and characterisation methodology. A basis for further generic and fundamental research of plasma-for-textiles. Publications, oral and poster presentations. Dissemination towards the textile industry of objective and no-nonsense information on plasma-for-textiles. Publications Leys, C., Temmerman, E. and Verschuren, J. (2003), ‘‘Non-thermal atmospheric pressure plasma sources for surface treatment applications (oral)’’, Proc. Spring Meeting of the German Physical Society, Aachen, Germany, 24-28 March 2003.
Verschuren, J. (2001), ‘‘The plasma treatment of textile products, taking into account their specific properties (poster)’’, Proc. PhD Symposium at Engineering Faculty, Ghent University, Ghent, 12 December 2001. Verschuren, J. (2004), ‘‘Gas flow around and through textile structures during plasma treatment (oral)’’, Proc. 4th AUTEX World Textile Conference, Roubaix, 22-24 June 2004. Verschuren, J. and Kiekens, P. (2001), ‘‘Plasma technology for textiles: where are we? (oral)’’, Proc. IXth International Textile and Apparel Symposium, C¸ec¸me-I˙zmir, 26-29 October 2001. Zamfir, M., Verschuren, J. and Kiekens, P. (2002), ‘‘Research on medical products made from spunbonded and hydroentangled nonwovens modified by plasma treatments (oral)’’, Proc. International Nonwovens Technical Conference INTC-2002, Atlanta, GA, 24-26 September 2002.
Guimara˜es, Portugal Universidade do Minho, Campus de Azure´m, 4810-058 Guimara˜es, Portugal Tel: 253 510 380; Fax: +351 253 510 293; E-mail:
[email protected] Prof. Maria Elisabete Martins Paiva Monteiro, Cabec¸o Silva, Ana Cristina da Luz Broega, Department of Textile Engineering, Center of Science and Textile Technology Research staff: Prof. Anto´nio Alberto Cabec¸o Silva, Prof. Emanuel Pedro Viana de Albuquerque, Prof. Charles Gaston Dominique Adolphe, Prof. Laurence Marie Schacher
Design of light weight wool fabrics; valorization and optimization of the total comfort for the high added value clothing Other partners: IWS – The Woolmark Company Academic Industrial Laboratory of Physical and Fareleiros – Fabrica de Lanificios, S.A Mechanical Textiles; ENSITM-Universite´ de Haute Alsace Project started: 1 February 2004 Project ends: 31 January 2007 Finance/support: 206 618 euros Source of support: ADI – Agencia de Inonac¸a˜o Keywords: Sensorial comfort, Hand, Thermophysiological comfort, Light-weight wool fabrics, Multivariate statistical analysis technique Modern consumers consider comfort as one of the most important attributes in their purchase of textile and apparel products, so there is a need to develop a reliable scientific understanding of the psychological perception of clothing comfort sensations. In this study, concerning the woollen sector, the trends toward lighter and lighter fabrics have significantly influenced the recent evolution of the wool industry, since the wool products became suitable for all the seasons around. The weight of
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traditional woven fabrics for jackets and suits has decreased in a probable irreversible way, consequently the existing technology in the worsted sector, has to be modified in many aspects, based on very innovative concepts of processes control, include the quality control of comfort properties. In this challenge we prepared a multiphase research program to develop a sensitive, reliable, standardized method for assessing the sensorial tactile characteristics of wool light fabrics for men summer suits, in order to develop a sensitive magnitude scale for rating fabrics/clothing comfort. It uses a psychophysical methodology that enables to quantify the descriptive aspects of hand sensation (subjective evaluation by a panel of experts). Simultaneously, we study the fabric objective measurements (physical and mechanical), using statistics multivariate analysis techniques to identify independent factors and their relative contribution for the objective evaluation of fabrics hand. Combining this sensory perception methodology with established instrumental measures of fabrics characterization, and with the help of neural network technique (which has a self-learning ability, able to model nonlinear functions such as the relationship between fabric objective measurement and subjective sensory perceptions), we may predict comfort perception.
Project aims and objectives The aim of this project is to design and develop materials of fine wool fibers for clothing, particularly for men’s wear, by methodology definition of subjective and objective evaluation of certain parameters such as the handle and comfort. Quantify and profile define for those parameters using methods and tools of Knowledge Engineering. Textile industry application with the objective of making products that respond to the comfort demands of the consumers, of extra value, and contributing for a more competitive textile industry. .
The objectives of this project are to:
.
design the materials (yarns and fabrics of fine wool for clothing);
.
define the most adequate instruments for handle and total comfort evaluation (psychological, sensorial and thermophysiological);
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define the terminology and standardization;
.
correlation of objective with subjective properties of comfort in order to define quality profiles for that type of fabrics;
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increase the quality of those products to respond to consumer demands;
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transfer the results a medium term to the SMEs;
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increase competitiveness of SMEs to an international level; and
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create a Comfort Label for this cane of materials.
Research deliverables (academic and industrial) None Publications None
Ibaraki, Japan Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, Umezono 1-1-1, Tsukuba, Ibaraki, Japan Tel: +81-29-861-5978; Fax: +81-29-861-5971; E-mail:
[email protected] Eiichi Ono, Kazuyuki Nagata and Yujin Wakita, Intelligent Systems Institute
Robotic handling system for limp materials Other partners: Academic
Industrial
None None Project started: 1 April 2003 Project ends: Continued Source of support: Ministry of Economy, Trade and Industry Keywords: Robot, Handling, Household articles, Assist, Textile, Garment We are researching a new basic technology which can make use of assistant robots in the daily environment of house, and robotic handling of household articles. Robot handling system for limp materials in house relates robot handling to textile and garments. One of the research targets is the development of robot handling of towels.
Project aims and objectives The development for robot technology of assistant robots in house. Robot technology for handling textile and garments. Robot technology for handling towels (2004 fiscal theme).
Research deliverables (academic and industrial) None Publications None
I˙zmir, Turkey ¨ BI˙TAK TAM The Scientific and Technical Research Council of TU ¨ BI˙TAK Tekstil Aras¸tırma Turkey, Textile Research Center, TU Merkezi, Ege Universitesi Kampu¨su¨ TR- 35100 Bornova, I˙zmir, Turkey Tel: +90 232 3399222; Fax: +90 232 3399222; E-mail:
[email protected]
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¨ BI˙TAK TAM / Ege University Joint Textile Research Prof. Dr Kerim Duran, TU Laboratories, Sabanci University, Faculty of Engineering and Natural Sciences
Research staff: Assoc. Prof. Dr Ays¸egu¨l Ekmekc¸i, PhD, O.Uur Sezerman, M. ˙Ibrahim Bahtiyari, Gu¨nseli Bayram
Preventing pilling problem of cellulosic fabrics with different types of enzymes and comparison of their effects Other partners: Academic
Industrial
Faculty of Engineering and None Natural Sciences, Sabanci University Textile Engineering Department, Faculty of Engineering, Ege University Project started: 1 August 2003 Project ended: 1 August 2004 Finance/support: US $ 52 500 Source of support: TU¨BI˙TAK TAM Keywords: Viscose, Cellulase, Biopolishing, Enzyme modification Cellulases have been widely used in the textile industry for modification of the surface and properties of cellulosic fibers and fabrics achieve a desired hand or surface effect. Cellulases are used to remove the fuzz or pills on the fiber or fabric surface which will decrease the pilling propensity of the fabric. Commercial cellulases currently used consist of multiple enzyme systems (cellobiohydrolases, endogluconases, glucosidases) which hydrolyse cellulose in a synergistic way. Cellulases from fungi such as T. reesei and H. insolens are widely used. Since cellulose is polymer of glucose monomers the multienzyme components act synergistically to produce glucose as the end product. Viscose is a regenerated cellulose fiber. Commercial cellulases are used to prevent pilling problem on the viscose fabrics. However, there is a major drawback. They decrease the bursting strength or increase the tensile strength loss, which cause the weakness of the fibers. Because of these shortcomings using commercial cellulases in biopolishing of viscose fabrics is not desired. In order to investigate the effect of commercial cellulases and optimization of biopolishing of viscose fabrics, different commercial cellulases were used in biopolishing of woven and knitted viscose fabrics. Duration of processes, enzyme concentrations and mechanical effects on viscose fabrics were investigated. Additionally, because of undesired effects of commercial cellulases, some modification opportunities were searched and crosslinking process was achieved in some commercial cellulases. Then the effect of crosslinked enzyme was determined with evaluating the pilling tendency and bursting strength of the fabrics. The project is still in progress.
Project aims and objectives Viscose is a cellulose based fabric. Commercial cellulases are used to prevent pilling problem on viscose fabric. However, there is a major drawback. They decrease the bursting strength or increase the tensile strength loss, which cause the weakening of the
fibers. In order to overcome this problem one approach is increasing the size of enzyme by crosslinking. Comparing the effects of commercial enzymes with the crosslinked enzymes, and optimisation of the bio-polishing treatment of viscose fabrics are the other objectives of this project.
Research deliverables (academic and industrial) None Publication A poster presentation titled ‘‘Treatment of viscose with crosslinked commercial cellulases’’ has been presented at the 3rd International Conference on Textile Biotechnology in Graz/AUSTRIA, 13-16 June 2004.
I˙zmir, Turkey ¨ BI˙TAK TAM The Scientific and Technical Research Council of TU ¨ BI˙TAK Tekstil Aras¸tırma Turkey Textile Research Center, TU Merkezi, Ege Universitesi Kampu¨su¨ TR- 35100 Bornova, I˙zmir, Turkey Tel: +90 232 3399222; Fax: +90 232 3399222; E-mail: karaboga@ textile.ege.edu.tr ¨ BI˙TAK TAM / Ege University Joint Textile Research Prof. Dr Kerim Duran, TU Laboratories Research staff: Asssoc. Prof. Dr Ays¸egu¨l Ekmekci, Tex. Eng. Cem Karaboga, Tex. Eng. Duygu Ozdemir
Usage of ultrasound combined with hydrogen peroxide and UV light in textile wet processing Other partners: Academic
Industrial
Faculty of Engineering, Textile None Department, Ege University Project started: 1 August 2002 Project ended: 1 August 2004 Finance/support: US $ 50,500 Source of support: TU¨BI˙TAK TAM Keywords: Cotton, Ultrasound, Washing, Hydrogen peroxide, UV light, Textile pretreatment It has been recognized for many years that power ultrasound has great potential in a wide variety of processes in the chemical and allied industries and the potential
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for the industrial use of power ultrasound is enormous, and yet industry seems somewhat reluctant to adopt it. Since the foreign substances on the surface of the textile materials affect the quality and the efficiency of the upstream processes such as dyeing and printing, it is very important to remove them effectively during pretreatment. Three effective washing and pretreatment processes depend on the following factors: (1) chemicals and auxiliaries; (2) mechanical effects; and (3) parameters (temperature, time, materials, etc.). In this project, it has been aimed to investigate the effects of ultrasound itself, ultrasound combined with UV light and ultrasound combined with hydrogen peroxide on the resulting properties of cotton pretreatment such as desizing, scouring and bleaching. As a result of the combined effects of ultrasound and UV light in the presence of hydrogen peroxide, the hyroxyl radicals, much more (106-109 times more) active than the conventional oxydizing agents, are generated and it provides the following advantages in the pretreatment processes of cotton textiles. .
reduced energy consumption;
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reduced water consumption;
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reduced chemical consumption;
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reduced process time;
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reduced environmetal problems; and
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reduced risk on the damage of fabric.
A new laboratory scaled equipment to apply ultrasound combined with UV light to the texile materials (especially to the cotton woven and/or knitted fabrics) in the continuous pretreatment processes has been developed and now the experimental workings on the effects of this combination is still going on and some achievements on mentioned topics are obtained.
Project aims and objectives .
New textile finishing technology.
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New equipment that provide US and UV light with combination for textile treatments.
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Energy savings in textile finishing.
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Reducing environmental problems.
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Reducing processing times.
Research deliverables (academic and industrial) The manufacturing of a laboratory machine that can supply the combined US and UV energy for continuous cotton pretreatment. Publications None
I˙zmir, Turkey ¨ BI˙TAK TAM The Scientific and Technical Research Council of TU ¨ BI˙TAK Tekstil Aras¸tırma Turkey Textile Research Center, TU Merkezi, Ege Universitesi Kampu¨su¨ TR- 35100 Bornova I˙zmirTurkey Tel: +90.232.339 92 22; Fax: +90.232.339 92 22; E-mail:
[email protected] Prof. Hu¨seyin Kadoglu (PhD),TU¨BI˙TAK TAM / Ege University Joint Textile Research Laboratories Research staff: Mustafa Erdem Ureyen (MSc), Pinar Celik (MSc), Dincer Yıldırım
Influence of spinning process parameters and cotton fibre characteristics on hairiness of ring spun yarns Other partners Academic
Industrial
Textile Engineering None Department, Ege University Project started: 1 November 2002 Project ended: May 2004 Finance/support: 40,000 e Source of support: TU¨BI˙TAK TAM Keywords: Ring spinning, Cotton fibre, Yarn, Hairiness, Hairiness index The concept of yarn hairiness as a quantitative parameter was first stated in early 1950s. Before this date hairiness had already been mentioned as a quality parameter, but only some rough techniques for its measurement had been developed. In global yarn market, customer demands are increasing everyday. As a result, yarn quality, manufacturing costs, and delivery became more important subjects of today. Yarn hairiness is one of the most considerable structural parameter for determining the yarn quality besides strength and evenness. In the last decade yarn hairiness has charmed increasing practical interest because of the commercialization of some instruments. Yarn hairiness is effected by fiber characteristics, machine and process parameters. For this reason, yarn manufacturers can reduce yarn hairiness by choosing the right machine and/or process parameters with a good raw material selection. Although there were so many research activities on particular process parameters, our aim was to prepare a comprehensive work embracing all the process parameters together. In this study, we experimentally analysed the effects of these parameters on yarn hairiness.
Project aims and objectives Yarn hairiness cannot be completely defined by a single figure. However, we can describe it simply in terms of the number of protruding hairs on the unit surface of the spun yarn. Hairiness is characterized by the quantity of freely moving fiber ends or fiber
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loops projecting from a yarn or a textile fabric surface. Usually yarn hairiness is an undesirable property for cotton yarns because it causes important problems in subsequent processes. The long hairs interfere with the processing operation, for example, due, to abrasion, fly formation, snagging and hooking. Yarn hairiness is effected by fiber characteristics, machine and process parameters. So yarn manufacturers can reduce yarn hairiness by choosing the right machine and/or process parameters with a good raw material selection. Since the fiber characteristics play very important roles in the spinning processes and the performance of yarns and fabrics, spinners need to know the effect of fiber properties on yarn hairiness for the selection of a suitable raw material. In this study, we analyzed the effects of the following concepts on yarn hairiness. .
cotton fiber parameters;
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roving twist and break draft;
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type, weight and speed of travellers;
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clip distance;
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delivery speed of carding machine;
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compact spinning; and
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roller distance setting.
Although a number of researches are being carried up to date on the effects of particular process parameters, our aim is to prepare a comprehensive work embracing all the process parameters together.
Research deliverables (academic and industrial) Effects of raw material Raw material characteristics highly effects hairiness of yarns. For this reason we did an experimental work including several cotton materials. The differences between hairiness values were found statistically important. Furthermore, the stepwise regression analysis gave the following regression equation (Ne 16 yarn): S3¼ 6048,423 – 164,244 UHML From this equation it is clear that upper half mean length is the most effective cotton fibre parameter in predicting the S3 hairiness of cotton yarn. If the upper half mean length of cotton increases then the S3 hairiness value decreases simultaneously.
Effects of traveller type, traveller weight and traveller speed Traveller type. For investigating the effect of traveller type, ten different orbit type travellers were used. The yarn count Ne 30/1 was selected for the tests. After analysing the hairiness results, the differences between the traveller types were found statistically important. The least hairy yarns were obtained by using nickel coated and wide half round cross sectioned traveller type. It is very clear from the results that the correct traveller selection is highly important for less hairiness. Traveller weight. For investigating the effect of traveller weight, four different traveller weights from three different traveller types were selected. The yarn count was again Ne 30/1. From the results it was clearly seen that there has been a tendency in
hairiness reduction when the traveller weight is increased. For all hair lengths, the same tendency was obtained. Regarding the effects of traveller speed on yarn hairiness, another experimental plan was applied. The yarn count selected again was Ne 30/1. The spindle speed was increased from 10.000 to 13.000, 14.000, 16.000 and 18.000 rpm, respectively. The difference between the hairiness values were found statistically important for all hair categories. Besides different spindle speeds four different types of travellers were also employeed as combination. For each traveller type, it was observed that there was a reduction tendency in hairiness when the spindle speed is increased.
The effects of roving twist and break draft in ring spinning machine on yarn hairiness For this part of the research Ne 1,1 roving was produced with twist values of 35, 42 and 48 tpm. By using these rovings Ne 16/1, Ne 24/1 and Ne 36/1 (am ¼ 115) yarns were produced by using predrafting ratios of 1.181, 1.288 and 1.417. The differences between the hairiness values were found statistically important for roving twist change and break draft change for all hair length categories. As a tendency, the hairines value decreases with the increasing break draft ratio and roving twist.
Effect of roller distance setting on yarn hairiness As it is known roller distance setting is very important especially for yarn evenness. Fibers arriving for processing exhibit very considerable length variations. In the drafting field they are therefore, found in two conditions which are guided and floating. Guided fibers are gripped by one pair of roller. But floating fibers are shorter and they pass the drafting zone without beign gripped for a longer time. In case of wrong setting the short fiber content of cotton can cause a high unevenness due to the drafting waves. In the content of this research the effects of roller distance settings on yarn hairiness were investigated. For this purpose, Ne 24 cotton yarns were produced from two rovings having three different twist values. The spinning was performed under two roller distance settings in main drafting zone and three different roller distance settings in predrafting zone.The correct value of the roller distance setting depends mainly on the fiber length; it is not possible to advise a fixed value. But it can be concluded from this work that the roller distance setting certainly effects the hairiness value and there is an important interaction between roving twist – predrafting zone roller distance setting and main drafting zone roller distance setting.
Effect of clip distance on yarn hairiness The x distance between aprons on a ring spinning machine is very important regarding spun yarn quality. In the context of this part, the effect of this distance on yarn hairiness was examined. For this purpose, Ne 20/1, Ne 30/1 and Ne 40/1 cotton yarns were spun under identical conditions by changing only the x distance between the aprons by means of different clips. These distances were chosen as 3.25, 3.50, 3.75, 4.00 and 4.50 mm. After analysing the hairiness results, it was concluded that the change of clip distance certainly effects the hairiness value of yarn. These effects were found statistically important. Therefore, the clip distance must be considered regarding yarn
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hairiness.There should be an interaction between the clip distance and number of fibers in yarn cross section regarding yarn hairiness value.
Effect of carding machine delivery speed on yarn hairiness
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Carding machine has a special importance in spinning room. Production of a perfect sliver is the most vital prerequisite of a successful spinning operation and sufficient yarn quality. In this part of the research the effect of card delivery speed on yarn hairiness was considerated. For this purpose Ne 16/1 and Ne 36/1 yarn counts were produced by using the slivers produced at 60, 110 and 160 m/min. After analysing the hairiness values of yarns, it was observed that the hairiness decreases with the increasing card delivery speed. These differences were found statistically important. The reason for this decrease can be attributed to the decreasing short fiber index of slivers produced at higher speed (short fiber content decrease from 7.4 to 6.9 percent).
Effect of compact spinning on yarn hairiness As it is known the compact spinning is a modified version of classical ring spinning machines.The basic feature of this machine is a fiber compacting zone at the exit of the drafting system. By means of this compacting system it is possible to minimize the spinning triangle. Minimizing the spinning triangle brings some benefits such as low hairiness. In this part of the research the effect of compact spinning machine on yarn hairiness versus classical ring spinning machine was investigated. For the tests carded and combed cotton yarns were produced on both compact spinning machine and classical ring spinning machine under the identical conditions. It was concluded that compact spun yarns had much lower hairiness values especially for hairs length >2 mm. All variance analysis showed a statistically important difference between the normal ring and compact yarns. Publications A research on the reasons of hairiness in cotton yarns and the possibilities of decreasing hairiness, Project Report Book, Project Nr. TU¨BITAK-TAM 2002-06, Turkish Textile Foundation, April 2004. Influence of spinning process parameters and cotton fibre characteristics on hairiness of ring spun yarns, Proceedings, AUTEX2004 World Textile Conference, ENSAIT-Roubaix, France, 22-24 June 2004.
I˙zmir, Turkey ¨ BI˙TAK TAM The Scientific and Technical Research Council of TU ¨ BI˙TAK Tekstil Aras¸tırma Turkey Textile Research Center, TU Merkezi, Ege Universitesi Kampu¨su¨ TR- 35100 Bornova, I˙zmir, Turkey Tel: +90 232 3399222; Fax: +90 232 3399222; E-mail:
[email protected] ¨ BI˙TAK TAM, Ege University Joint Textile Research Laboratories, TU ¨ ktem Assoc. Prof. Dr Tu¨lin O
Research staff: Prof. Dr Is¸ık Tarakc¸ıog˘lu, Prof. Dr Ahmet O¨ztarhan, ¨ zdoan, MSc Zekai Tek, MSc E. Sema Namlıgo¨z, Assis. Prof. Dr Esen O Tex. Eng. M. Ahmet Karaaslan
Investigating the applicability of metal ion implantation technique (MEVVA) to textile surfaces Other partners Academic
Industrial
Textile Department, None Faculty of Engineering, Ege University Project started: 1 May 2002 Project ended: 1 November 2003 Finance/support: US $ 69,000 Source of support: TU¨BI˙TAK TAM Keywords: MEVVA ion implantation, PET fabrics, Membrane, Electrical property, Friction coefficient, Wear Textile industry is, nowadays, strongly motivated to seek alternative process which could offer lower cost, environmentally-friendly manufacturing and routes to new products, with improved lifetime, quality and performance. Ion implantation is an advanced applied plasma technology using high-energy ions. Ion implantation technique involves bombarding a surface with ions at speeds of up to 1,500 km/s. The ions penetrate the surface and stay in the outermost layer of the surface. This changes its micro structure and can form chemical compounds. The difference between ion implantation and other plasma assisted surface coating treatment processes is that it is not on the surface, it is in it, forming a graded surface. In this project, PET samples were modified by Cu, C, Ti, W, Cr, TiN, CrN and CN implantation using a metal vapor vacuum arc (MEVVA) implanter. Ions were implanted at an accelerating voltage of 30 kV with a dose ranging from 11014 to 11017 ions/cm2. In the first part of this study, Cu ions were implanted to improve the electrical properties of PET woven fabrics, and in the second part, C, Ti, W, Cr ions and TiN, CrN, CN compounds were implanted to enhance the mechanical properties of PET fabrics coated with a PET membrane. After implantation, the results showed that the half charge decay time of implanted fabric lessened to milliseconds, and the friction coefficient and wear loss values decreased significantly. The surface morphologies of samples were examined by SEM and AFM. Changes in chemical structure were observed by IR spectra.
Project aims and objectives Modifying the mechanical and electrical properties of textile surfaces with MEVVA metal ion implantation technique.
Research deliverables (academic and industrial) .
Antistatic properties of PET fabrics are increased.
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The friction coefficient and wear loss values decreased after implantation.
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Negative effect of ion implantation on physical and mechanical properties of PET fabrics was not observed.
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AFM measurements indicated that there were significant differences in the surface morphology of untreated and Ti implanted samples.
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In addition, initial experiments suggested that in PET fabrics color efficiency increased after ion implantation at lower ion doses.
Publication An oral presentation titled ‘‘Investigating the applicability of metal ion implantation technique (Mevva) to textile surfaces’’, paper presented at the 4th AUTEX Conferences – World Textile Conferences, Roubaix, France, 22-24 June 2004.
I˙zmir, Turkey ¨ BI˙TAK TAM The Scientific and Technical Research Council of TU ¨ BI˙TAK Tekstil Aras¸tırma Turkey Textile Research Center, TU Merkezi, Ege Universitesi Kampu¨su¨ TR- 35100 Bornova, I˙zmir, Turkey Tel: +90 232 339 92 22; Fax: +90 232 339 92 22; E-mail:
[email protected] ¨ zgu¨ney Assoc. Prof. Dr Arif Taner O ¨ ˙ TUBITAK TAM / Ege University Joint Textile Research Laboratories ¨ zerdem, Research staff: Assoc. Prof. Dr Ays¸egu¨l Ekmekc¸i, MSc. Arzu O Zeynep C¸apaci
Pretreatment and reactive printing of viscose fabrics in different types and properties Other partners: Academic
Industrial
Dous¸ Genel Makine None Boya Apre LTD. S¸TI˙. Turgutlu–Manisa Textile Department, Faculty of Engineering, Ege University Project started: 1 July 2003 Project ended: 1 July 2004 Finance/support: US $ 20,000 Source of support: TU¨BI˙TAK TAM Keywords: Viscose, Reactive printing, Causticising, Sulphur In this project, the effect of sulphur, that may be present in the viscose fabric, on the color efficiency and consistency of the print has been investigated. With this aim viscose fabrics, obtained from different sources and containing different amounts of sulphur, were causticized, bleached, and impregnated with urea. Subsequently, fabrics were
printed with Cibacron Red P 4B and Cibacron Blue P 3R having the same reactivity, but different molecular sizes. Color values of both dyes were measured and fastnesses were tested and compared to observe the effect of sulphur in the fabric on the printing. Additionally, different systems of sulphur analysis were investigated and tested to determine the amount of sulphur in fabrics. Among these systems, lead acetate method, which is a subjective evaluation system, has been selected as the most appropriate one for the practical working conditions of the plants, and a sulphur scale was formed according to this method. Accuracy of the scale was also confirmed by elemental analysis (CHNS-O) method.
Project aims and objectives Before reactive printing, optimization of pretreatment processes for different types of viscose fabrics containing different sulphur amounts.
Research deliverables (academic and industrial) The sulphur scale we developed is a practical test system like ‘‘Tegewa Scale’’ that can be used easily in every plant. Sulphur can be removed from the fabric easily with the aid of appropriate pretreatment process combinations. Instead of traditional pretreatment processes like bleaching, bleaching and reductive washing, causticizing alone can easily remove sulphur residues from the viscose fabric in shorter duration. Furthermore unlike bleaching and reductive washing, causticizing increases the color efficiencies of viscose fabrics to be printed with reactive dyestuffs. Among the pretreatment processes of viscose fabrics, especially causticizing is the most important process that directly influences the properties of printing. Thus, in order to achieve a high color efficiency to remove the sulphur residues on the fabric, and to provide repeatability of the print, causticizing must be performed. To causticize and to make efficient hot washing after desizing removes all the sulphur residues, and provides sufficient whiteness degrees for viscose fabrics which are going to be printed, and also has an additional benefit especially for the fabrics which have the risk of containing iron. In this way, risk of catalytic damage in bleaching is eliminated, when high whiteness degree is not required. Additionally, because after causticizing viscose fibers are getting smoother, the pilling tendency of viscose fabrics is reduced. Publication An oral presentation titled ‘‘Pretreatment and reactive printing of viscose fabrics in different types and properties’’ has been presented at the 4th Autex Conferences – World Textile Conferences in Roubaix, France, 22-24 June 2004.
I˙zmir, Turkey ¨ BI˙TAK TAM The Scientific and Technical Research Council of TU ¨ BI˙TAK Tekstil Aras¸tırma Turkey Textile Research Center, TU Merkezi, Ege Universitesi Kampu¨su¨ TR- 35100 Bornova, I˙zmir, Turkey Tel: +90 232 3399222; Fax: +90 232 3399222; E-mail:
[email protected];
[email protected]
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¨ BI˙TAK TAM / Ege University Joint Textile Prof. Dr Abbas Yurdakul, TU Research Laboratories ¨ ktem, Assoc. Prof Dr Perrin Kumbasar, Research staff: Assoc. Prof. Dr Tu¨lin O Research Ass. Rıza Atav, MSc, Asli Korkmaz, Tex. Eng. Arzu Arabaci
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Effects of finishing processes and textile chemicals used after dyeing process on fastness properties Other partners: Academic
Industrial
Textile Department, None Faculty of Engineering, Ege University Project started: 1 May 2002 Project ended: 1 November 2003 Finance/support: US $ 35,000 Source of support: TU¨BI˙TAK TAM Keywords: Fastness, Dyestuff, Softener, Fixing agent, Hydrophility Today’s highly competitive world requires ‘‘the customer oriented’’ approach for being able to survive in world markets. Nowadays, much more powerful detergents are dominating the market; on the other hand, there is an ever increased and for enhanced fastness quality. The main problematic feature for the customers are color consistency, washing and wet rubbing fastnesses for particularly darker shades, and light-perspiration and light fastnesses for particularly lighter shades. The aftermath effects of aftertreatments following dying, insufficient rinsing process, or incorrect dyestuff selection, are the main disagreement topics between customers and producers. For this reason, in this project, the effects of softening and fixing agents used after reactive dyeing on fastness properties have been investigated. For this purpose, we classified these chemicals according to their chemical structures and then we have compared their effects on fastness properties of reactive dyed knitted cotton fabrics. Generally softeners do not affect the wet fastness properties, but in dry rubbing fastness some differences are determined according to their chemical types. Otherwise it is assigned that the fixing agents do not affect the rubbing fastnesses, but they increase the washing fastnesses according to the dyestuff.
Project aims and objectives Chemical finishing treatments, in accordance with the application domain and required properties, are employed after dying process. While enhancing some of the textile related qualities, those treatments however, may interfere with some other qualities. Because of this, the effects of the textile chemicals and finishing processes on the fastness qualities have gained remarkable importance. We have taken all these factors in consideration at this project. We inspected the effects of chemical agents and production processes following reactive dying on color fastness qualities.
Research deliverables (academic and industrial). .
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Softeners do not affect the wet rubbing and washing fastnesses, but according to the dyestuff they decrease the light fastnesses and according to the softener type they decrease the dry rubbing fastnesses. Quartamine, hydrophyl silicone and polyethylene based non-ionic softeners usually do not affect dry rubbing fastness negatively, whereas softeners generally decrease the hydrophylity of fabric, hydrophyl silicone and polyethylene based non-ionic softeners do not. Conventional fixing agents do not affect dry and wet rubbing fastnesses, but according to the dyestuff they increase the washing fastness. Otherwise they have the tendency to decrease the light fastness. Some special fixing agents increase both washing and wet rubbing fastnesses.
Publications An oral presentation titled ‘‘Effects of auxiliaries used after dyeing process on fastness properties’’ has been presented at the 9th Symposium of Recent Innovations in Textile Technology and Chemistry, Bursa, 30 April-02 May 2003. Effects of finishing processes and textile chemicals used after dyeing process on fastness properties, Textile Employers Association, ˙Izmir.
Karnataka, India University of Agricultural Sciences, Dharwad, Karnataka, Dr Geeta Mahale, Sr Scientist, Department of textiles and Apparel Designing, College of Rural Home Science, UAS, Dharwad, Karnataka 580005 Tel: 091-0836-2743190; Fax: 091-0836-2448349; E-mail:
[email protected] Dr Geeta Mahale, All India co-ordinated research project on clothing and textiles Research staff: Ms Sunanda R.K., MS Bhavani K., MS Sakshi S.
Value addition for agro and animal fibres Other partners: Academic
Industrial
None None Project started: 26 September 1996 Project ends: Continued project Finance/support: Rupees 11 Lakhs per year Source of support: Indian Council of Agricultural Research, New Delhi Keywords: Value addition, Agro and animal based fibres, Non-farming activities, Mestha, Agave, Hemp and pina fibres, Income generation Agro an animal based fibre, is of several types such as cotton, wool and silk, have been developed in major organized sectors but not developed to that extent in decentralized sector. On the other hand, the other minor agro and animal based fibres like rabbit wool,
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wild silk, mestha, camel’s hair, hemp, agave, pina, etc., are yet to be developed at the levels of organized and decentralized sectors. Some of these fibres are put to limited use at family level. Farming activities are seasonal, which also include cultivation/rearing of fibre yielding crops and animals. Processing of fibres from these sources takes place at farm level to some extent, for example, deseeding of cotton, retting of jute, agave and hemp. Shearing of wool, reeling of silk etc. These may give employment to the community to a limited extent. These fibres are further procured at industry level giving greater employment outside rural areas. It is generally observed that most of the farming families look for the additional income before the onset of farming activities as expand gains they have made through agriculture. If technologies were developed for cottage level processing of the fibres and for product diversification then value addition would augment income generation to the farming community even during lean season. Therefore, there is need for exploring the possibilities of income generation through non-farming activities using the local natural resources. This would also help the nonfarming families to earn their livelihood to a certain extent.
Project aims and objectives (1) To identify the resources – agro and animal based fibres, indigenous natural dyes, etc. and related by-products and their present utilization. (2) To evolve the national profile of availability and trend of agro, animal based fibres and dyes. (3) To introduce intervention for improvement in the existing practices in processing fibres and dyes. (4) To develop new technologies through different techniques for cottage level adoption. (5) To assess the economic viability of the developed technologies.
Research deliverables (academic and industrial) I phase (1996-98) – Identification of resources and utilization of agro and animal based fibres were studied. II phase (1998-99) – Optimization of dyeing conditions using arecanut and marigold flowers. Dyeing silk with arecanut and marigold. III phase (1999-2001) – Optimization of dyeing conditions using arecanut and marigold flowers. Dyeing cotton with arecanut and marigold IV phase (2001-2002) – Optimization of dyeing conditions using acalypha and teak leaves. Dyeing cotton and silk with acalypha and teak. Preparation of value added products, namely saree, cushion covers, files, purses, macrame´ wall hangings, pouches, bags, etc., using natural dye sources. V Phase (2002-2003) – Dyeing wool with arecanut, marigold, acalypha and teak dye extract. Optimization of dyeing conditions using aforesaid natural dye sources with different eco-friendly mordant combinations. VI Phase (2003-2004) – Optimization of printing conditions and printing with natural dye sources, Optimization of dyeing conditions using red sander bark and dyeing cotton, silk and wool with red sander bark. Preparation of value added products using natural
dye sources with printing techniques, table cloth, deewan set, dress material, pouches, greeting cards, namely cushion covers, files and hand kerchiefs. Publications Mahale, G., Bhavani, K. and Sunanda, R.K. (1998), ‘‘Bamboo (Bambusa arundinanca): immense possibilities’’, Textile Industry of India, pp. 12-14. Mahale, G , Bhavani, K. and Sunanda. R.K. (1999), ‘‘Karnataka – woollen blanket weavers’’, Indian Journal of Small Ruminats, Vol. 5 No. 2, pp. 39-42. Mahale, G., Sakshi, S. and Sunanda, R.K. (2002a), ‘‘Fastness properties of acalypha on cotton’’, International Dyer, Vol. 187 No. 9, pp. 39-41. Mahale, G., Sakshi, S. and Sunanda, R.K. (2002b), ‘‘Printing with natural dyes – an enterprise’’, NIRD Souvenir on Strategies for Rural Industrialization Through Decentralized Planning, 24-25 October, pp. 1-8. Mahale, G., Sakshi, S. and Sunanda, R.K. (2003a), ‘‘Acalypha leaves on eco dye for wool’’, Textile Asia, Vol. 35 No. 4, pp. 39-43. Mahale, G., Sakshi, S. and Sunanda, R.K. (2003b), ‘‘Acalypha leaves, on eco dye for wool’’, Textile Asia, Vol. 35 No. 4, pp. 39-43. Mahale, G., Sakshi, S. and Sunanda, R.K. (2003c), ‘‘Teak leaves, a dye source for cotton’’, Textile Asia, Vol. XXXIV No. 9, pp. 52-6. Mahale, G., Sakshi, S. and Sunanda, R.K. (2003d), ‘‘Arecanut – a natural colourant for silk’’, Man made Textiles in India, Vol. 46 No. 4, pp. 136-41. Mahale, G., Sakshi, S. and Sunanda, R. (2003e), ‘‘Silk dyed with acalypha (acalypha wilkesiana) and its fastness’’ Indian Journal of Fiber and Textile Research, Vol. 228 No. 3, pp. 86-9. Mahale, G., Sakshi, S. and Sunanda, R.K. (2004), ‘‘An eco-friendly dye for silk-teak leaves’’, Manmade Textiles in India, Vol. XLVII No. 4, pp. 130-4. Mahale, G , Sunanda, R.K. and Bhavani, K. (1998), ‘‘Value addition-cotton yarns’’, The Textile Industry and Trade Journal, Vol. 36 No. 11-12, pp. 75-9 Mahale, G., Sunanda, R.K. and Bhavani, K. (1999), ‘‘Karnataka-sheep farmers’’, Indian Journal of Small Ruminats, Vol. 5 No. 2, pp. 82-4. Mahale, G., Sunanda, R.K. and Sakshi, S. (2001a), ‘‘Natural dyeing of silk with teak leaves and its fastness’’, Proceedings of Convention on Natural dyes, IIT, New Delhi, pp. 111-16. Mahale, G., Sunanda, R.K. and Sakshi, S. (2001b), ‘‘Ecodyeing of cotton with teak and its fastness’’, The Textile Industry and Trade Journal, Vol. 39 Nos 9-10, pp. 33-6. Mahale, G., Sunanda, R.K. and Sakshi, S. (2002a), ‘‘Colour fastness of eco dyed cotton with marigold’’, Textile Trends, Vol. 44 No. 10, pp. 35-9. Mahale, G., Sunanda, R.K. and Sakshi, S. (2002b), ‘‘Ecodyeing – diversification of Teak leaves’’, Proceedings of the International Conference on Ecobalance and Life Cycle Assessment in India, 13-15 February, pp. 76-9. Mahale, G., Sunanda, R.K., and Sakshi, S. (2003), ‘‘Value addition – acalypha leaves extract’’, paper presented and also published in the seminar of ‘‘Natural seminar on Impact of New Economic policies on Rural Industrialisation’’, National Institute of Rural Development, Hyderabad, 8-10 September 2003. Mahale, G., Bhavani, K., Sunanda, R.K. and Sakshi, S. (1999a), ‘‘Colour fastness properties of areca catechu in alkaline pH’’, Indian Silk, Vol. 38 No. 7, pp. 18-21. Mahale, G., Bhavani, K., Sunanda, R.K. and Sakshi, S. (1999b), ‘‘Standardizing, dyeing conditions for African marigold’’, Manmade Textiles in India, Vol. 42 No. 11, pp. 453-58. Mahale, G., Bhavani, K., Sunanda, R.K. and Sakshi, S. (1999c), ‘‘Marigold – a natural colouring agent, assessment of its colourfastness’’, Textile Industry of India, Vol. 38 No. 11, pp. 7-13. Mahale, G., Sakshi, S. and Sunanda, R.K. (2001), ‘‘Colour fastness of arecanut dyed cotton’’, Manmade Textiles in India, Vol. 44 No. 6, pp. 243-6.
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Mahale, G., Sunanda, R.K., Bhavani, K. and Pratibha, B.R. (1999), ‘‘Natural dyeing-silk with arecanut extract’’, Textile Industry of India, Vol. 38 No. 7, pp. 20-2. Mahale, G., Sunanda, R.K., Bhavani, K. and Sakshi, S. (1999), ‘‘Tagets erecta: its colourfastness in acidic media’’, Textile trends, Vol. 42 No. 7, pp. 223-6. Mahale, G., Sunanda, R.K. and Bhavani, K. and Sakshi, S. (2000), ‘‘Colour fastness properties of areca catechu in acidic pH’’, The Textile Industry and Trade Journal, Vol. 38 Nos 11-12, pp. 159-63. Popular articles Mahale, G., Vanishree, and Sunanda, R.K. (2004), ‘‘Use eco-holi colours and keep your skin healthy’’, Samyukta Karnataka, Vol. 71 No. 306, p. 8. Mahale, G., Vanishree, and Sunanda, R.K. (2004), ‘‘Diversification of natural waste into dyestuff for textile material’’, Indian Silk, Vol. 43 No. 3, p. 29.
Research abstracts published (1997-2004) Geeta, M., Sunanda, R.K. and Bhavani, K. (2000), ‘‘Sheep farmers of Karnataka’’, paper presented at the Souvenir of Golden jubilee Seminar on ‘‘Sheep, Goat and Rabbit production’’ – CSWRI, Awikanagar, Jaipur, p. 67. Geeta, M., Sunanda, R.K. and Sakshi, S. (2002), ‘‘Eco-dyeing diversification of teak leaves’’ Proceedings of the International Conference on ‘‘Eco balance and lifecycle assessment in India’’ 13-15 February, pp. 76-9. Geeta, M., Sunanda R.K. and Sakshi, S. (2001), ‘‘Natural dyeing of silk with teak leaves and its fastness’’, New cloth market, Vol. 15 No. 10, p. 90. Geeta, M., Meera Rao, Bhavani, K. and Sunanada, R.K. (2000), ‘‘Woollen blanket weavers of Karnataka’’, paper presented at the Souvenir of Golden jubilee Seminar on ‘‘Sheep, Goat and Rabbit production’’ – CSWRI, Awikanagar, Jaipur. Geeta, M., Sunanda, R.K., Bhavani, K. and Sakshi, S. (2000), ‘‘Optimisation of dyeing conditions for arecanut dye’’, paper presented at the National Seminar on Indian Natural Colouring Agents beyond 2000 AD-Souvenir, National Academy of Chemistry and Biology, Kanpur, 11-13 February 2000.
Kaunas, Lithuania Faculty of Design and Technologies, Kaunas University of Technology, Studentu str. 56, Kaunas LT-3031, Lithuania Tel: +370 37 300205; Fax: +370 37 353989; E-mail:
[email protected] Dr Eugenija Strazdiene Department of Clothing and Polymer Products Technology Research staff: Doctoral students J. Domskiene, V. Dobilaite, V. Sidabraite, K. Dapkuniene
The effect of physical-mechanical properties upon the tailorability and appearance of textiles Other partners: Academic None
Industrial None
Project started: 15 January 2002 Project ends: 15 January 2006 Finance/support: N/A Source of support: Kaunas University of Technology Keywords: Technical textiles, Mechanical properties, Laminates, Coating, Shearing, Buckling, Surface Roughness, Image analysis The research project is orientated towards modern textiles, which is characterized by new original properties extending their functionality and the range of their end use. Laminates and coatings bring textile technology into a new dimension. High performance fabrics are used for leisure, sports, industrial and military garments. In this sense woven structure is very attractive as the reinforcement for composites because it is lightweight, flexural and strong. This makes textile composites suitable for the parts of complicated or curved shape due to their formability properties. Though technical textiles are designed for a specific performance, aesthetics for such garments is very important, too. Thus the main goal of this research is to study the effect of shearing and buckling properties for the behavior of technical textiles, especially for fitting such materials on three-dimensional surfaces without wrinkling and to analyze the conditions when these fabrics start to loose their stable shape, i.e. their surface becomes waved.
Project aims and objectives An experimental method based on image capturing and image analysis able to characterize deformational properties of coated and laminated composites in uniaxial and spatial tensile deformations will be developed. Comparative analysis of buckling wave’s propagation, i.e. alterations of its shape (changes of image intensity in certain zone of the specimen) and dimensions (length, width and number of waves) in uniaxial tension of bias (45 ) orientated samples will be performed. Furthermore, the ability of coated and laminated textile composites to be deformed into three-dimensional curvature, i.e. to obtain spherical shape of different diameter will be analyzed from the standpoint of such properties as tensile extension, shear stiffness, shear hysteresis, bending rigidity and bending hysteresis.
Research deliverables (academic and industrial) Theoretical results of this research will deepen the knowledge of technical textile mechanical behavior not only under in-plane and perpendicular loading conditions but also in spatial shape formation and will be used in textile and polymer garments design process. Publications Domskiene, J., Strazdiene, E. (2002a), ‘‘Shearing behavior of technical textiles’’, Material Science (Medziagotyra), Vol. 8 (in press). Domskiene, J., Strazdiene, E. (2002b), ‘‘Deformational properties of coated and laminated textile composites’’, Proceedings of the 2nd AUTEX World Textile Conference, Bruges, Belgium, p. 552. Domskiene, J., Strazdiene, E., Dapkuniene˙, K. (2002), ‘‘The evaluation of technical textiles shape stability by image analysis’’, Material Science (Medziagotyra), Vol. 8 (in press).
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Kaunas, Lithuania Kaunas University of Technology, Faculty of Design and Technologies, Studentu str. 56, Kaunas-3031, Lithuania Tel: 370-7-767066; Fax: 370-7-353989; E-mail:
[email protected] Department of Clothing and Polymer Products Technology Hab. Dr Professor Matas Gutauskas Research staff: Dr E. Strazdiene, Dr L. Papreckiene, Dr V. Daukantiene and master student G. Martisiute
New method of textile hand evaluation Other partners: Academic
Industrial
None None Project started: June 2001 Project ends: December 2004 Keywords: Textiles, Membrane, Pulling through, Biaxial deformation, Geometry, Wave, Jamming Although a large part of textiles is concerned with imparting desirable physical properties, theoretical understanding of the effect of these properties on material response is limited. The research project will provide new method for the evaluation of planar anisotropic material’s behavior and original experimental information will be obtained, contributing to the existing knowledge in the field of mechanics of heterogenic, e.g. textile structures. New pulling through a hole method is similar to a well-known punch test used to control strength parameters of knitted material. The difference is that rounded specimen is not firmly fixed by its external contour and the diameter of the hole and the punch are relatively small compared to that of the specimen. Latest investigations have shown that this method is sufficiently informative and able to characterise such hand properties as softness, slippery, roughness, etc. Besides, it provides useful information for the evaluation of textile’s drape and anisotropy.
Project aims and objectives The aim of the research is to set the relationship between the geometry and resistance parameters of textile membrane due to its type and testing conditions. Tests are performed by the original device mountable on the standard tensile testing machine. It consists of two perpendicular plates, replaceable stand with the hole in the centre and supporting plate with the hole of the same radius. Spherical punch is used to pull rounded specimen through the hole of the stand. The investigations are realised by two pulling through cases: free pulling through the hole of the stand; restrained pulling simultaneously through the limited crack of the plate and through the same hole of the stand.
Research deliverables (academic and industrial) New testing method for textile and its experimental base will extend the existing laboratory of material testing and will be used in the study process of the Kaunas University of Technology. Theoretical results of this research will deepen the knowledge of textile spatial shape formation and will be used in textile and polymer garments design process. Publications Martisiute, G. and Gutauskas, M. (in press), New Approach to the Evaluation of Fabric Handle, Materials Science, Kaunas. Martisiute, G. and Gutauskas, M. (in press), ‘‘Pulling through process of knitted membrane: analysis of geometry’’, Proc. of the Conf. Design and Technology of Consumer Goods - 2001, Kaunas (in Lithuanian). Strazdiene, E., Martisiute, G., Gutauskas, M. and Papreckiene, L. (in press), ‘‘New method for the objective evaluation of textile hand’’, Journal of the Textile Institute, UK.
Kaunas, Lithuania Kaunas University of Technology, Faculty of Design and Technologies, Studentu str. 56, Kaunas, LT-51424, Lithuania Tel: +370 37 300205; Fax: +370 37 353989; E-mail:
[email protected] Prof. H. Dr Matas Gutauskas, Department of Clothing and Polymer Products Technology Research staff: Dr Eugenija Strazdiene, Dr Virginija Daukantiene, Dr student Diana Grineviciute
New method for the objective evaluation of textile hand Other partners: Academic
Industrial
None None Project started: January 2002 Project ends: January 2006 Finance/support: 10, 000 Lt Source of support: Research program BMP4-12 ‘‘Creation and Evaluation of Multifunctional Materials and their Products’’ Keywords: Textiles hand, Subjective evaluation, Objective evaluation, Extraction through a hole For a long time textile hand was evaluated subjectively, i.e. questioning the panel of judges. Simultaneously the attempts were made to evaluate the hand objectively, i.e. through the suit of experimentally defined textiles properties. With the appearance of KES-F and FAST equipment the evaluation quality of these parameters has evidently improved. However, this equipment in many cases was inaccessible due to rather complicated interpretation of obtained data and long testing duration.
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Several testing devices of specimen’s extraction through a rounded hole already exist, on the basis of which the evaluation of hand is much more simple in the sense of methodology. Though the first data concerning this type of testing was presented sufficiently long ago, deeper investigations in this sphere were not done. So in this research the main attention is laid for the so-called restrained extraction of specimen through a rounded hole. This testing reminds punching test, which is used in material science to determine textiles strength properties and shape stability in biaxial loading. The difference between these testing methods is that in extraction test smaller punch is used and the outer contour of the specimen is not restrained, only limited by a spacing of certain height in which the specimen slides changes its geometrical shape. The regulation of spacing height is an additional mean enabling to control the extraction process. The aim of this research is to create original testing device KTU-Griff-Tester for the evaluation of such textile properties as hand, performance peculiarities in biaxial loading and anisotropy level.
Project aims and objectives This investigation is aimed to create the original KTU-Griff-Tester device for the realisation of specimen extraction through a rounded hole, to optimise testing conditions and to analyse the regularities of textile behaviour in extraction process on the basis of the dependencies between the variations of specimen geometry and its resistance due to textile material type and testing conditions. It is expected that with the help of this equipment differences between different fabric treatments can be distinguished more evidently than it was done before. Furthermore, the aim of this research was to choose the number of criterions in such a way that their total sum could guarantee sensitive and reliable evaluation of fabric properties due to their final treatment. Also – to compare the results of sensory evaluation with the objective data obtained on the basis of KTU-Griff-Tester.
Research deliverables (academic and industrial) The first obtained results allow to describe KTU-Griff-Tester as technically simple and methodologically reliable instrumental device, suitable to control the hand properties of textile materials. Also, these results show that simple, i.e. with small number of parameters, and reliable mathematical models (e.g. shortened epicycloids and Cassini ovals) can be used to describe the behaviour of disc shaped specimen at the initial stages of extraction through a rounded hole. The proposed testing method is able to reveal the inequality of textile material properties in different directions and provides new information about the behaviour of textile materials. Thus, it extends the existing laboratory basis and the ability of textile and polymer materials investigations. For industry the developed testing method can be suitable to evaluate the effect of softeners and other types of textiles finishings. Publications Daukantiene˘, V. and Gutauskas, M. (2002), ‘‘Textile hand: an analysis of knitted fabric behaviour’’, Material Science, Vol. 8 No. 6, pp. 299-303. Daukantiene˘, V., Papreckiene˘, L. and Gutauskas, M. (2003), ‘‘Simulation and application of the behaviour of a textile fabric while pulling through a round hole’’, Fibres and Textiles in Eastern Europe, Vol. 11 No. 2, pp. 38-42.
Daukantiene˘, V., Zmailaite˘, E. and Gutauskas, M. (n.d.), ‘‘Influence of concentrated liquid softeners on textile hand’’, Indian Journal of Fiber and Textile Research (in press). Martisˇite˘, G. and Gutauska, M. (2001), ‘‘A new approach to evaluation of textile fabric handle’’, Material Science, Vol. 7 No. 3, pp. 186-90. Strazdiene˘, E. and Gutauskas, M. (2003), ‘‘Behaviour of stretchable textiles with spatial loading, Textile Research Journal,Vol. 73 No. 6, pp. 530-4. Strazdiene˘, E., Daukantiene˘, V. and Gutauskas, M. (2003), ‘‘Bagging of thin polymer materials: geometry, resistance and application’’, Material Science, Vol. 9 No. 3, pp. 262-5. Strazdiene˘, E., Papreckiene˘, L. and Gutauskas, M. (2002), ‘‘New method for the objective evaluation of technical textile behaviour’’, paper presented at the 6th Dresden Textile Conference 2002, CD-ROM Page 1-8 of 8, available at: www.fiz-technik.de Strazdiene˘, E., Martisˇite˘, G., Gutauskas, M. and Paprckiene˘, L. (n.d.), ‘‘Textile hand: new method for textile objective evaluation’’, Journal of the Textile Institute, (in press).
Kaunas, Lithuania Kaunas University of Technology, Faculty of Design and Technologies, Studentu str. 56, Kaunas, LT-51424, Lithuania Tel: +370 37 300205; Fax: +370 37 353989; E-mail:
[email protected] Dr Eugenija Strazdiene, Department of Clothing and Polymer Products Technology Research staff: Dr Vaida Dobilaite, Dr Jurgita Domskiene, Dr Viktorija Sidabraite – Vaitkeviciene
Investigation and evaluation of textiles tailorability Other partners: Academic
Industrial
None None Project started: January 2003 Project ends: January 2006 Finance/support: 9,000 Lt Source of support: Research program BMP4-12 ‘‘Creation and Evaluation of Multifunctional Materials and their Products’’ Keywords: Textiles, Tailorability, Buckling phenomenon, Buckling wave, Seam puckering, Seam slippage, Drapeability Textile materials, unique in their structure and properties are constantly perfected thus widening the sphere of their utilization and over passing the limits of clothing production. Specific deformational properties and ability to obtain spatial shape are determined by the unique structure of these materials. In this regard complex assessment of fabric tailorability would allow forecast of its problematicity in the course of garment manufacture and would be important while making production solutions. On one hand textiles tailorability depends on its formability properties, which can be described by buckling phenomenon, often observed in processing and
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performance of textiles when it looses its plain shape and becomes waved due to inplane compression. On the other hand, formability influences drape properties and the formation of characteristic defects in seam joints (e.g. seam puckering), especially in lightweight fabrics. From the latter standpoint buckling waves do not allow to obtain smooth shape degrading the aesthetical view and quality of garments, but shapes of major curvature can be obtained by qualitative seams, i.e. when seam puckering is avoided. In this research methods of mathematical analysis are applied for complex evaluation of tailorability, whereas the interpretation of the results are closely connected with subjective tests, thus integrating research and manufacturing experience of experts. Detailed study of complex evaluation of fabric’s tailorability is addressed towards the design and implementation of modern sewing technology; the automatisation of manufacture processes of sewn garments; the development of advanced manufacture management forms, and the control of the manufacturing process.
Project aims and objectives The aim of the investigation is theoretical analysis and experimental investigation of textiles formability properties. Thus, the objectives of the research are the following (1) To investigate buckling processes in textiles and to determine its regularities in uniaxial tension and in-plane compression; (2) To investigate the effect of fabric properties upon the quality of thread joints. .
to find new criterions for seam defect (puckering, slippage, etc.) quantitative evaluation;
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to describe seam puckering wave and to define external forces effecting its propagation; and to create new method for fabrics tailorability subjective evaluation.
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(3) To create original method for the evaluation and prediction of fabrics drape behaviour considering its anisotropic level and construction (location of seams) of garment.
Research deliverables (academic and industrial) From the standpoint of complex evaluation of tailorability the results of the investigations are closely connected with subjective tests, thus integrating research and manufacturing experience of experts. The obtained results are valuable for product development stages of garment manufacture and for right selection of technological treatment modes. The method to record buckling wave and to analyse its shape can be successfully applied for the investigation of textiles drapeability and furthermore in the automation of sewing processes, e.g. in the creation of robotized grips for fabric lay separation and transportation. New methods of textiles behaviour investigation together with new criterions of their tailorability evaluation will add new knowledge in material science of flexible textiles. Publications Dobilaite, V. and Petrauskas, A. (2002a), ‘‘Analysis of fabric tailorability subjective evaluation’’, Fibres & Textiles in Eastern Europe, Vol. 10 No. (3/38), pp. 53-5. Dobilaite, V. and Petrauskas, A. (2002), ‘‘The method of seam pucker evaluation’’, Material Science (Mediagotyra), Vol. 8 No. 2, pp. 209-12.
Dobilaite, V. and Petrauskas, A. (2002), ‘‘The effect of fabric structure and mechanical properties on seam pucker’’, Material Science (Mediagotyra), Vol. 8 No. 4, pp. 495-9. Domskiene, J. and Strazdiene, E. (2002), ‘‘Shearing behaviour of technical textiles’’, Materials Science (Mediagotyra), Vol. 4 No. 8, pp. 489-94. Domskiene˘e, J., Strazdiene, E. and Dapkniene, K. (2002), ‘‘The evaluation of technical textiles shape stability by image analysis’’, Materials Science (Mediagotyra), Vol. 3 No. 8, pp. 304-10. Masteikaite, V., Petrauskas, A., Sidabraite, V. and Klevaityte, R. (2000), ‘‘The evaluation of fabric mechanical and surface properties’’, Materials Science (Mediagotyra), Vol. 6 No. 2, pp. 108-12. Sidabraite, V. and Masteikaite, V. (2002), ‘‘A preliminary study for evaluation of skirt asymmetric drape’’, International Journal of Clothing Science and Technology, Vol. 14 No. 5, pp. 286-98. Sidabraite, V. and Masteikaite, V. (2003), ‘‘Effect of woven fabric anisotropy on drape behaviour’’, Materials Science (Mediagotyra), Vol. 9 No. 1, pp. 111-15.
Kettering, UK Satra Technology Centre, Satra House, Rockingham Road, Kettering, Northamptonshire NN16 9JH Andrea Wilford, CTC
Clothing comfort (intended) Other partners: Academic None Project started: – Finance/support: N/A Source of support: SATRA Keywords: Clothing, Design
Industrial None Project ends: Ongoing
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A study of the factors important for comfortable clothing and development of a method to measure and assess comfort.
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To provide the clothing industry with a practical technique to quantify the comfort of clothing, highlighting strengths and weaknesses in design and making recommendations on how to improve the comfort of the garment.
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To provide guidance in product design, product manufacture and purchasing.
Project aims and objectives The development of a Clothing Comfort Index. A study of the factors important for comfortable clothing and to develop a practical technique for the quantification of clothing comfort.
Academic deliverables Production of a Comfort Index System.
Industrial deliverables A design guide for manufacturers and retailers to enable them to source materials and provide goods which meet consumer needs.
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Publication SATRA, ‘‘Clothing-Closeup’’.
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Satra Technology Centre, Satra House, Rockingham Road, Kettering, Northamptonshire NN16 9JH. Austin Simmons, CTC Research staff: Mark Gamble
Swimwear degradations Other partners: Academic None Project started: June 1998 Finance/support: N/A Source of support: SATRA Keywords: Elastane, Swimwear
Industrial None Project ends: Ongoing
Limited wear trials were conducted on a variety of elastane-containing swimwear and examinations were carried out on a selection of failed swimwear garments. The common feature of each garment’s failure was the breakdown of the elastane component. In each case of failure it was noted that garments exhibited a particular pattern of wear. The project currently being undertaken aims to reproduce the wear patterns in a laboratory setting. It is intended to investigate the flow of swimming bath water through the fabric structure of different garments and the effect of flow restriction in preserving the life of a garment. It is also intended to develop a test rig for assessing the effects of combined chemical and mechanical action on swimwear garments.
Project aims and objectives To establish an effective means of assessing the likely wear performance of elastanecontaining swimwear. The means of assessment to incorporate a chemical and mechanical system for degrading swimwear materials.
Academic deliverables An understanding of the mechanisms which contribute to elastane failure in swimwear garments.
Industrial deliverables A test apparatus for predicting garment performance. Publication SATRA, ‘‘Clothing-Closeup’’.
Kettering, UK Satra Technology Centre, Satra House, Rockingham Road, Kettering, Northamptonshire NN16 9JH Andrea Wilford, CTC Research staff: David McKeown, Mark Gamble
Water-resistant permeable membranes Other partners: Academic
Industrial
None None Project started: – Project ends: Ongoing Finance/support: N/A Source of support: SATRA Keywords: Garments, Wear Limited wear trials have been undertaken on a series of commercially available garments which incorporate membrane structures. The results of this testing, which may be advanced to moisture and temperature recording of wear trialled products, using data-loggers, will be made available to SATRA members. Much of the work that is to be undertaken will complement SATRA’s current Comfort Index work.
Project aims and objectives To understand the mechanisms at work in water permeable membranes which are used for clothing. We aim to draw on the expertise developed in the use of such materials in footwear.
Academic deliverables To develop performance guidelines for current market products.
Industrial deliverables To provide a service to industry for the development of membrane materials (and their testing). Publication SATRA, ‘‘Clothing-Closeup’’.
Kowloon, Hong Kong The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Tel: (852) 2766 6470; Fax: (852) 2773 1432; E-mail:
[email protected] Institute of Textiles and Clothing Professor Xiaoming Tao
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Research staff: Dr Kwok-po Cheng, Yam-kuen Yip, Dr Ka-fai Choi, Sing-kee Wong, Dr Ka-kee Wong, Dr Bingang Xu, Chak-lam Leung, Charlotte Murrells, Tao Hua, Kun Yang
Novel ring yarns and production technology
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Other partners: Government Innovation and Technology Commission The Government of the Hong Kong Special Administrative Region
Industrial Central Textiles (HK) Limited Chip Tak Weaving Factory Limited Fountain Set (Holdings) Limited Perfecta Dyeing Printing and Weaving Works Limited Project ends: 31 January 2005
Project started: 1 November 2002 Finance/support: HKD 6,000,000. Source of support: Innovation and Technology Commission; The Government of the Hong Kong Special Administrative Region; Central Textiles (HK) Limited; Chip Tak Weaving Factory Limited; Fountain Set (Holdings) Limited; Perfecta Dyeing Printing and Weaving Works Limited Keywords: Residual torque, Torque free, Knitting yarn, Weaving yarn Residual torque or twist liveliness of a twisted yarn is the most prominent and fundamental factor contributing to the spirality of single jersey knitted fabrics and distortion of woven fabrics. These occur when the residual torque, developed in the component fibres of a yarn by the twisting action during the spinning process, is released. Various techniques have been used in the past to reduce or eliminate these fabric imperfections. However, several drawbacks are associated with these techniques, such as unsatisfactory fabric performance and high production costs. Therefore, a new technique has been invented to produce torque free single ring yarns with a single step on ring spinning machines. Our laboratory results show that the resultant fabrics have clear and smooth surfaces, soft handle, lower pilling and good strength, in addition to very low spirality after washing-tumble-dry cycles. Furthermore, the newly developed technology can save production cost substantially in the yarn production and fabric finishing as well as material cost in the spreading and cutting stage of garment manufacturing. The project is intended to further develop these new technologies in the laboratory and transfer them to the Hong Kong textile and apparel companies for industrial application. Optimization of the machine design, product and processing parameters in terms of product performance and cost will be carried out with measurement methods of the yarn performance and structures.
Project aims and objectives (1) Optimization of machine designs in terms of yarn performance and structures. (2) Optimization of processing parameters in terms of yarn performance and structures. (3) Optimization of product parameters in terms of yarn performance and structures.
(4) Successful industrial production of torque free single spun yarns for both weaving and knitting sectors. (5) Establishment of quality assurance procedure in the production and application of torque free single spun yarns.
Research register
Research deliverables (academic and industrial) (1) Devices for ring yarn modification . Optimized devices for producing torque single yarns for weaving and knitting: Laboratory trials: 7, 10 16 and 20Ne. Production trials: 7Ne for weaving and 20Ne for knitting. (2) Test devices and methods for modified yarns . Yarn residual torque, yarn appearance. (3) Product and process parameters . Raw material, preparation procedure, yarn count/twist, splicing/ cleaning procedure, dye/finishing. (4) Completed industrial reports . Raw materials, yarn, fabric, finishing, garment, tests, wear trial and QA procedure. Publications None
Kowloon, Hong Kong Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Apparelkey, Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Tel: (852) 27664573; Fax: (852) 23656407; E-mail:
[email protected] Prof. Edward Newton (Project Leader 2000-2003; Project Advisor: 2003-Present), Dr Jintu Fan (Project Leader: 2003-Present; Deputy Project Leader 2000-2003), Dr Calvin Wong (Deputy Project Leader: 2003-Present), Dr Roger Ng (Co-principle investigator: 2000-Present), and Dr Frankie Ng (Co-investigator: 2003-Present), Institute of Textiles and Clothing Research staff: Lydia Fung (Project Manager: 2003-Present), Jane Chung (Project Manager: 2002-2003)
Apparel manufacturing knowledge portal site (apparelkey.com) Other partners: Academic
Industrial
Clemson University, USA,
JUKI Corporation, Japan, Brother
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Nottingham Trent University, UK, Industries, JapanCornell University, National Institute of Fashion USA Technology, India, Pearl Academy of Fashion, India Project started: May 1999 Project ends: On-going Finance/support: 10 million from Innovation & Technology Commission, HKSAR, 1 million from Dean’s Reserve Fund, plus membership fees from more than 40 companies. Source of support: None Keywords: Apparelkey, Apparel knowledge, Textile knowledge, Textile technology, Clothing technology, Clothing materials, Fashion, News, Fashion shows, Fashion resources, Fashion archive, Fabric library, Garment problems, Textile problems Apparel manufacturing knowledge portal site project aimed to develop a unique knowledge portal (www.apparelkey.com) for the global apparel industry. It provides an instant access to the internationally available knowledge, expertise and information important to the entire supply and demand chain network of apparel products. The portal site is developed by the Institute of Textiles and Clothing, Hong Kong Polytechnic University under the innovation and technology fund (ITF) of the Hong Kong Special Administrative Region (HKSAR). It has been officially launched in May 2000. Portal site has the following main functional features. . Knowledge and solution provider. The portal provides guidelines and solutions for all problems in the apparel business, whether it is technical or management. .
E-encyclopedia in fashion and textiles. The portal site has a comprehensive database containing information on almost every aspect of the apparel business, such as design, clothing materials, product development, manufacturing, management, merchandising, troubleshooting, etc.
There are eight directories of the apparel information database in portal. (1) Apparel manufacturing. It is the biggest directory in the portal. ‘‘Apparel manufacturing’’ involves knowledge of apparel management, clothing materials, production sketches and procedures, technical know-how, technology and systems for the apparel industry. (2) Coloration and finishing. The section of coloration and finishing provides a dye database, the knowledge of pre-treatment, dyeing, printing, finishing, environment concerns, equipment and systems as well as test methods/specification. Besides, technical know-how of dyeing and finishing specific fibres are suggested. (3) Problems and solutions. In problems and solutions, possible solutions to manufacturing and quality problems in the apparel, fabric and dyeing business sectors are addressed. (4) Fashion resources. In fashion resources, hundreds of international Web sites for fashion news, fashion shows, brand and designers, fashion trends, fashion arts and illustrations, magazines and books, etc., are addressed. Moreover, the fabric
(5) (6)
(7) (8)
library and fashion archives provide thousands of digital fabric swatches and fashion images of international famous designers in this directory. Infrastructural knowledge. The section of infrastructural knowledge consists of various business and logistic procedures and import/export documentation. Publication and education. In publication and education, many education materials of different disciplines, journals and conference paper of worldwide textiles and fashion universities can be found. Moreover, training programs and seminar information from other institutes or association are posted in this section. Others. Various deliverables of textile and clothing development projects supported by the Innovation and ITF can be found in this directory. Hot topics. Hot topics displays newly developed technology, information and the recent events in the apparel and textiles industry regularly.
Project aims and objectives . .
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provides instant access to worldwide apparel and textile knowledge. transfers apparel knowledge to the industry through Internet platform, trainings and seminars. provides teaching and learning materials for apparel/textile related subjects.
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locates and catalogues fashion trend and forecasting materials available in the industry.
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develops a fabric library and fashion archive for design inspiration.
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provides a virtual apparel community for knowledge sharing. provides up-to-date technologies and industrial information for the textile industry. provides a quick and efficient navigation tool of worldwide apparel information.
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Research deliverables (academic and industrial) . .
An electronic encyclopedia in fashion and textile on Internet. An intelligent search engine for apparel and textile related subjects.
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A digital fabric library with various classification.
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A fashion archive with digital fashion photos of international brands. Teaching and learning package for different apparel textile subjects by using apparelkey. The package includes online presentation and e-learning CD-Rom. A virtual discussion forum for knowledge sharing and transfer on the portal.
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Hot topics with up-to-date market news online.
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Trainings and seminars delivered by apparelkey. Problems and solution for textile and garment manufacturing problems.
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Publications None
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Kowloon, Hong Kong The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Tel: (852) 2766 6470; Fax: (852) 2773 1432; E-mail:
[email protected] Prof. Xiaoming Tao, Institute of Textiles and Clothing Research staff: Prof. Chung Loong Choy, Prof. Xiao Ming Tao, Dr John Xin, Dr Yau Shan Szeto, Dr Chun Wah Marcus Yuen, Prof. Lai Wah Chan Wong, Prof. C Surya, Dr Pei Li, Dr Mei Yi Leung, Dr Willy Chan, Dr C L Mak, Dr Pu Xue, Dr Cheuk Ka-leung, Dr Sun Xiao-hong, Dr Cheng Xiao-yin, Dr Ye Wei-jun, Ms Tsang hing-yee, Miss Kong Yee-yee, Dr Deng Jian-guo, Ms Deng Hua, Miss Xianqiong Chen, Mr Bin Fei, Mr Jin Zhang
Nanotechnology Center for Functional and Intelligent Textiles and Apparel Other partners: Government Innovation and The Government of the Hong Kong Special Administrative Region
Industrial Bondex International (HK) Limited, Technology Commission Cha Textiles Limited, Glorious Sun Holdings Limited, Sun Hing Elastic & Lace Fty. Ltd, Wah Tai Piece Goods Ltd, Link Dyeing Works Limited Project ends: 31 May 2006
Project started: 1 June 2003 Finance/support: HKD 14,481,762 Source of support: Innovation and Technology Commission, The Government of the Hong Kong Special Administrative Region, Bondex International (HK) Limited, Cha Textiles Limited, Glorious Sun Holdings Limited, Sun Hing Elastic & Lace Fty. Ltd, Wah Tai Piece Goods Ltd, Artex Fashions (Asia) Ltd, Link Dyeing Works Limited Keywords: Nanotechnology, Functional and intelligent, Textiles and apparel Nanotechnology Center established specifically for the textile and apparel industry in Hong Kong is one of the five largest exporters of textiles and apparel products in the world. This Nanotechnology Center will further strengthen the competitiveness of the industry by achieving the four-fold objectives listed in the following. Nanotechnology has been regarded as an essential enabling technology for the next generation of fiber based functional and intelligent textile materials and apparel. Our multidisciplinary research team actively worked in the area and demonstrated several new technologies with very promising industrial application potentials in the past. The 3-year program will extend our past research activities and develop the fundamental research into technology for industry. The program of the center will focus on nanofinishing systems and nanotechnology for intelligent textiles and apparel products.
The projects are devoted to investigation and development of environmentally friendly and effective nano-finishing processing systems for textile fabrics and garments, including surface polymerization system, systems for precise manufacture of nanoparticles, nano-scaled polymer bulk treatment system and printing/chemical vapor deposition system. These newly-developed processing systems will be used for producing various functional or smart/intelligent products, such as sensing textiles and apparel as well as nano-structured photonic fibers and films.
Project aims and objectives The main objectives for the Nanotechnology Center for Functional and Intelligent Textiles and Apparel are: (1) to provide research and develop infrastructure for textiles and apparel related nanotechnology; (2) to develop new nano-materials, new processing technologies and products for high-value-added functional and intelligent textiles and apparel; (3) to facilitate technology transfer to and collaboration with the industry; and (4) to provide training to postgraduate students and company technical personnel.
Research deliverables (academic and industrial) (1) Optimized surface polymerization systems for UV-blocking, stain-, oil-, waterrepellent, anti-bacteria finishing of cotton, polyamide and polybenzimidazole fabrics, nano-pigment coloration system. (2) Customer tailored synthesis systems for precise size and sensitivity control of nano-structures for functional finishing and photonic fibers. (3) Optimized fabrication system for conductive textiles sensing devices for strain, temperature and relation humidity, and a prototype of electrical sensing apparel. (4) Prototypes of photonic fibers that can regulate light intensity and color and a prototype of two-colored display fabric made from such fibers. In addition, the center will train several postgraduate research students, conduct training courses for company personnel, and carry out other promotion activities, etc. Publications None Journal papers Daoud W.A. and Xin, J.H. (2004), ‘‘Nucleation and growth of anatase crystallites on cotton fabrics at low temperatures’’, Journal of the American Ceramic Society, Vol. 87 No. 5, pp. 953-55. This work was reported in Nature as the headline news, entitled ‘‘Clothes launder own fabric’’, on 14 June 2004. Law temperature sol-gel processed photocatalytic titania coating, Journal of Sol-Gel Science and Technology, Vol. 25, 2004, pp. 25-29. Leung, M.Y., Tao, X.M., Yuen, C.W.M. and Kwok, W.Y. (n.d.), ‘‘Strain sensitivity of polypyrrole-coated woven fabrics under unidirectional tensile deformation’’, Textile Research Journal (in press). Wong, Y.C., Szeto, Y.S., Cheung, W.H., McKay, G. (2003), ‘‘Equilibrium studies for acid dye adsorption onto chitosan’’, Langmuir, Vol. 19 No. 19, pp. 7888-94. Xiaohong Sun, Xiaoming Tao, Jianguo Deng, Kai Cheong Kwan, (n.d.), ‘‘Blue and yellow random lasers in colloid solutions and PMMA films doped with nano-particles and laser dyes’’, Optics Letters (in press).
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Xin, J.H., Daoud, W.A. and Kong, Y.Y. (2003), ‘‘A new approach to UV-blocking treatment for cotton fabrics’’, Textile Research Journal, Vol. 74 No. 2. Xue, P., Tao, X.M., Yu, T.X., Kwok, K. and Leung, S. (2003), ‘‘Electromechanical behavior and mechanistic analysis of fibers coated with electrically conductive polymer’’, Text. Res. J. (in press). Conference papers Kwok, W.Y., Cheng, X.Y., Tao, X.M., Yuen, C.W., Leung, M.Y. and Xue, P. (2004), ‘‘Effect of liquids on the electrical resistance of polypyrrole-coated fabrics’’, paper presented at the 4th AUTEX Conference, Roubaix, 22-24 June 2004. Xiaohong Sun, Xiaoming Tao, Jianguo Deng, Kai Cheong Kwan (2004), ‘‘Random laser of colloid solution containing TiO2 nanoparticle and C480’’, paper presented at the 2004 FiO/LS Meeting, Rochester, NY. Xue, P. and Tao, X.M (2004), ‘‘Multi-scale investigation on fibres coated with electrically conductive polymer’’, paper presented at the 4th AUTEX Conference, Roubaix, 22-24 June 2004.
Kowloon, Hong Kong The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Tel: (852) 2766 6470; Fax: (852) 2773 1432; E-mail:
[email protected] Prof. Xiaoming Tao, Institute of Textiles and Clothing Research staff: Dr Kwok-po Cheng, Mr Yam-kuen Yip, Dr Ka-fai Choi, Mr Sing-kee Wong, Dr Ka-kee Wong, Dr Bingang Xu, Ms Suk-yee Chan, Ms Charlotte Murrells, Mr Tao Hua, Mr Kun Yang
Novel ring yarns and production technology Other partners: Government Innovation and Technology Commission, The Government of the Hong Kong Special Administrative Region
Industrial Chip Tak Weaving Factory Limited, Central textiles (HK) Limited, Fountain Set (Holdings) Limited, Perfecta Dyeing Printing & Weaving Works Limited Project ends: 31 January 2005
Project started: 1 November 2002 Finance/support: HKD 6,000,000 Source of support: Innovation and Technology Commission, The Government of the Hong Kong Special Administrative Region, Central Textiles (HK) Limited, Chip Tak Weaving Factory Limited, Fountain Set (Holdings) Limited Perfecta Dyeing Printing & Weaving Works Limited Keywords: Residual torque, Torque free, Nu-torque, Knitting yarn, Weaving yarn Residual torque or twist liveliness of a twisted yarn is the most prominent and fundamental factor contributing to the spirality of single jersey knitted fabrics and distortion of woven fabrics. These occur when the residual torque, developed in the component fibres of a yarn by the twisting action during the spinning process, is
released. Various techniques have been used in the past to reduce or eliminate these fabric imperfections. However, several drawbacks are associated with these techniques, such as unsatisfactory fabric performance and high production costs. Therefore, a new technique has been invented to produce torque free singles ring yarns with a single step on ring spinning machines. Our laboratory results show that the resultant fabrics have clear and smooth surfaces, soft handle, lower pilling and good strength, in addition to very low spirality after washing-tumble-dry cycles. Furthermore, the newly developed technology can save production cost substantially in the yarn production and fabric finishing as well as material cost in the spreading and cutting stage of garment manufacturing. The project is intended to further develop these new technologies in the laboratory and transfer them to the Hong Kong textile and apparel companies for industrial application. Optimization of the machine design, product and processing parameters in terms of product performance and cost will be carried out with measurement methods of the yarn performance and structures.
Project aims and objectives (1) Optimization of machine designs in terms of yarn performance and structures. (2) Optimization of processing parameters in terms of yarn performance and structures. (3) Optimization of product parameters in terms of yarn performance and structures. (4) Successful industrial production of torque free single spun yarns for both weaving and knitting sectors. (5) Establishment of quality assurance procedure in the production and application of torque free single spun yarns.
Research deliverables (academic and industrial) (1) Devices for ring yarn modification: optimized devices for producing torque single yarns for weaving and knitting . laboratory trials: 7, 10 16 and 20Ne, and .
production trials: 7Ne for weaving and 20Ne for knitting.
(2) Test devices and methods for modified yarns: yarn residual torque and yarn appearance. (3) Product and process parameters: raw material, preparation procedure, yarn count/twist, splicing/cleaning procedure and dye/finishing. (4) Completed industrial reports: raw materials, yarn, fabric, finishing, garment, tests, wear trial and QA procedure. Publications A method for improvement of denim fabric appearance by using Nu-torqueTM singles ring spun yarns, Proceedings of the Textile Institute 83rd World Conference, Shanghai, 23-27 May 2004, pp. 285-89. Developing Nu-torqueTM singles ring yarn to reduce spirality of singles jersey knitted fabric, Proceedings of the Textile Institute 83rd World Conference, Shanghai, 23-27 May 2004, pp. 515-18. Development of Nu-torqueTM singles ring yarns for industrial application, Proceedings of the Textile Institute 83rd World Conference, Shanghai, 23-27 May 2004, pp. 482-84. Nu-torqueTM singles ring yarn and its production technology, Proceedings of the Textile Institute 83rd World Conference, Shanghai, 23-27 May 2004, pp. 494-96.
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Production of torque-free singles ring yarn, Textiles Asia, August 2003, pp. 58-60. Study of yarn snarling in Nu-torqueTM singles ring yarns, Proceedings of the Textile Institute 83rd World Conference, Shanghai, 23-27 May 2004, pp. 401-4.
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Ksar-Hellal, Tunisia Unite´ de Recherches Textiles, ISET de Ksar-Hellal, 5070 Ksar-Hellal, Tunisie, 00216 Tel: 73 475900; Fax: 73 475163; E-mail:
[email protected] Dr Ivelin Rahnev, Department of Textiles
Mechanical module of spinning CAD Other partners: Academic
Industrial
None None Project started: 5 May 1998 Project ends: None Keywords: Thread mechanics, tensorial calculations, Elastic energy maximum, Potential minimum Among the multitude of methods, for the design of the threads, is distinguished the analytical modelling carried out by virtual simulation of the technological product and its behaviour in a describable mechanical medium. In this work, we offer a solution to the problem to determine the maximum elastic strength of the thread according to its twisted structure. There are two assumptions, which select and specify the applied mathematical apparatus. The structural assumption regards the thread like a concentric fibrous combination and like a helical formation obtained by technological treatment. The mechanical assumption regards the thread as a heterogeneous and anisotropic body built by autonomous solids, such are the fibres. The mechanical analysis envisages a consecutive increase in the external forces and calculation of the corresponding reactions in the limits of the elastic proportionality. The increase in the torsion conducts to the modification of the spatial situations of the fibres and common structure of the thread. The resolution of the mechanical exercise of the curvilinear continuums requires the application of the mathematical formulas constituting the apparatus of calculations of the method. The differential geometry describes the thread structure and the tensorial calculations solve the mechanical problem. The logical decisions and the formulas meet by an algorithm whose numerical realization makes practically possible the resolution of the exercise.
Project aims and objectives Considering the spinning CAD as a target, the energy analysis of the strained thread constitutes the mechanical module of the analytical application. In addition, the study of
the elastic behaviour has an educational destination in the discipline of the design of the linear textile products. The analytical functional calculus of the elastic properties of thread in dependence of the properties of fibres and torsion represents the principal result. This mechanical model does not consider the influence of the interactions of fibres on the strength of the thread. The prospects for modelling envisage the launching of the real structure of the thread; fibrous morphology and disposition, as well as the dynamic model of the compression bringing of the radial efforts of fibres. Publications Rahnev, I., (1998), Optimized technologies of the combined twisted yarns – Worsted - type, Doctoral thesis, TU-Sofia, Sofia. Rahnev, I. et al. (2002), ‘‘A volumetric method to conceive textile twisted threads, paper presented at the 2nd AUTEX Conference, Bruges’’, 1-3 July 2002, (presented by poster). Rahnev, I., (2003), ‘‘Vectorial description of a twisted textile thread’’, paper presented at the 3rd AUTEX Conference, Gdansk, 25-27 June 2003 (presented by poster). Rahnev, I., (2004), ‘‘Energy analysis of the strained textile thread’’, paper presented at the 4th AUTEX Conference, Roubaix, 22-24 June 2004 (presented by poster).
Kyeongsan, Korea School of Textiles, Yeungnam University, 214-1 Daedong Kyeongsan 712-749, Korea Tel: 82-53-8102771; Fax: 82-53-8125702; E-mail:
[email protected] Seung-Jin Kim Textile Processing Laboratory Research staff: K.S. Park, S.B. Sim, S.Y. Kim, M.Y. Park
Development of easy-care worsted fabric using drawn worsted yarns Other partners: Academic
Industrial
None None Project started: 1st March 2002 Project ended: 28 February 2003 Finance/support: US$ 50,000 Source of support: Ministry of Science and Technology Keywords: Easy-care, Drawn worsted yarns, Anti-shrinkable, Drawing temperature
Twist,
This project covers development of easy-care worsted garment using drawn worsted yarns. For this purpose, various chemical treatment technology are applied for marking drawn worsted yarns. The chemical treatment technology includes
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anti-shrinkable technology and various chemical agent treatment recommended by WRONZ in New Zealand. The optimum processing condition such as yarn twist, drawing temperature, drawing time and yarn count on the drawing machine for easy care clothing are surveyed and analysed. Finally the physical properties of garment are measured and discussed with the various processing conditions of draw worsted yarns.
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Project aims and objectives .
Development of antipilling worsted drawn yarns.
.
Development of easy-care worsted fabrics and garment.
Academic deliverables . .
One or more graduate theses. Presentation to seminar as a paper.
Industrial deliverables .
Manufacturing procedures for implant for making textile goods.
Publication Lee, D.H., Kim, S.J. and Seo, O.K., (2002), ‘‘Changes in the properties of wool fibres, yarns and fabrics by finedrawing of worsted yarns’’, Extended Abstracts of the 31st Textile Research Symposium at Mt. Fuji, Textile Science Research Group in Text. Mac. Soc. of Japan, August, 2002, p. 24.
Kyeongsan, Korea School of Textile & Fashion, Yeungnam University, 214-1 Daedong, Kyeongsan, Korea Tel: 82-53-8102536; Fax: 82-53-8125702; E-mail:
[email protected] Seung-Jin Kim, Textile Processing Lab Research staff: B.K. Seo, S.D. Hong, S.B. Sim
Development of knit and woven fabrics using drawn worsted yarns and their drawing system Other partners: Academic
Industrial
None O.K. Seo Project started: 1 July 2001 Project ended: 30 June 2003 Finance/support: US$24,600 Source of support: Ministry of Commerce, Industry & Energy Keywords: Worsted drawing yarns, Silk-like worsted yarn, Drawing ratio, Heating temperature This project surveys manufacturing technology of the silk-like worsted yarns and fabrics, and includes development of the drawing system of worsted staple yarn.
Using this drawing system, optimum drawing ratio and temperature are decided. Fine staple worsted yarns (100 Nm) are made from 66 Nm and 52 Nm staple worsted yarns using the drawing system. The optimum conditions in the drawing process such as drawing ratio and temperature for linen-like and silk-like knitted fabrics are decided through various experiments. The physical and mechanical properties of the specimens of the yarns and knitted fabrics are measured and discussed with various processing conditions in the drawing system. The yarn physical properties measured are thermal shrinkage, snarl index, bending rigidity, torsional rigidity, and fabric mechanical properties are tensile, bending, shear, compression and surface.
Project aims and objectives Objectives of this research are to develop the linen-like and/or silk-like worsted yarn for knitted fabric. Also this project aims at the development of drawing machinery for worsted yarns, which is available to control draw ratio and drawing temperature, and includes the determination of the optimum twist condition.
Academic deliverables .
one or more graduate theses;
.
presentation to seminar as a paper.
Industrial deliverables .
manufacturing procedures for implant for making textile goods.
Publications None
Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 M. Nakamura, T. Matsuo and M. Nakajima, Department of Polymer Science and Engineering
Analyses of tuft forming at bale opener Other partners: Academic None Project started: April 1994 Keywords: Simulation, Tuft, Yarns
Industrial None Project ends: To be continued
The purpose of the bale opener is to open the bale and to produce fine and uniform size tufts for the sequential process of yarn spinning. The opening mechanism at the tuft
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forming process was investigated, based on theoretical analyses of macroscopic mass balance and of tooth edge locus, and two experimental model tests. A theoretical model of microscopic mass balance was presented to simulate the opening process. Numerical calculations for several process conditions were carried out using the experimental results of model tufting studies. These simulation results have proved to be a good tool for better understanding of the process. The effect of good tuft forming by bale openers on the processibility of the sequential process of yarn spinning and the quality of yarn thus produced was also investigated through production tests of real mills.
Project aims and objectives (1) To clarify the opening mechanism at the tuft forming process of the bale opener. (2) To establish simulation technology for the processing. (3) To investigate the effect of good tuft formings by bale openers on the processibility of the sequential process of yarn spinning, and the quality of yarn thus produced. (4) To pursue means towards the improvement of the bale opener. Industrial deliverables Refer to the publication. Publication Nakamura, M., Matsuo, T. and Nakajima, M. (1997), Journal of Textile Machinery Society.
Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 M.N. Suresh and T. Matsuo, Department of Polymer Science and Engineering
Development of total material design system of woven fabrics for apparel use Other partners: Academic
Industrial
M. Nakajima
T. Harada M. Inoue Project started: September 1994 Project ends: To be continued Keywords: Apparel, CAD, Fabric, Woven fabrics Although much research has been done on colour/pattern designing related to fabric appearance and fashion, material design technology for apparel fabrics is still in the developmental stage. A review shows that the past 20 years have witnessed the
efforts towards trial construction of partial design systems and conceptualization of total material design logic. The main aim of this part in the series of our studies is to construct a fundamental logical structure of the computer-assisted total material design system for general apparel woven fabrics. The main components of the structure thus constructed and their functions are defined. The system consists of three sections: a user interface, the five design stages starting from conceptual design up to the detailed manufacturing design, and different types of databases which support the design stage. The format and contests of important system components are explained with examples. The executional logic of the system and its flow is also presented with a methodology to find a suitable design solution. Utilization of a ‘‘reference sample’’ has been introduced to simplify the design procedure. Some detailed case studies to illustrate application of this system have been carried out. The frame of the computer system is also being developed.
Project aims and objectives To develop a ‘‘computer-assisted total material design system of woven fabrics for apparel use’’.
Academic deliverables Refer to the publications. Publications Matsuo, T. and Suresh, M.N. (1997), Textile Progress. Suresh, M.N., Matsuo, T. and Nakajima, N. (1997a), Proceedings of IV Congress ATC, Taipei. Suresh, M.N., Matsuo, T. and Nakajima, N. (1997b), Journal of Text. Mac. Soc., Vol. 50, T146. Suresh, M.N., Matsuo, T. and Nakajima, N. (1997c), Proceedings of 25th Textile Research Symposium, Mt Fuji, Japan. Suresh, M.N., Matsuo, T. and Nakajima, N. (to be published), Journal of Text. Mac. Soc.
Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 D.A. Alimaq and T. Matsuo, Department of Polymer Science and Engineering
Sensory measurements of fabric hand/mechanical properties: part I – worsted fabrics; part II – knitted fabrics Other partners: Academic
Industrial
M. Nakajima T. Harada Project started: April 1993 Project ends: To be continued Keywords: Fabric, Knitwear, Sensory measurement, Worsted
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Systems of instrumental method for measuring fabric hand have been fairly successfully developed like KES and its basic way has been well established. On the contrary, systems of sensory method have remained controversial. In this paper, a practical sensory method is proposed on the basis of analogy to sensory colorimetry. Measurement of two kinds of worsted fabrics was conducted by making use of this sensory method. The effective range and the accuracy of this method are discussed based on the data of the above measurement. It is shown that, if a suitable control (temporary standard) sample is chosen, the instrumental values of bending rigidity, thickness and compressibility of worsted fabrics can be estimated by this sensory method with an error of around 20 per cent. The sensory measurement of main mechanical properties of knitted fabrics is now being conducted. Very good results have been obtained so far on these points.
Project aims and objectives (1) To develop handometry for fabrics by sensory method. (2) To investigate the effectiveness of sensory measurement of fabric mechanical properties.
Academic deliverables Refer to the publications. Publications Alimaa, D., Matsuo, T., Nakajima, M. and Takahashi, M. (1997), Proceedings of the 25th Textile Research Symposium, Mt Fuji, Japan. Matsuo, T., Harada, T., Saito, M. and Tsutsumi, A. (1995), Journal of Textile Machinery Society, Vol. 48, T244.
Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 T. Matsuo and Ryuichi Akiyama, Department of Polymer Science and Engineering Research staff: Fumitaka Okamoto
Surface mechanical properties of fabrics in terms of hand: part I - Shingosen fabrics Other partners: Academic M. Kinoshita
Industrial None S. Mukhopadhyay K. Izumi
Project started: April 1993 Project ends: To be continued Keywords: Fabric, Woven fabrics . A measurement method for surface mechanical properties (especially frictional properties) of fabrics in the relation with their surface hands has been developed. .
The effects of the friction probe form, probe velocity, probe weight and the selection of suitable parameters representative of frictional properties are investigated.
.
The relationships between surface hand and surface mechanical properties for Shingosen fabrics have been clarified, in comparison with silk-like fabrics and silk fabrics.
.
An attempt is also made to simulate frictional properties by certain theoretical structure models of woven fabrics.
Project aims and objectives (1) To develop a measuring method for surface mechanical properties (especially frictional properties) of fabrics. (2) To find the features of these properties and the relationships between hand and these properties. (3) To simulate frictional properties theoretically on the basis of fabric structure. (4) To analyze Shingosen fabrics from the viewpoint of (2).
Academic deliverables Refer to the publications. Publications Akiyama, R. et al. (1995), Journal of Textile Machinery Society, Vol. 48, T153. Kinoshita, M. et al. (1997), Journal of Textile Machinery Society, Vol. 50, T187.
Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 K. Kawabe and T. Matsuo, Department of Polymer Science and Engineering
Tow opening of reinforcing fibre and its application for thermoplastic composites Other partners: Academic
Industrial
None S. Tomoda Project started: June 1994 Project ends: To be continued Keywords: Fibre, Pneumatics, Thermoplastics Impregnation of matrix resin into fibre is further facilitated by using opened tow rather than compacted tow. A new processing system for spreading tow which is composed of
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plural rolls and a pneumatic device was introduced. Preliminary opening is conducted by threading it on plural fixed rolls under a suitable initial tension. Transverse air of suitable flow velocity is then applied to the tow of steadily sagged form. Some experimental results for carbon fibre and glass fibre, and theoretical analysis on these opening mechanisms were presented. The roles of roll part and pneumatic part were also discussed. Thus opened tows have been applied to the impregnation of thermoplastic composites. Significant effect of the tow opening on the facilitation of matrix impregnation has been proved.
Project aims and objectives (1) To develop tow opening of reinforcing fibre with high efficiency and low cost. (2) To analyze the opening mechanism. (3) To apply the tow opening technology to the production of thermoplastic composite prepreg. Academic deliverables Refer to the publications.
Industrial deliverables At present, laboratorial scale. Publications Kawabe, K., Matsuo, T. and Tomoda, S. (1997), Proceedings of 42nd International SAMPE, Vol. 42, p. 65. Kawabe, K., Tomoda, S. and Matsuo, T. (1997), Journal of Textile Mac. Soc., Vol. 50, T68.
Leeds, UK School of Design, Leeds University, Leeds, LS2 9PR, UK Tel: 0113 2333711; Fax: 0113-2333704; E-mail:
[email protected] CTT, Mechatronics Research Group Farzad Jahanshah, Duncan Borman Research staff: H. Gaskell (Mechanical Eng. Dept), Dr A.A. Dehghani (Textiles Dept), Professor T. King (Honorary Professor)
Mechatronics and machine vision for online fault detection and rectification in inkjet printing Other partners: Academic
Industrial
None Project started: September 2000
Dorma, Zaphire Flag and Banners, M & S Project ended: August 2003
Source of Support: EPSRC Keywords: Inkjet printing, Vision system, Machine vision, Textiles inkjet printing Implications for inkjet technology to be modified to print high-quality colour images on a wide range of surfaces have currently been recognized. This is particularly apparent for wide format designs. Using specialist inks, short run designs can be inkjet printed onto everything from floor coverings to textiles and ceramics. Speed and reliability are two important factors that can be developed to improve production printer results. Nozzle blockage can be a serious problem when using exotic inks and media. Imperfect prints mean wasted time, materials and energy and are very expensive. This has been seen particularly in the textile industry where attempts to inkjet print textiles at high speed with specialist inks have proven problematic. Current research addresses these problems with the emphasis being on the development of a vision and control system that can detect and rectify faults online. Using two scanners at either side of each colour printhead and an appropriately tuned illumination source, live images can be processed and analysed to detect the blocked nozzles. Results can be reported to a control system for online rectification. Colour line scan technology is still expensive in comparison to the technology used in desktop scanners. Work is being undertaken to develop hybrid-scanning devices that use the low cost modular technology, incorporated in scanner design, for monitoring inkjet printing. The developed system uses a novel approach to detect faults in real time. Low-cost modular scanner technology makes it possible for each printhead to have its own localized detection system.
Project aims and objectives The approach taken is based on the concept of checking the printed textile during the printing process and using a flexible machine topology that allows errors to be recovered in real time without wastage. Parallel developments of low cost vision systems for digitally printed textiles have provided a means to check textiles during printing and to take corrective measures when necessary. The potential for a high-speed high-reliability system is greatly increased with the inclusion of a vision and control system
Research deliverables (academic and industrial) .
Printing industries;
.
Micro detecting applications; Real time machine vision;
. .
Textiles inkjet printers manufacturer.
Publications Borman, D., Jahanshah, F., Dehghani, A.A., King, T. and Dixon, D. (2002), ‘‘Mechatronics system topology and control for high-speed, high-reliability textile inkjet printing’’, Mechatronics 2002, Holland.
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Borman, D.J., Jahanshah, F., Dehghani, A.A., King, T. and Gaskell, P. (2002), ‘‘Online vision system for ink-jet printed media’’, IS & T’s NIP18, International Conference, October 2002, San Diego, California, USA, pp. 562-7. Jahanshah, F., Borman, D., Dehghani, A.A., King, T. and Dixon, D. (2002),‘‘Mechatronics and machine vision for online fault detection and rectification in inkjet printing’’, Mechatronics 2002, Holland. Jahanshah, F., Borman, D., Dehghani, A.A., King, T. and Gaskell, P. (2002), ‘‘Real-time detection and rectification for ink-jet printing of specialist wide format surfaces’’, Machine Automation International Conference, September 2002, ICMA Finland, pp. 259-66.
Liberec, Czech Republic Technical University of Liberec, Faculty of Textiles, 461 17 Liberec, Ha´lkova 6, Czech Republic Tel: 00420 48 25441/25462 Professor Stanislav Nosek, Department of Weaving Technology (newly renamed Department of Mechanical Technologies in Textiles) Research staff: Ingolf Brotz, Petr Tumajer, Ales˘ Cvrkal and Jaroslava Richterova´
Research of shocks (impacts) and vibrations excited by technological processes in weaving and other textile machines Other partners: Academic
Industrial
None None Project started: 1998 Project ends: – Finance/support: Kc˘1,900,000 (estimated) Source of support: Applied with the Grant Agency of the Czech Republic (GACR) (or will be worked out as an internal project of TU Liberec) Keywords: Textiles, Weaving Many textile technological processes, especially the weaving process, produce during each working cycle a row of force impulses which affect the processed textile material as well as the machine. The impact of these impulses causes the propagation of delayed deformation of both media – textile material and machine parts – so that the deformation can return to the source of impulse through several paths. The result is that the next impulse changes with respect to the previous one and the technological process may become unstable or steadied in a different regime to that originally set on the producing system, etc. That can affect the quality of the produced good. At the same time, the excited shocks and vibrations in the system material – working machine – can be emitted in the air or into the floor as noise or vibrations on a wide band of frequencies and can affect the workers as well as the environment and the building. The problems of arising propagation and damping of technologically affected impulses and vibrations will be studied first on the process of fabric forming of the loom as the effect of beat-up, of shedding, back rest motion, functioning of fabric take-up and
warp let-off devices. Later, the research should be widened to further textile processes – winding, warping, etc.
Research register
Project aims and objectives The aim of the research is mainly to explain why and how the produced goods on textile machines often differ from the structure and quality of the goods originally (theoretically) set on the machine. One possible reason may be the deviated motions of textile material and machine parts caused by impulses and vibrations in these compliable and massive media, which impulses result from the technological process itself. The research will start with the weaving machines.
Academic deliverables A new theoretical view on the stability of technological processes as processes of propagation and returning (feedback) of impulses and vibrations in compliable textile material and machine parts in textile technologies. The research will also be explored as the source of problems for training of PhD students.
Industrial deliverables Results will be applied in textile machines design. Results concerning the propagation of vibrations into the air and into the floor will be used to research the protection of persons as well as buildings against damage by noise and vibrations. Publications Hanzl, J. (1995), ‘‘The behavior of the back rest on the loom’’, Poster and Book of Transactions, International Conference of Young Textile Science, TU Liberec. Nosek, S. (1994a), ‘‘The dynamics of fabric forming at high weaving rates’’, Industrial Journal of Fibre & Textile Research, Vol. 19 No. 3. Nosek, S. (1994b), ‘‘The dynamics of fabric forming on the loom and problems of weavability at high weaving rates’’, World Textile Conference, Huddersfield. Nosek, S. (1995a), ‘‘Dynamics and stability of beat-up’’, Fibers & Textiles in Eastern Europe, Vol. 1 No. 1, Lodz. Nosek, S. (1995b), ‘‘Feedback phenomena in textile processes’’, International Conference of Young Textile Science, TU Liberec. Nosek, S. (1995c), ‘‘Mechanics and rise of stop marks and structural bars in fabrics’’, Poster and Book of Transactions, IMTEX ’95, Lodz, Polsko. Tumajer, P. (1995), ‘‘Dynamics of start of a weaving loom and the possible rise of transition marks’’, Poster and Book of Transactions, International Conference of Young Textile Science, TU Liberec.
Liberec, Czech Republic Technical University of Liberec, Halkova 6, 461 17 Liberec, Czech Republic Tel: +420 48 5353498; E-mail:
[email protected]
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Zdene˘k Ku˚s, Head of Department, Department of Clothing Research staff: Jir˘´ı Militky´, Otakar Kunz, Antonı´n Havelka, Dagmar Ruz˘ic˘kova´, Vladimı´r Bajzı´k, Jana Zouharova´, Andrea Halasova´, Viera Glombı´kova´, Blaz˘ena Musilova´, Petra Koma´rkova´, Jaroslav Beran, Josef Olehla, Miroslav Brzezina
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Organoleptic properties of three-dimensional textile objects Other partners: Academic
Industrial
Other departments of the university Project started: 1 January 1999 Project ends: 31 December 2004 Finance/support: £70,000 Source of support: Ministry of Education, Technical University of Liberec Keywords: Fabric properties, Comfort, Handle, Thermal The research will be performed in the following areas:
Surface properties of textile formations, non-linear deformations of fabric .
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Computer simulation of impact surface parameters of the planispheric textile fabric to their chosen macroscopic properties. This is made with the aim of predicting and optimising these properties. Provide evolution for new measurement methods in this area. Computer simulation of non-linear deformation of the planispheric textile fabric with ballast, for example, by means methods of final elements.
Physiological properties of comfort textile formations, fabric handle .
Development of new methods for evaluation of physiology comfort and fabric handle. The following application progressive computers method. For example, the neural networks or the artificial intelligence for comparing objective new parameters with empirical find out values.
Thermal properties of textiles sandwich materials .
.
Development of new devices for measurements of thermal properties of textile composites and textiles sandwich materials, with special regard to these materials applied in extreme conditions. Objectification of the property evaluation of textile materials from the point of view of comfort and hygienic properties.
Project aims and objectives New methods of measurement, computer simulation of fabric deformation, etc.
Publications Halasova, A. and Glombı´kova´, V. (2000), ‘‘Problem of simulation working breakdown apparel production in program accessories witness’’, Proceedings of Textile Science 2000, Liberec, Czech Republic, 12-16 June, ISBN 80-7083-409-9, p. 375. Hes, L., Li, Y. and Kus, Z. (1999), Ochranna´ textilie proti sa´lavemu teplu a ochranny´ oblek z te´to textilie, Czech Republic Patent PV1673-99. Kus, Z. (1999), ‘‘Investigation of seam pucker with help of image analysis’’, Proceedings of the 5th Asian Textile in the 21st Century Conference, Kyoto, Japan, p. 333. Kus, Z. and Koma´rkova´, P. (2000), ‘‘Computer simulation of apparel production’’, Vla´kna a Textil, Vol. 7 No. 2, ISSN 1335-0617, pp. 113-16. Kus, Z., Glombı´kova´, V. and Brada´cova´, H. (2000), ‘‘Application of image analysis and neural network for the evaluation of seam pucker’’, Proceedings of Textile Science 2000, Liberec, Czech Republic, 12-16 June, ISBN 80-7083-409-9, pp. 391-3. Trung, N.C. and Kus, Z. (1999), ‘‘Computer simulation of sewing needle heating’’, Progress in Simulation, Modeling, Analysis and Synthesis of Modern Electrical and Electronic Devices and Systems, World Scientific and Engineering Society Press, Athens, Greece, ISBN 960-8052-08-4, pp. 166-70.
London, UK King’s College London, Department of Mechanical Engineering, King’s College, University of London, Strand, London WC2R 2LS, UK Tel:+44(0)2078482321; Fax: +44(0)2078482932; E-mail:
[email protected] Jian S Dai Research Staff: Honghai Liu
Robotic ironing Other partners: Academic
Industrial
None Paul M. Taylor Project started: June 2002 Project ended: April 2003 Finance/support: £65k Source of support: EPSRC Keywords: Robotic ironing, Handling and manipulation, Folding and unfolding, Garment handling, Gripping devices This is a collaborative project bringing two universities for a period of 8 month investigation with expertise in textile and garment handling and in flexible material manipulation and robotic gripper technology. The research programme looked into the dullest domestic chore which has not been changed for many hundreds of years, examined the existing techniques and required disciplines for automating the ironing process, established the detailed functionality of a robotic ironing device, and determined in detail the research needed to carry out the work. Successful results have been produced with four accepted international conference papers, six journal papers in preparation and 20 internal reports. A workshop with potential industrial partners was
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held at the end of the project and a number of presentations were given with technology studies into robotic ironing. The research further resulted in three proposals in preparation for submission to EPSRC and European Commission, and generated substantial impact on the advancement of robotics application to domestic tasks and aroused huge media interest including articles in The Engineer and in national newspapers.
Project aims and objectives The aims and objectives of this are: (1) establish the detailed functionality of a robotic ironing device; (2) examine the existing techniques and required disciplines to solve the technical problems; (3) determine in detail the research needed to carry out the work, the team to do it and the resource required; (4) identify potential industrial collaborators who might provide commercial follow-through; and (5) draft research proposal(s) to fund the research programme.
Research deliverables (academic and industrial) (1) Establish the detailed functionality of a robotic ironing device. (2) Examine the existing techniques and required disciplines to solve the technical problems. (3) Determine in detail the research needed to carry out the work, the team to do it and the resource required. (4) Identify potential industrial collaborators who might provide commercial follow-through. (5) Draft research proposal(s) to fund the research programme. Publications Dai, J.S., Taylor, P.M. and Sanguanpiyapon, P. (2003a), ‘‘Folding and ironing motion analysis in robotic ironing’’, Proc. INTEDEC 2003, Fibrous Assemblies and the Design and Engineering Interface, September 2003, Edinburgh. Dai, J.S., Taylor, P.M., Liu, H. and Lin, H. (2003b),‘‘Modelling, analysis and control issues in robotic ironing’’, Proc. INTEDEC 2003, Fibrous Assemblies and the Design and Engineering Interface, September 2003, Edinburgh. Dai, J.S., Taylor, P.M., Liu, H. and Lin, H. (2004), ‘‘Garment handling and corresponding devices – technology in robotic ironing’’, Proc. 11th IFToMM World Congress on Mechanisms and Machine Science , Tianjin, China. Taylor, P.M, Dai, J.S., Lin, H. and Liu, H. (2003), ‘‘Technologies for automated ironing’’, Proc. INTEDEC 2003, Fibrous Assemblies and the Design and Engineering Interface, September 2003, Edinburgh.
London, UK London College of Fashion, The London Institute, 20 John Princes Street, London W1G 0BJ, UK Tel: 020 7514 7690; Fax: 020 7514 7672; E-mail:
[email protected] or
[email protected]
Zane Berzina Research staff: Supervisory Team: Dr Frances Geesin, London College of Fashion – Director of the Studies Prof. Norma Starszakowna, Director of Research Development, The London Institute (First supervisor) Kay Politowicz MA (RCA) Course Leader, Textile Design, Chelsea College of Art and Design (Second supervisor) External Advisors: Dr Klaus Hausmann, Institute for Biology and Zoology, Freie Universita¨t Berlin, Germany Colin Dawson, Material Scientist, ex-MOD
Skin stories – charting and mapping the skin: research using analogies of human skin tissue in relation to my textile practice Other partners: Academic
Industrial
University of Arts, Berlin, Germany Supporters: Colbond Nonwovens Institute for Biology and Zoology, Cornelius Outlast Technologies Freie Universita¨t Berlin, Germany Hallcrest Project started: October 2000 Project ended: March 2004 Finance/support: £7.5000,-/year Source of support: The London Institute Keywords: Intelligent textiles, Smart materials, Textile design, Interior design, Art and science, Bio-mimetic design My practice led research project reflects on the current developments within material research and technologies, their properties and the possibilities of their application in design. The research contributes to multidisciplinary activities in science, art and design and demonstrates how they might influence the cultural, social and economic environment. It is proposed that the principle aim of this body of work is to investigate new design possibilities for interactive and functional mixed-media textile surfaces for interiors by using analogies of human skin tissue in relation to my textile practice. Key aspects of my research project are: .
to explore the potential of textiles as a latent heating system to control room temperature (the analogy of skin being a thermo-regulator);
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to examine the thermochromic and photochromic properties of textiles as indicators of fluctuating interior conditions (the analogy used is that of human skin reactions to physical and psychological stimuli – skin as a sensor and biochemical mechanism);
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to investigate the interactive and decorative potential of thermochromic and touch-sensitive surfaces to exploit transient images and patterns of the skin (the analogy used is skin as a sensor); to explore the olfactory and filtering potentials of textiles as a deodorising, antimicrobial and curative surface (analogy – the skin as immunological surveillance and biochemical mechanism).
Project aims and objectives Aims of the investigation are: . to examine the technical and practical processes within textile design by focusing my practice-led research on biological and medical aspects of human skin and body surface, in particular scientific imaging, magnified anatomical structures and textures (cells, fibres); its physical characteristics; . to translate these phenomena into a textiles vocabulary and following the principles of bio-mimetic design, combine aesthetic and functional aspects of skin characteristics; . to develop and test new applications and technologies within textile design, which arise from the research, particularly focusing on aspects of membrane and display, which embodies protection, identity, communication, camouflage; . to develop mixed media textile surfaces as a result of the process of scanning and mapping the surface of the body, using practical simulation and re-making of the skin’s physical and functional characteristics into fabrics by means of bonding, coating, layering, 3D-moulding, dyeing and various print processes; and . to produce a body of textile work accompanied by a written thesis. The overall intent of this research project is to develop functional textile membranes, which enable individuals to experience a dynamic polysensual and interactive environment. It is anticipated that the new intelligent design concept should respond to peoples needs, enable them to enhance their sense of well-being and offers them the possibility to interact with their surroundings by creating an ambience according to their own requirements at that particular moment. In order to do this, I am investigating the biological human skin tissue as a ‘‘technology’’ using biomedical research methods to examine the properties and functions of the epidermis. By doing so I am selecting relevant skin properties for translation into my design work. The focus is on criteria for inclusion in the interactive and polysensual textile installation for interiors, in addition to the regular interior functions anticipated. A series of technical experiments are executed to facilitate the incorporation of selected aspects of functionality.
Research deliverables (academic and industrial) .
Demonstration of textiles concept for interiors which is based on the analogies of human skin tissue and that by involving new technologies and innovative materials, enhances people’s well-being as well as enabling individuals to experience a polysensual and responsive environment by interacting with their biological senses. I hope that this will provide extensive evidence of the potential and the huge resources of opportunities still to be recognised by the textile industry: in the fashion and clothing sector, interiors sector, as well as in the technical textiles sector.
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Demonstration of how scientific thought influences contemporary art and design practice and vice versa: how art and design practitioners have the potential to influence scientific processes. Organisation of an exhibition featuring the outcomes and the process of my crossdisciplinary research project ‘‘Skin Stories – Charting and Mapping the Skin’’ which emphasises the future developments in research, in general, and will be the result of an active collaboration between professionals from a whole variety of backgrounds and disciplines: engineering, science, design, process development, and business and marketing. Audience will be able to literally follow the ‘‘red thread’’ which led me from the science of biology and material science to the actual textile concept. Moreover, they will be encouraged to explore their biological senses by interacting with artworks, to test the responsive skin-like properties of certain materials by touching, smelling and viewing them. My hands-on research project is a tangible try to bridge the gap between design, materials science and technology.
Publications Berzina, Z. (2003a), ‘‘Inteligentais tekstila dizains (Intelligent Textile Design)’’, Latvijas Architektura, Latvia, Vol. 45 No. 1 pp. 58-61 Berzina, Z. (2003b), ‘‘Topography of skin’’, Ballettanz, Germany, pp. 78-9 Hausmann, K. (2003), ‘‘Hautgeschichten – skin stories. Zane Berzina’’, Mikrokosmos, 4 July, Germany, pp. 241-3.
Louisiana, USA Louisiana State University, School of Human Ecology, LSU, Baton Rouge, Louisiana 70803-4300, USA Tel: 225-578-2407; Fax: 225-578-2407; E-mail:
[email protected] Yan Chen and Jianhua Chen, LSU School of Human Ecology, Department of Computer Science, LSU Teresa Summers, Jackie Robeck, Al Steward, and Ramesh Kolluru
Online fabric sourcing database with data mining and intelligent search Other partners: Academic
Industrial
University of Louisiana-Lafayette None Project started: 1 June 2001 Project ends: 30 June 2005 Finance/support: $119,822 Source of support: Louisiana Board of Regents
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Keywords: Database, Intelligent search, Online fabric sourcing, Fabric mechanical properties, Tailorability, Drapability With rapid development of Internet for business applications and e-commerce, textile manufacturers, garment makers, and clothing retailers are eager to go online for fashion tracking and material sourcing. The goal of this project is to establish an online intelligent database that will help the industry users to locate desired fabrics that match fashion trends in color, drape, and style, to narrow fabric selections to fabrics possessing good physical properties that insure high garment quality; to find better-buy fabrics; and to locate fabric manufacturers and determine earliest shipping date. Major objectives include: construction of a database server using a PC and the Oracle software; establishment of a dynamic database composed of fabric structural parameters, mechanical properties, drape images, tailorability, and manufacturers’ contacting information; development of an intelligent search engine allowing clients to scour the database for their own priorities; and investigation of new search patterns that relate client’s fashion requirements to fabric properties using the new data mining techniques of fuzzy clustering and decision tree approach. The new database will merge an existing database created by faculty at the Apparel-Computer Integrated Manufacturing Center (ACIM) at UL Lafayette. This existing database is providing information of the Louisiana Textile, Apparel, and Retail Consortium that aids the state economic development. With accessibility to this database, the new data resources, new search engine, and new search patterns developed in this research can be applied to this existing database. This will greatly enhance its functionality and help form a united textile and clothing sourcing database in the state and the US.
Project aims and objectives The goal of this project is to establish an online intelligent database server that will help the Louisiana clothing manufacturers and retailers to pinpoint desired fabrics that match fashion trends in color, drape, and style; to narrow fabric selections to fabrics possessing good physical properties that insure high quality of garment products; to find better-buy fabrics; and to locate fabric manufacturers and determine earliest shipping date of roll materials. The research objectives are: (1) to set-up a database server using a PC computer server, the Windows operation system, and IBM software; (2) to complete data collection from laboratories and manufacturers; (3) to complete the database infrastructure; (4) to develop a search engine with intelligent search patterns; and (5) to finish merging the existing database in the ACIM Center at University of Louisiana Lafayette.
Research deliverables (academic and industrial) .
Online fabric sourcing database.
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Intelligent search engine for finding fabric products with required tailorability and drape.
Publications Chen, J., Chen, Y., Zhang, B. and Gider, A. (2002), ‘‘Fuzzy linear clustering for fabric selection from online database’’, 2002 Annual Meeting of the North American Fuzzy Information Processing Society Proceedings, IEEE System, Man and Cybernetics Society, New Orleans, LA, pp. 518-22. Chen, J., Chen, Y., Gao, W., Zhang, B., Gider, A. and Kraft, D. (n.d.), ‘‘Fuzzy clustering and intelligent search for a web-based fabric database’’ in Zhang, Y., Kandel, A., Lin, T.Y. and Yao, Y.Y., (Eds), Computational Web Intelligence: Intelligent Technology for Web Applications, World Scientific Publishing, Singapore (in press). Chen, J., Chen, Y., Zhang, B., Vuppala, S., Gider, A. and Gao, W. (2003), ‘‘Online fabric database with intelligent search and fuzzy clustering’’, Proceedings of International Conference on Information and Knowledge Sharing, Scottsdale, AZ, 17-19 November 2003. Zhang, B., Chen, Y.S., Pawlowski, S., Chen, J. and Chen, Y. (2003), ‘‘Online data mining in franchising supply chain management: a demonstration in apparel industry’’, Proceedings of American Conference on Information Systems, Tampa, FL, 4-6 August 2003.
Manchester, UK Department of Clothing Design and Technology, Manchester Metropolitan University, Old Hall Lane, Manchester M14 6HR, UK Tel: 01612472632; Fax: 01612476329; E-mail:
[email protected] Dr J.E. Ruckman, Prof. M.K. Song
Heat and water vapour transfer through high performance clothing systems Other partners: Academic
Industrial
None None Project started: April 2002 Project ended: March 2004 Finance/support: £15,000 Source of support: British Council Keywords: High-tech fabrics, Layered clothing system, Mass transfer When technical fabrics are used in a clothing system it is to be expected that the performance of a fabric itself is not the only factor which contributes to thermophysiological comfort. In real life technical fabrics that are developed to suit outdoor activities are rarely worn on their own, but are incorporated into a layered clothing system, especially that incorporating a waterproof breathable fabric as an outer shell. For this reason, the characteristics and properties originally developed for specific end-uses (and evaluated using testing methods based upon Fick’s Law) may not be as decisive as originally anticipated. The aims of this project are to investigate the heat and water vapour transfer through high performance clothing systems and to identify the optimum combination of technical fabrics for each layer of a high performance clothing system.
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Manchester, UK UMIST, Department of Textiles and Paper, Sackville Street, PO Box 88, Manchester M60 1QD, United Kingdom Tel: 0161.200.64142; Fax: 0161.200.4019; E-mail:
[email protected] Prof. Peter W. Foster, Department of Textiles and Paper Research staff: Dr C.R. Cork, Mr A. Allam
High speed false-twist texturing of micro-fine denier polyester Water jet twisting, Evaluation of new ballistic resistant fabrics Other partners: Dr G.L.D. Wickramasinghe, Dr U.S.W. Gunasekera, Professor J.S. Hearle
Academic
Industrial
None None Keywords: False-twist texturing, Water-jet texturing, Air-jet texturing, Labyrinth, Pressurized labyrinth, Ballistic penetration, High strength sewing thread Water jet twisting and intermingling have been developed as an alternative to compressed air. The density of water is some 1,600 times greater than that of air so that water has a much greater kinetic energy than air and so has a substantially greater twisting effect in suitably designed jets. The water is contained within a pressurized labyrinth system. The twisting jet can also be employed as a cooling medium for hot yarn. Multiple labyrinths have been developed to permit heating, cooling and twisting to be carried out within one jet with no moving mechanical parts. In the ballistic projects new types of fabrics have been developed in which multilayers are woven into a contiguous fabric, with substantial benefits to reducing the penetration of bullets.
Project aims and objectives . . .
False-twist texturing of micro-fine denier polyester at 3,000 m/min. Improved water-air intermingling particularly for sewing threads. Improved ballistic So penetration.
Research deliverables (academic and industrial) None Publications Cork, C.R., Foster, P.W., Oulton, D.P. and Chowdhury, M.D.H. (1999), ‘‘The development of a new continuous dyeing method based on an aerosol delivery system’’, J. Soc. Dyers & Colourists, Vol. 115, pp. 333-78.
Foster, P.W. and Aggarwal, R.K. (1999), ‘‘Processing textile structures’’, Yarn Cooler, US Patent 5, 931,972, 3 August 1999 . Foster, P.W. and Aggarwal, R.K. (2000), ‘‘Processing textile structures’’ US Patent 6,139,588, 31 October 2000. Foster, P.W., Ferrier, D.C. and Gunasekera, U.S.W. (K1). (2002), ‘‘Apparatus and method for texturing yarn’’, US Patent 6,397,444 B1, 4 June 2002. Foster, P.W., Ferrier, D.C. and Gunasekera, U.S.W. (2004), ‘‘Processing Textile Materials’’, US Patent 6,701,704 B2, 9 March 2004, E/F/G. Foster, P.W., Oulton, D.P. and Khaled, K.K. (2000), ‘‘The influence of steam pretreatment on the wettability and dyeability of ecru fabric’’, paper presented at the Colourage Annual 2000, pp. 53-8. Foster, P.W., Ferrier, D.C. and Gunasekera, W. U.S.W. (I), (2002), ‘‘Apparatus and method for fabrication of textiles’’,US Patent 6,438,934 B1, 27 August 2002. Oulton, D.P., Foster, P.W. and Khaled, K.K. (2000), ‘‘A novel approach to continuous fabric wet-processing and dyeing using steam pre-treatment’’, paper presented at the AATC Conference, Winston-Salem, September 2000.
Maribor, Slovenia Faculty of Mechanical Engineering, University of Maribor, Smetanova ulica 17, SI-2000 Maribor, Slovenia Tel: +386 2 220-7960; Fax: +386 2 220-7990; E-mail:
[email protected] Associate Prof. Dr Sc. Jelka Gersˇak, Department for Textiles, Institute of Textile and Garment Manufacture Processes Research staff: Research Unit Clothing Engineering, Research Unit Textile Technology
Clothing engineering Other partners: Academic
Industrial
None None Project started: 1999 Project ended: 2003 Finance/support: 15.052.943,00 SIT or 65.840,62 ECU for 2001 Source of support: Ministry of Education, Science and Sport Keywords: Clothing, Fabric, Mechanical properties, Behaviour, Prediction The research programme was based on three main activities: basic research on fabric mechanics regarding the non-linear mechanical fabric properties at low stresses and search for model of a fabric as shell; study of response of a fabric against acting stresses in garment manufacturing processes; and study of a behaviour between fabric’s mechanical properties and quality of a produced garment. In frame of the first group of activities, the research was focused on study of a fabric as shell. We have studied the fabric behaviour from the point of view of continuum mechanics. This work resulted in mechanical model of a fabric that was described with rheological coefficients, i.e. elastic and shear module and
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Poisson’s number. Furthermore, the fabric was modelled using the finite elements method and programme package ABAQUS. The second group of activities referred to the study of fabric response to acting stresses in garment manufacture processes and contained:
(1) Study of relationship between tensional stresses and deformations of fabrics. Based on the study of the relationship between the parameters of mechanical properties of analysed fabrics and their response to acting tensional stresses, resp. resulted deformation, it was stated that deformation degree and relaxation time directly depended on mechanical properties of fabrics, acting load and length of the fabric layers. (2) Study of fabric behavior in garment manufacturing processes, which was focused above all on fabric response to acting stresses during cutting, fusing and finishing. The research resulted in: .
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definition of relationships between fabric mechanical properties and their behaviour in different garment manufacturing processes, definition of potential problematic spots in manufacturing processes and limit values of particular mechanical properties of fabrics, set-up of a model ‘‘NAPOVED1.1DZ’’ for prediction of fabric behaviour in garment manufacturing processes. The model was designed in Microsoft Access in such a manner that all respective data, i.e. parameters of mechanical properties were joined together using appropriate relation functions
Study of relationship between the mechanical properties of fabrics and quality of produced garments was carried out in the frame of the third group of research activities. The aim was to design the model for qualitative prediction of garment appearance quality using the principles of objective evaluation of the quality level of garment appearance and comparable estimation of garment suit.
Project aims and objectives Project aims are: definition of principles of fabric behaviour in garment manufacturing processes regarding the non-linear mechanical properties of a fabric, set-up of a model for prediction of fabric behaviour in garment manufacturing processes, definition of relationships between fabric mechanical properties and quality of a produced garment, design of a model for prediction of garment appearance and set-up of a model of fabric as shell.
Research deliverables (academic and industrial) Achieved knowledge in a field of fabric mechanics and fabric response to acting stresses, resp. fabric behaviour in garment manufacturing processes, as well as defined limit/critical values of fabric mechanical properties represent an important contribution of the research from the scientific as well as applied point of view. Designed model for prediction of fabric behaviour in garment manufacture processes, ‘‘NAPOVED1.1DZ’’, which comprehends achieved cognitions of basic
research on fabric mechanics, and designed knowledge base in Microsoft Access, can be also stated as important applied results of the research. The other important applied achievement is designed simulation of a fabric with the help of a programme package ABAQUS. Fabric model is designed on the basis of numeric modelling as a starting point for study of fabric draping and formability. Furthermore, using appropriate programming tools it will be possible to carry out the simulation of a garment suit. Publications Gersˇak, J. (2002a), ‘‘Development of the system for qualitative prediction of garments appearance quality’’, International Journal of Clothing Science and Technology, Vol. 14 No. 3/4, pp. 169-80. Gersˇak, J. (2002b), ‘‘A system for prediction of garment appearance’’, Textile Asia, Vol. 33 No.4, pp. 31-4. Gersˇak, J. and Zavec, D. (2000), ‘‘Creating a knowledge basis for investigating fabric behaviour in garment manufacturing processes’’, Annals of DAAAM for 2000 and Proceedings of the 11th International DAAAM Symposium Intelligent Manufacturing and Automation: Man-MachineNature, DAAAM International, Vienna, pp. 155-6. Jevsˇnik, S. and Gersˇak, J. (2001), ‘‘Use of a knowledge base for studying the correlation between the constructional parameters of fabrics and properties of a fused panel’’, International Journal of Clothing Science and Technology, Vol. 13 No. 3/4, pp. 186-97. Zavec, D. and Gersˇak, J. (2001a), ‘‘Modular development of prediction knowledge base’’, Annals of DAAAM for 2001 and Proceedings of the 12th International DAAAM Symposium Intelligent Manufacturing and Automation: Focus on Precision Engineering, DAAAM International, Vienna, pp. 519-20. Zavec, D. and Gersˇak, J. (2001b), ‘‘Prediction of fabric behavior as an input information for garment manufacturing process (Napoved obnasˇanja tkanin kot vhodna informacija za proces izdelave oblacˇil)’’, Tekstilec, Vol. 44 No. 9/10, pp. 271-9.
Maribor, Slovenia Faculty of Mechanical Engineering, University of Maribor, Smetanova ulica 17, SI-2000 Maribor, Slovenia Tel: +386 2 220-7960; Fax: +386 2 220-7990; E-mail:
[email protected] Prof. Dr Sc. Jelka Gersˇak, Department of Textiles, Institute of Textile and Garment Manufacture Processes Research staff: Dr Sc. Jelka Gersˇak, MSc. Andreja Rudolf
Introduce the new lubrication technology stretched PES filament sewing threads Other partners: Academic None
Industrial
TSP d.d. TOVARNA SUKANCEV IN TRAKOV Project started: April 2003 Project ended: September 2004 Finance/support: 8.379.335,00 SIT or 34.913,00 ECU
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Source of support: Ministry of the Economy Keywords: Sewing thread, PES filament, Hot extension, Lubrication, Viscoelastic properties Sewing thread as a joining element takes an important part in the sewing process as well as in the finished seam. In the sewing process technologically conditioned forces act on the thread, which are manifested in the form of tensile and frictional forces as well as mass acceleration forces. This is reflected in its processing properties, process reliability and seam quality. The reliability of the sewing process is directly influenced by thread behaviour during the sewing process, respectively, its resistance to the dynamic and heat loadings, and the type and method of the thread surface treatment are of highest importance. The dynamic thread behaviour during the sewing process is influenced by the mechanical properties of the thread. The mechanical properties depend on constructional parameters and drawing technology as well as the type and method of applying lubricant agent. Heat loading is influenced by the type, method and quality of surface treatment. The purpose of the investigation is to observe the sewing ability and specific demands of the PES filament threads according to the automobile industry demands. We also want to research the effect of the lubricant agent type and amount as well as the effect of lubrication technology on assuring reliability of the sewing process at minimal dynamic tension and alteration of the thread mechanical properties as well as introduce the new lubrication technology with the aim of improving processing properties and resistance of the drawing PES filament threads against the dynamic loadings in the sewing process at the minimal thread deformation, which is the condition for the process stability and assurance of the aimed seam strength.
Project aims and objectives: The main objectives of this project are. .
to investigate the effect of the lubricant agent type and amount as well as the effect of lubrication technology on assuring reliability of the sewing process at minimal dynamic tension and alteration of the thread mechanical properties; and
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to develop and introduce the new lubrication technology stretched PES filament sewing threads.
Research deliverables (academic and industrial) Important contribution regarding the academic as well as the industrial point of view can be seen as new cognitions of the influence of thread’s constructional parameters, hot extension and lubrication technology on change of viscoelastic properties of the thread and twisted filament yarns. Achieved cognitions can be considered as starting points for projecting the sewability of filament threads and their applied properties. The new lubrication technology stretched PES filament sewing threads to be adopted by industry. Publications Rudolf, A. and Gersˇak, J. (2001), ‘‘The influence of the surface treatment of the thread on dynamic load of the thread’’, Proceedings of the 1st Autex Conference, Povoa de Varzim, Portugal, Tecnitex 2001: Designing Textiles for Technical Applications, Vol. 1, pp. 335-43.
Rudolf, A. and Gersˇak, J. (2002), ‘‘Influence of twist on the mechanical properties of sewing thread’’, Proceedings of the 1st International Textile, Clothing & Design Conference ITC&DC, Dubrovnik. Magic World of Textiles, Faculty of Textile Technology, University of Zagreb, Zagreb, pp. 395-400. Rudolf, A. and Gersˇak, J. (2003), ‘‘The planning of thread mechanical properties’’, Proceedings of the 4th International Conference Innovation and Modelling of Clothing Engineering Processes IMCEP 2003, Faculty of Mechanical Engineering, Institute for Textile and Garment Manufacture Processes, Maribor, Slovenia, pp. 252-58. Rudolf, A. and Gersˇak, J. (2004), ‘‘The influence of thread twist on alteration of fiber mechanical properies’’, Textile Research Journal (in press).
Maribor, Slovenia Faculty of Mechanical Engineering, University of Maribor, Smetanova ulica 17, SI-2000 Maribor, Slovenia Tel: +386 2 220-7960; Fax: +386 2 220-7990; E-mail:
[email protected] Prof. Dr Sc. Jelka Gersˇak, Department of Textiles, Institute of Textile and Garment Manufacture Processes
Research staff: Research Unit Clothing Engineering, Research Unit Textile Technology
Clothing engineering and materials Other partners: Academic
Industrial
None None Project started: 1999 Project ended: 2003 Finance/support: 18.914.260,00 SIT or 78.800,00 ECU for 2003 Source of support: Ministry of Education, Science and Sport Keywords: Clothing, Fabric, Mechanical properties, Behaviour, Prediction The research programme was based on complex research on the study of fabric mechanics and fabric as a shell – garment, and was subdivided into three thematically connected parts, which included: (1) basic research on the study of fabric mechanics from the point of view of nonlinear mechanical properties of fabrics at lower loading and modelling the fabric and fused panel as a shell; (2) study of behaviour of fabrics and partly also nappa leather clothing at lower loading, i.e. during garment manufacturing processes and has the applied character; and (3) the study of the relationship between the mechanical properties of the fabrics and appearance quality of the produced garment. The most important results of the research programme can be given in the form of the following achievements. .
Definition of the principles of fabric behaviour during garment manufacturing processes from the point of view of non-linear mechanical properties of the fabric.
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Designed and experimentally confirmed was the geometrical and mechanical model of the fabric as a shell and fused panel. Simulations of fabric and fused panel draping have been made using the programme package ABAQUS, based on numerical analysis with the finite elements method.
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Definition of the relationship between the parameters of mechanical properties of fabrics and their response to acting tensional loading, respectively, relationship between the resulted deformation and relaxation.
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Design of the system for prediction of the behaviour of the fabric during garment manufacturing processes ‘‘NAPOVED1.1DZ’’, which integrates the achieved cognitions based on basic research on fabric mechanics into the knowledge base, consisting of three modules using the programme Microsoft Access.
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Definition of the relationship between nappa leather clothings’ mechanical properties and its processing properties, respectively, the characteristics of its use, as well as definition of limit values of individual parameters of those mechanical properties.
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Definition of the principles and relationship between fabric mechanical properties and appearance quality of a produced garment.
Project aims and objectives The main objectives of this project are definition of principles of fabric behaviour in garment manufacturing processes regarding the non-linear mechanical properties of a fabric, set-up of a model for prediction of fabric behaviour in garment manufacturing processes, definition of relationships between fabric mechanical properties and quality of a produced garment, design of a model for prediction of garment appearance and set-up of a model of fabric as shell.
Research deliverables (academic and industrial) Achieved cognitions, respectively, discovered principles about behaviour of fabrics and nappa leather clothing at lower loading, important for garment manufacturing processes and for use of garments, as well as designed and experimentally confirmed fabric simulation models, prediction of fabric behaviour in garment manufacturing processes and cognition about the relationship between the parameters of mechanical properties of fabrics and appearance of produced garments, represent an important contribution to the development of science and can be stated as a starting point for setting-up the engineered concept for garment planning, based on knowledge. An important contribution, from the academic, as well as from the applied point of view, represent the achieved cognition, respectively, discovered principles regarding the mechanical properties of the fabric and its response on acting loading, respectively, behaviour of the fabric in garment manufacturing processes, as well as defined limit, i.e. critical values of particular parameters of fabric’s mechanical properties. An important achievement is also the definition of the relationship between nappa leather clothings’ mechanical properties and the characteristics of its use. The limit values of these parameters have been defined for pig- and sheepskin nappa leather clothing, which will serve for planning and optimising the process of pigskin finishing as a competitive
product regarding the sheepskin. Results – the defined limit values of mechanical properties of nappa leather clothing are the first contribution of this kind in the area of the study of nappa leather mechanics and can be stated as an important contribution towards the engineered planning of processing properties of nappa leather clothing and thus, connected quality of such kind of garments.
Research register
Publications Blekacˇ, R., Gersˇak, J. and Gubensˇek, I. (2003), ‘‘Model for simulating fabric loading and deformartions during spreading process’’ (Model simulacije obremenitev in deformacij tkanin pri polaganju), Tekstilec, Vol. 46 Nos 11/12, pp. 348-53. Gersˇak, J. (2002a), ‘‘Development of the system for qualitative prediction of garments appearance quality’’, International Journal of Clothing Science and Technology, Vol. 14 Nos 3/4, pp. 169-80. Gersˇak, J. (2002b), ‘‘A system for prediction of garment appearance’’, Textile Asia, Vol. 33 No. 4, pp. 31-4. Gersˇak, J. (2003), ‘‘Investigation of the impact of fabric mechanical properties on garment appearance’’ (Istraivanje utjecaja mehanicˇkih svojstava tkanina na izgled odjec´e), Tekstil, Vol. 52 No. 8, pp. 368-78. Gersˇak, J. (2004), ‘‘Study of relationship between fabric elastic potential and garment appearance quality’’, International Journal of Clothing Science and Technology, Vol. 16 Nos 1/2, pp. 238-51. Gersˇak, J. and Zavec, D. (2000), ‘‘Creating a knowledge basis for investigating fabric behaviour in garment manufacturing processes’’, Annals of DAAAM for 2000 and Proceedings of the 11th International DAAAM Symposium: Intelligent Manufacturing and Automation: Man-Machine – Nature, DAAAM International, Vienna, pp. 155-6. Jevsˇnik, S. and Gersˇak, J. (2001), ‘‘Use of a knowledge base for studying the correlation between the constructional parameters of fabrics and properties of a fused panel’’, International Journal of Clothing Science and Technology, Vol. 13 Nos 3/4, pp. 186-97. Jevsˇnik, S. and Gersˇak, J. (2004), ‘‘Modelling the fused panel for a numerical simulation of drape’’. Fibres Text. East. Eur., Vol. 12 No. 1, pp. 47-52. Sˇajn, D., Gersˇak, J. and Bukosˇek, V. (2003), ‘‘Study of the relationship between loading and relaxation of fabrics containing elastane yarns’’ (Sˇtudij odnosa med obremenitvijo in relaksacijo tkanin z dodanim elastanom). Tekstilec, Vol. 46 Nos 9/10, pp. 274-81. Urbanija, V. and Gersˇak, J. (2004), ‘‘The impact of nappa leather clothings’ mechanical properties on the characteristics of its use’’, Journal of the Society of Leather Technologists and Chemists (in press). Zavec, D. and Gersˇak, J. (2001), ‘‘Prediction of fabric behaviour as an input information for garment manufacturing process’’ (Napoved obnasˇanja tkanin kot vhodna informacija za proces izdelave oblacˇil). Tekstilec, Vol. 44 Nos 9/10, pp. 271-9. Zavec Pavlinic´, D. and Gersˇak, J. (2003), ‘‘Investigations of the relation between fabric mechanical properties and behaviour’’, International Journal of Clothing Science and Technology, Vol. 16 Nos 3/4, pp. 231-40. Zavec Pavlinic´, D. and Gersˇak, J. (2004), ‘‘Design of the system for prediction of fabric behaviour in garment manufacturing processes’’, International Journal of Clothing Science and Technology, Vol. 16 Nos 1/2, pp. 252-61.
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Manchester, UK Manchester Metropolitan University, Hollings Campus, Old Hall Lane, Manchester, M14 6HR Tel: 0161 247 2636; Fax: 0161 247 6354; E-mail:
[email protected]
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Department of Clothing Design and Technology David J. Tyler Research staff: Julie D. Wilson
Mass customisation for the interior textiles sector
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Other partners: Academic None
Industrial Acton and Acton Ltd Direct Textile Imaging Ltd John Clegg and Bros Ltd Project ends: 31 January 2004
Project started: 1 September 2002 Finance/support: £28,000 Source of support: Department of Trade and Industry Keywords: Textile printing, Ink-jet technology, Cost modelling
Until recently, the market for the digital printing of textiles has been dominated by sampling. There have been some applications involving production for consumers (ties, flag, banners) but the volumes have not been large. Advances in machinery technology have created new business opportunities. Widewidth printers suitable for textile applications have been introduced to the market with significant productivity improvements. There are now opportunities for businesses to move from sampling into consumer products. The research involves the analysis of costs in the supply of digitally-printed textile products. Sampling businesses generally provide a design service to interpret the needs of the customer and translate it into printed products. Such businesses do not have a high utilisation of their printing machinery and much of the cost is associated with set-up. The productivity of the printer is not a primary consideration. As the core business moves from a sampling service towards the supply of printed textiles, an internal culture change is needed. The productivity of the machinery is an issue, and there are significant benefits from batch-printing without the need for operator supervision. The cost of the ink (dye) becomes a more important element in the price structure. Pre- and post-printing treatments are significant costs affecting the price to consumers. This research examines these cost issues from the perspective of prioritising cost factors and identifying targets for technology innovation. The findings are relevant to the wider implementation of digital printing technologies in the textiles sector.
Project aims and objectives .
To analyse the cost structure of textile digital printing.
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To develop an economic cost model. To develop tools for evaluating technology developments.
.
Research deliverables (academic and industrial) Validated economic cost model.
Research register
Publications None
Newcastle upon Tyne, UK University of Newcastle upon Tyne, Stephenson Building, University of Newcastle, Newcastle Upon Tyne NE1 7RU, UK Tel: 0191-2227145; Fax: 0191-2228600; E-mail:
[email protected] Paul M Taylor, School of Mechanical and Systems Engineering Research staff: Hua Lin
A feasibility study into robotic ironing Other partners: Academic King’s College London Project started: 1 August 2002 Finance/support: £38,742 Source of support: EPSRC Keywords: Garment, Ironing, Robotics
Industrial None Project ended: 28 February 2003
This is an adventurous research aiming at investigating a development in applying robotics techniques to one of the most demanding household activities, performing a feasibility study into robotic ironing. Customer market research will be carried out to establish the minimal functional requirements for a range of potential users. Technical requirements will be established for complete and decomposed ironing tasks. A preliminary technology study will then be made, covering the relevant technologies in the UK, Europe, Japan and the USA to establish the state of the art and to determine advances that must be made. These technologies will cover gripping, handling, folding and manipulation, ironing and relevant textile technologies. Potential machinery manufacturers will be approached to bring their perspective into the study. Gaps in theories and knowledge will be identified and these will be used to determine the further research that must be carried out to provide solutions to the technical problems in a way that should eventually lead to a product acceptable to the consumer. Finally, a consortium will be established which could carry out this research and proposal(s) will be prepared.
Project aims and objectives .
Establish the detailed functionality of robotic ironing devices.
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Examine the existing techniques and required disciplines to solve the technical problems. Determine in detail the research needed to carry out the work, the team to do it and the resource required.
.
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Identify potential industrial collaborators who might provide commercial followthrough.
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Draft research proposal(s) to fund the research programme.
Publication These surveys will be published in appropriate journals, such as the International Journal of Clothing Science and Technology, Journal of Robotic Systems, and at the 11th IFToMM World Congress in Tianjing in 2003, and at the IEEE ICRA in 2003.
Newcastle upon Tyne, UK University of Newcastle upon Tyne, Stephenson Building, The University, Newcastle upon Tyne NE1 7RU Tel: (0191) 222 7145; Fax: (0191) 222 8600 Professor P.M. Taylor, Department of Mechanical, Materials and Manufacturing Engineering Research staff: D. Pollet
Vibration of fabric panels and automated garment assembly Other partners: Academic
Industrial
None None Project started: 1 October 1992 Project ends: – Keywords: Bending, Environment, Friction, Grippers The primary aim is to understand the way fabrics and garments interact with mechanical devices designed to hold them and move them around and how their behaviors are affected by environmental changes. Studies are being undertaken on an analysis of the behavior of fabric during the pinch gripping operation and on how fabric panels move on vibratory surfaces. To complement this, the relevant properties of fabrics are being studied, particularly buckling, bending and friction under zero and low applied normal forces. Friction and bending tests are also being undertaken over a wide range of environmental conditions to see the effects of humidity changes on handling processes.
Project aims and objectives The primary aim is to understand the way fabrics and garments interact with mechanical devices designed to hold them and move them around and how these are affected by environmental changes.
Academic deliverables Gripping analysis – vibration analysis, new instrumentation, results showing strong links between handling behavior and environmental conditions.
Industrial deliverables None yet
Publications Taylor, P.M. and Pollet, D.M. (1996), ‘‘Why is automated fabric handling so difficult?’’, 8th International Conference on Advanced Robotics (ICAR 97). Taylor, P.M., Pollet, D.M. and Griesser, M.T. (1994), ‘‘Analysis and design of pinching grippers for the secure handling of fabric panels’’, Proceedings of Euriscon ’94, Vol. 4, Malaga, Spain, 22-26 August, pp. 1847-56.
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Ontario, Canada University of Guelph, Ontario, Canada, N1G 2W1 K. Slater, School of Engineering Research staff: various graduate students
Protective clothing design for agricultural uses Other partners: Academic
Industrial
None None Project starts: April 1999 Project ended: April 2003 Finance/support: Applications under development Source of support: Various groups to be approached Keywords: Agriculture, Protective clothing The project depends on the ability of textile materials to be incorporated into designs of garments which can resist the ingress of harmful chemicals yet allow the escape of perspiration moisture. Preliminary design considerations have been established, but continuation of the work depends on the successful negotiation of adequate funding, a step which is currently in progress.
Project aims and objectives The aim of the project is to develop a clothing system capable of providing agricultural workers with adequate protection from the various chemical and microbiological hazards which they continually encounter in their daily work.
Academic deliverables One or more graduate theses. One or more journal articles.
Industrial deliverables Protective clothing capable of preventing health deterioration in agricultural workers continually exposed to harmful chemical or microbiological hazards, with the added advantage of being comfortable enough for the workers to accept it without demur. Publications No publications stemming directly from this project have appeared to date, but some of my earlier work (e.g. protective clothing for operating room use) is relevant and has appeared in the past. I have also presented papers dealing with the need for protection of agricultural workers at several recent conferences.
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Ontario, Canada University of Guelph, Ontario, Canada, N1G 2W1 K. Slater, School of Engineering Research staff: various graduate students
Protective clothing design for industrial use Other partners: Academic
Industrial
None None Project starts: April 1999 Project ended: April 2003 Finance/support: Applications under development Source of support: Various groups to be approached Keywords: Clothing, Industrial clothing, Protective clothing Industrial accidents frequently cause injuries which could have been prevented by the use of appropriate protective clothing. Flying projectiles, violent contact with machinery, vehicles or the ground, and exposure to harmful chemical or biological materials are encountered regularly in accident reports. This project is intended to build on my previous research in the degradative changes occurring in textiles, and on my comfort research, to match the protective needs of clothing intended to safeguard human beings from the hazardous conditions to which they are exposed. A major need is to ensure that wearers are not likely to discard the protective garments for reasons of physical or mental comfort, so that protection is abandoned. As the work is still in the planning stage, it is not possible to provide any detailed synopsis of its course.
Project aims and objectives The aim of the project is to use textile materials, in conjunction with other components, to prevent (or minimise injury from) industrial accidents.
Academic deliverables One or more graduate theses. One or more journal articles.
Industrial deliverables Protective clothing capable of reducing or eliminating injury, and hence reducing financial costs, arising from workplace accidents. Publications No publications stemming directly from this project have appeared to date, but some of my earlier work relates closely to the needs of this research.
Pennsylvania, USA Philadephia University, Henry Avenue and School House Lane, Philadelphia, Pensilvania 19144, USA Tel: 215-951-5356; E-mail:
[email protected] Les Sztandera, Computer Information Systems
Genetic algorithms in molecular design of novel fibers Research staff: Graduate students Other partners: Academic
Industrial
Chih-Chung, Chu/Cornell, University/ None
[email protected]/Chemical Structures of Polymers and Fibers; Hugh Cartwright/Oxford University, UK/hugh.Cartwright@ chem.ox.ac.uk/Computational Chemistry Source of support: US Department of Commerce; National Textile Center This project will use the newest approaches from GAs research to establish an extensive structure-property correlation database library that can be used to design a range of novel polymers and fibers with improved characteristics such as exceptional stretch, recovery, strength, increased bulk, improved hand and comfort properties, and which are easy to dye. These technically advanced fibers of commercial importance to the US textile industry will combine the best properties of nylon and polyester. The goal of this project is ambitious. Initially, we will address the issues of monomer design and polymerization to demonstrate the proof of concept. Subsequently, the project will expand to fiber spinning, yarns and fabrics. With the help of GAs we will be able to create and examine extremely large virtual databases of polymer molecular structures. The project is theoretical in concept, but highly practical in both, its aims, implementation and eventual applications. We plan to design fibers that offer increased bulk, improved softness and are easy-dye. They will be ideally suited for the apparel, home furnishings and automotive markets, and will offer cost-effective, highperformance alternatives to current commercial textile products. In the 3 years of this project we intend to demonstrate that by utilization of GAs technology we can overcome the design limitations of current polymers and fibers, thus paving the way to the production of yarns and textiles with novel functionality.
Research deliverables (academic and industrial) This year’s goal is the: (1) development of a GA that can create a large (essentially infinite) number of polymers from a variety of monomeric materials; (2) construction of an intelligent software tool that will permit the prediction of the properties of a model polymeric material from a structure created by the GA; and (3) development of a neural network for the automated correlation of structure features of polymers with their know properties.
Research register
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Outreach to industry. Commercially available monomers, polymers, and chemical reagents will be used in the proposed project to facilitate technology transfer. Close relationships between academic and industry will be established through exchange of ideas and the feedback of information on the production and performance of new products. Consultation with personnel from related chemical and fiber industries will be sought to explore product and market possibilities and to provide feedback on industrial needs in this area. Publications None
Philadelphia, USA School of Textiles and Materials Technology, Philadelphia University, School House Lane and Henry Avenue, Philadelphia 19144, USA Tel: 215-951-2680; Fax: 215-951-2651; E-mail:
[email protected] Dr Mohamed Abou-iiana, Textiles Department Research staff: S. Youssef
Knitting and knitting related projects, knitted composites, . . . etc on-line weight and shrinkage control of knits Other partners: Academic Auburn University Project started: May 2001 Finance/support: $200,000 Source of support: National Textile Center
Industrial National Textiles, Greensboro, NC, USA Project ends: May 2004
An automatic fabric evaluation system has been developed to automatically analyze the knit structures and objectively evaluate fabric properties. Fabric images are captured by CCD camera and preprocessed by Gaussian filtering and histogram equalization. Fabric construction parameters such as courses per inch, wales per inch, fabric cover, weight per unit length are measured and evaluated. The structural changes occurred to the fabric at different levels of fabric relaxation were documented. It has been shown that the system is capable of capturing the structural changes during stress relaxation. This system can be used to on-line control of knit structures during processing by having this image quality acquisition probe determine the spatial characteristics of knitted loop before and after wet treatment. For years knitting has been considered more of an art than a science. Many attempts have been made over the past century to quantify the characteristics of knitted fabrics. The key to unlocking a knitted structure lies within its basic element,
the single knitted loop. It has been shown that the length of yarn knitted into a single loop will determine such overall fabric qualities as hand, comfort, weight, extensibility, finished size, cover factor and most importantly fabric dimensional stability. Therefore, to gain control over the characteristics of the fabric performance, the single knitted loop must be controlled to meet certain performance criteria. The problem then arises of how to determine that a knitted loop is of the correct size and shape for a given set of fabric properties. The answer lies in the ability to objectively measure the knitted loop size/shape during processing. Once the loop shape in a fabric is measured, the loops of that size/shape can then be correlated with specific properties of that fabric. With the advent of computers, and more specifically of image analysis and processing, this age old problem of measuring a knitted loop size/shape has been solved [1,2,3,4,5,6,7,8]. Today during fabric processing, a loop can characterize in a matter of seconds with great accuracy instead of the traditional inaccurate techniques of measuring the course spacing or courses per unit length. Computers have not only provided an accurate method for characterizing the loop shape but also a means for checking the loop shape to the required shape to achieve certain fabric properties. The knitted structure consists essentially of a yarn bent into the shape of a loop, and this basic element, the loop repeated across the width of the fabric and along its length. The distinctive property of a knitted fabric is its high extensibility in both length and width, which gives it the ability to take up the shape of the wearer and allows it to fit. Attempts to specify the dimensional properties of a knitted fabric in terms of length or width parameter (courses per inch and wales per inch) are subject to high degree of inaccuracy because of its inherent stretch at low loads and poor recovery. Nevertheless, the construction of a fabric is still today frequently described in terms of courses and wales per inch. It is the use of this unreliable and inaccurate parameter for specifying the tightness of a knitted construction, which is directly or indirectly responsible for many of the problems associated with the control of dimensions of knitted structures. This characteristic of a knitted fabric when strained in length or width is due to the fact that the loop shape is easily distorted under low strain conditions and is caused by a change in loop shape without any associated stretching of the yarn forming the loop. In an industrial setting, the techniques of counting the course per inch, wales per inch or unraveling the fabric to determine stitch length are subjected to human error and time consumption. An automatic structure analysis and objective evaluation of knit structures using image analysis techniques will determine the fabric construction parameters and eliminate the subjectivity of the human element.
Pisa, Italy Interdipartimental Research Center E. Piaggio, Via Diotisalvi 2, 56126 Pisa, Italy Tel: +39-050-2217050; Fax: ++39-050-2217051; E-mail:
[email protected] Danilo De Rossi, Center E.Piaggio Research staff: Ghelarducci, Gemignani, Scilingo
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Wealthy Other partners: Academic INSA. HSR, CRSSA, CNRS Project started: 1 September 2002 Finance/support: 3859060 Source of support: UE Keyword: Wearable healthcare interface
Industrial Millior, CSEM, ATKO, MESSE Project ends: After 30 months
A new concept in healthcare, aimed at providing continuous remote monitoring of user vital signs, is emerging. In our project smart material in fiber and yarn form endowed with a wide range of electrophysical properties (conducting, piezoresistive, etc.) will be integrated and used as basic elements to be woven or knitted in fabric form. The simultaneous recording of vital signs will allow parameters’ extrapolation and intersignal elaboration, that contribute to make alert messages and synoptic patient table. Wealthy system will be implemented by integrating computing techniques, smart sensors, portable devices and telecommunications, together with local intelligence and decision support system. The proposal system will assist patients during rehabilitation or subjects working in extreme stressful environment conditions, ensure continuous intelligent monitoring.
Project aims and objectives The main objective of Wealthy is to set-up a wearable healthcare system that will improve patient or user autonomy and safety. Wealthy building blocks are: (1) cost-effective, non-invasive system based on wearable and wireless instrumented garments, which are able to detect user specific physiological signals; (2) intelligent system for data representation and alert functions for creating intelligent feedback and deliver information to a target professional; (3) electronic devices for signals transmission by using 3G wireless network, allowing to monitor the patient ‘‘anywhere’’; (4) advance telecommunication protocols and services; and (5) effective and user-friendly data format. Wealthy solution will be validated in two pilot sites, with an active participation of users and health.
Research deliverables (academic and industrial) A user requirements specification report as a result of expectations and user requirements. Functional specification report, where the system design and infrastructure are described. The development phase implements the smart garment, the comunication device and software modules of the system realised as mock-ups and beta versions. The integration and verification phase develops the final system to be used during the pilot validation. Exploitation and dissemination plans are available. Publications De Rossi, D., Della Santa, A. and Mazzsoldi, A. (1999), ‘‘Dressware: wearable hardware,’’ Materials Science & Engineering, Biomimetic and Supramolecular Systems, Vol. 7 pp. 31-5.
De Rossi, D., Carpi, F., Lorussi, F., Mazzoldi, A., Paradiso, R., Pasquale Scilingo, E. and Tognetti, A. (2003), ‘‘Electroactive fabrics and wearable biomonitoring devices’’, AUTEX Research Journal, Vol. 3 No. 4, pp. 180-5. Mazzoldi, A., De Rossi, D., Lorussi, F., Scilingo, E.P. and Paradiso, R. (2002), ‘‘Smart textiles for wearable motion capture systems’’, Autex Research Journal, Vol. 2 No. 4, pp. 199-203. Scilingo, E.P., Lorussi, F., Mazzoldi, A. and De Rossi, D. (2003), ‘‘Strain-sensing fabrics for wearable kinaesthetic-like systems’’, IEEE Sensors Journal, Vol. 3 No. 4, pp. 460-7.
Pisa, Italy Institution: Interdipartimental research center E. Piaggio, Via Diotisalvi 2, 56126 Pisa, Italy Tel: +39-050-2217050; Fax: ++39-050-2217051; E-mail:
[email protected] Danilo De Rossi, Center E. Piaggio Research staff: Ghelarducci, Gemignani, Scilingo, Landini
MyHeart Other partners: Academic
Industrial
Commissariat a l’energie Atomique (CEA-LETI), Eidgenossische Technische Hochschule Zurich (ETH Zurich), Universidad Politecnica de Madrid, Instituto de Aplicaciones de las Tecnologı´as de la Informacio´n y de las Comunicaciones Avanzadas–Asociacio´n, Consorzio di Bioingegneria e Infomatica Medica Politecnico di Milano, Universita’degli studi di Padova (university of Padova), Universita degli studi di Firenze (University of Firenze), Mayo Clinic Rochester, Universitaetsklinikum Aachen (University Clinic Aachen), Hospital Clinico San Carlos de Madrid Insalud, Fondazione Centro San Raffaele del Monte Tabor, Fondazione Salvatore Maugeri Clinica del Lavoro e della
Philips GmbH Forschungslaboratorien (Philips Research Labs. – Aachen), Philips Electronics UK Limited (Philips Research Labs. – Redhill and Philips Design – London), Philips International B.V. (Design – Eindhoven), Philips Innovative Technology Solutions NV (Philips DSL), Medtronic Iberia SA, Nokia Corporation, Fundacion Vodafone, Nylstar CD S.p.A., Manifatture Filati Riunite SPA (Lineapiu Group), Milior – S.P.A., Smartex – S.R.L, Dr.Hein GMBH, Mind Media B.V., Medgate AG, CSEM Centre Suisse, D’Electronique et de
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Riabilitazione (University Pavia Microtechnique SA, IRCCS/FSM), Universidad Politecnica Philips Electronics Nederland b.v. de Valencia (Technical University (Philips Research Labs – Eindhoven) of Valencia–Sports Center), Facludade de ciencias e technologia da universidade de Coimbra (University of Coimbra), Hospital de Unisersidate de Coimbra Project started: 1 January 2004 Project ends: After 18 months Finance/support: 443580 (amount only for our Center) Source of support: UE Keyword: Wearable healthcare interface The MyHeart approach for solving the key challenges is based on the development of intelligent biomedical clothes for preventive care application tailored to specific user groups. In order to focus on the user motivation and the individual benefit, we define the main objectives along five different application areas. These application areas reflect the main risks for developing a CVD and addres the user need for early diagnose to limit the severity of an acute event. The five identified application areas are: (1) CardioActive: application cluster for improved physical activity; (2) CardioBalance: application cluster for improved nutrition and dieting; (3) CardioSleep: application cluster for improved sleep and relaxation phases; (4) CardioRelax: application cluster for improved solutions to deal with stress; (5) CardioSafe: application cluster for early diagnosis and prediction of acute events.
Project aims and objectives The set of functional clothes will comprise innovative fabric sensors for ECG, breathing rate, galvanic skin, response, blood circulation and trans-thoraic impedance. The implementation of innovative pizo-resistive fibres will allow us to dynamically measure all movements of the body enabling dynamic posture and gesture detection for all degrees of freedom of movement. In addition, we will develop a wearable electronic system integrated into the functional clothes. This on-body electronic system will be flexible, bendable and washable and offering the same look-and-feel experience as normal clothing. This allows integrating the system un-obtrusively into the daily life of the user and utmost convenience. The on-body electronics will add additional sensors for the detection of movement, detection of context information (e.g. GPS location) as well as sensors for blood pressure and oxygen saturation. The core of the electronic system will be a scalable low-power processing unit that can be designed according to different applications needs. The system will not only allow the acquisition and storage of data but also the online analysis of the data will provide the needed processing power for diagnosing the health status. On top of that, wireless technology will be used to seamlessly connect the system to wired and wireless communication infrastructure and to acquire data from external sensor and intelligent (home) environments. As it will be an open, modular system design,
additional (future) sensors or specific user needs (e.g. for disabled people) can be implemented later on.
Research register
Research deliverables (academic and industrial) In Project (Months 01-18) we will implement basic functional prototypes and test these concepts in user focus group. The definition of concepts will also enable us to assess the validity of each concept with relevant stakeholders from the medical domain and from payers like health insurance, employers, pension funds and specific user groups and boards. This intense co-design with users is a key innovation element addressing the main risk of user/stakeholder acceptance. The outcome of this assessment will be used to validate business plans for each individual concept and also to select the most promising concepts for further technical and business development in the next phase. The selection criteria at milestone 3 will be based on the technical feasibility, the business plan and the user acceptance. Publications De Rossi, D., Della Santa, A. and Mazzoldi, A. (1999), ‘‘Dressware: wearable hardware’’, Materials Science & Engineering, Biomimetic and Supramoluecular Systmes, Vol. 7, pp. 31-5. De Rossi, D., Carpi, F., Lorussi, F., Mazzoldi, A., Paradiso, R., Pasquale Scilingo, E. and Tognetti, A. (2003), ‘‘Electroactive fabrics and wearable biomonitoring devices’’, AUTEX Research Journal, Vol. 3 No. 4, pp. 180-5. Mazzoldi, A., De Rossi, D., Lorussi, F., Scilingo, E.P. and Paradiso, R. (2002), ‘‘Smart textiles for wearable motion capture systems’’, Autex Research Journal, Vol. 2 No. 4, pp. 199-203. Scilingo, E.P., Lorussi, F., Mazzoldi, A. and De Rossi, D. (2003), ‘‘Strain-sensing fabrics for wearable kinaesthetic-like systems’’, IEEE Sensors Journal, Vol. 3 No. 4, pp. 460-7.
Port Elizabeth, South Africa Centre for Fibers, Textiles and Clothing, CSIR, P.O. Box 1124, Port Elizabeth 6000, South Africa Tel: 0415 0 83273; Fax: 0415 8 32325; E-mail:
[email protected] Dr Rajesh Anandjiwala, Dr Illona Racz Research staff: Michael Mkhize, Gabriella S.
Preparation and properties of b-nucleated polypropylene nanocomposites Other partners: Academic None
Industrial BAYATI, Hungary Project ends : 31 March 2004
Project started: 1 April 2002 Finance/support: R550,000 Source of support: CSIR – Parliament Grant+NRF Bilateral Funds Keywords: Nanocomposite, Polypropylene, Packaging, Composite sheets
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Intensive research on nanocomposites started about 10 years back, when Toyota developed and used the first polyamide nanocomposite. The composite was prepared by in situ polymerization from caprolactone and layered silicate filler. The main advantages of the composite containing only a few percent of filler were its high stiffness, high strength and improved thermal resistance, which were naturally accompanied by a significantly lower mass. Since then, intensive research is carried out in many laboratories and at numerous companies all over the world in order to produce nanocomposites with the most diverse matrices. The most important projected application fields of the present proposal are the automotive and packaging industries. The packaging industry is interested in the new materials because of the significantly decreased permeability of films produced from the composite compared to simple polymeric matrix. Isotactic polypropylene (iPP) is a crystalline polymer, which is manufactured all over the world in great mass and applied for variety of end-uses. iPP is not in the range of the technical or engineering polymers traditionally, but functionally it is so widely used that it is allowed to label it as technical material. Hungary is one of the biggest polypropylene producers in the East-and Central-European region, therefore, both the application development and the research focus are essential. iPP is a polymorphic material, it can crystallize in three different crystal modifications, such as the monoclinic a-form, the trigonal b-form, and the orthorhombic g-form. Traditional types of the iPP forms predominantly a-iPP under processing circumstances and the b-modification is observed only occasionally during the crystallization, and it appears as a minor constituent in the structure. The relative amount of the b-modification can be increased by special methods. g-form starts up in the case of small molecular mass or partially degraded iPP ingredients, or rather during the crystallization process of small co-monomer weight propylene random copolymers. Crystallization under high pressure also assists the inducement of g-form rich products. In the past decade the need for basic and applied research, which are related to the biPP increased greatly when research proved that several additive actuate as b-nucleator. In this manner, b-modification-rich or pure b-modification can be achieved. The industrial importance of b-iPP is the outstanding impact grade, which is multiple (up to four or fivefold) of the a-iPP and may exceed the characteristics of the copolymers with the same melt index. Ductility index, tensile and impact energy together with bursting strength values are better than that of the a-iPP. Beyond that b-iPP turned out to be satisfactorily good for some special applications, such as: .
roughened surface films,
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microporous membranes,
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films with higher burst factor,
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filaments with high adsorptive capability,
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constructional units of impact-resistant piping systems, and
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helps the deformability and stability of shape in the case of thermoforming.
The improvement of these characteristic data affects deterioration in the strength of the b-modification (like Young’s modulus or necking stress), independently from the type of the iPP. These values are 10-15 percent lower when compared to the a-iPP.
Project aims and objectives In the scientific literature – although several teams carry out research on polymer nanocomposites or b-polypropylene – no data were found on b-nucleation of polypropylene in nanocomposites. By developing nanocomposite with b -polypropylene matrices the advantages of each component is intended to combine. By using layered silicate depending on the type of nanocomposite – intercalated or delaminated – the strong improvement of thermal and/or mechanical and transport properties is anticipated. By the application of cellulose-based nanoparticles, the improvement of mechanical properties is expected, at the same time the composite will be at least partly biodegradable.
Research deliverables (academic and industrial) The proposed project on developing nanocomposites with b -polypropylene matrices will enable us in developing new products for automotive applications such as: . . . .
injection moulded components, door bracing, thermoformable sheets (e.g. rear window shelf), and presentation and publication of results.
Publications None
Port Elizabeth, South Africa Centre for Fibers, Textiles and Clothing, CSIR, P.O. Box 1124, Port Elizabeth 6000, South Africa Tel: 0415 0 83273; Fax: 0415 8 32325; E-mail:
[email protected] Dr Rajesh Anandjiwala
Buckling phenomenon in woven fabric Other partners: Academic
Industrial
None None Project started: 1 April 2003 Project ends: 31 March 2005 Finance/support: R300,000 Source of support: CSIR – Parliament Grant Keywords: Buckling, Woven fabric, Sewing automation The automation of labor intensive garment manufacturing operation is a key to enhance competitiveness of clothing and apparel industries, particularly in the developed nations where unit labor cost is very high. The problem of automation is attempted in some
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clothing research centers as modular manufacturing similar to what is applicable in the manufacturing of many engineering goods. However, the automatic feeding of the fabric is notoriously attributed to inherent the flexibility of the structures with difficulty. The fabric tends to buckle even under small forces while feeding to the sewing machine and therefore human intervention is unavoidable. The accurate estimation of critical buckling force is therefore necessary to understand the onset of buckling. Current fabric buckling models are deficient in this respect due to the hypothesis on which they are based. A more precise, computer driven model is required, which can provide information on critical buckling force to the feeding robot. In this proposal, we will develop a model that can be utilized for the automatic feed mechanisms in physical phenomenon such as sewing. We propose to modify the assumptions on which the current fabric buckling models are built. A more realistic assumption based on real phenomena of moment – curvature relationship and fabric frictional resistance will be considered to estimate the critical buckling load. The information can then be utilized to develop an automatic feeding mechanism for sewing machine.
Project aims and objectives Development of new fabric buckling model was based on more realistic assumptions and then analyzing through computer driven packages. The comparison of the model with real experimental behavior will be conducted to test the model.
Research deliverables (academic and industrial) .
Papers in reputed journals.
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A new approach for designing automatic feeding for the sewing machine.
Publications None
Port Elizabeth, South Africa CSIR Division of Manufacturing and Materials, Gomery Avenue, Summerstrand, Port Elizabeth, South Africa Tel:+27 41 5083282; Fax: +27 41 5832325; E-mail:
[email protected] Centre for Fibres, Textiles and Clothing S.A.Chapple Research staff: Dr F.A. Barkhuysen, Mr D. Qamse
Multi-functional natural fibres Other partners: Academic
Industrial
None Project started: April 2002
None Project ends: March 2004
Finance/support: Rand 300,000 (2003) Rand 170,000 (2002) Source of support: Internal funding – Government grant Keywords: Natural fibres, Cotton, Wool, Sol-gel, Microencapsulation, Grafting, Multi-functionality There has been an increasing demand for textile materials with special functionalities that can meet the existing and new application requirements. Such functionalities can be met by the development of new polymers, by using special fibre spinning processes and the modification of existing fibre surfaces by physical and chemical methods. Chemical methods include chemical modification (graft copolymerisation, alkalising, mercerisation, etc.), enzymatic treatments and application of chemicals (cross-linking, adsorption, inclusion, anchoring biopolymers, supramolecular chemistry, sol-gel coating etc.) Natural fibres have many unique properties, notably comfort and renewable/environmentally friendliness, however, it is not always easy to impart multi-functional or high performance characteristics, especially without affecting the inherent properties of the fibre. New technologies and new applications of technologies are emerging, for example, sol-gel coating, microencapsulation and grafting, which can be used to impart multifunctionality to fibres. These new technologies will be examined for use in imparting other functionalities, for example, retardency and repellency to natural fibres such as cotton and wool.
Project aims and objectives The objective of the project is to develop novel products / processes for imparting additional functionalities to natural fibres.
Research deliverables (academic and industrial) .
To build up skills, knowledge and capacity in this field.
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To develop at least one novel treatment for imparting additional functionality to natural fibres.
Publications None
Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia. Prof. Dr habil sc. ing, Austrums Klavins Research staff: Assoc. Prof. Dr habil sc. ing, V. Priednieks, Lecturer I. Ziemele, postgraduate (Master and doctoral study programs) students
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Control, optimisation and monitoring of the stitch formation process in sewing machines Other partners: Academic
Industrial
None
Company ‘‘Promshveymash’’ Orsha, Byelorussia (1969-1991) Sewing Company ‘‘Latvia’’ from 1991
Project started: 1969 Finance/support: N/A Source of support: N/A Keywords: Sewing machines, Stitch
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Effective operation of sewing machines is of crucial importance for the qualitative production of sewn goods. It is possible to attain it by improving the mechanisms of the machine, controlling and monitoring them. These problems are being solved by applying mathematical methods of statistics, theory of probability and experimental design. The research is based on the unconformity of interaction of stitch formation tools (mechanisms) and needle thread as a complex parameter which permits one to estimate the process as a whole in each cycle and to simulate this process. It allows one to find out the impact of separate mechanisms, to improve the quality of the stitch formation process, so that it is possible to control, optimise and monitor them. On this basis the sewing machines are modernised or rationally used in mass production lines.
Project aims and objectives . .
To work out the investigation methods of the sewing machine process. To develop methods of the basic, complex parameters control, optimization and monitoring.
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To develop practical methods for increasing the sewing machine’s serviceability, improving separate mechanisms of the machine.
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To work out methods for the selective application of sewing machines for a rational organization of mass production lines in the garment industry.
Academic deliverables .
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The following part of the study programs for Master’s has been worked out, namely, control and monitoring of the sewing machine process. The results of the research have been used by doctoral students acquiring investigation methods.
Industrial deliverables .
Control, monitoring and improving the quality and serviceability of sewing machines.
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Rational organization of garment mass production lines.
Publications Aizpurietis, A.V., Klavins, A.R., Poluhin, V.P. and Sharamet, U.I. (1988), ‘‘Raschot chetirjohzvennogo mechanizma nitepritjagivatelja shvejnih machin na EVM’’, Journal Tehnologia logkoi promishlennosti, Moscow, Vol. 6, pp. 94-7. Klavins, A. and Priednieks, V. (1998), ‘‘The quality improvement problems of the operation sewing machines and the prospects of the development of scientific research’’, Scientific Conference of ‘‘Technologies and Design of Consumer Goods’’, Kaunas University of Technology, 21-22 April. Klavins, A.R., Salenieks, N.K. and Rachok, V.V. (1974), ‘‘Diagramma ispolzovanija igolnoi niti’’, Machinostrojenie dija logkoi promishlennosti, Moscow, No. 3, pp. 3-7. (The) Method for Plotting Needle Thread Take-up Curve, Pat (USSR), Nr. 324322 IPCI. D. 05 B45/00. (The) Method for Plotting Needle Thread Take-up Curve, Pat (USSR), Nr. 461189 IPCl. D. 05 B45/00. Olshanskij, V., Fedoseyev, G. and Klavins, A. (1987), ‘‘Raschot parametrov prushinih kompensatorov shvejnih mashin’’, Journal Tehnologia logkoi promishlennosti, Moscow, Vol. 4, pp. 114-15. Priednicks, V. and Klavins, A. (1997), ‘‘The optimization of lockstitch formation system in sewing machines’’, The 78th World Conference of The Textile Institute in Association with the 5th Textile Symposium of SEVE and SEPVE, Vol. 11, Thessaloniki, Greece, pp. 195-204. Some Adjusting Techniques for Sewing Machines, Pat (USSR) 442252. IPCl D 05 B 69/24. Ziemele, I., Klavins, A. and Priednieks, V. (1997), ‘‘Selection of lockstitch sewing machine obtaining a high quality of thread joints in garment’’, abstract of the papers presented at the 26th Textile Research Symposium at Mt Fuji, Shizouka, Japan, 3-5 August, pp. 60-3.
Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia Prof. Dr habil. sc. ing. Viktoria Kancevicha Research staff: Prof. Dr habil. sc. ing, V. Kasyanov, Assoc. Prof. Dr sc. ing. H. Vinovskis, postgraduate (Master and doctoral study programs) students
Development of new textile technology for manufacturing hybrid textile vascular grafts Other partners: Academic Latvian Medical Academy Project started: 1980 Finance/support: N/A Source of support: N/A Keywords: Technology, Textiles
Industrial None Project ends: No limit
In the fields of medicine and bioengineering extensive efforts have been directed to the development of various new types of vascular grafts using different technologies. The textile industry has a lot of practical experience in the production of different kinds of vascular grafts and allows a high production rate to be reached.
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Nevertheless there are practical needs for compliant grafts for patients with cardiovascular disease. Clinical implantation and chronic experiments on animals with various grafts have indicated a fairly good correlation between their compliance and patency (especially for a diameter less than 6 mm) because the compliance vascular graft practically does not change the haemodynamics of the blood flow. Thus compliant vascular grafts having mechanical properties matching the human arteries are very promising for successful reconstruction operation and good patency. This problem of developing new textile technology and producing compliant vascular grafts is very important for Latvia because cardiovascular disease is very high – and not only in the Baltic states. The investigation of the peculiarities of the mechanical behavior and structure of human blood vessels is carried out at RTU. On this basis the new structure of the hybrid textile materials is developed. Using the system of two threads having substantially different modulus of elasticity, it is possible to model peculiarities of the biomechanical behavior of the arterial tissue.
Project aims and objectives .
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Development of the new textile technology for manufacturing novel hybrid compliant vascular grafts using knowledge of the biomechanical properties and structure of human arteries. Manufacturing of novel compliant hybrid vascular grafts with biomechanical properties matching the host arteries. Establishing the new principles of the manufacturing of the hybrid material composed of two different types of threads for creation of the reinforced composite structure applicable to different engineering purposes. As expected, these structures will provide unique properties and will be characterised by improved reliability and durability.
Academic deliverables .
The part of the study Masters program in textile technology has been worked out.
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The methods and results of the research have been used in Doctoral study programs.
Industrial deliverables The new textile technology for manufacturing novel hybrid compliant vascular grafts. Publications Chnourko, M. and Kancevich, V. (1998), ‘‘Woven textile biomaterials international conference’’, Textiles Engineered for Performance, UMIST, Manchester, 8-11 July. Kancevicha, V. and Kasyanov, V. (1994)., ‘‘Small diameter blood vessel prostheses’’, Fibres and Textiles in Eastern Europe, Vol. 2 No. 3, pp. 32-3. Kancevicha, V. and Kasyanov, V. (1996), ‘‘Crimp vascular graft’’, Latvian Patent, Nr. 10836. Kancevicha, V. and Kasyanov, V. (1998), ‘‘Crimp vascular graft’’, Latvian Patent, Nr. 12175.
Kasyanov, V., Purinya, B. and Kancevich, V. (1994), ‘‘Compliance of human blood vessels and novel textile vascular grafts’’, Abstracts of Second World Congress of Biomechanics, Amsterdam, The Netherlands, 10-15 July, Vol. 1, p. 28. Kasyanov, V., Kancevich, V., Purinya, B. and Ozolanta, I. (1996), ‘‘Design of biomechanically compliant vascular grafts’’, 10th Conference of the European Society of Biomechanics, Leuven, 28-31 August, p. 26. Kasyanov, V., Kancevich, V., Purinya, B., Izolanta, I. and Ozols, A. (1998), 1st Conference of the European Society of Biomechanics, Toulouse, 8-11 July.
Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia. Associate Professor, Dr sc. ing. Ivars Krievins Research staff: Msc, Dipl. ing. V. Sorokins, Msc, Dipl. ing. S. Valaine, postgraduate (Master and doctoral study programs) students
Latvian clothing market product oriented research Other partners: Academic Terminology Committee of Academy of Sciences
Project started: 1988 Finance/support: For particular objectives Source of support: N/A Keywords: Clothing, Fashion
Industrial Ministry of Light Industry of Latvia (1988-89) Ministry of Economics of Latvia (1997–98) Lauma Co., Liepaja, Latvia (1996–97) Project ends: No limit
General long-term Latvian clothing market studies embrace common information areas met through market secondary (desk) research. Mainly it is based on the analysis of the Latvian 8000 household budget survey data and others available, e.g. pricing statistical data. The results of the Latvian clothing market general monitoring are oriented towards use in academic and industrial fields. In addition, the results are used for planning of primary clothing market research within a narrower in-depth range of clothing products. The morphological structure of ladies’ underwear demand has been determined by the studies of catalogues, that of corresponding retail outlets and by administering questionnaires to 300 respondents on their actual and planned underwear wardrobe in 1997. In order to carry out the inquiry, Latvian/Russian terminology has been developed for naming illustrated product characteristics of the questionnaires. An elaborated thesaurus of clothing production terms is included in wider consumer education programmes as well as in the academic and professional ones. Conceptual analysis can be used for coordination and subordination of the educational contents within different levels and sectors of clothing education.
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Project aims and objectives . .
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General monitoring of Latvian clothing market size and segmentation trends. Distribution of consumer preferences by morphological attributes within in-depth analysis of clothing products. Simulation of the garment quality evaluation based on consumer perception/satisfaction analysis.
Academic deliverables .
Morphological simulation of clothing product differentiation.
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Comprehensive clothing quality evaluation methodology. Mathematical simulation of clothing sizing.
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Dictionary of Latvian/Russian clothing terms as the basis for product information processing.
Industrial deliverables .
General information on Latvian clothing market.
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Particular information on the women’s underwear style preferences in Riga, 1997.
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Feasibility of textiles and clothing standardization items in Latvia.
Publications Blinkens, P., Be¯zina, V. and Krievins˘, I. (1989), Tekstilr & u¯pniecibas terminu v & a¯rdnica, Zina¯tne Riga, 855, 1p. (Dictionary of 14,000 textile terms). Der lettische Textil- und Bekleidungsmarkt ¼ LR tekstiliju un apgerbu tirgus – Riga (1997), 57 S. (German/Latvian: Latvian textiles and clothing market, Desk research). Krievins, I. (1996), ‘‘Systematization of clothing technology concepts for Latvian terminology’’, (Lengvsios pramones tehnologios ir dizainas), Kauno, pp. 221-8. ‘‘Rigas sievies˘u apaks˘g`e rbu pieprasi-juma struktu¯ra’’ (1997), gada¯, ZPD pa¯rskats; Riga, 97,1p (Structure of ladies’ underwear demand in Riga).
Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia Prof. Dr habil sc. ing. Silvia Kukle Research staff: Assoc. Prof. Dr sc. ing. A. Vilumsone, Lecturer I. Vilumsone, Postgraduate (Master and doctoral study programs) students
The investigation of the geometry and composition of Latvian folk art designs Other partners: Academic Latvian Council of Science 1989-1996 Project started: 1989
Industrial Latvian Crafts Chamber, 1993-present Project ends: No limit
Finance/support: N/A Source of support: N/A Keyword: Textiles Folk art is the form of ethnic consciousness to consolidate not only people of one nation but also of many generations. It is a means for manifesting and forming the specific face of the country and investment in the worldwide cultural heritage. We started our work on computerized collections in 1989, involving scholars of our university and many generations of students. As a result, material from museum and private collections and published works were collected together and systematized and presentations were prepared. The data address different users and applications, such as teaching materials to support school and university courses such as home economics, crafts technologies, ethnography ornamentation and composition; teaching materials for craftsmen for use in design studies libraries to support reproduction for local users – householders, artists and tourist markets; as a source of ideas – motifs and symbols, technologies, ways of material combination with different properties, fashions, placement of ornamentation, compositional solutions, creation of motifs, methods of designing double-face ornamented fabrics, pattern designing; methods of forming color ranges; leveraged space filling; fantasy for imagination. The other application is a well organized source of multipurpose scholastic studies, for example, to sort and classify, to study decoration methods and/or technologies, to find out rules; ethnographic studies, historical studies; regional studies; ethnoastronomy studies, linguistic studies.
Project aims and objectives Aim: Creation of the computerized knowledge basis of Latvian folk designs, crafts, technologies and tools. Objectives: Creation of the image and text libraries for different groups of folk textiles (mittens, table cloths, towels, girls’, women’s and men’s folk costumes, blankets), woodwork tools; investigation of basic rules followed in forming motifs, symbols, compositional groups and composition; investigation of the colour, symbol preferences in different regions and products; comparative analysis of ornamentation traditions in Latvian and Lithuanian folk art; analysis of the information structure and creation of the codification system; calculation of data leading system.
Academic deliverables New knowledge supplementing basics of Latvian folk art; creation of new methods of investigation; creation of databases for further investigations; investigation of the use of prehistorical symbols and signs in Latvian border patterns, comparison with other ancient cultures; creation of the system of hypothesis; highly systematized teaching materials supporting different study courses.
Industrial deliverables Methods of motifs’ creation, organization of rhythms, color ranges, border and panel type compositions; methods of creation of two face fabric designs; library of designs for reproduction (crafts companies, crafts people, students) and as an inspiration for new designs (artists, craftsmen, designers, students), knowledge of folk art basics (artists, craftsmen, designers, technologists).
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Publications Kukle, S. (1993), Geometry of Latvian Designs, thesis of Dr habil ing dissertation, Latvia. Kukle, S. (1995), Geometry of the Crosses and Diamond Type Signs Preferably Used in Latvian Folk Designs. The Investigation and Optimization of the Textile Technology, Riga, Latvia, pp. 67-78. Kukle, S. (1996), ‘‘Computer graphics as a tool giving unambiguous results’’, poster abstracts, 2nd World Congress on the Preservation and Conservation of Natural History Collections, University of Cambridge, 20-24 August. Kukle, S. (1997), ‘‘Latvian border patterns, Lengvosios pramones technology’’, Kauno tecgnologijos universitetas, Lithuania. Kukle, S., Vilumsone, A., Vilumsone, I. and Kikule, D. (1996), ‘‘Database of Latvian folk designs’’, poster abstracts, 2nd World Congress on the Preservation and Conservation of Natural History Collections, University of Cambridge, 20-24 August. Vilumsone, I., Kukle, S. and Zingite, I. (1995), ‘‘The ornaments and rhythms of sashes of Alsunga (town on Western Baltic seaside)’’, The Investigation and Optimization of the Textile Technology, Riga, Latvia, pp. 54-60.
Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia Tel: 00371 708 9333 Assistant Professor Ilze Baltina, Department of Mechanical Technology of Fibre Materials Research staff: Assistant Professor I. Brakch, Associate Professor H. Vinovskis and postgraduate students
Wool carbonizing in the radio frequency electromagnetic field Other partners: Academic None
Project started: 1989 Keywords: Electromagnetics, Radio, Wool
Industrial Textile factory at Kustanai (Kazakhstan) 1992-present Textile factory at Cernigov (Ukraine) 1993-1995 Textile factory ‘‘Riga tekstils’’ (Latvia) 1991-1994 Project ends: No limit
In wool carbonizing the baking process is usually carried out at very high temperatures, 120-125 C, but sometimes also at 130 C. At such temperatures wool decomposes and turns yellow. It is advanced by a high concentration of sulphuric acid solution. In the new method, instead of baking with hot air, there is inclusion of radio frequency electromagnetic field, which creates vegetable matter energy that is extracted as heat.
Wool temperature does not exceed 100 C and end moisture is 10-15 per cent, but vegetable matter temperature is sufficient for hydrolysis. Sulphuric acid concentration in this case does not exceed 35–40 per cent. Wool fibre rapid hydrolysis and dissolution occurred when the acid concentration ranged from 40 per cent up.
Research register
Project aims and objectives To work out new carbonizing technology in which vegetable matter can be removed maximally, but wool fibre damage is very low.
Academic deliverables Practice and new knowledge for Master’s and postgraduate students.
Industrial deliverables New carbonizing technology which prevents wool damage during carbonizing. Publications Baltina, I. and Brakch, I. (1997), ‘‘Wool carbonizing in a radio frequency electromagnetic field’’, World Textile Congress on Natural and Natural-Polymer Fibres, University of Huddersfield. Baltina, I. and Reihmane, S. (1998), ‘‘Use of cellulose production waste product lignosulphonate in carbonisation of wool’’, 7th International Baltic Conference on Materials Engineering, Jurmala, Latvia, pp. 161-5. Zarina, I. (Baltina, I.), Reihmane, S., Braksch, I. and Liepa, I. (1995), ‘‘Wool carbonizing methods’’, Progress in New Polymer Materials: Seminar Materials of TEMPUS Programme, Riga.
Roubaix, France Ecole Nationale Supe´rieure des Arts et Industries Textiles, ENSAIT 9, Rue de l’Ermitage BP30329, F – 59056 Roubaix, France Tel: +33(0)320256457; Fax: +33(0)320272597; E-mail:
[email protected] Joseph Lok-wai Lo, GEMTEX (Ge´nie et Mate´riaux Textile) Research staff: Prof. Besoa Rabenasolo, Prof. Anne-Marie Jolly Desodt, Prof. Jean-Marie Castelain, Mauricio Camargo
Benchmarking performance: supply chains in the textile-garment industries Other partners: Academic None
Industrial Clothing Industry Training Authority (CITA, Hong Kong, China), Centro de Investigacion y Desarrollo Tecnologico Textil Confeccion de Colombia (CIDETEXCO, Colombia), Participating companies (names cannot be disclosed)
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Project started: January 2002 Project ends: May 2005 (estimated) Finance/support: 45700 e Source of support: Instituto colombiano para el desarrollo de la ciencia y la tecnologia ‘‘francisco jose de caldas’’, colciencias Keywords: Benchmarking, Performance evaluation, Clothing, Textile, Supply chain, China, Colombia, Trade-off The aim of this multinational project is to provide organizations in the textile and garment industries the initiatives in performance improvement through benchmarking with their peers within their industrial domain. We have collaborations with several textile associations around the world, most notably CITA in Hong Kong (China) and CEDITEXCO in Colombia. Trained facilitators from the textile associations collect solid and quantitative data from day-to-day documents on the participants’ sites. Collection data were then consolidated to perform various analyses. From the management point of view, each participating company will receive a detailed, individual report, which consists of different easy-to-follow benchmarking tools such as process mapping, force field analysis to improve their lead time, quality, and resource utilization. The first hand data from the industry will provide valuable information to understand the nature of performance, as well as the most appropriate methodology to carry out benchmarking. In particular, this research will address the following questions. (1) Are there performance trade-offs in the garment factory and textile mill respectively? If any, how they interact? (2) How the performances of one supply chain player affect the performances of another? (3) Companies can have very different natures, such as the size and products, how can we group different benchmarking partners together to evaluate the performance of each benchmarking partner? (4) On a national wide scale, what are the different competitive advantages in different nations It is believed that the developed performance measurement framework is generic enough to be applied to other industries. Besides, the whole process employed in this project will certainly provide an excellent example for future benchmarking projects.
Project aims and objectives To construct a framework of supply chain performance metrics to allow an efficient and meaningful data collection to be carried out. To collect performance data from the textile and garment industries in China and Colombia. To analyze the performance of textile-garment supply chains, as well as individual players involved. To suggest improvement initiatives based on the detailed analyses.
Research deliverables (academic and industrial) Seven conferences in Hong Kong, Macau, South China and Colombia to promote benchmarking and share findings with the industry. Individual reports to be delivered to participating companies. Publications Lo, J.L.W., Rabenasolo, B. and Jolly-Desodt, A-M. (2004), ‘‘A fashion chain which employs a speed-oflight operation to gain competitive advantage’’, Textiles and Clothing, No. 20. Lo, J.L.W., Rabenasolo, B. and Jolly-Desodt, A-M. (2004), ‘‘Fashion supply chain – the Spanish style’’, Logistics, No. 20 (in press). Lo, J.L.W., Rabenasolo, B. and Jolly-Desodt, A-M. (2004c), ‘‘Performance trade-offs in the clothing industry – empirical results’’, Journal Europe´an de Syste´me Automatise, No. 20 (in press).
Selkirkshire, Scotland Heriot-Watt University, Netherdale, Galashiels, Selkirkshire, Scotland Tel: 01896 892136; Fax: 01896 758965; E-mail:
[email protected] School of Textiles George Stylios, Bert Mather, Bob Christie, Dean Robson, The School of Textiles, Heriot-Watt University
Engineering the performance and functional properties of technical textiles Other partners: Academic
Industrial
UMIST British Textile Technology Group University of Leeds Industrial Member companies Project started: 1 December 2002 Project ends: 31 November 2005 Finance/support: £1,000,000 Source of support: Department of Trade & Industry Engineering and Physical Science Research Council Keywords: Industrial textiles, Non-woven, Biomedical, Fibres, Yarns, Fabrics, Garments Technical textiles are defined as textile materials and products manufactured for their technical performance and functional properties rather than their aesthetic and decorative characteristics. Despite market predictions for technical textiles, and incremental advances in some companies, many fundamental problems relating to the engineering and development of technical textiles remain to be solved; these become more urgent due to fierce global competition. There are many areas that still employ subjectivity and tradition that hinder the leap forward the sector needs to enable the
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development of new products and applications of textiles as engineered materials. Structural mechanics of textiles has been researched extensively, focusing on the understanding of simple textile structures mainly for apparel applications. Whilst such research may have solved specific problems, there are serious limitations to the production of generic solutions for precision engineering and manufacture of technical textiles, due to the inherent complexity of technical textile materials and their structures. Limited research has been carried out on the engineering of other properties such as thermal and fluid, which are equally important for the engineering of technical textiles. Consultation within the academic community, and with industrial members of the TechniTex Partnership over the past 12 months has established three key themes of research required to enable the proposed underpinning platform of knowledge to be established. These mutually dependent themes are modelling (to enable 3D design, simulation, and visualisation), measurement (to define and understand the relationships between structure, performance, and functionality), and manufacture (to enable appropriate manufacturing conditions to create the engineered textile). Within each a fundamental understanding of materials is required. The three themes are reflected in the technical textile challenges. To ensure the industrial relevance and applicability of the theme-based research proposed, it is not possible to explore each theme in isolation. As shown above the level of mutual dependency requires that an integrated programme of research be conducted.
Project aims and objectives The rapidly growing technical textiles industry draws ideas and expertise from a diverse range of academic groups and disciplines. The aim of the TechniTex core research programme is to formalise and extend this distributed generic body of knowledge relating to textiles. This extended and integrated body of knowledge will generate a platform for the creation of methodologies for specification, design and manufacture of technical textiles, and relate performance and functionality with manufacturing processes. The specific objectives are to: .
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establish databases of existing technical textiles, associated technical data, and the associated body of knowledge; classify existing technical textile structures on the basis of their function, properties, and end use; classify processing conditions for fibres, yarns, and fabrics; identify missing data in terms of structural and mechanical detail, and fibre and yarn properties; research and develop new and enhanced test methods and equipment for technical textiles; generate new data to further establish the body of knowledge on existing yarns, fibres and fabrics;
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establish the performance criteria necessary for technical textiles appropriate to their end use;
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create geometric and mechanical models of technical textile structures using the derived classification and data;
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create predictive models for these processes specific to the demands of technical textiles, and to optimise their manufacturing conditions to fulfil the specified performance criteria; conduct an experimental programme for the verification of the models;
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create interfaces between the models and generate an integrated suite for the engineering of technical textiles;
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conduct a programme of dissemination and technology transfer through established TechniTex Faraday practices.
Research deliverables (academic and industrial) .
an integrated suite of databases encapsulating the body of knowledge on technical textiles;
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geometric models for visualisation and input into performance modelling;
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mechanical models for performance and manufacturability; new and enhanced test methods and equipment;
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new standards for the specification and manufacture of technical textiles; methodologies for the creation of engineered technical textile structures;
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methods for optimising manufacturing conditions, processes and materials geared to the specific needs of these engineered structures;
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a technology transfer pathway through to the wider industrial and academic networks of the TechniTex Partnership.
Publications Bandara, P. and Islam, S. (1991), ‘‘Yarn spacing measurement in woven fabric with special reference to start-up marks’’, J. Text. Inst., Vol. 87, Part I, pp. 107-19. Finn, J.T., Sagar, A. and Mukhopadhyay, S.K. (2000), ‘‘Effect of imposing a temperature gradient on moisture vapour transfer through water resistant breathable fabrics’’, Tex. Res. J., Vol. 70 No. 5, pp. 460-6. Partridge, J.F., Mukhopadhyay, S.K. and Barnes, J. (1998), ‘‘Dynamic air permeability behavior of Nylon66 air bag fabrics’’, Text. Res. J., Vol. 68 No. 10, pp. 726-31. Potluri, V.V.P., Atkinson, J. and Porat, I. (1992), ‘‘Performance assessment of a robot for use in a fabric test cell’’, 29th International Matador Conference, Manchester, April. Russell, S.J. and Mao, N. (2000), ‘‘Directional permeability in homogeneous nonwoven structures. Part 2: permeability in idealised structures’’, J. Text. Inst., Vol. 91, pp. 344-58.
Selkirkshire, Scotland Heriot-Watt University, Netherdale, Galashiels, Selkirkshire, Scotland Tel: 01896 892136; Fax: 01896 758965; E-mail:
[email protected], Professor G.K. Stylios, School of Textiles Research staff: Ms Fan Han
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HOMETEX: a virtual trading centre for textiles Other partners: Academic None
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Industrial OCF Ltd Silicon Graphics Inc. Scottish Enterprise Borders Scottish Textiles Manufacturers Association Borders Textile Forum Project ends: 31 August 2004
Project started: 1 September 2001 Finance/support: £1,000,000 Source of support: EU ERDF Objective 2 Keywords: Drape, Augmented reality, Virtual trading, Home shopping, 3D simulation, Dynamic draping In recent years we have witnessed a revolution in networking of information on a global scale via the Internet. Many companies have capitalised on this provision and have used it in many diverse ways, from electronic mailing to marketing, selling and trading of products and services. Marketing and selling of limp products such as textiles and, particularly, garments using new multimedia techniques would be extremely beneficial to the industry, since it would enable companies to reduce product to market, to enhance product development through 3D visualisation and to trade directly without the intervention of retailers. But selling of garments is not as easy as selling other commodities; garments are made of limp materials which take up the configuration of the wearer; customers would in most cases like to wear the garment, or, in the case of buyers, see the garment worn by a model. For the effective exploitation of these possibilities, we should, therefore, develop a multimedia environment to enable the simulation of drape behavior of garment designs on virtual models who may resemble real customers. The textile industry chain, being a traditional industry, is very conservative in the use of multimedia for manufacture, advertising and/or sales. The reason is firstly because the industry consists of small companies which do not have the resources to use multimedia technologies effectively without training, and secondly there is no technological infrastructure available to realistically visualise new products from home. This project aims to pilot such possibilities which have other benefits to this industry in terms of ‘‘just-in-time’’ manufacture, 3D visualisation of new products and better communication with their customers.
Project aims and objectives The main objectives of this scheme are as follows: . To develop a virtual Home Trading Centre for the textile, clothing and retailing industries: ‘‘HomeTex’’. . To enable the production of virtual fashion shows for buyers through CD-ROM and Internet presentations.
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To network 40 companies with 500 homes (directly) via the technology and to regularly upgrade and manage company trade data, for piloting the technology.
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To establish and provide through ‘‘HomeTex’’ other trade data, real-time electronic mail, Tele Trading and, possibly, banking.
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To enable textile and clothing companies to interface with this technology so that new products can be made much faster and to minimise energy, raw materials and other resources. To network with other services, such as Cyber Tex and SPIN.
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Research deliverables (academic and industrial) A Virtual Trading Centre in Textiles operating from the Borders of Scotland. Publications Stylios, G.K. and Wan, T.R. (1998), ‘‘A new collision detection algorithm for garment animation’’, International Journal of Clothing Science and Technology, Vol. 10 No. 1 pp. 38-49. Stylios, G.K. and Zhu, R. (1998), ‘‘The characterization of static and dynamic drape of fabrics’’, Journal of the Textile Institute, Vol. 88 No. 4, pp. 465-75. Stylios, G.K., Wan, T.R. and Powell, N.J. (1995), ‘‘Modeling the dynamic drape of fabrics on synthetic humans: a physical lumped parameter model’’, International Journal of Clothing Science and Technology, Vol. 7 No. 5, pp. 10-25. Stylios, G.K., Wan, T.R. and Powell, N.J. (1996), ‘‘Modeling the dynamic drape of garments in synthetic humans in a virtual fashion show’’, The International Journal of Clothing Science and Technology, Vol. 8 No. 3, pp. 44-55.
Selkirkshire, Scotland Heriot-Watt University, Netherdale, Galashiels, Selkirkshire, Scotland Tel: 01896 892234; E-mail:
[email protected] Dr Lisa Macintyre, School of Textiles and Design
A study of pressure delivery for hypertrophic scar treatment Other partners: Academic
Industrial
None None Keywords: Pressure garments, Pressure measurement, Elastic fabrics Pressure garments are the most common treatment for hypertrophic scars resulting from serious burn injuries. However, very little scientific research had ever been conducted on the properties of the fabrics, or the effects of different garment construction methods, used to make pressure garments. This investigation was done using the following three parts.
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(1) Properties relating to the construction, composition, durability, tension and comfort of 18 different fabrics currently used in pressure garment construction in the UK were quantified. These fabrics were shown to have a wide range of properties. (2) A new method of calibrating I-scan pressure sensors (made by Tekscan Inc.) was developed, which enabled low interface pressures up to 50 mm Hg to be measured with an accuracy of ±2.1 mm Hg. This development was a significant improvement in the accuracy of low interface pressure measurement. (3) The I-scan sensors were used to measure the pressures exerted by pressure garment samples on a range of cylinder models and human limbs. This investigation showed that the actual pressure delivered depended upon: the reduction factor used; the fabric used; and the circumference of the cylinder model or limb. Therefore, to achieve a particular pressure on a patient’s body the reduction factor should be varied to suit both fabric tension and limb circumference. This is not currently done in NHS hospitals (survey conducted in 1999). Therefore, pressure garments currently constructed in NHS hospitals are likely to exert pressures ranging from ineffectively low to dangerously high. Work will continue in this area. Conference papers Macintyre, L. and Baird, M. (2004), ‘‘A study of elastic fabrics for use in the treatment of hypertrophic scars’’, paper presented at the British Burn Association 37 Annual Meeting, Manchester Conference Centre, 28-30 April 2004, winner of best paper BBA 2004. Macintyre, L., Baird, M. and Weedall, P. (1999), ‘‘Elastic fabrics for use in the treatment of hypertrophic scars’’, paper presented at the Ghent University’s 3rd International Conference on New Products and Production Technologies for a New Textile Industry, 1-2 July 1999, pp. 16-26. Macintyre, L., Baird, M. and Weedall, P. (1999), ‘‘Elastic fabrics for use in pressure garments –- comfort properties’’, paper presented at the Bolton Institute’s ‘‘Medical Textiles’99’’ Conference, 24-25 August 1999 (Published in Medical Textiles, Woodhead Publishing Ltd, Cambridge, ISBN 0-8493-1226-4), pp. 74-81. Macintyre, L., Baird, M. and Weedall, P. (2003a), ‘‘The study of pressure delivery for hypertrophic scar treatment’’. paper presented at the Bolton Institute’s Medtex, 3, 8-9 July 2003a (book of conference proceedings not yet published). Macintyre, L., Baird, M. and Weedall, P. (2003b), ‘‘The study of pressure delivery for hypertrophic scar treatment’’, Heriot-Watt University’s INTEDEC, Edinburgh, 22-24 September 2003. Macintyre, L.M., Baird, M. and Weedall, P.J. (1998), ‘‘A study of elastic fabrics for use in the treatment of hypertrophic scars’’, Conference Proceedings from World Textile Congress, Industrial, Technical and High Performance Textiles, Huddersfield, 15-16 July 1998, pp. 319-27. Journal papers Macintyre, L. and Baird, M. (2004a), ‘‘The study of pressure delivery for hypertrophic scar treatment’’, International Journal of Clothing Science and Technology, Vol.16 Nos 1/2, pp. 173-83. Macintyre, L. and Baird, M. (2004b), ‘‘Pressure garments for use in the treatment of hypertrophic scars – a review of the problems associated with their use’’, BURNS (in press).
Magazine articles Macintyre, L., Baird, M., Weedall, P.J. and Hassall, C. (1999), ‘‘Elastic fabrics for the treatment of hypertrophic scars – comfort and colour’’. Technical Textiles International, Vol.8 Nos 9, pp. 19-22 ISSN 0964-5993. ‘‘Wound management – treating serious burns’’, Medical Textiles, April 1998, p.9, ISSN 0266-2078. Macintyre, L. (1998), ‘‘Elastic fabrics for treating hypertrophic scars’’, Medical Textiles, ISSN 0266-2078. ‘‘Lecturer cuts her cloth to help heal scars’’, Times Higher Education Supplement, July 1998.
Research deliverables (academic and industrial) None Publications None
Tampere, Finland Tampere University of Technology, Institute of Fibre Materials Science, P.O. Box 589, FIN-33101 Tampere, Finland Tel: +358-3-311511; Fax: +358-3-31152955; E-mail:
[email protected] Dr Ali Harlin Research Staff: Pirjo Heikkila¨, Esa Leppa¨nen
Self-organized functional materials Other partners: Academic
Industrial
Helsinki University of Technology None University of Helsinki University of Art and Design Helsinki Project started: None Project ended: 31 December 2003 Source of support: Tekes, the National Technology Agency of Finland The aim of the project is to combine the expertise of block copolymer RAFT-synthesis expertise, nanostructure expertise, textile fibre expertise and processing and filter expertise to assess novel types of nanostructured fibres. The hypothesis is that such fibres could be added within the supporting fibre mat to: (1) add surface area for absorptive filters; (2) act as a delivery media in specific applications; (3) act as catalyst support; and (4) act as templates for sensors functions. In all these cases, response to environmental changes is an additional very attractive goal. The goal is to achieve enhanced surface area for nanofilters.
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Project aims and objectives The technical target for the project is to demonstrate nanostructured fibre filter and special web containing self-organized polymer structures. Technically feasible products and processes are aimed. The products should be environmentally friendly and incinerable. The products should lead to acceptable mechanical, chemical, and heat resistance. Publications None
Tampere, Finland Tampere University of Technology, Institute of Fibre Materials Science, P.O. Box 589, FIN-33101 Tampere Tel: +358 - 3 - 3115 11; Fax: +358 - 3 - 3115 2955 docent Eija Nieminen Research staff: Pa¨ivi Talvenmaa, Auli Sipila¨
Kitex Other partners: Academic
Industrial
None
SOK, Kesko, Virke FINATEX & Tekstiili- ja jalkinetoimittajat ry Project started: 1 May 2003 Project ended: 31 December 2003 Source of support: Tekes (National Technology Agency of Finland) and the partners Keywords: Textiles, Recycling, Reducing the waste amount The aim of the waste policy in European Union and Finland is to reduce the waste amount and increase the recycling of all materials. In the first part of this project, the information of the finnish and international textile recycling systems is collected with the information of volumes, used technology and business operation models. The information is also collected concerning the preconditions and goals of the producers, importers and trade in the area of developing a recycling system for the textile products. Project is realized in the co-operation with partners (producer, importer and trade).
Project aims and objectives The aim of this project is to prevent the waste attached to the consumers’ textile products and rise to challenge the future by developing the ways of actions to the situations when textile waste is not allowed to take to the dumping place. Publications None
Tampere, Finland Tampere University of Technology, Institute of Fibre Materials Science, P.O. Box 589, FIN-33101 Tampere, Finland Tel: +358-3-311511; Fax: +358-3-31152955; E-mail:
[email protected] Dr Heikki Mattila Research Staff: Auli Sipila¨, Nina Ojala
Smart store Other partners: Academic
Industrial
Designium / Helsinki University of Art and Designs (leader) Institute of Software Systems Tampere University of Technology
Lectra Finland Major Blue Ltd Turo Tailor Luhta/L-Fashion Group Sokos/SOK Project started: 1 August 2002 Project ends: 31 January 2004 Source of support: Tekes, National Technology Agency of Finland Industrial partners Keywords: Concept, Customer study, Mass customization, Software integration The goal of the project The goal of the Smart Store project is to create a concept of a new intelligent garment store that takes advantage of the new available technologies. In the first phase of the project, till the end of year 2003, focus is in studying the possibilities and background technologies to achieve this goal. The technologies available open new possibilities to the customer by providing support in choosing, ordering, and paying the garment – a new kind of shopping experience, in general. The technologies examined include 3D measurement and visualization of the human body, virtual 3D try-on of the garment, automated decision of the appropriate and fitting size of the garment, and – on the other hand – enhancing the whole logistic chain.
Actions (1) University of Art and Design Helsinki (Uiah) Industrial Design Department . Use of consumer decision-making models from economics; .
Information gathering from defined target groups with probes method;
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Observation of target groups; Evaluation of similar concepts;
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User centric design process from the gathered information;
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Platform-based concept; Usability testing of the concept’s interactive prototype;
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Scenarios of use from the main features of the concept;
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(2) Tampere University of Technology, Fibre Materials Science . Offer information from the apparel industry and trade to the other academic partners; . Gather information from other concepts and their working methods (benchmarking); . Apply the technological know-how when comparing the options e.g. different body scanners or mass customization methods; . Find out the way the garment producers (who are partners in this project) work and define how the new concept will fit in their working methods and what kind of changes are needed; . Find the solutions for the logistic chain behind the concept; .
Take part in concept building.
(3) Tampere University of Technology, Institute of Software Systems . Designing an architecture for software integration; . Studying the systems of the industrial partners for the above, including current data flow, data formats and protocols employed; . Studying the promise and applicability of 3D visualization and virtual tryon systems.
Project aims and objectives (1) Boost the efficiency of supply chains and networks of the textile and clothing industry and trade by creating a new e-business concept. (2) ‘‘Semi-virtual’’ buying experience: body scanning – virtual fitting. (3) Mass customisation: best fit / made to measure = instant delivery / order delivery. (4) More efficient logistics – smaller forecast errors – faster response to demand. (5) New kind of buying experience – boosted sales – better visibility for alternative articles – repeat orders possible, etc. Publications None
Tampere, Finland Tampere University of Technology, Institute of Fibre Materials Science, P.O.Box 589, FIN-33101 Tampere, Finland Tel: +358-3-311511; Fax: +358-3-31152955; E-mail:
[email protected] Arja Puolakka Research staff: Pertti Nousiainen, Arja Puolakka, N.N.
Biotechnical quality improvement of synthetic textile fibres Other partners: Academic TU-Graz, Austria VTT Biotechnology, Finland University of Minho, Portugal
Project started: 1 October 2001 Finance/support: 1739220 e Source of support: EC
Industrial Sattler AG, Austria Textil Alberto de Sousa SA, Portugal Rhodia Industrial Yarns AG, Switzerland FISIBE, Portugal Inotex, Czech AB Enzymes Project ends: 30 September 2005
Publications None
Tehran, Iran Amirkabir University of Technology, No. 424, Hafez Ave., TehranIran Tel: +98216959148; Fax: +98216959148; E-mail:
[email protected] Textile Eng. Department Research staff: Dr F. Dadashian, Dr M. Montazer, Dr M. Arami
The effect of enzymatic treatments on Iranian wool Other partners: Sh. Rahimi and Gh. Bazyar
Academic
Research register
Industrial
None None Project started: December 2002 Project ended: March 2004 Finance/support: 15000$ Source of support: The management and planning organization of Iran Keywords: Wool fibre, Enzymatic treatments, Environmental friendly process, Iranian wool, Hand-woven carpet Regarding the Iranian wool fibres and its thickness that causes it to be used only in handwoven carpet, it is important to find the methods for improving the physical properties such as finesse. Enzymatic treatments as an environmental friendly process can be used to enhance the quality such as whiteness, finesse, and flexibility.
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This study investigates to detect the optimum enzyme concentration, time and the pH of enzymatic treatments for the desirable changes. The results show that the amount of reductions in weight, strength and elongation of treated samples are appropriate for its usage in other process.
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The aim of this investigation is improving the physical properties of Iranian wool fibres, such as whiteness, finesse, and flexibility. Enzymatic treatments as an environment friendly process can be used to enhance the quality.
Research deliverables (academic and industrial) None Publications Dadashian, F. and Montazer, M. (2003a), ‘‘The effect of enzymatic treatments on Iranian Wool’’, paper presented at the 7th Asian Textile Conference, New Delhi, 2003. Dadashian, F. and Montazer, M. (2003b), ‘‘The effect of enzymatic treatments on Iranian Wool’’, paper presented at the CEC 2003 Conference, University of Maribor, Slovenia, 2003.
Terrassa, Spain INTEXTER (Instituto de Investigacion Textil), UPC, Colon,15, 08222-Terrassa, Spain Tel: 34-937398270; Fax: 34-937398272; E-mail:
[email protected] Laboratory of Physical-Chemistry of Dyeing and Finishing Riva, Ascensio´n Research staff: Riva, Ascensio´n, Algaba, Ine´s, Prieto, Reme
Ultraviolet radiation protection proportioned by textiles: study of the influence of the most significant variables and application of specific products for its improvement Other partners: Academic
Industrial
Yes None Project started: 1 January 2000 Project ended: 31 December 2002 Finance/support: 88.854 e Source of support: Spanish Ministry of Science and Technology Keywords: Ultraviolet radiation, Diffuse spectral transmittance, Solar protection factor (SPF, UPF), Textiles, UV-absorbers, Dyestuffs, Optical brightening agents, Finishing products, Colorimetry, Spectrophotometry, Comfort parameters, Ecological parameters
The main objective of the project is to study the protection factor to the UV radiation achieved by the fabrics in function of the most significant variables that have influence on it, as they are: type of fiber, structural parameters of the fabric, color, UV-absorbent finishing products, and optical brightening agents. For this aim, fabrics have been elaborated with different fiber composition (including new fibers that incorporate absorbent products of the radiation) and structures. Specific finishing and optical brightening products have been applied. The diffuse spectral transmittance in the UV wavelength of the different fabrics has been determined by means of the technique that has been put onto point in this project. Other complementary objective of the project is the influence that finishing specific products, applied to improve the UV protection factor, can have on some characteristics of quality and comfort of the fabrics, as well as their permanency after repeated laundries and the ecological incidence of the application baths. The results of the project can directly benefit our textile industry contributing to their know-how and facilitating their specialization in high value added products. They can also be of great utility as contribution to the public health.
Project aims and objectives To establish the influence of the main parameters of fabrics on the ultraviolet protection factor (UPF) values and propose the mathematical models that permit to predict the behavior of the new fabrics with predetermined characteristics. To give support to the textile industry in the knowledge and possibilities to produce new protective articles of great value. To conscious industrialists and people of the importance of the textile UV protection. Academic deliverables Scientific publications Industrial deliverables Application of deduced mathematical equations as models to predict the influence of several fabric parameters. To impart courses and training. Publications Algaba, I. and Riva, A. (2002), ‘‘In vitro measurement of the ultraviolet protection factor of apparel textiles’’ Coloration Technology, Vol. 118, pp. 52-8. Algaba, I., Riva, A. and Crews, P. (2002), ‘‘Influence of fiber type and fabric porosity on the ultraviolet protection factor provided by summer fabrics’’, Proceedings of the 2002 International Conference and Exhibition of the American Association of Textile Chemists and Colorists, October 2002, Charlotte, North Carolina (USA), AATCC Review (in press). Gueguen, V., Riva, A. and Prieto, R. (2001), ‘‘Effect of UV absorber on photoyellowing of wool’’, Proceedings of the 2001 International Textile Congress, June 2001, Terrassa, Spain. Riva, A. (2000), ‘‘¢Que´ es el UPF de un tejido?’’, Revista de Quı´mica Textil, Vol. 144, pp. 72-8. Riva, A., Algaba, I. and Prieto, R. (2002a), ‘‘Action of UV protective auxiliary products applied in the wool dyeing with metal complex dyes’’, Proceedings of the 71 IWTO Congress, May 2002, Barcelona, Spain. Riva, A., Algaba, I. and Prieto, R. (2002b), ‘‘Influence of color on the UV protection supplied by fabrics of cellulose fibers’’, Proceedings of the VI National Congress of Color, September 2002, Sevilla, Spain.
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Vila Nova de Famalica˜o, Portugal CITEVE – Centro Tecnolo´gico das Indu´strias Teˆxtil e do Vestua´rio de Portugal, Quinta da Maia – Rua Fernando Mesquita, 2785, 4760-034, Vila Nova de Famalica˜o, Portugal Tel: 252300300; Fax: 252300317, 252300374; E-mail:
[email protected] Anto´nio Vieira and Renato Dias, Environmental
Anoxitrata – Integrated treatment of textile effluents by an anaerobic/aerobic process with the application of advanced oxidation methods Other partners: Academic
Industrial
Interagua Universidade do Minho, Faculdade de Engenharia da Universidade do Porto Project started: 1 November 2003 Project ends: 31 October 2006 Source of support: POCTI/Consortium investigation Keywords: Anaerobic/aerobic, Ozone/activated carbon, Textile, Wastewater Integrated treatment of textile effluents by an anaerobic/aerobic process with the application of advanced oxidation methods. The effluents of wool and cotton sub-sectors will be studied. It is pretended to make a demonstrator prototype for reutilisation and treatment of textile effluents.
Project aims and objectives Anaerobic treatment is an emergent technology for textile wastewater treatment, given its effectiveness in colour removal, refractory substances degradation, organic matter removal and methane production. Additionally, the wastewater biodegradability is enhanced which improves the aerobic post-treatment. The present project consists on the development of a technology for treatment of textile effluents regarding recycling of a part, based on anaerobic-aerobic process completed with a tertiary treatment using activated carbon-ozone. If salt originated from dyeing operations (reactive, direct, sulphur dyes, etc.) is present in high concentration the effluent is divided in two streams according to dissolved inorganic content. The less concentrated stream can be recycled after treatment without need of reverse osmosis. Biodegradability studies and tests performed in the beginning for most representative dyes and chemicals make easier driving laboratory trials to treat real industrial effluents. The results of these tests help to design the bioreactors for the pilot plant, one for the anaerobic step, and the other for the aerobic prototype and also the ozonation column with activated carbon.
Tests will run sequentially in three enterprises corresponding to the main types of effluent (cotton, home textiles and wool) to search the required conditions for performing the treatment and to identify eventual substances that may disturb the process. According to all the data obtained with laboratory and pilot scale trials, the system at industrial scale will be designed.
Research deliverables (academic and industrial) None Publications None
Vila Nova de Famalica˜o, Portugal CITEVE – Centro Tecnolo´gico das Indu´strias Teˆxtil e do Vestua´rio de Portugal, Quinta da Maia – Rua Fernando Mesquita, 2785 4760-034, Vila Nova de Famalica˜o, Portugal Tel: 252300300; Fax: 252300317, 252300374; E-mail:
[email protected] Jose´ Morgado, Renato Dias, and Anto´nio Vieira, Textile Technology Environmental
Aquatex – objective characterization of the water quality parameters influence in the textile process with the aim to implement optimized and safe recycle processes Other partners: Academic
Industrial
CITEVE Tecialgo, Prafil Project started: 7 November 2002 Project ends: 7 November 2004 Source of support: POCTI/Consortium investigation The project is divided into three major phases. (1) Determination of the influence of certain substances present in the water, in the efficiency of the different stages of the dyeing process and identification of possible adaptations of the process to one determined quality of the water. (2) Characterization of the partial effluents, gauging of the best techniques for its handling and identification of the stages where its reuse is viable. (3) Elaboration of a computer tool useful to the water management in the industrial unit.
Project aims and objectives In the first phase, that encloses most of the project period, are determined by the water characteristics that make it suitable to its use in the dyeing and finishing processes. In order to do that, certain substances are chosen and their threshold level will be investigated in the shade evenness and colour fastness in samples of dyed fabric.
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It is the most laborious phase of the project that involves the red tape and the assay of thousands of samples in a research to detect the simple influence or combine, on the diverse stages of the textile process (including the tingimento), of diverse substances dissolved in the water. In the cases where it is verified undesirable, the productive process adaptation is investigated. In the second phase, that will begin during the course of the first one and precedes the third, the characterization of the partial effluents from the different textile dyeing and finishing plants will be carried out. The effluents responsible for the less contaminated water flows will be selected and the available best treatment technologies will be searched. The selective reuse of the waters that better fit to each process step is expected. Therefore, a methodology is developed to a systematic approach of the textile processes water-recycling and water logic selection problem. In the third phase an informatic tool is developed, which will be an instrument for the water quality surveillance and for water managing on the textile plant, including the recycling processes managing. Integrating the requirable characteristics of the water determined on phase 1 with the characterization of the produced effluents and the list of treatment technologies determined on phase 2, the informatic tool will be of great help to decide in which process step and textile subtract the water can be safely reused. Information concerning the implementation of water recycling processes or how to optimise an existing process can also be obtained from the tool.
Research deliverables (academic and industrial) None Publications None
Vila Nova de Famalica˜o, Portugal CITEVE – Centro Tecnolo´gico das Indu´strias Teˆxtil e do Vestua´rio de Portugal, Quinta da Maia – Rua Fernando Mesquita, 2785 4760034,Vila Nova de Famalica˜o, Portugal Tel: 252300300; Fax: 252300317, 252300374; E-mail:
[email protected]
Garment dryer – tumble micro wave dryer Other partners: Academic
Industrial
CITEVE Tequimaq IDITE Minho Orfama Project started: 7 October 2002 Project ended: 7 October 2004 Source of support: POCTI/Consortium Investigation
The garment dryer meets the general principles that Clothing and Textile Industry should rule, like: the improvement of the productivity, increment of differentiation/innovation, increase of quality, reduction of the delivery term for increase of the competitiveness of the sector in an environment each time clean and safer. The project consists in a development of a new equipment for the cloth pieces drying, appealing to the micro-wave technology in assembly with the traditional drying technologies, like for example, the ones that resort to the thermofluid. The objective to reach is the decrease (40-20 min) in the drying time of an cloth article by about 50 per cent is composed by the most varied raw material (cotton, viscose, polyamide, polyester, acrylic, etc.).
Research deliverables (academic and industrial) None Publications None
Vila Nova de Famalica˜o, Portugal CITEVE – Centro Tecnolo´gico das Indu´strias Teˆxtil e do Vestua´rio de Portugal, Quinta da Maia – Rua Fernando Mesquita, 2785, 4760-034, Vila Nova de Famalica˜o, Portugal Tel: 252300300; Fax: 252300317, 252300374; E-mail:
[email protected] Gilda Santos, Textile Technology
Sewnew – multimedia advanced training for sewing new textile materials Other partners: Academic SEPEE AITEX INNOVATEXT BTTG Project started: 1 January 2004 Source of support: Leonardo Keywords: Sewing, Textile, Materials
Industrial Lousafil
Project ends: 31 December 2005
This project aims to increase/improve the knowledge about the sewing machines and equipments and their suitability to the several advanced textile materials, improving the quality of the produced articles. Increase the competence of the active workers, encouraging the training along life. Increase the multi-task of the active workers, with consequent increase of their productivity. Familiarize the workers with informatics. To render more attractive training through non-traditional means (utilizing multimedia and
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the computer). Promoting the equality of opportunities (normally women have less opportunities to do training due to familiar commitments). Sensibility the companies to the importance of the correct seam specification and parameterization of the machines in the quality of the final article (as more important as expensive are the materials which they work like in the case of the work with technical textiles in the production of high added value).
Project aims and objectives The training tool SEWNEW allows the training (and the auto-training) at any place and at any time (including at home) and will make possible the familiarization with computers, making easier the work with machines with microprocessors and with the necessary specific machines for the clothing production that uses technical textiles, namely the sports and leisure clothing, ‘‘medical clothing’’, personal protective clothing. The project objective is to develop an interactive training tool for clothing workers, or persons who intend to work in the clothing industry (dressmakers, quality controllers, commercials, . . .) in a CD-ROM version. The tool will consist in an interactive manual (with videos, drawings, plugging to the Internet to interest sites) with two main modules, each one of them with sequential levels of access; it only will be possible to access to level 2 after having the approval in level 1. The first module will contain information for the transmission of basic sewing knowledge, namely equipment and methods of sewing. It will include subjects such as. .
Needles: constitution, features, types. . .;
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Yarns: features (composition, count, resistance, etc.), applications. . .;
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Types of points: main types of point, its features. . .; Types of machines: lockstitch machines, chain stitch machine, . . . (including the special machines for the sewing of the technical and smart textiles); Stitch types: lockstitch (301), single thread chain stitch, . . .;
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. .
Accessories: presser foot, mirrors, guides. . .;
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Maintenance: when and were to put oil, to change the needle, . . .;
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To prepare the machine to the work: choice of the adequate parameters to sew; Hygiene and security in the work: the choose of the right chair, the adequate height of the table machine, . . ..
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At the end of each subject, the user only can access to the following topic (in principle more complex) after the realisation of a test with approval. The second module will have essentially exercises to ‘‘details’’ assembly (collars, pockets, special operations realized in the sports and leisure clothing, ‘‘medical clothing’’, personal protective clothing and others), also with different access levels in function of the complexity, for application of the knowledge obtained in the first module.
Research deliverables (academic and industrial) None
Publications None
Vila Nova de Famalica˜o, Portugal CITEVE – Centro Tecnolo´gico das Indu´strias Teˆxtil e do Vestua´rio de Portugal, Quinta da Maia – Rua Fernando Mesquita, 2785, 4760-034, Vila Nova de Famalica˜o, Portugal Tel: 252300300; Fax: 252300317, 252300374; E-mail:
[email protected] Manuel Rei, Research & Analysis of Defects
Smadetex – multimedia system for the analysis of defects in textile products Other partners: Academic SEPEE AITEX INNOVATEXT ATP Project started: 6 January 2003 Source of support: Leonardo Keywords: Multimedia, Defects, Textile
Industrial None
Project ends: 6 January 2005
Development of an informatics tool for the support and training in analysis and research defects in the Clothing and Textile Sector. The tool will establish a correlation between the cause and type of each defect and the associated productive processes, contributing to the increase of the technical training level of the partners involved in the quality control processes.
Project aims and objectives This project consists basically of the elaboration of a multilingual CD-ROM to support the resolution of the problems related with the defects that can appear in the textile products. Thus, it is intended to characterize the defects originated in different phases of the textile process, in the following form: Name; Definition; Repairing; Methodologies for analysis of the defects in a laboratory. All the identified defects will be correlated with the corresponding process in the textile productive chain.
Research deliverables (academic and industrial) None Publications None
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Villeneuve d’Ascq., France Technical Sciences University of Lille (USTL), UFR Mathe´matiques pures et applique´es, 59655 Villeneuve d’Ascq. France Tel: 33 3 20 43 67 83; Fax: 33 3 20 43 67 74; E-mail:
[email protected] Pure and Applied Mathematics Department USTL Research staff: Dr Jean-Jacques DENIMAL, Dr Franc¸ois BOUSSU
Development of a decision aid software for textile retailer firms Other partners: International Data Processing and Engineering firm
Academic
Industrial
None International Textile Retailer Project started: 1 March 2003 Project ends: 1 January 2005 Source of support: French National Agency for Innovation (ANVAR Lille) Keywords: Decision aid software, Data mining tools, Data visualization tools The research program tends to achieve a decision aid software mainly oriented in the understanding of past sales behaviors and forecasting of the new textile items collection. Different tools will be provided to each of the supply chain actors (marketing executive, textile collection responsible, logistic manager and chief executive). All of these tools are designed to be as concise as possible and precise to give an efficient aid for the decision process. At the end, the prototype software will be adapted to any data processing environment, any users categories and levels.
Project aims and objectives The project aims at providing different decision aid tools to each of the supply chain actors involved inside a textile retailer firm. Different organizational scheme of stock delivery and management are considered in the methodology. So, different models can be adapted to these different textile items managements. The challenge is to propose tools based on complex mathematical and statistical methods. However, these tools will have to remain accessible for unskilled statistical persons.
Research deliverables (academic and industrial) Two main functions are to be present in the prototype software.The first one deals with the understanding of the nearest past sales seasons. Data mining tools helps to highlight the significant parameters influencing the sales behaviors. The second one treats the two stages of the forecasting process. Before the season, different decision tools allow to provide estimated future sales. During the season, an efficient and fast algorithm provides forecasted sales values including the recent changes.
Publications Boussu, F. and Denimal, J.J. (2002a), ‘‘Statistical modeling and data mining to identify the consumer preferences. Application to a Textile sales data set’’, in Warren, C. (Ed.), Neel Conference on the New Frontiers of Statistical Data Mining and Knowledge Discovery, 22-25 June 2002, Marriot Knoxville, Tennessee, USA, p. 30. Boussu, F. and Denimal, J.J. (2002b), ‘‘The data-mining : a competitive advantage to the textile firms’’, World Textile Conference – 2nd AUTEX Conference, Textile Engineering at the Dawn of a New Millennium: An Exciting Challenge, Poster session, 1-3 July 2002, Bruges, Belgium, p. 589. Boussu, F. and Denimal, J.J. (2003), ‘‘Data visualization tools to highlight sales and products relationships’’, Application of a Data Mining Method to Textile Sales, Las Vegas, Nevada, USA, CSREA Press, 23-26 June, 2003, Vol. II, pp. 475-81. Boussu, F., Denimal, J.J. and Ousmane Wora DIALLO (2002), ‘‘Reduction of the estimation uncertainty of the textile sales profiles by using a data-mining technique’’, Paper 54, Special Session on Information Processing and Management of Uncertainty in Textile/Garment Industry, IPMU 2002, 15 July 2002, Annecy, Vol. 3, pp. 1895-1900.
Virginia, USA Department of Mechanical and Aerospace Engineering, Mechanical Engineering Building, University of Virginia, Room 342, 122 Engineer’s Way, Charlottesville, Virginia 22904-4746, USA Tel: 4349246216; Fax: 4349822037; E-mail:
[email protected] William W. Roberts, Jr, Commonwealth Professor, Director of Applied Mathematics, and Director of the Mathematical-Computational Modeling Laboratory, Mathematical – Computational Modeling Laboratory
Fibrous assemblies: modeling/computer simulation of compressional behavior Other partners: Academic
Industrial
None
None
An important problem that has been researched by fiber and textile scientists and engineers for over 50 years is modeling the compression and recovery behavior of fibrous assemblies. The computational aspect of solving this problem is the focus of the present research. We develop a three-dimensional model to relate the mechanical properties of individual fibers and how they are arranged in a fibrous assembly to the bulk properties of the fibrous assembly. The model allows the prediction of the bulk properties of the fibrous assembly during compression from the physical properties of its component individual fibers, taking into account both static and kinetic friction at contacts between fibers. Plate 2 shows a representative model fibrous assembly undergoing compression, as the top wall is slowly depressed. Computer simulations are run for a number of cases with specific friction conditions applied in order to compare predictions of this model with experimental results and with van Wyk’s theory of the
Research register
199
IJCST 16,6
200
Plate 2.
uniaxial compression of an initially random fibrous assembly. These computer simulations demonstrate a reasonable ability to predict the undetermined constant K in van Wyk’s theory. The computer simulations also show a significantly greater number of fiber-fiber contacts being formed than theories based only on the diameter and arrangement of fibers have predicted. The predicted contacts have a wide range of contact forces, while only a small percentage of them do not slip. The model may be used to investigate the phenomena associated with the compression of fibrous assemblies, such as fiber crimp and hysteresis. We track computationally the potential energy in the assembly and the work done on the assembly, and we are able to produce realistic looking hysteresis plots and can predict the amount of frictional energy dissipated as a function of time. We find that fiber crimp has a large effect on the compressional properties of a fibrous assembly in that more highly crimped fibers absorb more energy as they are compressed. They also absorb a higher proportion of their energy in the twisting mode, which has been neglected by previous investigators. The model not only allows exploration of the characteristics of a fibrous assembly under compression at a level of detail impossible to achieve through experiment but also allows inclusion of effects that are very difficult to account for quantitatively through theory alone. Factors that can be accounted for include initial arrangement and configuration of the assembly, fiber crimp, various types of friction, distribution of contact forces, and steric exclusion of fibers. Applications of this work include predicting the properties of wool or fiber fill based on the fibers and on the processing used, designing insulation that retains its insulating properties after being compressed, developing materials for acoustic noise and vibration control, understanding fibrous cytostructural invadopodia in malignant tumor cancers, and simulating other medical fibrous malfunctions.
Project aims and objectives The model is to relate the mechanical properties of individual fibers and how they are arranged in a fibrous assembly to the bulk properties of the fibrous assembly. The model is to allow the prediction of the bulk properties of the fibrous assembly during compression from the physical properties of its component individual fibers taking into account both static and kinetic friction at contacts between fibers. Computer simulations are to compare predictions of this model with the experimental results and with van Wyk’s theory of the uniaxial compression of an initially random fibrous assembly.
The model is to be used to investigate the phenomena associated with the compression and decompression of fibrous assemblies, such as hysteresis, crimp, and orientation effects.
Research register
Research deliverables (academic and industrial) None Publications Roberts, W.W. Jr. and Beil, N.B. (2003), ‘‘Fibrous assemblies: modeling/computer simulation of compressional behavior’’, paper presented at the INTEDEC 2003 – Fibrous Assemblies at the Design and Engineering Interface, Heriot-Watt University, Edinburgh, ISBN No. 0-9546162-0-0. Roberts, W.W. Jr and Beil, N.B. (2003), ‘‘Computational modeling of fibrous assemblies’’, paper presented at the Fiber Society 2003 Fall Annual Meeting – Fibers and Fibrous Structures: From Science to Applications, NCSU, Raleigh, NC. Roberts, W.W. Jr and Beil, N.B. (2004), ‘‘Fibrous assemblies: modeling/computer simulation of compressional behavior’’, International Journal of Clothing Science and Technology, Vol. 16 Nos 1/2, pp. 108-18.
Zagreb, Croatia Faculty of Textile Technology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia Prof. Dr Ruz˘ica C˘unko, Department of Textile Chemistry and Testing of Materials Research staff: Dr Maja Andrassy, Dr Emira Pezelj, Dr Mirjana Gambiroz˘aJukic´, Vera Fris˘c˘ic´, Biserka Vuljanic´, Antoneta Tomljenovic´, Marija Kovac˘evic´
Ecological aspects of fiber properties and quality of textiles Other partners: Academic
Industrial
None None Project started: 1 June 1997 Project ends: – Finance/support: N/A Source of support: Ministry of Science and Technology of the Republic of Croatia Keywords: Ecology, Textiles Research activities proposed are related to the environmental aspects of textile materials and will include investigations of the impact of some environmental parameters on fiber properties, as well as the investigations of a possibility of evaluating textile products on the basis of their ecological safety. Textile products interact with their environment, which influences the changes occurring in them, covered by the term ‘‘ageing’’. The changes are complex and varied and in most cases quite specific and sophisticated investigations are necessary to understand them. The investigation of fibre ageing under the influence of UV-radiation, ozone and pollutants, is supposed to contribute to understanding the mechanism of the changes on molecular, structural and morphological levels. The other research task
201
IJCST 16,6
202
deals with the problem of a possible harmful influence of textiles on human health, covered by the expression of ‘‘human-environmental safety’’. This kind of safety has become one of the basic prerequisites, when speaking about the quality of textile products, and the most important one when trying to sell on the European market. The investigations are supposed to create basic prerequisites for laboratory evaluation of humane-environmental safety. Part of the research task concerns modification of fibre properties using ultrasound waves, as an environmentally very acceptable solution. The effect of ultrasound waves will be investigated on cellulose fibres, polypropylene, polyamide, polyester and wool. The results will be published in scientific research periodicals and conferences, making possible their usage, checking and evaluation.
Project aims and objectives In the area of polypropylene and aramide fibres ageing the aim is to complete the investigations started by the previous project, especially concerning the impact of atmospheric pollutants, sunlight, weather conditions and ozone concentration in various stress conditions. The second aim is to investigate possible modifications of fibre properties through the application of ultrasound, and the third aim is to create a scientific and expert basis for testing and objective evaluation of human-environmental safety as a basic prerequisite for textile quality assurance. Publications C˘unko, R. and Pezelj, E. (1997), ‘‘The ageing of polypropylene through environmental agency’’, The 78th World Conference of Textile Institute, Thessaloniki. C˘unko, R., Andrassy, M. and Pezelj, E. (1998), ‘‘Elimination of polyester fibre oligomers using ultrasound waves’’, Proceedings TEXSc ’98, Liberec. C˘unko, R., Pezelj, E. and Andrassy, M. (1997), Tekstil, Vol. 46, pp. 677-83. Pezelj, E., C˘unko, R. and Andrassy, M. (1997a), ‘‘The effect of global climatic change on the fibre ageing’’, Proceedings Slovenia Chemical Days. Pezelj, E., C˘unko, R. and Andrassy, M. (1997b), ‘‘The influence of repeated maintenance treatments on properties of PP fibers’’, Proceedings The 78th World Conference of Textile Institute, Thessaloniki.
Zagreb, Croatia University of Zagreb, Faculty of Textile Technology, HR-10000 Zagreb, Croatia Tel: ++385 (1) 37 03 153; Fax: ++385 (1) 37 74 029; E-mail:
[email protected] Edita Vujasinovic, Department of Textile Chemistry and Material Testing
Sorption characteristics of medullated wool fibres Other partners: Academic
Industrial
None
None
Project started: 1999 Project ended: 2001 Finance/support: 3,000 DEM/year Source of support: Croatian Ministry of Science and Technology Keywords: Textiles, Wool, Sorption, Medullated wool From 500 to 700 tons of greasy wool are sheared in Croatia every year (annual statistics of Croatia 1990-1995). Because of the widely heterogeneous character of the wool sheared, the number of different breeds of sheep, inadequate shear preparation and extremely high content of medullated fibres (Tekstil, Vol. 41 (1992), 591; Stocarstvo, Vol. 48 (1994), 443), coarse wool of domestic sheep is not used in the textile and garment industry. Under these conditions, the quantities of wool stated cease to be a useful raw material and become an ecological hazard. Some developed European countries are faced with the same problem (Nuova Sel Tess, Vol. 5 (1996), 28), and, as coarse wool, due to high content of medullated fibres, can be a useful absorbing and insulating material (both sound and heat insulating), investigations were started to establish the possibilities of using domestic wool as raw material in the manufacture of technical textiles for a wide range of applications (e.g. in civil engineering, building and construction, agriculture and some other branches of industry). Investigations of the physico-chemical (and especially absorptive) properties of medullated wool fibres will show how they can be used in the manufacture of technical textiles, such as various filters, agro-, geo- and thermo-textiles. In this way, coarse domestic waste wool will be used as an environmentally and economically acceptable product, which is in tune with European and global trends of more a rational managing of natural resources, with the purpose of preserving and protecting the environment.
Project aims and objectives The quality of most of the domestic wool does not meet the technological requirements stated by the Croatian wool industry, meaning that it is an industrial raw material that cannot be utilised. The aim of the investigation proposed is to explore the possibilities of using coarse domestic wool as a raw material in the manufacture of technical textiles. Fine wool fibres are appropriate, ecologically acceptable and a cheap natural raw material for the textile garment industries. Coarse wool fibres are most often a byproduct of sheep breeding, which cannot be properly used. The results of investigating the physio-chemical, and especially absorptive, properties of medullated wool fibres will indicate the feasibility of using such fibres as a proper absorbing material (primarily for liquid and solid waste), in the manufacture of a wide range of technical textiles, such as filters, geo-, agro-textiles, sound and heat insulators, etc. In this way, coarse domestic wool, which has become harmful waste through burning without control and years of depositing, will be used as an environmentally acceptable and economically profitable product. Publications Raffaelli, D., Dosen-Sver, D. and Vujasinovic, E. (1999), Kemija u Industriji, Vol. 48 No. 5, pp. 189-96. Vujasinovic, E. and Andrassy, M. (2000a), Proceedings of the 4th International Conference TEXSCI 2000, Liberec, Czech Republic, 12-14 June, pp. 84-8. Vujasinovic, E. and Andrassy, M. (2000b), Tekstil, Vol. 49 No. 6, pp. 277-86.
Research register
203
Research index by institution
IJCST 16,6
204
Institution Advanced Industrial Science and Technology (AIST), Ibaraki, Japan Aitex, Asociacion de la Investigacion de la Industria Textil, Alcoy-Alicante, Spain Amirkabir University of Technology, Tehran, Iran
Page 93 6-10 189-190
Bolton Institute, Bolton, UK
12-13
Budapest University of Technology and Economics, Budapest, Hungary
62-68
CITEVE – Centro Tecnolo´gico das Indu´strias Teˆxtil e do Vestua´rio de Portugal, Vila Nova de Famalica˜o, Portugal
192-197
CSIR Centre for Fibers, Textiles and Clothing, Port Elizabeth, South Africa
165-169
Ecole Nationale Supe´rieure des Arts et Industries Textiles ENSAIT, Roubaix, France
177-179
Ghent University, Ghent, Belgium
74-91
Heriot-Watt University, Selkirkshire, Scotland
179-185
Hong Kong Polytechnic University, Kowloon, Hong Kong
117-126
Interdipartimental Research Center E. Piaggio, Pisa, Italy
161-165
INTEXTER (Instituto de Investigacion Textil), Terrassa, Spain
190-191
Kaunas University of Technology, Kaunas, Lithuania
108-115
King’s College London, London, UK
139-140
Kyoto Institute of Technology, Kyoto, Japan
129-134
London College of Fashion, London, UK
140-143
Louisiana State University, USA
143-145
Manchester Metropolitan University, Michigan, USA
145, 153-155
National Research and Development Institute for Textile and Leather – Division Leather and Footwear Research Institute, Bucharest, Romania
48-55
National Technical University of Athens, Athens, Greece
10-11
Philadephia University, Philadephia, USA
159-161
Riga Technical University, Riga, Latvia
169-177
Satra Technology Centre, Kettering, UK
115-117
¨ BI˙TAK TAM The Scientific and Technical Research Council of Turkey, TU ˙Izmir, Turkey
93-105
Tampere University of Technology, Tampere, Finland
185-189
Technical Sciences University of Lille (USTL), Villeneuve d’Ascq., France
198-199
Technical University of Liberec, Liberec, Czech Republic
136-139
Technological Education Institute of Piraeus, Athens, Greece
11-12
The Research – Development National Institute for Textile and Leather, Bucharest, Romania
13-62
UMIST, Manchester, UK
146-147
Unite´ de Recherches Textiles, Ksar-Hellal, Tunisia
126-127
Universidade do Minho, Guimara˜es, Portugal
91-92
University of Agricultural Sciences, Karnataka, India
105-108
University of Guelph, Ontario, Canada
157-158
University of Leeds, Leeds, UK
134-136
University of Maribor, Moribor, Slovenia
147-153
University of Newcastle upon Tyne, Newcastle upon Tyne, UK
155-157
University of Twente, Enschede, The Netherlands
68-74
University of Virginia, Virginia, USA
199-201
University of Zagreb, Zagreb, Croatia
201-203
Yeungnam University , Kyeongsan, Korea
127-129
Index by institution
205
Research index by country
IJCST 16,6
206
Country
Page
Belgium
74-91
Canada
157-158
Croatia
201-203
Czech Republic
136-139
Finland
185-189
France
177-179, 198-199
Greece
10-12
Hong Kong Hungary India
117-126 62-68 105-108
Iran
189-190
Italy
161-165
Japan
93, 129-134
Korea
127-129
Latvia
169-177
Lithuania
108-115
Portugal
91-92, 192-197
Romania
13-62
Scotland
179-185
Slovenia
147-153
South Africa
165-169
Spain The Netherlands
6-10, 190-191 68-74
Tunisia
126-127
Turkey
93-105
United Kingdom USA
12-13, 115-117, 134-136, 139-143, 145-147, 155-157 143-145, 153-155, 159-161, 199-201
Research index by subject Subject 3D simulation Absestos-substitute yarns Added value textiles Aerial delivery systems Aerodynamic studies Aeronautic accessories Agriculture Agro and animal based fibres Air and water proofing Air filling structures Air jet Anaerobic/aerobic Anti-shrinkable Apparel Apparelkey Aquatex Artificial grass Assist Augmented reality Ballistic penetration Behaviour Benchmarking Bending Biaxial deformation Bifurcated structures Bioactive and bioresorbable Biocompatibility Biomaterials Biomedical Biopolishing Biopolymers Biomimetics and biomimetics Bioscouring Biotechnical Bleach Bovine leather Braiding Buckling CAD Carboxymethylation
Page 181 18 8 58 24 24 44, 157 105 36 36 78, 87, 146 192 127 122, 130 119 193 88 93 181 146 147 177 156 110 35 51 30, 80 80 179 93 82 77, 140 71 188 72 53 30 108, 113, 167 130 62, 67
Cardovascular surgery Cartilage Causticising Cavitation Cellulase Cellulose Chemical modification China Chitosan Clean technologies Cleaner processes Clothing
Index by subject
Crop protection Customer study
25, 35 74 102 68 69, 93 62 67 177 82 41, 50 47 79, 115, 147, 158, 173, 177 89 51 177 87 137 39 18, 51, 165 199 199 187 153 73 12, 62, 71, 95, 168 44 187
Data mining tools Data visualisation tools Database Decision aid software Defects Delivery media De-polluting Design Dimensional stability Dioxins Drape Drawing ratio Drawing temperature Drawn worsted yarns
198 198 143 198 197 185 38 115 12 81 143, 181 128 127 127
Cold plasma Collagen Colombia Colour Comfort Component layers Composites Compressional behaviour Computer simulation Concept Cost modelling Contact angle Cotton
207
IJCST 16,6
208
Dyeing Dyestuffs Dynamic surface tension
87 103, 190 73
Easycare Eco-technologies Ecological fibres Ecological sheepskin Ecology Eco-products Elastane Elastic energy maximum Elastic fabrics Elastomer covering Electrical property Electrically conductive textiles Electrochemistry Electro-conductive fibres Electromagnetics Emergency services Enhanced mass transfer Environment, environmentally friendly, environment fprotection Enzyme treatment and ftechnology European norms Eventration Extraction through a hole Extreme meteorological conditions resistance Extrusion
127 18 41 50 201 48 116 126 183 38 100 11 81 86 176 29 68 13, 156, 186, 189
Fabric properties
130, 137, 143 146 119
False-twist texturing Fashion (news, shows, resources, archives) Fastness Feathers and down Fibre Fibres, Yarns, Fabrics, Garments Fibrillation Filter cartridges Finishing Fixing agent Flame retardant Floats Folding and unfolding Footwear Friction Friction coefficient Functional and intelligent
41, 69, 93, 189 16 33 111 36 88
103 6-8 133 179 41 47 45 103 8 38 139 53 156 100 122
Garment Garment dryer Garment handling Gas flow Genetic algorithms Geometry Gradual compression Grafting Grippers, gripping devices Hail, thunder showers Hairiness Hand, handle Handling and manipulation Handwoven carpet Heat insulation Heating temperature High-tech fabrics Home shopping Hot extension Household articles Human health Hydrophility Hypothermia protection Implantable products Income generation Industrial clothing and textiles Inflatable equipment Informatic system Inkjet printing and technology Innovation Intelligent Search Intelligent textiles Interior design Ironing Knitted textiles Knowledge (Textile, apparel) Laminates, coating Laundering Layered clothing system Leather garment Life quality Life safety Light-weight wool fabrics Lubrication
39, 117, 155 194 139 89 159 110 45 168 139, 156 44 97 91, 137 93, 139 189 15 128 145 181 149 93 29 103 23 25 105 158, 179 21 27 134, 153 83 143 140 140 155 32, 44, 59, 117, 124, 131, 160 119 108 12 145 48 45 21 91 149
Lyocell fibres Machine vision Man protection Management Manufacturing technologies Mass customisation Mass transfer Materials Mechanical model Mechanical properties Mechanical risks Medical applications Medullated wool Membrane Mercerisation, Chemical modification Mestha, Agave, Hemp and Pina fibres MEVVA ion implantation Microencapsulation Military technique Modelling Molecular design Multifunctionality Multimedia Multivariate statistical analysis technique Nanocomposites, nanostructures, nanotechnology Natural fibres NIRA Non-farming activities Non-toxicity Non-woven Novel fibres Nu-torque Numerical methods
41 134 13 83 29, 53 187 145 195 10 108, 147 59 29, 76, 82 202 51, 100, 110 62 105 100 168 58 199 159 168 195 91
73, 122, 165, 185 168 6-8 105 50 179 159 124 56
Objective evaluation, measurements Online fabric sourcing Online shrinkage control Online weight control Optical brightening agents Oxydative catalysts Ozone/activated carbon
10, 111
Packaging Parachute, parachute cargo, parachute systems, paratroopers deployment
165, 24
143 160 160 190 72 192
56
PCB Pectinase Performance evaluation Performance level Performance fibres PES filament Pesticide protective clothes PET fabrics Plant dyes Plasma Pneumatics Polluting phenomena Polypropylene Potential minimum Prediction Pressure garments, measurement Pressurized labyrinth Problems (Garments, textiles) Procedure microcellular plates Process intensification Processes filters Products and eco-technologies Protection, protective equipment, protective clothing Quality Quarternary ammonium hydroxide
81 71 177 15 39 149 67 100 42 87 133 13 165 126 147 183 146 119 20 68, 72 47 47 15, 39, 61, 110, 157 16, 84 62
Radio Reactive printing Recycling Reducing waste Reinforced mesh Residual torque Ring spinning Risk factor Robot, robotic ironing, robotics
176 102 186 186 32 117, 124 97 15 93, 139, 155
Safe recycling Safety Scaffold Sea rescue equipment Seam puckering, slippage Sensor functions Sensorial comfort Sensory measurement Sewing, sewing automation, sewing machines, sewing threads Silk Silke worsted yarn Simulation
193 8, 20 74 23 113 185 91 131 149, 167, 195 74 128 27, 78 129
Index by subject
209
IJCST 16,6
210
Smart materials, smart textiles Sodium hydroxide Softener Software, software integration Soil release Sol Solar protection factor Sonocess engineering Sorption Speed Spider Spider silk Spinning Stitch Subjective evaluation Sulphur Supply chain Surface area Surface modification, surface roughness Surgical thread Swelling Swimwear Synthetic fibres Tailorability Technical textiles
76, 140 65 103 56, 187 67 168 190 68 202 87 74 80 27 169 111 102 177 185 69, 108 30 62 116 188
113, 143 18, 36, 47, 83, 108 Technology (textiles, clothing) 119, 171 Tensorial calculations 126 Tetraalkylammonium compounds 65 Textiles 42, 122, 136, 171, 186, 192, 195, 201 Textile design 140 Textile, Garment 93 Textile fabrics 10 Textile materials 21 Textile pretreatment 95 Textile printing 153 Textile soil coverings 16 Textile structures 89 Textile structures 30 Textiles hand 111 Textiles inkjet printing 134
Thermal, thermal risks Thermophysiological comfort Thermoplastics Thread mechanics Tissue engineering, tissue prosthetics Torque free Training
59, 137 91 133 126 51, 74
Tuft Tumble microwave dryer Turkey Twist
117, 124 79, 83, 195 129 194 79 127
Ultrasound UV absorbers, light, radiation, resistance
68, 95 36, 44, 95, 190
Value addition Variation law Virtual trading Viscoelastic properties Viscose Vision system Visual signalling
105 45 181 149 93, 102 134 61
Warning clothing Washing Wastewater Water quality Water texturing Wave Wear Wearable Healthcare interface Weaving, weaving technology, weaving yarns Weft insertion Wetting Wicking properties Wool Worsted, worsted drawing yarns Woven fabrics Wrinkling Yarns
61 95 192 193 146 110 117 161 25, 35, 78, 87, 117, 124, 136 78 73 89 168, 176, 189, 202 128, 131 130, 167 12 97, 129
Research index by principal investigator Principal investigator
Page
Abou-iiana, M.
160-161
Agrawal, P.B.
71-72
Alimaq, D.A. Anand, S.C. Anandjiwala, R. Anghel, E.
Index by principal investigator
Gospodariu, A.
44-47
Grecu, D.
24-25
Gutauskas, M.
110-113
131-132
Harlin, A.
185-186
12-13
Hertleer, C.
76-77
165-168
Higgins, L.
12-13
36-39
Isar, D.
18-20, 47-48
Ascensio´n, R.
190-191
Jahanshah, F.
Baltina, I.
176-177
Kadoglu, H.
97-100
140-143
Kancevicha, V.
171-173
Kawabe, K.
133-134
Kim, S-J.
127-129
16-18
Klavins, A.
169-171
Carbonell, A.
8-10
Krievins, I.
173-174
Carpus, E.
39-40
Kukle, S.
174-176 137-139
Berzina, Z. Borsa, J.
62-68
Botı´, R.
6-8
Buriceanu, R.
134-136
Chapple, S.A.
168-169
Ku˚s, Z.
Chen, Y. C˘unko, R.
143-145
Ledoux, M.
201-202
Lok-wai Lo, J.
Dadashian, F.
189-190
Lopez-Lorenzo, M.
Dai, J.S.
139-140
Louwagie, J.
83-86
De Rossi, D.
161-165
Macintyre, L.
183-185
Denimal, J-J.
198-199
Mahale, G.
105-108
Drambei, P.
41-42
Matsuo, T.
132-133
Dumitrescu, I.
42-44
Mattila, H.
187-188
93-96
Mihai, C.
25-27
Moholkar, V.S.
68-69
Monteiro, M.E.M.P.
91-92
Duran, K. Ene, A. Foster, P.W. Gaidau, C.
25-27, 30-36 146-147 50-51, 53-55
Gellynck, K.
80-81
Gersˇak Sc. J.
147-153
Gheorghe, N.
13-14
78-79, 87-88 177-179 69-71
Morgado, J.
193-194
Nakamura, M.
129-130
Newton, E.
119-121
Niculescu, C.
20-24, 29-30, 56-57
211
IJCST 16,6
212
Nieminen, E. Nosek, S. ¨ ktem, T. O Ono, E. ¨ zgu¨ney, A.T. O
186
Suresh, M.N.
130-131
136-137
Sztandera, L.
159-160
Tao, X.
117-119, 122-126
Taylor, P.M.
155-157
100-102 93 102-103
Pop, M.
48-50
Provatidis, C.
10-11
Puolakka, A. Radulsecu, R. Rahnev, I.
Toma, D.
15-16, 59-62
188
Topalovic, T.
72-73
58-59
Trandafir, V.
51-53
126-127
Rangoussi, M.
11-12
Regelbrugge, H.
77-78
Rei, M.
199-201
Ruckman, J.E.
145
Simmons, A.
195-196 116
Slater, K.
157, 158
Storme, S.
79-80
Strazdiene, E. Stylios, G.K.
153-155
Vajusinovic, E.
202-203
Van de Velde, K.
82-83 88-89
Van Langenhove, L.
74-76
197
Roberts, W.W. Santos, G.
Tyler, D.J.
108-109, 113-115 179-183
Verschuren, J.
87, 89-91
Vieira, A.
192-193
Visileanu, E.
27-28
Warmoeskerken, M.M.C.G.
73-74
Westbroek, P.
81-82, 86
Wilford, A.
115-117
Yurdakul, A.
103-105
