The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Analysis of the modeling methodologies for predicting the sewing thread consumption M. Jaouadi, S. Msahli, A. Babay and B. Zitouni Textile Research Unit of ISET Ksar-Hellal, Ksar-Hellal, Tunisia
Analysis of the modeling methodologies 7 Received January 2005 Accepted May 2005
Abstract Purpose – This paper aims to provide a rapid and accurate method to predict the amount of sewing thread required to make up a garment. Design/methodology/approach – Three modeling methodologies are analyzed in this paper: theoretical model, linear regression model and artificial neural network model. The predictive power of each model is evaluated by comparing the estimated thread consumption with the actual values measured after the unstitching of the garment with regression coefficient R 2 and the root mean square error. Findings – Both the regression analysis and neural network can predict the quantity of yarn required to sew a garment. The obtained results reveal that the neural network gives the best accurate prediction. Research limitations/implications – This study is interesting for industrial application, where samples are taken for different fabrics and garments, thus a large body of data is available. Practical implications – The paper has practical implications in the clothing and other textile-making-up industry. Unused stocks can be reduced and stock rupture avoided. Originality/value – The results can be used by industry to predict the amount of yarn required to sew a garment, and hence enable a reliable estimation of the garment cost and raw material required. Keywords Clothing, Predictive process, Manufacturing systems, Neural nets Paper type Research paper
Introduction The sewing thread is a strategic supplying for the garment industry considering the consumed important quantities. An important consideration in selecting thread after its performance and appearance have been settled is the cost. Total thread costs are made up of the costs of the thread that is actually used in a production run of garments, the thread that is wasted during sewing, and the thread stock that remains unused at the end of a contract, and the lastly, but no means the least, the cost that can arise in production or during the subsequent use of the garment because the thread was faulty. The more the required sewing thread consumption is defined precisely, the more the quantities which should be available for the garments manufacture are reduced and the unused stocks are avoided. The objective of this survey is to determine accurately the required quantity of thread and to estimate the corresponding actual costs. Thread consumption varies not only between different types of garment but also between garments of the same type. Differences in size, style, and material of the garment determine the amount of thread used. Thread consumption is also directly related to the stitch length, stitch density and seam type (Ukponmwan et al., 2000).
International Journal of Clothing Science and Technology Vol. 18 No. 1, 2006 pp. 7-18 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610637477
IJCST 18,1
8
Materials Two types of fabrics have been chosen in our study. The first one is heavy, tight and destined for Jean’s trousers manufacture whereas the second one is light, loose and used for shirts manufacture. These two fabrics, with different characteristics shown in Table I, have been chosen in order to cover a large range. Four types of stitch are considered in our survey. They are the more used for sewing trousers and shirts which are the most sewn articles in Europe. These stitches are: (1) lockstitch (301); (2) two-thread chain stitch (401); (3) three-thread overedge stitch (504); and (4) safety stitch (504 þ 401). Thus, our study is essentially carried out accordingly to these four stitches. The seam is realized using two kinds of worsted cotton sewing threads having two different counts (48 and 30 tex). For each test, we realized a seam having 10 cm of length (Figure 1) varying the following parameters: (1) the fabric thickness (e); (2) the stitch density (stitch number/cm) (n); and (3) the yarn count (t). Later, the seam was unstitched and the consumed sewing thread length was measured using the “maillemeter” device accordingly to the French Standard NF G07 101. Theoretical model Mathematical models for predicting the sewing thread consumption were used. They were established for different stitch types on the basis of their geometrical parameters as following: . L: the sewing length; . c: the sewing width;
Table I. Fabrics properties
Figure 1. Seam configuration
Characteristics
Fabric 1 (Jean trousers)
Fabric 2 (shirt)
Weave Warp density (picks/cm) Weft density (ends/cm) Weight (g/m2) Thickness (mm)
Twill 21 15 422 0.91
Plain 22 20 172 0.27
n: the stitch density (stitch number per centimeter); e: the fabric thickness; and . d: the thread diameter. The lockstitch model This stitch is formed by a needle thread passing through the material and interlocking with a bobbin thread, both threads are meeting in the center of the seam. Stitch looks the same top and bottom. For 301 lockstitch seams, it is generally recommend to use the same thread count for both the needle and bobbin. Consequently, the two yarns (needle and bobbin threads) have the same diameter. The amount of the sewing thread (Q301) needed for the 301 lockstitch, whose geometry is represented in Figures 2 and 3, is estimated by the following formula: . .
Analysis of the modeling methodologies 9
Q301 ¼ Qa þ Qb Q301 ¼ 2Lð1 þ 2ne þ ndðp 2 1ÞÞ where Qa: consumption of needle thread, Qb: consumption of bobbin thread, and Qa ¼ Qb ¼ Lð1 þ 2ne þ ndðp 2 1ÞÞ: The three-thread overedge stitch model The 504 stitch is formed with one needle thread and two looper threads, the looper threads are forming a purl on the edge of the seam (Figure 4). The amount of the sewing thread (Q504) needed for this stitch is predicted by the following formula: Q504 ¼ ðQ1 þ Q2 þ Q3 ÞnL Q504
3 ¼ 2L þ 4ne þ nc þ n 2
! rffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 c 2 þ 2 þ 3ndðp 2 2Þ n
Figure 2. Stitch configuration in a lockstitch seam
Figure 3. Thread interlacing for 301 lockstitch
IJCST 18,1
10
where Q1: needle thread consumption, 1 Q1 ¼ þ 4e þ 2dðp þ 1Þ; n Q2: upper looper thread consumption, 1 þ 2e þ 2c þ 2dðp 2 2Þ; Q2 ¼ 2n Q3: lower looper thread consumption, rffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 3 Q3 ¼ 2 c 2 þ 2 þ þ 2e þ 2dðp 2 3Þ: n 2n The two-thread chainstitch model The 401 stitch is formed by one needle thread (1) passing through the material and interlooped with one looper thread (a) and pulled up to the underside of the seam. The geometry and the chainstitch thread interlacing are represented, respectively, in Figures 5 and 6. The amount of the sewing thread (Q401) needed for the 401 chainstitch, whose geometry is represented in Figure 6, is estimated by the following formula: Q401 ¼ ðQ1 þ Qa ÞnL Q401 ¼ Lð4 þ 4ne þ ndð3p 2 1ÞÞ where Q1, needle thread consumption, 1 Q1 ¼ þ 4e þ dðp þ 1Þ; n Qa, looper thread consumption,
Figure 4. Stitch configuration for three-thread overedge stitches (504)
Figure 5. Stitch configuration for two-thread chain stitches
Qa ¼
3 þ 2dðp 2 1Þ: n
The thread safety stitch model The 516 (401 þ 504) stitch consists in a single needle (401) combined with a thread overedge stitch (504) that are formed simultaneously. The consumption thread of the 516 stitch is calculated with the following formula: Qð504þ401Þ ¼ Q504 þ Q401 Q516
7 þ 12e þ 2c þ 2 ¼ nL n
Analysis of the modeling methodologies 11
! rffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 2 c þ 2 þ dð9p 2 13Þ n
To calculate a circular yarn diameter, the following general equation suggested in literature (Seyam and El-Sheikh, 1994) was used: dðinchesÞ ¼
1 pffiffiffiffiffiffiffiffiffiffiffi 29:30 frf N
where f, yarn packing fraction (ration of yarn density to fiber density); rf, fiber density; and N, yarn count in cotton system. The yarn packing fraction is a function of yarn structural parameters, which are influenced by spinning method, twist level, fiber diameter, and fiber cross-sectional shape. We have used a value of 0.6 and 1.34, respectively, for the packing fraction and the fiber density (Seyam and El-Sheikh, 1994). To obtain the d value in centimeter, the following expression of the yarn diameter was used: dðcmÞ ¼
pffiffiffiffiffiffiffiffiffi 1 £ T tex 251:37
All the theoretical models explained above were used to predict the consumption of the sewing thread for both fabrics. The results relative to the 301 lockstitch varying the thickness from 0.27 to 3.64 mm and the stitch density between 3 and 6 are reported on Figure 7. This figure illustrates a considerable gap between the estimated and the actual consumptions (about 90 percent of the estimated consumption values are outside of the confidence interval calculated at a confidence level of 95 percent). The relative errors vary from 14.52 to 35 percent. Similar results were obtained for the other stitch types.
Figure 6. Interlacing of threads for 401 chainstitch
IJCST 18,1
12
Figure 7. Comparison between estimated and actual consumption of sewing thread in the case of the 301 lockstitch
The weakness of the theoretical models can be explained by the negligence of many other parameters such as the yarn tension, the cloth compression and the stitch distortion. Design of experiments Design of experiments dates from the beginning of the twentieth century with the works of Fisher. But, the theoretical aspect of the proposed approach has delayed the application of this technique in factories to the sixties thanks to the works of Taguchi in Japan who clarified and simplified the utilization of this method (Sado and Sado, 2000). The main objective of this statistical technique is to reduce the number of tests carried out when many parameters are studied by passing from a complete factorial plan to a fractional one in which one or many combinations of levels are excluded and to determine the more significant parameters. In order to determine the factors that really influence the yarn consumption and reveal the possible interactions between these factors, a design of experiments was developed to model the sewing thread consumption by using a multiple linear regression. Table II shows the control factors that we have considered in our survey with their respective levels. The design of experiments was developed using the software “Minitab”, it contains 256 tests ð4 £ 2 £ 4 £ 2 £ 4Þ:
Table II. Factors included in the design of experiments
Factors
Levels
Type of stitch Type of cloth Stitch density (n) Linear density (t) Cloth thickness (e)
301; 401; 504; 516 Jean trousers; shirt 3; 4; 5; 6 48 tex; 30 tex e; 2e; 3e; 4e
In order to identify the principal factors and interactions affecting the sewing thread consumption, two types of diagrams were realized (Figures 8 and 9). According to the Figure 9, the analysis of the experimental design (Harter, 1970) has revealed the following results with a reliability of 95 percent: . The stitch type is the most significant factor. Therefore, our design has been divided into four under-designs, which are analyzed separately. . The cloth thickness and the stitch density have significant effects. . The cloth type has a statistically negligible effect. . The yarn count has not any effect. . The meaningful interactions are: Stitch density £ thickness fabric, and Yarn count £ thickness fabric.
Analysis of the modeling methodologies 13
Figure 8. Diagram of principal effects
Figure 9. Diagram of interactions
IJCST 18,1
14
Modeling by multiple linear regression For each stitch type, we have established a linear regression model coupling the thread consumption (Q) to the most influent factors: . the stitch density (n); . the fabric thickness (e); . the yarn count (t); . stitch density £ thickness fabric interaction (n £ e); and . yarn count £ thickness fabric interaction (t £ e). In the case of the 301 lockstitch, the linear model obtained on the basis of 32 tests is the following: Q301 ¼ 22:8 2 9:5e 2 0:89n þ 19:1e £ n 2 0:28e £ t;
R 2 ¼ 95 percent
This model has been validated by an analysis of variance (Saporta, 1990) (F ¼ 130:9 and p ¼ 0:00). Furthermore, Figure 10 shows a high correlation between the actual values and those calculated by this model (the regression coefficient R 2 is about 0.95). The relative error for this model varies from 0.22 to 17.65 percent. The relative linear models for the other stitch types are presented in Table III. Compared to the results of the theoretical models, the gap between the predicted and the actual consumptions has been reduced. This improvement is essentially attributed to the selection of the most significant factors, with the help of experimental design, to build the sewing thread consumption model. Neural network modeling A neural network is composed of simple elements operating in parallel, which are inspired from biological nervous systems. As in nature, the network function is
Figure 10. Relationship between actual values and linear predicted values for 301 lockstitch
determined largely by connections between its elements. A neural network is usually adjusted, or trained, so that a particular input leads to a specific output (Dreyfus et al., 2004). Figure 11 shows the neural network architecture that we have programmed under the software “Matlab”. Thus, a feed-forward neural network was created using three units in the input layer (corresponding to the three experimentally determined inputs [The cloth thickness (e), the stitch density (n) and the yarn count (t)]), one hidden layer and one unit in the output layer (corresponding to thread consumption (Q)). After trial, the number of the hidden neurons was fixed at three. The data were all scaled to lie between 2 1 and þ 1 and the hyperbolic tangent sigmoid function (tan sig) was used as activation function for the hidden neurons and the linear function for the output neuron. This structure is known as multilayer perceptron (MLP).Training MLP in a supervised manner with the error backpropagation algorithm which is based on the error correction rule constitutes a feed forward backpropagation network. There are three distinctive characteristics each neuron in the network includes a non-linearity output; there are one or more layers of hidden neurons and the network has a high connectivity determined by the structure between layers. The performance of the obtained model was evaluated with the root mean square error (RMSE) and the correlation coefficient (R 2) between the computed output and desired target. vffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi uX n u u ðy^ i 2 yi;real Þ2 t i¼1 RMSE ¼ n
Analysis of the modeling methodologies 15
To test our network, we have divided each under-plan of experiences formed of 32 tests into two samples: (1) A training sample, which contains 22 random tests. (2) A validation sample that contains the 10 remaining tests. Type of stitch
R2
F
p
Regression model
504 Three-thread overedge stitch 401 Two-thread chainstitch (401 þ 504) Safety stitch
96.1 94.7 95.6
1094 817.32 4161.4
0.00 0.00 0.00
Q504 ¼ 36:1 2 0:2e þ 17:9n þ 39:1n £ e Q401 ¼ 38:8 2 2:58e 2 0:453n þ 19:5n £ e Q516 ¼ 33:3 2 3:1e þ 18:7n þ 40:5n £ e
Table III. Linear models relative to the other stitch types
Figure 11. A multilayer neural network architecture
IJCST 18,1
Thus, for the obtained neural model, the regression coefficient between the actual values and the predicted ones is equal to 0.98, and the relative errors were the lowest, comparing to the other models, varying from 0.84 to 7.12 percent. Figure 12 shows the accuracy of the obtained values using the validation sample to test this neural network model.
16
Comparison of the performance of the three different models In order to assess the performance of the theoretical, statistical (based on regression equations) and neural-network models for predicting the thread consumption, we calculated the relative error, the coefficient of determination R 2 and the RMSE for each type of stitch, and then we calculated the average for each parameter. The obtained results for the three models were summarized in Table IV. It can be seen that the maximum relative error among the different stitch models is lowest for the neural network model. Moreover, the correlation coefficients of the neural network models are greater or comparable with those relative t the theoretical and statistical models.
Figure 12. Relationship between actual values and neural network predicted values for 301 lockstitch
Stitch type
Table IV. Comparison between the three predicting models
Lockstitch (301) Three-thread overedge stitch (504) Safety stitch (516) Two-thread chainstitch (401) Average
Theoretical model Error R 2 percentage RMSE 0.92
35
0.79 0.99
5.65 5.29
0.72
8.33 13.57
Statistical model Error R 2 percentage RMSE
R2
Neural network Error percentage RMSE
0.428
0.95
8
1.89
0.98
4
0.103
0.787 0.787
0.991 0.997
6.19 1.18
4.4 1.82
0.99 0.99
0.79 0.86
0.176 0.138
0.414 0.987 0.604
1.72 4.27
1.2 2.33
0.98
2.17 1.96
0.133 0.137
As for the RMSE values, it is worthwhile to note that the neural network models perform better giving an average RMSE value equal to 0.137. Thus, the obtained results show that the neural network models give the best performance comparing to the other models for predicting the sewing thread consumption. Significance for industrial application The study illustrates the feasibility of the sewing data and predicting neural models for thread provisioning management. Objective characterization of principal sewing parameters such as cloth thickness, yarn count and stitch density which are specific to each garment will allow to estimate the sewing thread consumption. This is particularly useful for the apparel industry in provisioning the sewing thread and determining the required stocks. In fact, the predicting neural system proposed in this survey is composed of several models, which perform forecasts on various stitch types and fabrics. It provides rapidly an accurate prediction of the sewing thread quantity required to make up a garment. Thus, the unused stocks will be reduced and stock rupture will be avoided. Consequently, this predicting system allows a more reliable estimation of the garment cost. Conclusions In this survey, three models were proposed in order to predict the sewing thread consumption. First of all, mathematical models were established for different stitch types (301, 401, 504, 516) on the basis of the geometrical parameters such as the sewing length, the stitch density, the fabric thickness, etc. The obtained results have shown an important gap between the calculated and the actual consumptions. Secondly, with the help of the design of experiments, we have measured the importance of the parameters influencing significantly the sewing thread consumption. Both the regression analysis and the neural network, allow predicting the quantity of yarn required to sew a garment. Yet, the predictions from the neural network showed higher accuracy than those provided by the regression analysis. In fact, the neural network model has the best results for the task of predicting sewing thread consumption with a reliability of 95 percent and more. This study is quite interesting for industrial applications where samples are taken for different fabrics and garments, thus a large data is available. Another advantage of using a neural network approach is that when new data belonging to another region of the training data domain are available, the neural network can be updated by retraining, thus it can be expected to perform significantly better. References Dreyfus, G., Martinez, J.-M. and Samulides, M. et al. (2004), Re´seaux de Neurones: Me´thodologies et Application, Edition Eyrolles, Paris. Harter, H.L. (1970), Order Statistics and Their Uses in Testing and Estimation, US Government Printing Office. Sado, G. and Sado, M.C. (2000), Les Plans D’expe´riences: de L’expe´rimentation a` L’assurance Qualite´, Edition AFNOR, Paris.
Analysis of the modeling methodologies 17
IJCST 18,1
Saporta, G. (1990), Probabilite´s: Analyse des Donne´es et Statistique, Edition Technip, Paris. Seyam, A. and El Sheikh, A. (1994), “Mechanics of woven fabric, Part IV: critical review of fabric degree of tightness and its applications”, TRJ, Vol. 64 No. 11, pp. 653-62. Ukponmwan, J.O., Mukhopadhyay, A. and Chatterjee, K.N. (2000), “Sewing threads”, Textile Progress, The Textile Institute, Vol. 30, pp. 79-80.
18 Corresponding author M. Jaouadi can be contacted at:
[email protected]
To purchase reprints of this article please e-mail:
[email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Automatic segmenting and measurement on scanned human body Yueqi Zhong and Bugao Xu Department of Human Ecology, University of Texas at Austin, Austin, Texas, USA
Automatic segmenting and measurement 19 Received February 2005 Accepted October 2005
Abstract Purpose – This paper presents methods and algorithms to automatically segment and measure the human body. Design/methodology/approach – In the segmentation procedure, two different methods are designed to find the crotch point for the situation of non-contacted thigh and contacted thigh, respectively. Three different methods: minimum distance algorithm, minimum inclination angle algorithm, and directional neighbor identification algorithm are introduced to search the branching points or triangle. In the body measurement procedure, a pre-sorted circling method is designed for circumference measurement, and the basic principle of landmark acquisition has been discussed. These techniques are validated via testing over different type of scanned model. Findings – The results of automatic segmentation and body measurement have verified that our methods are efficient and versatile in processing different type of scanned body. Research limitations/implications – The accurate and automatic locating of wrist, ankle and knees contour can be more difficult than it appears to be. Practical implications – The main usage of scanned body in our research is for 3D garment try-on. Originality/value – This paper introduces the methods for crotch identification, and the methods including minimum distance algorithm, minimum inclination angle algorithm, and directional neighbor identification algorithm for human body segmentation. It also explains the fundamental measuring techniques, and outlines the results of using these techniques in segmentation and measurement. Keywords Measurement, Garment industry, Body regions Paper type Research paper
1. Introduction The whole-body scanner has been introduced into apparel industry for years. More and more researches have been focused on how to utilize the scanned body data to serve the demands of apparel industry in design and manufacturing. Among which, an interesting attempt is to directly integrate the data obtained from scanned digital human body with size measurement and drafting, which can provide the future pattern making or made-to-measure procedure a more flexible and reasonable foundation. Under such a circumstance, automatic segmenting and measuring become an important issue. Geisen et al. (1995) proposed a method to obtain traditional landmarks in terms of image processing and neural networks. However, subjects need to be manually marked with color fiducials by an anthropologist before scanning. When performing the segmentation on the raw data clouds, cusp detection became a critical issue, some
International Journal of Clothing Science and Technology Vol. 18 No. 1, 2006 pp. 19-30 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610637486
IJCST 18,1
20
researcher developed an efficient discrete point cusp detector that can be used to separate the data clouds linearly (Nurre, 1997, Nurre et al., 2000). Based on the nature of the body scanner, Li and Jones (1997) developed a method to separate the human body in terms of the horizontal slices of data. The change of slices below armpit had been recognized to generate a categorizing bisector. Dekker et al. (1999) formulated a signal-to-symbol language of shape operators for handling body-scanning data. Their work mainly focused on developing and testing a library of reusable operators. Manually measured data sets had been used in training feature detectors of the neural networks, and landmarks on surface had been drawn heuristically. Certain and Stuetzle (1999) described a model for the lower body consisting of two stacks of ellipses. To find out the crotch between left and right ellipses, they used a distance analysis method. Similar with the model used by Dekker et al. (1999), in this paper, we choose meshed surface instead of point clouds. Since the main usage of scanned body in our research is for 3D garment try-on, the meshed surface model is more convenient as been integrated into 3D CAD software. Another issue put into consideration is that almost all the scanner that appeared on the market cannot cover the entire subject surface without any small holes occurred in the raw data clouds. If performing the measurement across such an area, the result would definitely be wrong. Hence, we generate a meshed surface from the raw data clouds and fill the small holes in terms of quadric-based surface simplification (Garland, 1999), while the Loop’s subdivision algorithm (Loop, 1987) has been employed afterwards to produce a smooth surface that can provide a good approximation to the original data. More details of this topic could be found in Yu (2004). To facilitate the body measurement, we ask the subject to spread their legs and to separate their arms from the torso during the scanning procedure. Exact symmetry is not assumed, and posing as shown in Figure 1(a) is acceptable. To respect the privacy of subject, the face has been over-simplified. This paper is organized as follows, in Section 2, we introduce the methods for crotch identification, and the methods including minimum distance algorithm, minimum inclination angle algorithm, and directional neighbor identification algorithm for human body segmentation, while in Section 3, the fundamental measuring techniques have been explained. The results of using these techniques in segmentation and measurement can be found in Section 4. 2. Body segmentation The methodology of segmentation is first to locate the target zone on the human body and then to find out the branching points that can form a dividing plane to separate one part of body from another. When locating the target zone, we find that the proportion of head length to the height of human body is very helpful. However, throughout the literatures, no absolutely ideal proportion has been defined. Some specialist believed that body height equals to eight head tall appears to be more reasonable (Ratner, 2003). From our practice, we also find eight-head-tall is a good proportion. With this predefined parameter for target zone locating, we conduct the segmentation procedure in a four-step manner, which will be explained in the following sections.
Automatic segmenting and measurement 21
Figure 1. Illustrations of crotch points (red spot) on various scanned subject
2.1 Finding out the crotch point The crotch point is a point that implies the potential boundary between left and right body, and between upper and lower body. It is also a benchmark for crotch height measurement. As shown in Figure 1, it can be regarded as the origin point of human body. During the body scanning procedure, the subject should spread their legs by request. However, when the subject is overweight, it is highly possible that their left thigh and right thigh contacted with each other (and this phenomenon can also be found in slightly overweight subject that their thigh is thicker than that of normal weight people). To make the crotch searching more versatile and accurate, we introduce two different methods in solving the situation for contacted thigh and non-contacted thigh, respectively. 2.1.1 Method 1. For non-contacted thigh, a plane paralleling to XZ plane is placed at the height of 5.0h, where h is the head length (see Figure 1(b)). Here, the selection of 5.0h is to make sure that this plane intersects with the upper thigh. The intersection points are sorted in þ X direction and the distance between two neighbor-points are performed. The maximum gap between two neighbor-points (notify as Pl and Pr) separates the points from left leg to that of right leg. Now taking the middle point of Pl and Pr as P0, and starting a plane through P0 while parallels to YZ plane, the point with minimum y coordinates value in the vertical intersection contour will be regarded as the crotch point O, as shown in Figure 1(b). 2.1.2 Method 2. For contacted thigh, firstly, a set of scan line is placed in front of the human body, and the point set of each scan line is defined as: S i ¼ {P j : 2 0:5h # P jx # 0:5h; j ¼ 0; 1; . . . ; n}; where i is the index of scan line, and j is the index of the points in Si, while n is the number of points in Si. If starting a set of ray from each point of Si to body triangles, the intersection point set will demonstrate the shape change from right thigh to left
IJCST 18,1
thigh, and the progressive scan will reveal the section shape change from thigh to hip, as shown in Figure 2(b). The target zone that the scan lines covered is defined as: T ¼ {P [ S b : 2 0:5h , P x , 0:5h; Y max 2 6:2h , P y , Y max 2 3:8h};
22
Figure 2. Finding the crotch point from obese subject
where Sb is the set of body surface points. The magic number of 6.2 and 3.8 is coming from the observation of anthropometry, and such experimental constant for target zone definition can also be found elsewhere in this paper. Secondly, the gap between left leg and right leg is calculated repeatedly until there is no significant gap, which means we reached the cusp where left leg and right leg starts to contact. Thirdly, after finding out the cusp, we calculate the inclination angle between two neighbor segments P j21 P j and P j P jþ1 : Figure 2(c) shows the cosine value of inclination angle against its index. For each scan line above the contact cusp, we calculate its cosine angle plot and find out how many significant peaks are there in the plot. This can be solved by first getting the maximum and minimum cosine value from the plot, and then marking out how many values are higher than 2ðcosmax u 2 cosmin uÞ=3; where cosmax u and cosmin u is the maximum and minimum cosine value, respectively. In general, the thigh contacted area will produce one peak, while starting from crotch area, there will be more than one peak occur, which is corresponding to the shape change from thigh to hip. Once we find a plot that starts to have more than one peak, it indicates the crotch point should be located between this plot and its previous plot. Denoting the scan line corresponding to these two plots as S iþ1 and Si, where S iþ1 is the one with multi-peaks, we use Binary search to iterate the peak checking routine until the difference between Si and Siþ 1 in y direction is smaller than 1 mm. At this point, we define the coordinates of crotch point O as:
Ox ¼ ðP 1x þ P 2x Þ=2; Oy ¼ ðP 1y þ P 2y Þ=2 and Oz ¼ ðzmax þ zmin Þ=2; where P1, P2 are the two peak points, and zmax, zmin are the maximum and minimum z values of the section contour, where O is positioned, as shown in Figure 2(b). In the software we developed, the user can choose different methods for different body shape, since method 1 is fast when left thigh and right thigh has no contacts, and method 2 is guaranteed of convergence in finding the crotch point on the subject whose left thigh and right thigh has touched.
Automatic segmenting and measurement 23
2.2 Separating arms from torso To separate the arms from torso, we must find out acromion (shoulder point) and armpit. For the convenience of explanation, unless specified otherwise, we take left arm as the default example. As shown in Figure 3, the left acromion Qa is marked as the triangle vertex that has the minimum 2D distance with point A, whose coordinates is defined as: xa ¼ MinðOx þ 1:5h; X max Þ
ya ¼ Y max 2 h;
where Ox is the x value of crotch point O, and Xmax and Ymax are the maximum value of human body in 3D coordinates, respectively. The target zone for acromion locating is chosen by acknowledging the anatomic feature that the shoulder width usually equals to three head width, therefore reach out from center (where x ¼ Ox ) to each side of 1.5 head length will definitely cover the target zone. The right acromion is obtained in the same manner, and even though the left and right acromions are not symmetric, this minimum distance algorithm can still work. To obtain the armpit point Qb, the target zone is defined as: T ¼ {P [ S b : Ox , P x , Ax ; Y max 2 2:5h , P y , Y max 2 1:5h}: When comparing the inclination angle between two neighbor triangles in this area that share the same edge, Qb can be regarded as the middle point of an edge where
Figure 3. Find out the left acromion
IJCST 18,1
24
minimum inclination angle generates. In practice, this minimum inclination angle algorithm is quite useful in locating many landmark points, such as elbow, knee, etc. when suitable target zone is provided in advance. After finding out Qa and Qb, a cutting plane that passes through these two points and perpendicular to XY plane is formed to get the intersection contour C, which separates the left arm from torso in terms of the intersection point set: S I ¼ {P [ S b : MinðQbx ; Qax Þ , P x , MaxðQbx ; Qax Þ; Qby , P y , Qay }: Considering the variety of arm pose, we propose a directional neighbor identification algorithm for the arm/torso segmentation. Before starting this procedure, four kinds of set are predefined, which are (1) Available set V: these are triangles that have yet to be considered for arm triangle recognizing. (2) Arm seed triangle set As: these are triangles that have been regarded as seed triangle for arm triangle recognizing. (3) Arm triangle set A: these are triangles that belong to arm. (4) Temporary seed triangle set Ts: these are triangles that have been temporarily regarded as next layer of arm seed triangle. The directional neighbor identification algorithm is described as: Step 1: Initially all triangles are placed in set V. Sets As and A are empty. Step 2: All the triangles in set V is tested to see if it has intersections with contour C, and if such a triangle also has more than two vertices located to the left of C (herein, left and right is defined in the local coordinate of human body, which means if a point Pi is to the left of a point Pj, then P jx , P ix ), it will be regarded as arm seed triangle (denote as ti) and will be transferred from set V to set As. Step 3: A search is made of set V for all triangles that share a vertex with the triangle ti ð{t i [ As ; i ¼ 0; 1; . . . ; n}Þ; where n is the size of set As. The successful candidates must have more than two vertices located to the left of C and the x coordinates of these two vertices should be larger than Qbx. Such neighbor triangles are transferred into set Ts as next layer of arm seed triangle. When the search finished, the elements of set As are transferred into set A, while the elements of set Ts are transferred into set As. Step 4: Repeating Step 3 until the minimum y coordinates ( ymin) of more than 95 percent triangles in set As is smaller than Qby. This criterion is designed to make sure that the current triangles in set A will cover most area of shoulder. Step 5: For each triangle ti of As, the searching constraints in Step 3 is redefined as finding the triangles in set V who shared a vertex with Ti and its ymin is smaller than the ymin of ti. This is because when the element in set As is lower than armpit, its lower neighbor triangle will always belong to
arm. This step is repeated until no new triangle has been added into set A. Step 6: In case of exception, any triangle with all three vertices been shared by other arm triangles will be regarded as arm triangle. After these steps, we can obtain the entire arm triangles no matter what pose it is and the convergence is guaranteed.
Automatic segmenting and measurement 25
2.3 Separating legs from torso The methodology of segmenting legs from torso is similar with that of arm/torso segmentation, except that the dividing plane is defined as a half plane that passes through the crotch O while parallels to XZ plane. 2.4 Separating neck from torso Sometimes, neck/torso segmentation can be very useful in the neck size measurement. The feature point that separates neck from torso is named as neck base point. It can be identified by using minimum inclination angle algorithm. For left side, the target zone is defined as: T ¼ {P [ S b : Ox , P x , Qax ; Qay , P y , Qay þ 0:5h}: Once obtained the left-side neck base point, we form a plane that pass through this point and has 208 inclination angle with XZ plane, as shown in Figure 4. This angle is selected from the observation on neck pose, and can be altered in terms of the variety of neck pose. The right-side neck base point is calculated in the same manner. After obtained neck base points for both sides, we compute the length of the two intersection contour that pass through these two points, respectively. The one generating the minimum circumference will be regarded as the separating line between neck and torso. In the following sections, we will discuss automatic body measurement based on the segmentation results acquired in this section.
Figure 4. Finding out the neck base point
IJCST 18,1
26
3. Body measurement The task of body measurement is to extract the size data from the target zone or feature area around the model. Different subject (sex, age, race, etc.), different implementation situation (real-time online shopping, offline 3D CAD software, and size survey for mass customization, etc.) and different pattern design requests different shape analysis and data acquisition technique to fulfill the size chart. Under such a context, it is hard to cover all the possible requirement of tailor-measurements and detailed them one by one. Therefore, we only exploit the most fundamental measurement types and techniques in this paper. 3.1 Key measurement extractions Generally, there are three basic parameters that need to be measured: circumference, distance (both linear and curvilinear) and angle (usually the angle among three given points). 3.1.1 Circumference measurement. From our observation, circumference measurement can be subdivided into two types: tight contact circumference and tangential contact circumference, as shown in Figure 5. The tight contact circumference is the curve length of the “section” contour when cutting the body parts at a given position, such as waist circumference, while tangential contact circumference is the curve length of a tangential contour that is formed by the “convex hull” of the original section contour, such as the bust and hip circumference. Usually, to get the circumference of concern, we can cut the 3D model at the given position to obtain the intersection point set, and then sorting this set in counter-clockwise or clockwise direction to get the correct answer. Throughout the techniques developed by computational geometry society, there are many ways to sort a point set in 3D space. However, due to the variety of body shape, we find many 3D sorting algorithms may fail in either getting wrong order of point set or becoming too complex in implementation. Since we need a versatile and fast method to deal with all kinds of situation, we approach this problem from another angle of view, i.e. using a pre-sorted circle to get the intersection contour instead of sorting the intersection point set in 3D space. To obtain the intersection contour, a bounding circle is equally subdivided in counter-clockwise direction (as shown in Figure 6) to generate a point set S c ¼ {P i [ C r ; i ¼ 0; 1; 2; . . . ; m}; where Cr is the bounding circle and m is the subdivision
Figure 5. Two different types of circumference measurement
number. Starting a segment from Pi to the center Oc of target zone, the corresponding intersection point set (denote as S I ¼ {P i [ S b ; i ¼ 0; 1; 2; . . . ; m}) can be generated counter-clockwise. Here, the x and y coordinates of Oc is set as Ocx ¼ ðxmin þ xmax Þ=2 and Ocy ¼ ð ymin þ ymax Þ=2; where xmin, xmax, ymin and ymax are the minimum and maximum coordinates of target zone, respectively. In this way, the contour for circumference calculation (type A) can be acquired by sequential connecting the intersection points. Obviously, the accuracy of circumference measurement is determined by the subdivision number m. From our experience, we find that setting m as 360 is a good approach. Due to the fact that most of the computation time is consumed in finding the potential triangle who would have the intersection point with segment PiOc, an axis-aligned bounding box (AABB) tree is pre-built for each body parts to accelerate the segment/triangle collision detection before starting the measurement procedure. Actually, in the previous crotch searching procedure, we use AABB accelerated ray/triangle collision detection technique as well. More details of building and using AABB trees can be found in the work of (Bergen, 1997). To obtain the circumference of type B measurement, SI is treated in the following way. Firstly, SI is divided into quadrant in terms of the xmin, xmax, ymin and ymax in the cutting plane. Secondly, the inflexion points (Plf, Prf, Plb, Prb) are searched at each quadrant by comparing the z values in the local coordinate of cutting plane. Thirdly, the points located between Plf and Prf are removed, as well as those between Plb and Prb (see Figure 5). Now the sequential connection among the remaining points in SI would generate the contour for type B measurement. It’s noticed that the method for type B circumference reorganization would only suitable for the case of bust and/or hip circumference since both of them has two peak areas in the 2D silhouette. 3.1.2 Distance measurement. As mentioned before, distance measurement includes linear and curvilinear measurement, respectively. The linear distance is the length of the direct connection between two given points, while the curvilinear distance can be generated by taking a part from SI between two given points. Thus, no special treatment is necessary. 3.1.3 Angle measurement. Sometimes in body measurement, we may need to know the angle between three given points. From our experience, it can be computed directly without special treatment.
Automatic segmenting and measurement 27
3.2 Basic landmark acquisition techniques In the physical world, body measurement is a procedure based on experience and observation. Though the size chart may be various, the landmark acquisition is always
Figure 6. Using pre-sorted circle to find out the intersection contour with body
IJCST 18,1
28
the first step. When perform the similar work in the virtual world, we use minimum inclination angle algorithm to get the possible feature point that sharpest shape change occurs and then set the target zone based on the 3D coordinates of this feature point within a range that is defined by a function of head length h, the same methodology as we introduced in segmentation. After this, the target zone is scanned progressively from top to bottom in order to position the exact landmark via contour shape reorganization (cusp, reentrant angle, length, or triangle partitioning by body segment). In practice, the size is categorized as independent size and dependent size. Independent size can be acquired directly from the target zone (e.g. chest/bust, or waistband), while dependent size needs the acquisition of an independent size before obtain such data itself (e.g. crotch height, it needs to find out the waistband in advance). 4. Results To evaluate the methods and algorithms discussed in this paper, automatic body measurement software has been developed using Cþ þ and OpenGL platform, several male and female subjects with different body shapes and ages (from 25 to 65) as well as a series of size dummy have been scanned and measured. Figure 7 shows some examples of segmentation based on the algorithms discussed in Section 2. With the knowledge of body segmentation, several basic automatic landmark acquisition and measurements have been conducted, as shown in Figure 8. Figure 8 also illustrates the skin deformation driven by a skeleton system acquired directly from the data of body measurement. Since the information obtained from body segmentation and measurement can be employed in computing the 3D coordinates of each joint, such a skeleton system could be reasonably used in a 3D virtual dressing system to provide more realistic visual effects in animation. Another advantage of these techniques is that they can be used for any surfaced human model, such as the Obj model (the fourth model shown in Figure 7) generated from 3D figure design software. It provides the capacity of measuring any human model in a desired way, which extends the versatility of the methods and algorithms proposed in this paper.
Figure 7. Examples of segmented model
Automatic segmenting and measurement 29
Figure 8. Illustration of landmark acquisition, body measurement and skeleton-driven skin deformation
However, it is noticed that the accurate and automatic locating of wrist, ankle and knees contour can be more difficult than it appears to be. For the variety of human body shape space, it is hard to give an exact definition for such an area. Therefore, we provide the options of using free-hand measurement tools to extract the correct size measurement from the human model directly. With the techniques described in this paper, the user can click on any point of the human body as the user-defined feature point and the measurement will be performed accordingly. 5. Conclusion In this paper, the shape of different scanned model is analyzed by first defining the target zone and then specifying the feature point in terms of the methods and algorithms we developed. The proportion of head length to body height has been used as the benchmark in determining the potential target zone. During the segmentation procedure, we treat the situation of non-contacted thigh and the contacted thigh with different methods, and three shape-reorganization algorithms are detailed as well. In the body measurement procedure, a pre-sorted circle has been used in finding the intersection point sets that formed the circumference contour and the fundamental principles of landmark acquisition have been discussed. The results of automatic segmentation and body measurement have verified that our methods are efficient and versatile in processing different type of scanned body. References Bergen, G.v.d. (1997), “Efficient collision detection of complex deformable models using AABB trees”, Journal of Graphics Tools, Vol. 2 No. 4, pp. 1-13. Certain, A. and Stuetzle, W. (1999), “Automatic body measurement for mass customization of garments”, Proceedings of Second International Conference on 3-D Imaging and Modeling (3DIM ’99), pp. 405-12.
IJCST 18,1
30
Dekker, L., Douros, I., Buxton, B.F. and Treleaven, P. (1999), “Building symbolic information for 3D human body modeling from range data”, Proceedings of Second International Conference on 3-D Imaging and Modeling (3DIM ’99), pp. 388-97. Garland, M. (1999), “Quadric-based polygonal surface simplification”, PhD thesis, School of Computer Science, Carnegie Mellon University. Geisen, G.R., Mason, C.P., Houston, V.L., Whitestone, J.J., McQuiston, B.K. and Beattie, A.C. (1995), “Automatic detection, identification, and registration of anatomical landmarks”, Proceeding of the Human Factors and Ergonomics Society, Vol. 2, pp. 750-3. Li, P. and Jones, P. (1997), “Automatic editing and curve-fitting of 3-D surface scan data of the human body”, Proceedings of International Conference on Recent Advances 3-D Imaging Modeling, pp. 296-301. Loop, C.T. (1987), “Smooth subdivision surfaces based on triangles”, Master’s thesis, Department of Mathematics, University of Utah, Salt Lake City, UT. Nurre, J. (1997), “Locating landmarks on human body scan data”, Proceedings of International Conference on Recent Advances in 3-D Digital Imaging and Modeling, pp. 289-95. Nurre, J.H., Connor, J., Lewark, E.A. and Collier, J.S. (2000), “On segmenting the three dimensional scan data of a human body”, IEEE Transactions on Medical Imaging, Vol. 19 No. 8, pp. 787-97. Ratner, P. (2003), 3-D Human Modeling and Animation, 2nd ed., Wiley, New York, NY, pp. 55-7. Yu, W. (2004), Human Body Modeling based on Mesh Simplification and Subdivision, technical report, Department of Human Ecology, University of Texas, Austin, TX. Corresponding author Bugao Xu is the corresponding author.
To purchase reprints of this article please e-mail:
[email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Interactive garment pattern design using virtual scissoring method In Hwan Sul and Tae Jin Kang School of Materials Science and Engineering, Seoul National University, Seoul, South Korea
Interactive garment pattern design 31 Received September 2005 Accepted October 2005
Abstract Purpose – The designing and initial alignments of 2D garment patterns in 3D space are the key procedures in 3D apparel design. This paper presents a new methodology to prepare and edit initial pattern shape in 3D space by simulating virtual cloth scissoring. Design/methodology/approach – In conventional apparel CAD tools, flat 2D patterns are drawn and sewn in 3D space. Thus, the final appearance of 3D garment cannot be easily predictable for non-specialized personnel from the flat patterns. This paper adopts the real pattern designing method of “draping”, incorporating it into computer-based designing so that the user can realistically cut, sew and add the cloth by only using a mouse. 2D and 3D meshes are edited simultaneously and thus a flattening process is not needed. Findings – Several mesh-based operations such as cutting, sewing, adding, and fixing are devised and have been successfully applied to virtual garment cutting. Practical implications – Our new pattern drawing method has an advantage that designer can look and feel the garment appearance interactively during the design process. Virtual cutting is identical to the real pattern draping technique and is easy to adopt for designers. Originality/value – With current computer hardware speed and through using the drape simulation technique, it was possible to drape and cut cloth in real-time. In addition, both the 3D pattern and 2D flat pattern could be simultaneously acquired. Keywords Clothing, Garment industry, Design, Computer-aided design, Simulation Paper type Research paper
Introduction The recent cloth drape simulation and rendering technology has made it possible to simulate almost any kind of garment in either a static or dynamic situation even when the manikin is in motion such as on catwalks (Choi and Ko, 2002; Yang and Magnenat-Thalmann, 1993). There are several drape modules and tools such as 3DS Maxw and Mayaw to graphically design 3D garment. Their methodology is mainly mesh-based such as particle-dashpot model (Fontana et al., 2005) and the initial 2D patterns should be prepared, positioned and given sewing information before actual draping calculations start (Kim and Kang, 2003; Yang and Magnenat-Thalmann, 1993; Choi and Ko, 2002). But this is far from an actual garment pattern design procedure in that the designer cannot predict the final garment shape from the flat 2D patterns and the 3D patterns cannot be modified freely. A researcher (Chiricota, 2003) has applied mapping algorithms for secondary garment parts but mathematical manipulation was needed and small inaccuracies are encountered when the area of the pieces are small. Others (Kim and Kang, 2003) acquired the pattern shapes from the convex body mesh
International Journal of Clothing Science and Technology Vol. 18 No. 1, 2006 pp. 31-42 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610637495
IJCST 18,1
32
data to represent and fit the body shape, however, their method needs to deform the body shape and do not supply an editing mechanism. Wang et al. (2005) proposed body feature based 2D sketching algorithm, but their patterns do not represent body shapes because meshing starts from the simple polyhedra of feature points. This paper mimics pattern designers’ draping technique which lays down cloth on a dummy and finds a final pattern shape through by iterative cutting. Real garment patterns are designed by using chalks, pins and scissors, but we replaced them with NURBS cutting curve and mesh cutting algorithm. Artificial cloth is draped on a manikin and cut and edited interactively. A female two piece dress was designed for demonstration. Method Preparation of 3D manikin body data Any kind of mesh data can be used for a manikin, such as human body scan data or a graphically synthesized dummy. We implemented a manikin dummy model from 3DS Maxw with an input file format from 3DS, DXF or VRML. Triangular mesh generation algorithm Our method deals with repetitive mesh manipulation and thus versatile mesh generation algorithm is necessary. We devised triangular mesh generation algorithm using Delaunay triangulation (Sul and Kang, 2004), which can deal with arbitrary boundary shapes, inner holes and even darts with angle 0. The input data needed were exterior boundary nodes, hole boundary nodes and inner nodes with either clockwise or counter-clockwise rotational direction. But it is critical that exterior nodes should be sorted in advance for exact mesh generation. The exterior node order was explained in the mesh-cutting algorithm. Figure 1 shows the mesh generation example of extreme geometry with inner holes. Inner nodes were randomly distributed and Gaussian mesh relaxation (Taubin, 1995) was applied after triangulation. NURBS cutting curve drawing Just as a chalk is used for specifying cutting lines on real cloth, NURBS of degree 3 (Farin, 1997) was used to draw a cutting path on virtual cloth. The user clicks several points on the cloth scissoring path and then interpolation is done to find NURBS curve, which connects those points. Note that the cutting curve is drawn on 2D image space (the surface of monitor) and the virtual cloth is a 3D object space. To find a cutting path on 3D cloth mesh surface, 3D cloth is projected on to an image space (as shown in Figure 2) and the projected cloth mesh is tested with NURBS to locate the intersection points by using computational geometric rules (Rourke, 1998). The OpenGL projection function gluProject( ) (OpenGL ARB, 2003) was used to find the projection image of 3D cloth mesh. Cutting path is assumed to be a closed loop and its inside area is to be deleted. Mesh cutting algorithm Figure 3 shows a simple example of the mesh cutting algorithm. Once the cloth mesh (designated as 3D raw mesh) was projected on the image plane (Figure 3a), its projected 2D mesh (designated as 2D raw mesh) was overlapped with the NURBS cutting path and intersection points were found (solid triangular marks in Figure 3b). They should
Interactive garment pattern design 33
Figure 1. An example of the triangular mesh generation with inner holes
Figure 2. Projection of 3D mesh onto 2D image plane to find intersection points with cutting spline
be used as new exterior boundary nodes after re-meshing and they need to be ordered with respect to the spline arc length. They were designated as Group A: Group A Intersection points between 2D raw mesh and cutting path (ordered by spline arc length). The NURBS cutting path were divided into a series of line segments and each part was given a correspondent knot value which is a continuous parametric value to specify the
IJCST 18,1
34
Figure 3. An example of 2D mesh cutting algorithm
relative curve position in NURBS (Farin, 1997). If a mesh edge collides with any linear part, the collision point (Group A) has a knot value of the part. For mesh generation to be successful, these Group A points should be well ordered and sorting with respect to knot value gives a stable mesh result even when the initial 3D cloth mesh is folded as shown in Figure 7b. If Group A is found and sorted out, nodes and elements to be deleted should be found. Nodes to be deleted include: Group B Nodes inside NURBS cutting path; Group C Nodes of edges on which any Group A point lies.
Figure 3c shows Group B and C nodes as solid circles. Elements to be deleted were designated by: Group D All neighbor elements of Group B and C
Interactive garment pattern design
as shown in grey filled elements in Figure 3d. The other group of new exterior boundary nodes should also be found to construct and graft new mesh: Group E Nodes which are not to be deleted and lie around Group C, which is shown as solid rectangular nodes in Figure 2d. After nodes and elements were eliminated from 2D raw mesh (Figure 3e), a new mesh was constructed from the above group points (designated as local mesh) using our mesh generation algorithm (Figure 3f). Local mesh was combined with the deleted mesh resulting in the desired final mesh. Groups B, C and D were eliminated from the raw mesh and we get results like Figure 3e. Group C was inserted as inner nodes into the new local mesh and Group A and E became exterior boundaries of local mesh. Group E was not ordered yet while Group C was already ordered. As Group E points were exterior boundary points, they could be ordered from neighbor information through using the following lemmas. Lemma 1 Boundary edges always have one neighbor element. Lemma 2 Boundary nodes are nodes of boundary edges. Lemma 3 Boundary nodes always have two neighbor boundary nodes. Finally the rotational direction of Group A and E were synchronized and local mesh could be calculated and combined with the deleted mesh. As Group E points existed in both deleted mesh and local mesh, they were given their original node number in deleted mesh and thus are not inserted. Modification of 3D cloth mesh Figure 4 is an illustration of pattern mesh cutting and shows that 3D raw mesh and 2D raw mesh have the same element information, differing only in node coordinates. Thus, 3D raw mesh is simultaneously edited as 2D raw mesh is modified and additional inverse projection or pattern flattening is not needed. Moreover, the final mesh retains the original surface shape before mesh cutting, as nodes of Group A lie on 3D raw mesh. Mesh adding algorithm Mesh adding is a process used to create a number of mesh elements at the boundary and combine them to the original mesh, thus different from an un-doing of mesh cutting. In reality, cloth cannot be made but only cut. Therefore, careless scissoring can result in a failed pattern design. But in the virtual environment, cloth can be freely cut or expanded. The only difference between mesh adding and cutting is that new mesh nodes cannot lie on the original mesh surface. Their approximate node coordinates are determined by assuming that surface normal vector is the same with those of neighbor
35
IJCST 18,1
36
Figure 4. An example of 3D mesh cutting algorithm where 3D and 2D meshes are edited simultaneously
elements. Figure 5 shows an application of mesh adding to a neck line design. Figure 5a is the original neck shape and circled areas of Figure 5b are locally changed examples by mesh adding. Note that this is not the inverse process of cutting. The mesh adding method has an advantage that it can virtually create and modify cloth even if a design has been finished. Pinning Pinning is a process used to fix node coordinates so that the cloth does not slip off a manikin just as in real pattern designing. Figure 6 shows an example of using pins.
Interactive garment pattern design 37
Figure 5. An example of neck line modification using virtual adding
Figure 6. Using pins to fix cloth
Pins are especially useful when a dart line should be made by folding clothes around a dart. Result Designing a female jacket As an example of the virtual cutting method, a female jacket on a manikin body was designed. First the cloth data required for front-right pattern is only a simple
IJCST 18,1
38
Figure 7. Designing steps of front shirt pattern
rectangular sheet as shown in Figure 4a and is a not ready-drawn 2D flat pattern. The rectangular sheet was draped on a manikin and the redundant part under the waistline is deleted using virtual cutting. Some necessary pins were used to fix and flatten the cloth on manikin. Cloth parts above the bust points were well draped but parts around the waistline had wrinkle as they did not have proper darts. To find vertical waist darts, cloth around the front waist was folded by using pins and dart guide points were found by drawing NURBS cutting path (Figure 7b). Figure 7 shows that the cutting line detection works whether the cloth is three dimensionally folded or not. The horizontal dart line is found in the same way and the final front-right pattern is as shown in Figure 7c. Some sewing information can be given to sew the dart line before combining four pieces of patterns altogether (Figure 7d).
Other pieces such as back-right pattern can be prepared in the same way. Not only dart line, but details can be edited by virtual cutting as shown in Figure 8. Four pieces of patterns are needed for this shirt design and after sewing information is given (Figure 9a) final product is acquired as seen in Figure 9b. Skirt can be designed also easily (Figure 10b) and texture maps were applied to give reality (Figure 10a). Fur effects were simulated by using OpenGL 2.0 shading language (Kano, 2004) and fur length, colors and density can be freely chosen as seen in Figure 11c.
Interactive garment pattern design 39
Conclusion Our new pattern drawing method has an advantage that designer can look and feel the garment appearance interactively during the design process. Conventional method
Figure 8. Designing steps of back shirt pattern
IJCST 18,1
40
Figure 9. Final shirt pattern
Figure 10. 2D patterns of a shirt
which imports ready-drawn 2D patterns and align them do not guarantee if patterns would fit the manikin size and do not provide an easy way to edit patterns. Moreover, initially aligning patterns in a proper position in 3D space requires the skilled handling of input devices. Virtual cutting is identical to the real pattern draping technique and is easy to adopt for designers. The user has only to draw a cutting path curve to cut the cloth and fix proper nodes to find dart lines. Furthermore, the 2D flattening procedure of 3D patterns is not needed because the editing process is done both for the 3D and 2D cloth meshes at the same time. For further work, use of a head-mount display and a data glove is considered for more realistic operations.
Interactive garment pattern design 41
Figure 11. Texture mapping results
References Chiricota, Y. (2003), “Three-dimensional garment modeling using attribute mapping”, International Journal of Clothing Science and Technology, Vol. 15 No. 5, pp. 346-58. Choi, K. and Ko, H. (2002), “Stable but responsive cloth”, ACM Transactions on Graphics, SIGGRAPH 2002, Vol. 21 No. 3, pp. 604-11. Farin, G. (1997), Curves and Surfaces for CAGD, Academic Press, San Diego, CA. Fontana, M., Rizzi, C. and Cugini, U. (2005), “3D virtual apparel design for industrial applications”, Computer-Aided Design, Vol. 37, pp. 609-22. Kano, T. (2004), “Dynamic fur using SmartShaders”, ATI 3rd Party Samples, available at: www. ati.com/developer/indexsc.html Kim, S.M. and Kang, T.J. (2003), “Garment pattern generation from body scan data”, Computer-Aided Design, Vol. 37 No. 5, pp. 611-8. OpenGL ARB (2003), OpenGL Programming Guide, Addison-Wesley, Boston, MA.
IJCST 18,1
42
Rourke, J.O. (1998), Computational Geometry in C, Cambridge University Press, New York, NY. Sul, I.H. and Kang, T.J. (2004), “Improvement of drape simulation speed using constrained fabric collision”, International Journal of Clothing Science and Technology, Vol. 16 Nos 1/2, pp. 43-50. Taubin, G. (1995), “Curve and surface smoothing without shrinkage”, Computer Vision, Vol. 1995, pp. 852-7. Wang, C.C.L., Wang, Y. and Yuen, M.M.F. (2005), “Feature based 3D garment design through 2D sketches”, Computer-Aided Design, Vol. 37, pp. 659-72. Yang, Y. and Magnenat-Thalmann, N. (1993), “An improved algorithm for collision detection in cloth animation with human body”, Computer Graphics and Applications, Pacific Graphics ’93 Proceedings, Vol. 1, pp. 237-51. Corresponding author In Hwan Sul is the corresponding author.
To purchase reprints of this article please e-mail:
[email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Garment washed jeans: impact of launderings on physical properties Ayanna Card Carter’s Atlanta, Atlanta, Georgia, USA
Mary Ann Moore
Garment washed jeans
43 Received May 2005 Accepted September 2005
College of Human Sciences, Florida State University, Tallahassee, Florida, USA, and
Mary Ankeny Cotton Incorporated, Raleigh, North Carolina, USA Abstract Purpose – This paper reports on the effects of laundering on physical properties (pilling and edge abrasion) of washed denim fabrics. Design/methodology/approach – Garment washed denim blue jeans were subjected to repeated launderings; the effects of the cycles on pilling and edge abrasion were determined. Data were collected by means of a laboratory experimental factorial design. Analysis of variance was used to determine significant differences in the three garment washed treatments; pre-washed, stone washed and enzyme treated blue jeans. Duncan’s test of multiple range determined the source of significance. Findings – The pre-washed jeans were more prone to pilling than the enzyme and stone washed jeans. On the other hand, the pre-washed jeans experienced the least amount of edge abrasion while the stone washed experienced the most. Practical implications – The results can be used by the denim garment manufacturers to design and engineer their products to suit the customer demands. Originality/value – Jeans are an important part of a consumer’s wardrobe and a large portion of denim garments are manufactured with some type of garment wash treatment. Results of this study will provide denim garment manufacturers with pilling and abrasion information regarding garment washing treatments to allow them to utilize the garment treatment that best meets their needs. Keywords Clothing, Abrasion, Wear resistance Paper type Research paper
1. Introduction Denim jeans evolved into a part of the fashion gamut during a time when the median age of the American population was declining (Behling, 1985-1986) and popular culture has embraced denim since its inception into the fashion world in the 1960s (Magiera, 1989). “The success of denim is due to its ability to change with every social and cultural evolution” (Spevack, 1997, p. 7). Denim jeans evolved into a fashion icon and the “universal uniform [that] could simultaneously express the highest level of individualism” (Wilson, 1991, p. 124). Currently, denim jeans are still a major part of America’s consumer wardrobe. Cotton Incorporated Lifestyle Monitore (2004) reported for 2003 that “. . .consumers reported that they owned, on average, eight pairs of jeans and 16 denim garments. For the 2004, 25 percent said they would likely buy
International Journal of Clothing Science and Technology Vol. 18 No. 1, 2006 pp. 43-52 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610637503
IJCST 18,1
44
several more denim items, while nearly half (47 percent) admitted they might buy one or two”. Denim garment manufacturers are interested in producing garments that consumers want to purchase. Consumers demand for blue jeans with a “distressed” or aged look began a revolution in denim processing (Hargraves et al., 1991). Consumers are interested in “broken in” finishes and want “all the aging work done to the jeans now, by the manufacturer, instead of doing it themselves” (Cone Denim, 1996, p. 2). Noting this increase in demand, the idea of garment washing was initiated with pre-washed jeans in the mid 1980s (Cotton Incorporated, 1992; O’Grady, 1991). The pre-washed treatment removed sizing applied during the manufacturing process. In a garment, many layers are sewn together in areas making them rigid, “and thus more susceptible to abrasion” (p. 2) than the adjacent single layers because of their tendency to hold position while being subjected to abrading forces in garment washing. On indigo denim, as abrasion occurs, the surface of the yarn is worn away exposing the un-dyed core of the yarn (Hatch, 1993). The decreased amount of dyed fiber on the surface of the fabric gives the illusion of an aged look. By the late 1980s, 60 percent of all domestically produced denim garments received some type of garment wash treatment (Hargraves et al., 1991). “Not long after the introduction of pre-washed jeans, the idea of using abrasive stones to accelerate the aging process was developed and ‘stone washing’ was born, creating an even more ‘broken-in’ look” (Cotton Incorporated, 1992, p. 1). Stones were incorporated in the manufacturing process after the garment had been desized and laundered. Abrasion resulted by removing fibers from the fabric’s surface. However, the use of pumice stones created many problems and the process was very labor intensive (Zimmerman, 1993). Because the stones were a product of volcanic eruptions, they were not always available in abundance and were expensive to acquire (Hoffer, 1993). The removal of used stones from stitching and pockets, as well as removal of sediments from the wash water had to be incorporated into the manufacturing process. Problems with the machinery and the environment resulted from the use of the stones. The interior of the laundry machines wore out prematurely and sediments from the stones clogged sewer lines (Hargraves et al., 1991; Mock and Rucker, 1991). By the early 1990s, 90 percent of all domestically produced garments received some type of garment wash treatment (Hargraves et al., 1991). Given these percentages, it is likely that consumers own or will own denim garments that have been processed through a wash treatment. With this increased use of garment washes, solutions to some of the manufacturing problems were developed. To avoid waste-water contamination from impurities found in pumice stones, manufacturers began to use synthetic stones as an alternative to natural ones. Since synthetic stones are able to be manufactured into consistent sizes and shapes, reproducibility of the garment treatment was improved. Synthetic stones seemed to solve many of the problems, but still created some of their own. The stones, made of ceramics, coal or other materials, were very expensive and required a longer drying period than pumice stones (Hargraves et al., 1991; Sullivan, 1997). As technologies advanced, denim garment manufacturers discovered that the stone washed look could be achieved with cellulase enzymes (Cotton Incorporated, 1992). Use of cellulase enzymes was more appealing to denim manufacturers than the use of stones due to the alleviation of many problems the stones created (Zimmerman, 1993).
Life of the garment washing equipment was not lessened and the liquor ratio required was decreased, allowing more garments to be processed at one time (Kochavi et al., 1990). In addition, there were no stones or grit to remove from the garments, wastewater or sewer lines. Enzymes are naturally occurring, specialized proteins that catalyze biochemical reactions in all living cells (Stewart, 1996). Over 3000 enzymes have been discovered (Pedersen et al., 1992). Each enzyme works on one specific reaction for one specific organic material. Cellulase enzymes are a mixture of multiple enzymes that depolymerize cellulose to glucose and other lower molecular weight polysaccharides (Clarkson et al., 1994; Stewart, 1996). Cellulase enzymes are added to the bath with the garments in the same manner as stones (Cotton Incorporated, 1992). In fabrics that contain cellulosic fibers, the cellulase enzymes remove surface fibers, including those that hold dye, by partially hydrolyzing the surface of the fabric (Kochavi et al., 1990). Cellulase enzymes were introduced to gradually replace the use of stones and therefore the problems stones created (Cavaco-Paulo and Almeida, 1995; Lantto et al., 1996); however, the enzymes also had negative attributes. To gain desired results, the garment washing process-using enzymes had to be carefully controlled (Zimmerman, 1993). According the Hargraves et al. (1991), the amount and temperature of the water used, the time of garment exposure to the enzymes and the pH of the liquor had to remain at specific settings. Any fluctuation in these settings could cause an increase or decrease in surface fiber. Once in the consumer’s possession, denim jeans are subjected to repeated launderings. Laundering significantly alters the appearance of garments and accounts for 50 percent of abrasion damage to garments (Bresee et al., 1994). According to Annis and Bresee (1990), fuzz is formed during the abrasion process when fibers partially separate from the surface of the garment. Lint is formed when the fibers completely separate and pills are formed when those separated individual fibers tangle together and remain on the fabric surface; therefore, pills affect the appearance of garments. Wilcock and Van Delden (1985) found that pilling increased to a point and then decreased with repeated launderings in 100 percent cotton momie (or granite weave) cloth. The researchers attributed this finding to the possibility that the fibers holding the pills to the surface of the garment weakened with subsequent launderings. Given these results, it can be purported that repeated launderings can therefore increase pilling (Bhavani and Shailaja, 1997; Raheel and Dever Lien, 1982). Edge abrasion is another form of abrasion that alters the appearance of the garment’s surface. Edge abrasion is best described as wear occurring at fabric folds producing a frayed appearance (Hatch, 1993). This form of abrasion is commonly seen in all garments but especially in denim jeans because of the rigid areas such as seams and cuffs. Areas that are layered are firm and tend to hold their position during laundering more so than the adjacent flat areas. This held position or rigid area also leads to an increase in abrasive damage during laundering (Morris and Prato, 1975). Ruppenicker et al. (1972) found that repeated home launderings increased edge abrasion in durable press and untreated cotton twill fabrics. Likewise, Morris and Prato (1975) found that “laundering resulted in some edge discoloration on all of the cotton samples regardless of the treatment used” (p. 397). Morris and Harper (1994) when evaluating the influence of repeated launderings on the cuffs of durable press cotton twill trousers, also found that repeated launderings increased edge abrasion.
Garment washed jeans
45
IJCST 18,1
46
Farias (1998) reports that “abrasion in wrinkle-resistant slacks tend to be located at contact points such as pockets, cuffs, and belt loop areas and also particularly on the crease lines. In addition, Tyndall (1999) elaborates that “this white edge line is primarily formed by abrasion along the crease. The. . .undyed areas within the yarn bundle are caused by the lack of dye penetration into the yarn bundle”. Information is available regarding the physical condition of garment washed denim jeans after processing; however, there is a void in the literature on the effect of laundering on garment washed denim jeans. Card et al. (2005) found that these three types of garment washed and laundering cycles had a significant effect strength, stiffness, and the interaction between denim type and fabric direction had a significant effect on breaking elongation. The purpose of this experimental laboratory study was to evaluate and compare the pilling and edge abrasion of 100 percent cotton garment washed denim blue jeans that have been pre-washed, washed with stones, or washed with cellulase enzymes. Independent variables were the garment washed denim jean samples and laundering cycles. Dependent variables, pilling and edge abrasion, were evaluated after repeated launderings. Information from this study will aid manufacturers of blue jeans in selecting the garment washing method that suits their marketing/manufacturing plans. 2. Garment washed jeans Samples of 100 percent cotton denim jeans were supplied by four manufacturers based on the company’s method of production. The use of actual samples was chosen because the seams and cuffs allowed for a more realistic depiction of the effect of laundering on pilling and edge abrasion of jeans than the use of flat denim fabric. And the use of denim jean samples from four different denim manufacturers allows for a more representative sample of the population identified for this study. Pre-washed, stone washed, and cellulase enzyme washed were the garment washed denim treatments that were used. 3. Experimental method A completely randomized factorial laboratory experimental design was used; factors were garment washed denim jeans samples and laundering cycles. Laundering cycles were zero or control, five and 25; pilling and edge abrasion were the parameters by which the laundering cycles were measured. A total of 90 samples were utilized; 30 of each of the three garment washed denim treatments (pre-washed, stone washed, and cellulase enzyme washed). From each group of 30 samples, ten samples were randomly assigned to each of the three laundering cycles (0/5/25). Provisions were made to assure even and random distribution of the samples from the manufacturers. Samples were laundered according to AATCC test method 143: appearance of apparel and other textile end products after repeated home laundering using standard washing procedure 8.22, machine wash. Each sample was laundered in a water temperature of 49 ^ 38C (120 ^ 58F) on the “normal/cotton sturdy” wash cycle using 66.0 þ 0.1 g of 1993 AATCC standard reference detergent and enough 100 percent cotton wash load ballast type one to make a 1.8 ^ 0.06 kg (4.00 ^ 0.13 lb) load. Upon completion of each laundering cycle, the entire load (sample and ballast fabrics) was dried in an automatic tumble dryer on the cotton/sturdy cycle using the high exhaust temperature (150 ^ 108F) and a cool down of five minutes. Prior to evaluation, the samples were
conditioned for at least 4 hours at 70 ^ 28F (21 ^ 18C) and 65 þ 2 percent RH according to ASTM D 1776, standard practice for conditioning textiles for testing prior to evaluation. 3.1 Pilling Pilling ratings were determined after 0, 5 and 25 cycles based on procedures for evaluating pilling as determined by Bresee et al. (1994). Subjective human evaluation procedures were used to rate pill grades. Three trained observers, using a viewing room with standard lighting, compared the samples to ASTM photographic rating standards as prescribed in ASTM test method 3512, standard test method for pilling resistance and other related surface changes of textile fabrics: random tumble pilling tester. Each observer viewed the samples at a 458 angle. Observers worked independently, were not given a time restraint and were allowed to reevaluate any sample as needed. Each observer rated pilling on a scale of grade five (no pilling) to grade one (very severe pilling). 3.2 Edge abrasion Samples were independently rated for edge abrasion after laundering intervals according to the procedure used by Morris and Harper (1994). Subjective human evaluation by three trained observers was conducted. Edge abrasion was evaluated at the bottom cuff and side seam areas of each sample and rated on scale of four or no damage to one or major damage. The samples were examined using either the human eye or a stereomicroscope. 4. Results and discussion Statistics generated by the statistical package for the social sciences (SPSS) were used to investigate the differences in pilling and edge abrasion for the pre-washed, stone washed and cellulase enzyme washed denim blue jean samples after laundering. Analysis of variance (ANOVA) was used to determine the presence of significant differences among the denim types and laundering cycles. A p-value # 0.05 was used as the level of significance of differences between means of the variables. Duncan’s test of multiple ranges was used in each data set to determine the source of any significance determined. 4.1 Pilling Analysis of variance showed that garment washed treatment had a significant effect ( p ¼ 0.000) on pilling after laundering while laundering cycle ( p ¼ 0.412) was not significant (Table I). Post hoc analysis (Table II) revealed that the source of significance for the denim treatment was the pre-washed (mean ¼ 4.21); the pre-washed garments experienced significantly more pilling than the enzyme and stone washed garments. Duncan’s also revealed there was no significant difference in the amount of pilling for the enzyme (mean ¼ 4.47) and stone washed (mean ¼ 4.61) garment. The reason for more pills on the pre-washed is because the surface fibers of pre-washed jeans have not been dissolved by enzyme washing or abraded away by stone washing. Table III illustrates that laundering did not have a significant effect on the pilling for all three garment washed denim treatments. After five launderings, the pre-washed and enzyme washed samples had an increase in pilling (noting that an increase in pilling is signified
Garment washed jeans
47
IJCST 18,1
48
by a decrease in pilling rating) while the stone washed experienced a decrease. After 25 launderings, the amount of pilling was similar to the controls for all three garment washed denim treatments. A possible explanation is that after 25 cycles, the surface fibers were weakened by the mechanical abrasion action of laundering and were removed so that there was nothing available to form pills. Overall, both the enzyme treated and the stone washed garments experienced less pilling than the pre-washed garments. Therefore, both enzyme and stone wash treatments offer serviceable denim blue jeans with respect to pilling. 4.2 Edge abrasion There was a significant difference found for the main effects of denim treatment ( p ¼ 0.000) and laundering cycles ( p ¼ 0.000) for edge abrasion (Table IV). The two-way interaction between fabric and laundering was not significant ( p ¼ 0.130). Duncan’s multiple range test (Table V) shows that the three garment washed treatments were significantly different from each other. The pre-washed garments experienced the least amount of edge abrasion (mean ¼ 2.86) followed by the enzyme treatment (mean ¼ 2.42) while the stone washed samples had the most edge abrasion (mean ¼ 1.91). There was no significant difference between the amount of edge abrasion after 5 cycles (mean ¼ 2.33) compared to after 25 cycles (mean ¼ 2.171) as presented in Table VI. Overall laundering did have a significant effect on edge abrasion compared to the controls whose mean was 2.96. There was significantly more edge abrasion in the stone washed control jeans because processing with stones results in torn surface fibers. The high level of mechanical action generated through stone washing accelerates the edge abrasion activity. The stones aggressively removed fibers from the fabric surface thereby exposing lower yarn surfaces that can be worn away further. Further abrasion from laundering aggravates the torn fibers, causing a more worn appearance. The desizing process of pre-washing removes the sizing agents from the blue jeans after
Sources
Table I. Analysis of variance for effect of cycles on pilling
Table II. Duncan’s multiple range test for pilling by denim treatment
Main effects Treatment (T) Laundering (L) 2 £ 2 T£L Explained Residual Total
SS
dF
MS
F
p
2.62 2.42 0.208 0.309 0.309 2.93 9.40 12.3
4 2 2 4 4 8 81 90
0.656 1.21 0.104 0.077 0.077 0.367 0.116 0.139
5.65 10.4 0.896 0.665 0.665 3.16
0.000 0.000 0.412 0.618 0.618 0.004
Denim
Pre-washed
Enzyme washed
Stone washed
Mean Subset
4.21 A
4.47 B
4.61 B
F
Sig.
10.40
0.000
Variable Overall Control Pre-washed Stone washed Enzyme washed 5 Launderings Pre-washed Stone washed Enzyme washed 25 Launderings Pre-washed Stone washed Enzyme washed
Sources Main effects Treatment (T) Laundering (L) T£L Explained Residual Total
Denim type
Mean
Standard deviation
Variance
398.67 134.50 43.00 45.83 45.67 131.02 40.67 46.50 43.83 133.19 42.67 45.83 44.67
4.43 4.48 4.30 4.58 4.57 4.37 4.01 4.65 4.38 4.44 4.27 4.58 4.67
0.37 0.29 0.32 0.24 0.32 0.33 0.38 0.21 0.39 0.38 0.36 0.35 0.44
0.14 0.09 0.10 0.06 0.10 0.11 0.14 0.05 0.15 0.15 0.13 0.13 0.19
SS
dF
MS
F
p
17.68 13.41 4.27 1.33 19.01 14.74 550.56
4 2 2 4 8 81 90
4.42 6.71 2.14 0.33 2.38 0.18
23.37 35.45 11.29 1.83 13.05
0.000 0.000 0.000 0.130 0.000
Stone washed
Enzyme washed
Pre-washed
F
Sig.
1.91 A
2.42 B
2.86 C
35.45
0.00
Mean Subset
Laundering interval Mean Subset
Sum
25
5
Control
F
Sig.
2.171 A
2.33 A
2.69 B
35.45
0.00
construction. Pre-washing removes the starch by reducing the starch to a simple sugar that is water-soluble; therefore, this results in little fiber damage (Table VII). 5. Conclusions Denim jeans as well as denim garments have a strong presence in today’s fashion world; denim has a stable and viable foundation. And garment washing is a technology incorporated by garment manufacturers to be able to provide a product in response to
Garment washed jeans
49
Table III. Summary of pilling by denim treatment and laundering interval
Table IV. Analysis of variance for effects of cycles on edge abrasion
Table V. Duncan’s multiple range test for edge abrasion by denim treatment
Table VI. Duncan’s multiple range test for edge abrasion by laundering cycles
IJCST 18,1
50 Table VII. Summary of edge abrasion by denim treatment and laundering cycles
Variable Overall Control Pre-washed Stone washed Enzyme washed 5 Launderings Pre-washed Stone washed Enzyme washed 25 Launderings Pre-washed Stone washed Enzyme washed
Sum
Mean
Standard deviation
Variance
215.67 80.67 32.67 20.67 27.33 70.00 29.00 18.33 22.67 65.00 24.00 18.33 22.67
2.3963 2.69 3.27 2.07 2.73 2.33 2.90 1.83 2.27 2.17 2.40 1.83 2.27
0.6160 0.33 0.38 0.34 0.26 0.36 0.23 0.28 0.58 0.52 0.60 0.28 0.56
0.3790 0.11 0.14 0.12 0.07 0.13 0.05 0.08 0.34 0.27 0.37 0.08 0.32
consumers’ wants. This comparison of the effects of repeated launderings on pilling and edge abrasion of garment washed jeans provides garment manufacturers with information about methods to allow them to seek the garment treatment that best meets their needs. This study revealed the following regarding garment washed treatments: (1) The pre-washed garments experienced more pilling than the enzyme treated or stone washed garments. (2) The enzyme and stone washed treated garments performed similarly with respect to pilling; therefore, both should offer serviceable denim jean with respect to pilling. (3) The pre-washed garments experienced the least amount of edge abrasion after repeated home launderings. (4) The stone washed garments experienced the most amount of edge abrasion after repeated home launderings. (5) The enzyme treated garments experienced more edge abrasion than the pre-washed jeans, but less abrasion than the stone washed jeans after repeated home laundering. (6) The change in edge abrasion was significant when measured against the unwashed samples for all denim treatments after 25 cycles. References Annis, P.A. and Bresee, R.R. (1990), “An abrasion machine for evaluating single fiber transfer”, Textile Research Journal, Vol. 60 No. 9, pp. 541-8. Behling, D. (1985-1986), “Fashion change and demographics: a model”, Clothing and Textiles Research Journal, Vol. 4 No. 1, pp. 18-24. Bhavani, K. and Shailaja, D.N. (1997), “Effect of laundering on tensile and tear strength of p/c blend uniform fabric”, Textile Dyer and Printer, Vol. 30 No. 9, April 23, pp. 15-16. Bresee, R.R., Annis, P.A. and Warnock, M.M. (1994), “Comparing actual fabric wear with laboratory abrasion and laundering”, Textile Chemist and Colorist, Vol. 26 No. 1, pp. 17-23.
Card, A., Moore, M.A. and Ankeny, M. (2005), “Performance of garment washed denim blue jeans”, AATCC Review, Vol. 5, No. l6, pp. 23-7. Cavaco-Paulo, A. and Almeida, L. (1995), “Cellulase activities and finishing effects”, AATCC International Conference and Exhibition – Book of Papers, pp. 545-54. Clarkson, K., Collier, K., Larenas, E. and Weiss, G. (1994), “Opportunities for use of biochemicals in textile finishing”, AATCC International Conference and Exhibition – Book of Papers, pp. 319-23. Cone Denim (1996), Denim 101, A Special Educational Supplement by Cone Denim – Lesson 3: Finish, DNR, Huntingdon Valley, PA. Cotton Incorporated (1992), Technical Bulletin (No. TS 312-R), Cotton Incorporated, Raleigh, NC. Cotton Incorporated Lifestylee (2004), Cotton Incorporated, Raleigh, NC. Farias, L. (1998), The Effect of Dye Type and Color on the Physical Properties of Woven Fabrics, Cotton Incorporated Research Report. Hargraves, R., Eissele, E. and Pisarczyk, K. (1991), “Innovation in pellet technology for garment dyeing”, American Dyestuff Reporter, Vol. 80 No. 5, pp. 28, 30, 32. Hatch, K.L. (1993), Textile Science, West Publishing Company, St Paul, MN. Hoffer, J.M. (1993), “Identifying acid wash, stone wash pumice”, Textile Chemist and Colorist, Vol. 25 No. 2, pp. 13-15. Kochavi, D., Videbaek, T. and Cedroni, D. (1990), “Optimizing processing conditions in enzymatic stonewashing”, American Dyestuff Reporter, Vol. 79 No. 9, pp. 24, 26, 28. Lantto, R., Miettinen-Oinonen, A. and Suominen, P. (1996), “Backstaining in denim wash with different cellulases”, American Dyestuff Reporter, Vol. 85 No. 8, pp. 64, 65, 72. Magiera, M. (1989), “Levi’s broadens appeal”, Advertising Age, 17 July, pp. 1, 48. Mock, G.N. and Rucker, J.W. (1991), “The yellowing of indigo-dyed acid washed denim”, American Dyestuff Reporter, Vol. 80 No. 5, pp. 15, 16, 61. Morris, C.E. and Harper, R.J. (1994), “Resistance of durable press cotton fabrics to abrasion during laundering”, American Dyestuff Reporter, Vol. 83 No. 10, pp. 34, 37-41. Morris, M.A. and Prato, H.H. (1975), “Edge discoloration of durable-press cotton fabric during laundering with phosphate- and carbonate-built detergents”, Textile Research Journal, Vol. 45, pp. 395-401. O’Grady, R. (1991), “Stonewash: the fashion statement for denim”, American Dyestuff Reporter, Vol. 80 No. 5, p. 41. Pedersen, G.L., Screws, G.A. and Cedroni, D.M. (1992), “Biopolishing of cellulosic fabrics”, Canadian Textile Journal, Vol. 109 No. 12, pp. 31-5. Raheel, M. and Dever Lien, M. (1982), “Effect of detergents on wear and appearance characteristics of cotton broadcloth”, Textile Chemist and Colorist, Vol. 14 No. 6, pp. 27-31. Ruppenicker, G.F., Rhodes, P.L. and Kingsberry, E.C. (1972), “The effect of structure on the properties of cotton durable press work trouser fabric”, Textile Chemist and Colorist, Vol. 4 No. 10, pp. 33-5. Spevack, R. (1997), “Jeans business needs to get more creative”, Daily News Record, Vol. 27 No. 128, October 24, p. 7. Stewart, C.W. (1996), Enzyme Finishing Technology, AATCC International Conference and Exhibition – Book of Papers, pp. 212-7. Sullivan, R. (1997), “Cleaning agents: in the denim wars, it’s the wash experts with their secret formulas who are the ultimate SWAT team”, Vogue, October, pp. 184, 190, 204.
Garment washed jeans
51
IJCST 18,1
52
Tyndall, J. (1999), The Effects of Reactive Dye Type and Process on Crease Edge Abrasion and Color Retention after Multiple Home Launderings of Unmercerized, Mercerized, Hot Mercerized, and Sandoflex Treated Fabrics, Cotton Incorporated Research Report. Wilcock, A.E. and Van Delden, E.L. (1985), “A study of the effects of repeated commercial launderings on the performance of 50/50 polyester/cotton momie cloth”, Journal of Consumer Studies and Home Economics, Vol. 9 No. 3, pp. 275-81. Wilson, E. (1991), “The evolution of blue jeans”, Utne Reader, Vol. 78, March/April, pp. 122, 124. Zimmerman, K. (1993), “Cellulase enzymes won’t leave your laundry washed up”, Bobbin, Vol. 34, December, pp. 62, 64, 66, 68. Further reading American Association of Textile Chemists and Colorists (AATCC) (2003), Technical Manual, AATCC, Research Triangle Park, NC. American Society for Testing and Materials (ASTM) (2003), Annual Book of ASTM Standards (Vol. 7.01 and 7.02), ASTM, Philadelphia, PA. Corresponding author Ayanna Card is the corresponding author.
To purchase reprints of this article please e-mail:
[email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Proactive product development integrating consumer requirements Traci May-Plumlee and Trevor J. Little Department of Textile and Apparel Technology and Management, College of Textiles, North Carolina State University, Raleigh, North Carolina, USA
Proactive product development 53 Received February 2005 Accepted October 2005
Abstract Purpose – This paper presents a model for an effective product development process, which is now becoming increasingly critical to success of apparel firms. Design/methodology/approach – This research modeled apparel product development as a market driven process and integrated the consumer purchase decision in the model of proactive product development integrating consumer requirements (PPDICR). The PPDICR links the consumer purchase decision and multiple consumer research strategies to specific stages of the no-interval coherently phased product development model for apparel through 15 avenues of consumer input. Findings – The PPDICR model contributes to our understanding on how consumer input can be used to facilitate the process and through what avenues that input may be acquired. This model provides an effective tool for intra-company to inter-business analysis of consumer input into the apparel product development process. Research limitations/implications – The PPDICR provides a theoretical understanding of apparel production, and is useful to researchers in visualizing the impact of changes in the business environment, integrating research projects, and establishing research priorities. Practical implications – Practitioners may use the model to improve and develop products, select appropriate consumer input, and strategically plan organizational changes. Originality/value – This model is a useful tool for effective product development both for researchers and industrialists alike. It brings in the important element of the integration of consumer information. Keywords Garment industry, Product development, Customer orientation Paper type Research paper
Introduction In recent years, the paradigm of effective management in the apparel industry has become one of predicting the needs and wants of the consumer and responding with innovative, well designed and executed products. Given the importance of appropriate product to the success of a manufacturing firm, it is not surprising that the product development process continues to be the focus of much attention in both the academic and trade literature (Senanayake and Little, 2001). Progressive apparel companies continue to develop innovative strategies for delivering consumer oriented product (DesMarteau, 1999; Coleman, 2001; 3D Body Scanning[1]; Brooks Brothers[2]; IC3D[3]; Fralix, 2001). Researchers continue to explore rapid prototyping, body scanning and other innovative product development technologies to improve the development process (Istook, 2001). These efforts continue without benefit of a thorough understanding of how various types of consumer information may be obtained and
International Journal of Clothing Science and Technology Vol. 18 No. 1, 2006 pp. 53-66 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610637512
IJCST 18,1
used in the current and future development process. Researchers have also examined the consumer purchase decision process in general, and the apparel purchase decision specifically. However, the purchase decision has not been directly linked to apparel product development, although making that link is a necessary step in developing marketable new apparel products and effectively integrating new technologies. The model developed in this paper addresses these issues.
54 Market research for product development Market research provides a means for understanding the consumer purchase decision and anticipating consumer behavior. In the product development process, use of market research focuses on identifying opportunities for product innovation and understanding the evaluative criteria used by the consumer in reaching a purchase decision. Fortune 500 managers cited 24 product development methods and models used by their firms (Mahajan and Wind, 1992). Those most frequently cited, along with the percentage of respondents citing each, are found in Table I. Other methods and models were cited by less than 5 percent of the respondents and encompassed a variety of sales forecasting techniques and sensory work with panels. In studies of new product successes, researchers concluded that satisfying consumer wants was key to developing successful new products (Cooper, 1994; Calantone et al., 1995). Alternatively, Chay (1989) related the new product failure rate to inadequate expenditures on strategic market analysis and on assessment of consumer needs and wants. Market research is also useful in identifying new product opportunities (Bossu, 1995). Consumer focused strategies Consumer focused product development strategies include both quantitative and qualitative techniques and methods. Use of qualitative strategies for identifying consumer needs or wants is sometimes considered a preliminary step in a research process providing the foundation for quantitative research (Weiner, 1994). Focus groups provide a qualitative strategy for examining consumers feelings and attitudes toward purchase and use of a product (Engle et al., 1995; Tull and Hawkins, 1993). Such research provides in-depth insights into consumers’ preferences, decision
Model/method
Table I. Product development models and methods (Mahajan and Wind, 1992)
Focus groups Limited rollout Concept tests Show tests and clinics Attitude and usage studies Conjoint analysis Delphi Quality function deployment Home usage tests Product life-cycle models Synectics
Percent using 68 42 26 22 19 15 9 9 9 8 8
processes and priorities. Table II summarizes ways in which focus group interviews are used in product development (Tull and Hawkins, 1993). Although they are commonly used in the apparel industry, focus groups must be repeated regularly to keep abreast of changing consumer attitudes. So, they are often used in combination with other methods. Synectics is an alternative, more structured group process for generating product ideas (Urban and Hauser, 1980). This strategy is useful for generating quality new product concepts, but because this technique requires a substantial time commitment it is more appropriate for expensive products with a long development cycle. Ethnography, including observational research, is a qualitative method growing in importance for product development (Fellman, 1999; Woods, 1998). Limited rollout, or test marketing, involves duplicating a planned national new product marketing program in limited geographic areas to determine market acceptance and test alternative mixes (Tull and Hawkins, 1993). Limited rollout can be quite useful for products with a longer life cycle, but for fashion apparel it provides minimal opportunities. The majority of fashion products are test marketed through presentation to buyers at regional apparel marts rather than directly to consumers, although private label and brand product developers, often engage in test marketing through their own outlets (Kurt Salmon Associates, 1995b). Concept tests frequently gather data on likelihood of purchase, product importance, perceived product quality and perception of specific product attributes (Gruenwald, 1992). For fashion apparel lines, concept testing via mall intercept surveys of consumer opinion regarding planned colors and fabrications is frequently used prior to developing actual product. When concept testing is used to assess opinions regarding finished garments, it is referred to as style testing. In style testing, actual products or drawings are presented to consumers and preferences are discerned by determining the likelihood of purchase (Fratto, 1986; Souza, 1996). Both prototype garments and sketches have been shown to be effective ways of presenting products for style testing (Kushmider, 1988; Anderson, 1990). Quantitative attitude and usage studies provide data on consumers’ attitudes, past behaviors, and intended behaviors, and other forms of descriptive information (Tull and Hawkins, 1993). Attitude and usage studies are used to assess similarities between products, tradeoffs among attributes, preference among products, intent to purchase and propensity to innovate (Urban and Hauser, 1980). These studies are of limited applicability for apparel with it’s short development cycle, though firms may execute limited versions of such studies through website, hangtag, package and mail questionnaires (Martin, 1999). Conjoint analysis assesses perceptual position in the market and the optimal combination of product attributes (Urban and Hauser, 1980; Weiner, 1994), and
Basic need studies for product idea creation New product idea or concept exploration Product positioning studies Advertising and communication research Background studies on consumers’ frames of reference Determination of attitudes and behaviors Establishment of consumer vocabulary prior to questionnaire development
Proactive product development 55
Table II. Applications for focus group interviews (Tull and Hawkins, 1993)
IJCST 18,1
56
predicts consumer preferences for a new product. This strategy is typically time consuming, therefore it has limited application in the fashion apparel industry. Home usage tests, or wear tests for apparel (especially intimate and protective apparel), are sometimes referred to as simulated test markets. In these tests, prescreened consumers are given a new product to evaluate. These evaluations become the basis for estimating market share or making product improvements (Tull and Hawkins, 1993). Product life cycle models are used to determine when existing products should be replaced with newer, more profitable products. When a product moves into the decline phase, profits decrease (Urban and Hauser, 1980), and it must be replaced with a new or revised product. Again, though this strategy may be appropriate for basic apparel products, most fashion products are replaced according to a seasonal calendar. Point of sale (POS) or scanner data provides a source of information about consumers purchase patterns for many products. Commercial research firms record consumer purchases from thousands of stores, and form aggregate models reflecting consumer purchase patterns (Tull and Hawkins, 1993). The quick response (QR) fulfillment relationship model presented in the trade literature, shown in Figure 1, provides for direct consumer input into the product development process via this type of consumer research (Kurt Salmon Associates, 1995a). POS data was used to analyze trends, test new products, plan product introductions and forecast sales volume in this replenishment cycle (Kurt Salmon Associates, 1995c). Applicability of POS data alone as a means of measuring consumer demand, however, is limited by challenges to accuracy (Kurt Salmon Associates, 1995a). Commercial market research firms also use consumer surveys and panels to solicit consumer input that is then compiled and presented to industry for use in the product development process. These groups provide syndicated research periodically for the soft goods industry. For example, the apparel market monitor distributed by the AAFA is widely used by the soft goods industry, and is based on NPD data (American Apparel and Footwear Association, 2001). These sources provide extensive information on aggregate consumer trends, but little specific information relevant to a company’s target consumer and apparel product development. Another quantitative approach for integrating consumer input into the product development process is through product customization that incorporates data directly from the consumer. Levi Strauss’s, Second skin, IC3D, etc. have been at the forefront of customized product development for the apparel industry (Henricks and Hasty, 1995; DesMarteau, 1999; Rabon, 1996; IC3D[3]). Information about the customer and that customer’s preferences are acquired in the process. Body scanning often provides the anthropometric data used for customizing apparel product. The scanned data is useful for mass customization, best size selection and for assessment and modification of sizing systems. Development of customized products demands superior information handling strategies to facilitate decision making, and to manage related data. Such computer integrated approaches provide the opportunity for incorporating consumer input, but necessitate a thorough understanding of what information is needed and how to use it in apparel product development.
Proactive product development 57
Figure 1. QR fulfillment relationship
Expert focused development strategies The Delphi technique is a method for forecasting new product sales utilizing a panel of experts and an estimation and evaluation cycle that repeats until a consensus is reached (Tull and Hawkins, 1993). This strategy provides a means of estimating the sales potential of new products having longer product development cycles. Researching fashion trends tends to be an ongoing process at most fashion apparel firms (Burns and Bryant, 1997). Designers and merchandisers review trade publications and popular literature, subscribe to color and fashion trend forecasts and shop the market in order to maintain a sense of what is “in fashion”. From these sources, they discern trends in color, style and fabrication. Although this strategy is viewed as essential to development of fashion apparel products, it is insufficient to remove the uncertainty from the process. In this type of research, others predict what consumers will desire, while consumers have minimal, if any, direct input. Intermediaries such as retail buyers and sales representatives also provide input to product development via opinions regarding products in development. Fit models used in evaluating prototypes contribute similarly to the apparel development process.
IJCST 18,1
58
Figure 2. EBM model
Consumer decision process Consumer decision process theory provides a framework for understanding how consumers select and purchase products in the market (Howard, 1963; Engle et al., 1968). Given a competitive marketplace where the objective is to provide consumers with a product that will be chosen from among alternatives, it is essential that the selection process be understood. Engle et al. developed a model, shown in Figure 2, that delineates the consumer decision process (Engle et al., 1995). It has been used in a number of studies to describe the consumer decision process for making apparel purchases (Cassill and Drake, 1987; Lix, 1991; Jenkins and Dickey, 1976; Shim and Drake, 1990). Briefly, a consumer “need” (want) is recognized when a desired state (i.e. possessing a product) differs from the existing state. A consumer searches for information regarding products to fulfill that “need”, and, when the “need” has been clearly defined, evaluates alternative products to determine which best fulfill it.
Following purchase and consumption of the selected product, the consumer engages in post-purchase evaluation and perhaps repurchase. In the context of the model, purchase decisions are based on a continuum of involvement in the decision making process (Engle et al., 1995). On one end of the continuum lies the extended problem solving process depicted in Figure 2, and on the other lies habitual purchasing. Because apparel items are identified as high involvement purchases (Laurent and Kapferer, 1985), extended problem solving processes are typical of many of those purchases. The EBM model and product development In relation to the new product development process, the “need recognition” and pre-purchase alternative evaluation stages are crucial. Within these stages, the consumer formulates a desire for a new product and selects from among alternatives. Product innovations are one source of stimulating “need recognition” (Engle et al., 1995). Effective market research is required to recognize opportunity for product innovations, and, once consumers formulate a “need”, few, if any, alternatives are available. Rebok’s introduction of the pump athletic shoe is an example of a product which was focused on stimulating “need recognition” for an innovative apparel product (Engle et al., 1995, p. 180). When products are less innovative, alternative evaluation becomes the focus of product development. Consumers choose from among alternatives based on evaluative criteria. Evaluative criteria are particular dimensions or attributes, such as style, color, price, and brand name, that are used in judging alternative choices (Engle et al., 1995, p. 208). Evaluative criteria used by consumers in making a purchase vary in quantity and salience, with some criteria exerting more influence than others, and specific criteria differing from decision to decision. Evaluative criteria may take the form of product characteristics, marketing characteristics, and even feelings associated with ownership of the product, e.g. prestige, image. For any given purchase, the consumer imposes decision rules that allow alternative products to be compared on the basis of the chosen evaluative criteria, and a purchase decision to be completed. Post-purchase alternative evaluation is also important for effective product development. Experiences with purchased products may influence the evaluative criteria used in future purchase decisions, and may affect perception of a specific product or an entire brand. To develop successful products, an apparel firm must understand the evaluative criteria used by the consumer in making a purchase decision. Most products, even complex ones, are evaluated primarily on the basis of five to seven attributes (Boecker and Schweikl, 1988). In studying consumer preferences for products, those attributes which are “very important or relevant to most respondents” (Green and Srinivasan, 1978) are used. These relevant attributes are considered to be those that have been identified most often, or rated most important by consumers. Research on evaluative criteria for apparel demonstrates which criteria are relevant to consumers of apparel. Evaluative criteria for apparel Published research revealed 13 “universal” evaluative criteria, cited in Table III, used by apparel consumers in a variety of situations and for a number of products (May-Plumlee, 1999). The criteria were garnered from research representing a
Proactive product development 59
IJCST 18,1
60
cross-section of market segments and variety of cultures suggesting that this core of commonly used evaluative criteria may be broadly applicable. For non-store purchases, a more limited range of criteria are available. Although the literature clearly establishes that evaluative criteria are used by consumers in making purchase decisions, only a few practitioners and researchers have linked evaluative criteria and the apparel product development process. Quality function deployment (QFD) is one way consumers have been linked with the product development process. QFD is a method implemented to aid in developing marketable products with attributes desired by customers (Griffin, 1992; Himmelfarb, 1992; Erhorn and Stark, 1994). It has been used by Japanese manufacturers and academicians as a tool for developing functional apparel products (May-Plumlee, 1996, 2002). Because of the time constraints imposed by the apparel market, QFD has limited applicability in this industry. These methods represent major strategies are used for consumer requirements capture (Bruce and Cooper, 2000) and to facilitate the product development process, but no model exists to integrate the consumer data with the appropriate phase of the product development process. Such a model would provide a foundation for integrating research efforts and identifying research opportunities, and would benefit practitioners implementing a consumer-responsive product development process. Modeling apparel product development using consumer purchase criteria A consumer driven model of apparel product development is developed in this section. The no-interval coherently phased product development (NICPPD) model for apparel (May-Plumlee and Little, 1998) was used to represent the apparel development process component in the proactive product development integrating consumer requirements (PPDICR) model (Figure 3). Previous research provides confidence in a set of universal evaluative criteria used by consumers during the decision to purchase apparel. Therefore, those evaluative criteria are essential components of the model providing linking product development and the consumer purchase decision. Although some criteria require that the consumer be in physical contact with the product, the four most frequently cited criteria are as accessible during non-store shopping experiences. The ranked and categorized list of universal apparel evaluative criteria (Table III) was used to expand the “prepurchase alternative evaluation” stage of the Engle et al. (1995) extended problem solving (EBM) model of the consumer purchase decision. The EBM model was selected due to its’ importance to previous research in the area of the apparel consumer purchase decision, and to the body of consumer behavior literature.
Table III. Ranked and categorized universal evaluative criteria
Extrinsic Brand image
Frequency
Brand/label Price
23 16
Aesthetic design Color/pattern Style/design/uniqueness Fabrication Fashionability Appearance/attractiveness
Intrinsic Frequency Technical design 18 18 15 11 9
Care Construction Durability Fit/sizing Quality Comfort
Frequency 15 13 12 11 11 8
Proactive product development 61
Figure 3. Proactive product development integrating consumer requirements
IJCST 18,1
62
By specifying the criteria used for evaluating alternative apparel products in the PPDICR model, the generic EBM model has been adapted specifically to the apparel consumer and that consumer’s purchase decision, whether in a traditional environment or alternative shopping environment. Development of the PPDICR was initiated by integrating consumer requirements capture into the NICPPD model for apparel. The skeletal structure of the EBM model with the expanded alternative evaluation stage was placed at the end of the NICPPD model (beyond production) to represent the flow of product from manufacturer to consumer. Next, avenues for bringing consumer input into the product development process were built so as to engage the EBM and NICPPD models where appropriate. Each avenue was placed into the developing model as a link between new product development and the consumer or the purchase decision. Each avenue represents a potential flow of information from consumer to the new product development process. Finally, each avenue and the evaluative criteria were linked to the appropriate phases in the product development process. These links establish both where decisions affecting apparel product evaluative criteria are made in the product development process and avenues useful for acquiring consumer input regarding the product development process step. Avenues found in the model, and the abbreviations used for each are summarized in the legend (Figure 3). The PPDICR model links product development to potential avenues of consumer input and to a list of consumer apparel product evaluative criteria organized hierarchically according to the frequency of citation in the literature. Consumer inputs in the model are segmented into indirect and direct consumer inputs. Trend forecasts and commercial surveys are examples of indirect sources through which the consumer input comes to the process via a third party. Although direct sources are abundant, many are not widely used, often due to financial and personnel limitations. Most of the mechanisms of consumer input documented in the PPDICR model have been discussed previously in this research, so further explanation is not needed. However, the evaluative criteria (ECR) avenue merits discussion. Many traditional market research methods provide means of learning about consumer evaluative criteria. However, other mechanisms exist. Traditional and developing retail channels offer less contrived opportunities for direct interaction between manufacturer and consumer than the retail store environment. Purchases through catalog and televised home shopping retail channels often place the consumer in contact with a sales representative who can solicit information regarding evaluative criteria. Some catalog retailers already use records of requests for out of stock items, an expression of purchase intent, to improve inventory management (Robins, 1995). Internet and kiosk sales represent developing retail channels through which consumer preferences and intent can be ascertained in the purchase environment (DeWitt, 1995; Schneider, 1995). Each of these offers a means to learn about consumer evaluative criteria. And, although they do not capture the purchase decision real time, methods such as focus groups and concept tests often attempt to predict the purchase decision by studying evaluative criteria. Though mentioned previously, fit models, intermediaries, sizing data and consumer created product warrant further discussion. Because fit models are selected to represent a target consumer, and work closely with designers and merchandisers, their input is often taken to be an accurate reflection of that consumer. Likewise,
intermediaries such as sales representatives and buyers share their insights regarding the ultimate consumer with apparel development teams. These indirect inputs from consumers, interpreted through a third party, are popular ways of bringing the consumer into the apparel development process. Sizing data acquired for customized fitting or best-fit prediction can provide valuable consumer information to improve apparel sizing and fit. Consumer created products are a developing avenue that not can only provide information to the apparel development process, but could dramatically influence how apparel is developed. Consumer created product models require that products be developed based on individual components and features rather than by complete style. Conclusion The PPDICR model contributes to the theoretical understanding of apparel product development, how consumer input can be used to facilitate the process and through what avenues that input may be acquired. This model provides an effective tool for intra-company to inter-business analysis of consumer input into the apparel product development process. The PPDICR model allows researchers to: . strategically segment and direct consumer input into the apparel product development process, . visualize the impact of changing business environment, consumer base and customer requirements, . integrate multiple research projects, and . identify opportunities and establish priorities for research. The PPDICR allows the practitioner to: . develop better and more salable products for the target consumer, . benchmark and modify strategies for integrating consumer input into the apparel development processes, . build the organizational structure required to effectively utilize available consumer information during the apparel development process, . develop effective strategies for using consumer input to create market responsive product lines, and . strategically plan organizational and procedural changes to facilitate consumer driven apparel development.
Notes 1. 3D Body Scanning at Body Scan Central, available at: www.bodyscancentral.com [2002, June 17]. 2. Brooks Brothers – Classically Modern Men’s and Women’s Apparel, available at: www. brooksbrothers.com/ [2002, June 17]. 3. IC3D Interactive Custom Clothes Company, available at: www.ic3d.com/2002/index.html [2002, June 17].
Proactive product development 63
IJCST 18,1
64
References American Apparel and Footwear Association (2001), Apparel Market Monitor Annual, Publication of the AAFA Marketing Committee, Arlington, VA. Anderson, L. (1990), “A methodology for consumer style preference testing of apparel at the product development level”, PhD dissertation, Auburn University, Auburn, AL. Boecker, F. and Schweikl, H. (1988), “Better preference prediction with individualized sets of relevant attributes”, International Journal of Research in Marketing, Vol. 5, pp. 15-24. Bossu, F. (1995), “A few principles guide new product success”, Marketing News, Vol. 29 No. 10, 8 May, p. 11. Bruce, M. and Cooper, R. (2000), Creative Product Design: A Practical Guide to Requirements Capture Management, Wiley, New York, NY. Burns, L. and Bryant, N. (1997), The Business of Fashion: Designing, Manufacturing and Marketing, Fairchild Publications, New York, NY. Calantone, R., Vickery, D. and Droge, C. (1995), “Business performance and strategic new product development activities: an empirical investigation”, The Journal of Product Innovation Management, Vol. 12 No. 3, June, pp. 214-23. Cassill, N. and Drake, M. (1987), “Employment orientations’s influence on lifestyle and evaluative criteria for apparel”, Home Economics Research Journal, Vol. 16 No. 1, pp. 23-35. Chay, R. (1989), “Discovering unrecognized need with consumer research”, Research Technology Management, Vol. 32 No. 2, March-April, pp. 36-42. Coleman, D. (2001), “For the man with a 15.95-inch neck”, New York Times, November, available at: www.nytimes.com/2001/11/18/fashion/18CYBE.html Cooper, R. (1994), “Debunking the myths of new product development”, Research Technology Management, Vol. 37 No. 4, pp. 40-50. DesMarteau, K. (1999), “Levi: a landmark case for customization”, Bobbin, Vol. 41 No. 2, October, pp. 50-1. DeWitt, J.W. (1995), “Kiosk data supports manufacturing flexibility”, Apparel Industry Magazine, Vol. 56 No. 5, pp. 42, 44, 46. Engle, J., Kollat, D. and Blackwell, R. (1968), Consumer Behavior, 1st ed., Holt, Rinehart and Winston, New York, NY. Engle, J., Blackwell, R. and Miniard, P. (1995), Consumer Behavior, 8th ed., The Dryden Press, Fort Worth, TX. Erhorn, C. and Stark, J. (1994), Competing by Design: Creating Value and Market Advantage in New Product Development, Omneo, Essex Junction, VT. Fellman, M.W. (1999), “Breaking tradition”, Marketing Research, Vol. 11 No. 3, Fall, pp. 20-4. Fralix, M. (2001), “From mass production to mass customization”, JTATM, Vol. 1 No. 2, Winter, available at: www.tx.ncsu.edu:8190/jtatm/volume1issue2/issue2_abstracts.htm Fratto, K. (1986), “Style testing as a merchandising tool”, Proceedings of the 13th Annual International Apparel Research Conference, Atlanta, GA. Green, P. and Srinivasan, V. (1978), “Conjoint analysis in consumer research: issues and outlook”, Journal of Consumer Research, Vol. 5, pp. 103-23. Griffin, A. (1992), “Evaluating QFD’s use in US firms as a process for developing products”, Journal of Product Innovation Management, Vol. 9 No. 3, pp. 171-87. Gruenwald, G. (1992), New Product Development, 2nd ed., NTC Business Books, Lincolnwood, IL.
Henricks, M. and Hasty, S. (1995), “L.S. & Co. tries on custom fit jeans”, Apparel Industry Magazine, Vol. 56 No. 1, January, pp. 32, 34. Himmelfarb, P. (1992), Survival of the Fittest: New Product Development in the 90’s, Prentice-Hall, Englewood Cliffs, NJ. Howard, J. (1963), Marketing Management: Analysis and Planning, rev. ed., Richard D. Irwin, Inc, Homewood, IL. Istook, C. (2001), “Rapid prototyping in the textile and apparel industry: a pilot project”, JTATM, Vol. 1 No. 1, available at: www.tx.ncsu.edu:8190/jtatm/volume1issue1/current_abstracts. html Jenkins, M. and Dickey, L. (1976), “Consumer types based on evaluative criteria underlying clothing decisions”, Home Economics Research Journal, Vol. 4 No. 3, pp. 150-62. Kurt Salmon Associates (1995a), “Improving the demand fulfillment/replenishment mega-process”, QR & Beyond: Success Strategies for Integrating QR and Business Process Re-engineering, pp. 17-21, (Supplement to RIS News & Consumer Goods Manufacturer). Kurt Salmon Associates (1995b), “Improving the new product development process”, QR & Beyond: Success Strategies for Integrating QR and Business Process Re-engineering, pp. 30-3, (Supplement to RIS News & Consumer Goods Manufacturer). Kurt Salmon Associates (1995c), “QR implementation moves into advanced stages”, QR & Beyond: Success Strategies for Integrating QR and Business Process Re-engineering, pp. 14-16, (Supplement to RIS News & Consumer Goods Manufacturer). Kushmider, L. (1988), “The effects of design technology on marketing strategies: an analysis of consumer style testing and measurement of textile-apparel-retail attitudes towards style testing and private label manufacturing”, Masters thesis, North Carolina State University, Raleigh, NC. Laurent, G. and Kapferer, J. (1985), “Measuring consumer involvement profiles”, Journal of Marketing Research, Vol. 22 No. 1, pp. 41-53. Lix, L. (1991), “Maternity employment apparel purchase decisions of pregnant working women”, Masters thesis, University of Manitoba, Canada. Mahajan, V. and Wind, J. (1992), “New product models: practice, shortcomings and desired improvements”, Journal of Product Innovation Management, Vol. 9 No. 2, pp. 128-39, June. Martin, J. (1999), personal interview with John Martin, Vice President of Marketing conducted on-site at VF Playwear, Greensboro, NC, March 15. May-Plumlee, T. (1996), “QFD”, Proceedings of the 1996 Annual Conference of the International Textile and Apparel Association, International Textile and Apparel Association, Monument, CO, p. 99. May-Plumlee, T. (1999), “Modeling apparel product development using consumer purchase criteria”, PhD dissertation, North Carolina State University, Raleigh, NC. May-Plumlee, T. (2002), “An integrative process for design and development of functional apparel”, paper presented at The Textile Institute 82nd World Conference, Parallel Session 13, Paper 1, Cairo, Egypt, March 23-27, presented March 25. May-Plumlee, T. and Little, T. (1998), “No-interval coherently phased product development model for apparel”, International Journal of Clothing Science and Technology, Vol. 10 No. 5, pp. 342-64. Rabon, L. (1996), “Custom fit comes of age”, Bobbin, Vol. 37 No. 12, pp. 42-8, August. Robins, G. (1995), “Data warehousing: retailers on the cutting edge”, Stores, September, pp. 19, 24, 26, 28.
Proactive product development 65
IJCST 18,1
66
Schneider, B. (1995), “Interactive kiosks used for retail research”, Marketing News, Vol. 29 No. 12, pp. H35-6. Senanayake, M. and Little, T.J. (2001), “Measures for new product development”, JTATM, Vol. 1 No. 3, available at: www.tx.ncsu.edu:8190/jtatm/volume1issue3/issue3_abstracts.htm Shim, S. and Drake, M. (1990), “Consumer intention to purchase apparel by mail order: beliefs, attitude and decision process variables”, Clothing and Textiles Research Journal, Vol. 9 No. 1, pp. 18-26. Souza, M. (1996), “Qualitative marketing research: a new tailored approach to fashion”, Marketing and Research Today, pp. 117-23, May. Tull, D. and Hawkins, D. (1993), Marketing Research: Measurement and Method, 6th ed., Macmillan Publishing Company, New York, NY. Urban, G. and Hauser, J. (1980), Design and Marketing of New Products, Prentice-Hall, Englewood Cliffs, NJ. Weiner, J. (1994), “Forecasting demand: consumer electronics marketer uses a conjoint approach to configure its new product and set the right price”, Marketing Research, Vol. 6 No. 3, pp. 6-11, Summer. Woods, T. (1998), “Giving the people what they want”, Marketing News, Vol. 32 No. 7, p. 12, 30 March. Further reading Kurt Salmon Associates (1998), KSA’S Consumer Pulse, Kurt Salmon Associates, Atlanta, GA, January. Corresponding author Traci May-Plumlee can be contacted at:
[email protected]
To purchase reprints of this article please e-mail:
[email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
IJCST 18,2
Complex estimation of bending elasticity of hemp woven fabric after washing treatment
70 Received February 2005 Revised May 2005 Accepted May 2005
T. V. Mihailovic Textile Engineering Department, Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia and Montenegro, UK Abstract Purpose – This paper aims to investigate the elasticity of hemp woven fabric under action of bending force, before and after washing treatment. Design/methodology/approach – Bending elasticity was monitored in three different ways: through the value of bending modulus, on the basis of fabric’s resistance to creasing expressed through the value of quality number, and through the value of bending deformation components. On the basis of the results obtained from the mentioned three types of investigations, the complex criterion of quality of washed and unwashed hemp fabric, from the aspect of their elasticity, was formulated. Findings – Values of complex criterion as well as the values of bending modulus, quality number and total recurrent deformation pointed to the conclusion that investigated hemp fabric has, not good, but satisfied bending elasticity, especially after washing treatment. The values of bending deformation components served for establishing Frenkel’s model of elastic behaviour under action of bending force of washed as well as unwashed hemp fabric. Practical implications – Shows that the way on which Frenkel’s model was established might be interesting because of its simplicity. Originality/value – Provides information on the elasticity of hemp woven fabric before and after washing. Keywords Fabric testing, Elasticity, Estimation Paper type Research paper
International Journal of Clothing Science and Technology Vol. 18 No. 2, 2006 pp. 70-82 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610645739
Introduction In which way will the woven fabric behaviour in real conditions of its exploitation depends on great number of structural and technological characteristics, from one side, and conditions of its usage and maintenance, from the other side. During the exploitation, fabric is exposed to the action of various influences (mechanical loads, temperature, humidity) which might provoke its deformation. Deformation of material is manifested through the change of dimensions, form and fabric’s surface. This phenomenon leads to the total aesthetic value of fabric being disturbed and represents negative indicator of its quality. Because of that it is possible to say that elasticity represents very important indicator of fabric’s form stability as well as its durability. It is well-known fact that woven fabrics are easily bending under action of small intensity forces, even under their own mass. Because of that, bending deformation is a frequent topic in various scientific textile researches. In some scientific works This work was supported by the Serbian Ministry of Science, Technologies and Development (Project No. MHT.2.10.0221).
bending deformation is monitored through the influence of fabric’s structure parameters (Clapp and Peng, 1990a, b; Smuts and Hunter, 1991), ability of buckling (Amirbayat, 1991; Nhan, 1985), creasing (Chapman, 1974; Grey and Leaf, 1985), drapability (Collier et al., 1991; Stump and Fraser, 1996; Gan et al., 1995; Kang and Yu, 1995) and stiffness (Schwartz, 1982; Savast’yanova et al., 1987). Also certain number of works is devoted to the investigation of the influence of atmospheric conditions on development of bending deformation (Chapman, 1976; Hayes et al., 1975; Wortmann, 1985). Sometimes it is necessary to take into consideration the finishing of some fabric, because the way in which one fabric is finished might lead to the change of its elastic behaviour. Such investigations are of specific importance because of the fact that woven fabrics represent daily human environment and they breach through the all pores of human’s life, especially clothing fabrics. Keeping this in mind, in this paper the influence of washing treatment on elastic properties of hemp fabric which is exposed to the action of bending force was investigated. The results of investigation of hemp fabric’s elasticity before and after washing treatment, obtained from various methods (determination of bending modulus, crease recovery angle and quality number as well as the size of bending deformation components), enabled establishing complex criterion of quality. Complex criterion was used for the estimation of the degree of elasticity of investigated fabric. For determination the value of bending modulus, simple, but effective method, which does not demand the usage of complicated mathematics apparatus, was applied. In contrast to some other investigators, who established models of fabric’s buckling (Clapp and Peng, 1990; Postle and Postle, 1997, 1998) and creasing (Chapman, 1974; Grey and Leaf, 1985) and for that purpose used very complicated differential equations, in this paper in easy, quick and simple way Frenkel’s model of elasticity of washed and unwashed fabric under action of bending force was established.
Bending elasticity of woven fabric 71
Experiment Woven fabric of 13 per cent cotton – 87 per cent hemp made in twill 2/2 weave was used as experimental material. Fabric was made from 100 per cent cotton two-folded warp yarn and 100 per cent hemp weft yarn. Investigated woven fabric, according to the values of mass, belongs to the category of heavy fabrics. The basic characteristics of investigated fabric are shown in Figure 1. Surface of the investigated hemp fabric has expressive rib and rough texture which is caused by the differences of warp and weft yarn fineness. Fineness of very coarse, uneven weft yarn is eight times less than fineness of warp yarn. Because of that, weft yarns dominate on the surface of the fabric. An appearance of the investigated hemp fabric is shown in Figure 2.
Figure 1. Basic characteristics of investigated fabric
IJCST 18,2
72
Figure 2. An appearance of the investigated hemp fabric
In order to perceive the influence of washing treatment on behaviour of woven fabric which was exposed to the action of bending force, the fabric has been washed in powdered soap solution for 10 min at boiling temperature. After that it has been rinsed and dried in a free spread state at room temperature. Elasticity of washed and unwashed fabric, in the first phase of investigation, was monitored through the value of bending modulus (E) (Buzov et al., 1986): Bs ¼ EI x
ð1Þ
from which is: E¼
Bs Ix
ð2Þ
Bs, bending stiffness (N m2); and Ix, principal moment of inertia of the surface (m4). Principal moment of inertia of the surface (Ix) is given by the relationship (Raskovic, 1962): Ix ¼
bt 3 12
ð3Þ
b, sample’s width, which is 0.03 m; and t, fabric’s thickness (m). The cantilever method for determination the bending stiffness (Bs) of washed and unwashed fabric, as shown in Figure 3, was used (Luvishis and Birenbaum, 1971). The stripe of fabric to be tested (1) in dimensions of 16 £ 3 cm was placed on a horizontal supporting platform (3) and fixed in place by a weight (2). When the toggle switch (8) was cut in the mechanism (7), smoothly and uniformly lowered the movable side shelves of the platform, thus imparting a flexural deformation to the test stripe.
Bending elasticity of woven fabric 73
Figure 3. Flexometer for determining stiffness of fabrics at bending
From the moment of its separation from the platform, the stripe flexed under the action of its own mass. When the side shelves were completely lowered, the flexure indicator (5) was displaced upwards by screw (6), noting on scale (4) the flexure ( f ) of both free ends of the stripe. The relative deflection ( fo) was calculated by the formula (Luvishis and Birenbaum, 1971; Koblyakov, 1989): f sr ð4Þ fo ¼ l fsr, average deflection of both ends of the fabric’s stripe (cm); and l, the length of the hanging-down ends of the test stripe; this length was determined by the formula (Luvishis and Birenbaum, 1971): L22 ð5Þ l¼ 2 L, the length of test stripe, in this case is 16 cm. The size of relative deflection ( fo) is not allowed to be greater than 0.65, and the size of average deflection ( fsr) not less than 1 cm. If at the length of test stripe of 16 cm, these conditions are not satisfied, the length of stripe is reduced for 1 cm and relative deflection as well as average deflection are determined again. The procedure of reducing the length of test stripe is repeated as long as it is need to obtain the values of ( fo) and ( fsr) which will satisfy the mentioned limited conditions. Fabric’s bending stiffness (Bs) was calculated according to the formula (Luvishis and Birenbaum, 1971): Bs ¼
ml 3 A
ð6Þ
m, weight of test stripe (Nm2 1); l, hanging length of test stripe, which was determined according to the formula (5) (m); and A, dimensionless value, in dependence of relative deflection ( fo), shown in Table I.
IJCST 18,2
74
Table I. Value (A) in dependence of relative deflection ( fo) according to Luvishis and Birenbaum (1971)
fo 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18 0.19 0.20 0.21 0.22 0.23 0.24 0.25 0.26 0.27 0.28 0.29 0.30 0.31 0.32 0.33 0.34 0.35 0.36 0.37 0.38 0.39 0.40 0.41 0.42 0.43 0.44 0.45 0.46 0.47 0.48 0.49 0.50 0.51
A 0.10 0.18 0.26 0.35 0.42 0.51 0.60 0.68 0.76 0.84 0.92 1.01 1.08 1.18 1.25 1.35 1.43 1.51 1.60 1.69 1.76 1.84 1.95 2.04 2.14 2.23 2.32 2.42 2.53 2.63 2.74 2.83 2.94 3.05 3.15 3.26 3.38 3.49 3.61 3.75 3.87 4.04 4.17 4.29 4.42 4.56 4.70 4.83 4.98 5.13 5.33 (continued)
fo 0.52 0.53 0.54 0.55 0.56 0.57 0.58 0.59 0.60 0.61 0.62 0.63 0.64 0.65
A 5.51 5.64 5.84 6.06 6.26 6.47 6.68 6.92 7.18 7.50 7.79 8.12 8.44 8.76
Bending elasticity of woven fabric 75
Table I.
In the second phase of investigation, elasticity of washed and unwashed hemp fabric was monitored through the value of crease recovery angle (Figure 4). Standard method of determination the crease recovery angle of fabric (JUS F.S2.018, 1958; German Standard DIN 53890; ISO, 1972), which is modified in a certain extant, was used as a starting method for determination of fabric’s resistance to bending. Investigated samples in dimensions of 5 £ 2 cm were folded through the narrow side at 1808 (Figure 5). The length of the folded part, for fabrics whose mass is over 500 g/m2, is 15 mm. A load of 9.81 N was applied on a folding part of fabric in a period of 60 min. After the removal of the load, angle (a) was measured in degrees after 5 min (a5) and after 60 min (a60). If the angle is bigger, the fabric has fewer tendencies to crease. The angle appearing immediately after unloading the investigated sample, angle of leap (a0), which is hard to measure precisely, was calculated according to the formula (JUS F.S2.018, 1958; Mihailovic and Nikolic, 1995):
Figure 4. Crease recovery angle
Figure 5. Determination of crease recovery angle
IJCST 18,2
76
log a0 ¼ log a60 2 3:5 log
a60 a5
ð7Þ
Modification of the described method of determining the crease resistance of fabrics by introducing the measurement of crease recovery angle (a) in a period of time of 1,440 min served for determination of elastic, viscoelastic and plastic bending deformation component. Results and discussions Influence of washing treatment on bending modulus values of washed and unwashed hemp fabric are shown in Figure 6.
Figure 6. Bending modulus values of washed and unwashed fabric in
It can be noticed, from Figure 6, that elasticity of both washed and unwashed fabric is greater in warp than in weft direction. Besides, elasticity of investigated fabrics decreases according to the following sequence: washed fabric in warp direction, unwashed fabric in warp direction, washed fabric in weft direction and unwashed fabric in weft direction. Presented sequence of investigated fabrics elasticity might be explained by the usage of much coarser yarn in weft in regard to the warp direction. Also, it might be seen that for 70 per cent of the results in warp direction as well as for 80 per cent of the results in weft direction, elasticity of washed fabric is better than elasticity of unwashed fabric. Elasticity of investigated fabrics, as it was already said, was monitored also from the aspect of their recovery after action of pressure of 32.67 KPa. The results of measuring the crease recovery angle in degrees of washed and unwashed fabric in both structural directions (warp, weft direction) in definite time intervals are shown in Table II. As additional indicator of woven fabrics quality, in regard to their resistance to creasing, quality number was used. Quality number (Qn) was calculated according to the formula (JUS F.S2.018, 1958): Qn ¼
a0 a60 per cent 324
Bending elasticity of woven fabric 77
ð8Þ
Calculated values of quality number are also presented in Table II. Higher value of quality number means better ability of recovery from creasing. Results given in Table II showed that with the increase of relaxation time (5, 10, 1,440 min), values of crease recovery angle of washed and unwashed fabric in both structural directions also increase. In other words, with the increase of relaxation time, the recovery of fabrics after action of bending force improves. Besides, it can be seen that elasticity of investigated (washed and unwashed) fabrics, monitored from the aspect of crease recovery angle value and quality number, decreases according to the same sequence as in the case of determination of bending modulus. In that sense the best elasticity has washed fabric in warp direction, after that unwashed fabric in warp direction, then washed fabric in weft direction and the poorest elasticity expresses unwashed fabric in weft direction. On the basis of crease recovery angle values in definite time intervals, elastic, viscoelastic and plastic bending deformation component were calculated (Figure 7). The size of bending deformation components was the third indicator of elasticity of investigated fabrics. The size of elastic deformation (1e) was determined on the basis of calculated values of angle of leap (a0) within a moment of unloading the sample (instantaneous recovery). Sample Characteristic
Unwashed fabric Warp Weft
Washed fabric Warp Weft
Crease recovery angle a5 (8) Crease recovery angle a60 (8) Crease recovery angle a1,440 (8) Angle of leap a0 (8) Quality number (per cent)
98 121 135 58 21.7
116 146 151 65 29.3
74 89 120 47 12.9
81 95 127 54 15.8
Table II. Recovery of investigated fabrics after action of pressure of 32.67 KPa
IJCST 18,2
78
Figure 7. Values of bending deformation components of washed and unwashed fabric
The size of plastic deformation (1p) was determined on the basis of measuring the value of crease recovery angle after 1,440 min (24 h). The size between elastic and plastic deformation was estimated as viscoelastic deformation (1v). On the basis of the values of total recurrent deformation ð1e þ 1v Þ (Figure 7), it can be noticed that elasticity of investigated fabrics, in this case, also decreases according to the following sequence: washed fabric in warp direction ð1e þ 1v ¼ 96:6percentÞ; unwashed fabric in warp direction (89.6 per cent), washed fabric in weft direction (74.8 per cent) and unwashed fabric in weft direction (74.2 per cent). Average value of elastic, viscoelastic and plastic bending deformation component of washed and unwashed fabric in warp as well as in weft direction is given in Table III. Presented data in Table III point to the fact that elasticity of washed fabric is better than elasticity of unwashed fabric. Calculation of the ratio of components of total deformation, whose values are given in Table III, enabled establishing Frenkel’s model of elasticity at bending of washed and unwashed fabric (Figure 8). In this work, Frenkel’s model was chosen, because of the following:
Table III. Average value of bending deformation components of washed and unwashed fabric
Sample Unwashed fabric Washed fabric
Average value of bending deformation components Elastic (1e) (per cent) Viscoelastic (1v) (per cent) Plastic (1p) (per cent) 41.0 42.8
41.0 42.9
18.0 14.3
Bending elasticity of woven fabric 79
Figure 8. Frenkel’s model of investigated fabrics elasticity at bending . . . .
it can be easily adapted to experimental data; it describes all three deformation components; this model can be made in fast and simple way; and it does not demand the usage of complicated mathematics apparatus.
First part of original Frenkel’s model consists of spring, which corresponds to elastic deformation (Hook’s model). In second part, spring and piston immersed in liquid parallel connected, represent viscoelastic deformation as in the case of Kelvin-Foygt’s model. Third part of Frenkel’s model is piston immersed in liquid, which corresponds to the plastic deformation (Newton’s model). Frenkel’s model adapted according to the results of investigation of bending deformation components, presented in this paper, consists of two (three) springs, two (three) parallel connected springs and pistons, and one piston in the case of unwashed (washed) fabric (Figure 8). Frenkel’s model of elastic behaviour of investigated fabrics on picturesque manner presents the already noticed fact that elasticity of washed fabric is better than elasticity of unwashed fabric. At the end, on the basis of the values of bending modulus, quality number and total recurrent deformation, complex criterion (Qc) for the estimation quality of investigated fabrics from the aspect of their elasticity was established. For the calculation of complex criterion (Qc) of investigated fabrics, the following formula was used (Nikolic et al., 1995): Qc ¼
3 1 Q1
þ Q12 þ Q13
ð9Þ
Q1, dimensionless indicator of fabric’s quality expressed through the value of bending modulus; Q2, dimensionless indicator of fabric’s quality expressed through the value of quality number; and Q3, dimensionless indicator of fabric’s quality expressed through the value of total recurrent deformation.
IJCST 18,2
In a general case, complex criterion (Qc) is given by the relationship (Nikolic et al., 1995): P ni ð10Þ Qc ¼ P 1 Qi
80
Table IV. Gradation of the quality
ni, total number of investigated characteristics; and Qi, dimensionless indicator of fabric’s quality expressed through the value of investigated characteristic. Values of complex criterion, that indicate to the quality of some fabric, are given in Table IV. Dimensionless indicator of fabric’s quality (Q) was calculated according to the expression (Nikolic et al., 1995; Solov’ev and Kiryukhin, 1974): XD X ðfor X . X D Þ or Q ¼ ðfor X , X D Þ ð11Þ Q¼ XD X XD, die value; and X, measured value of investigated characteristic. In the case of lack of die value, measured value (minimal or maximal) of investigated characteristic which means the best quality of fabric is used. Values of dimensionless indicator of fabric’s quality as well as the complex criterion for judging the elasticity of investigated fabrics are shown in Table V. Values of dimensionless indicator of fabric’s quality shown in Table V point to the fact that both washed as well as unwashed fabric have the best quality estimated through the value of total recurrent deformation, and the poorest through the value of quality number. Also, values of complex criterion given in the same Table, testify about satisfied quality of investigated washed and unwashed hemp fabric, except unwashed fabric in weft direction which has poor quality. On the basis of the average value of complex criterion in warp and in weft direction, it can be seen that washed fabric has 50 per cent better quality, concerning the bending elasticity, in regard to the unwashed fabric.
Interval of complex criterion values
Quality
1.00-0.76 0.75-0.51 0.50-0.26 0.25-0.00
Excellent Good Satisfy Poor
Dimensionless indicator of fabric’s quality Table V. Values of dimensionless indicator and complex criterion for gradation of investigated fabrics quality
Sample
Q1
Q2
Q3
Values of complex criterion
Average value of complex criterion
Unwashed fabric (warp) Unwashed fabric (weft) Washed fabric (warp) Washed fabric (weft)
0.35 0.14 0.62 0.37
0.22 0.13 0.29 0.16
0.90 0.74 0.97 0.75
0.35 0.18 0.49 0.29
0.26 0.39
Conclusion Comparative analysis of the results of investigation the elasticity through the values of bending modulus, quality number (i.e. crease recovery angle) and bending deformation components, enabled establishing the complex estimation of elastic properties of washed and unwashed hemp fabric. Complex estimation was realized through the value of complex criterion. Besides, mentioned investigations made possible to perceive the influence of fabric’s finishing (washing) on its behaviour under action of bending force. On the basis of the imposed investigations, conducted in such way to simulate the real conditions of the investigated fabrics usage, it is possible to conclude the following: . washed fabric in warp direction has the best elasticity, but unwashed fabric in weft direction-the poorest; . elasticity of washed and unwashed fabric is greater in warp than in weft direction; . washing treatment of investigated hemp fabric in powdered soap solution improves its elastic properties; and . washed fabric has 50 per cent better quality than unwashed fabric. On the basis of the obtained results of investigation it can be considered the quality of investigated hemp fabric from the aspect of its elasticity before and after washing treatment. Gained measuring results as well as the value of complex criterion pointed to the relatively satisfied stability of form and dimensions of investigated fabric. However, because of the little lower values of quality number, the usage of the investigated fabric in wearing purposes is not recommended. Regardless of the fact in which purpose will be use, investigated fabric (washed and unwashed) should be exploitated only in warp direction. This conclusion was confirmed by the values of complex criterion. Calculated values of bending deformation components as well as their ratio, enabled the assumption of Frenkel’s model of elastic behaviour of investigated washed and unwashed hemp fabric. By the application of Frenkel’s model, picture of elastic properties of investigated fabrics under action of bending force was gained, which is of importance at prognosis the behaviour of some material in various exploitation conditions. References Amirbayat, J. (1991), “The buckling of flexible sheets under tension, part I: theoretical analysis”, Journal of the Textile Institute, Vol. 82 No. 1, pp. 61-77. Buzov, B.A., Modestova, T.A. and Alymenkova, N.D. (1986), Investigation of Ready-Made Products, Legprombytizdat, Moscow. Chapman, B.M. (1974), “A model for the crease recovery of fabrics”, Textile Research Journal, Vol. 44 No. 7, pp. 531-8. Chapman, B.M. (1976), “A shorter stress-relaxation wrinkle test”, Textile Research Journal, Vol. 46 No. 9, pp. 697-9. Clapp, T.G. and Peng, H. (1990a), “Buckling of woven fabrics, part I: effect of fabric weight”, Textile Research Journal, Vol. 60 No. 4, pp. 228-34. Clapp, T.G. and Peng, H. (1990b), “Buckling of woven fabrics, part II: effect of weight and frictional couple”, Textile Research Journal, Vol. 60 No. 5, pp. 285-92. Collier, J.R., Collier, B.J., O’Toole, G. and Sargand, S.M. (1991), “Drape prediction by means of finite-element analysis”, Journal of the Textile Institute, Vol. 82 No. 1, pp. 96-107.
Bending elasticity of woven fabric 81
IJCST 18,2
82
Gan, L., Ly, N.G. and Steven, G.P. (1995), “A study of fabric deformation using nonlinear finite elements”, Textile Research Journal, Vol. 65 No. 11, pp. 660-8. Grey, S.J. and Leaf, G.A.V. (1985), “The nature of inter-fibre frictional effects in woven-fabric bending”, Journal of the Textile Institute, Vol. 76 No. 5, pp. 314-22. Hayes, R.L., Leeder, J.D. and Taylor, D.S. (1975), “The wrinkling behavior of wool fabrics-conditions of testing”, Textile Research Journal, Vol. 45 No. 10, pp. 712-6. International Organisation for Standardisation (1972) ISO 2313-1972 (E), ISO, Jersey City, NJ. JUS F.S2.018 (1958), Determination of Crease Recovery Angle of Woven Fabrics. Kang, T.J. and Yu, W.R. (1995), “Drape simulation of woven fabrics by using the finite-element method”, Journal of the Textile Institute, Vol. 86 No. 4, pp. 635-48. Koblyakov, A. (1989), Laboratory Practice in the Study of Textile Materials, Mir Publishers, Moscow. Luvishis, L.A. and Birenbaum, E.I. (1971), Technical Control during Weaving and Finishing of Wool Woven Fabrics, Legkaya Industriya, Moscow. Mihailovic, T., Nikolic, M. and Simovic, Lj. (1995), “Resistance to creasing of clothing wool fabrics”, International Journal of Clothing Science and Technology, Vol. 7 No. 4, pp. 9-16. Nhan, G.Ly. (1985), “A model for fabric buckling in shear”, Textile Research Journal, Vol. 55 No. 12, pp. 744-9. Nikolic, M., Mihailovic, T., Nikolic, S. and Simovic, Lj. (1995), “Methodology of estimation woven fabrics from the aspect of their behaviour under half-cyclic and one-cyclic strain”, Textile Industry, Vol. 43 Nos 7/9, pp. 11-20. Postle, J.R. and Postle, R. (1997), “The mechanics and dynamics of wool fabric drape, folding, buckling and wrinkling”, paper presented at the 9th International Wool Textile Research Conference, Biella-Italy, 28 June-5 July 1995, book of abstracts,Vol. 5, pp. 66-77. Postle, R. and Postle, J.R. (1998), “The dynamics of fabric drape”, International Journal of Clothing Science and Technology, Vol. 10 Nos 3/4, pp. 305-12. Raskovic, D. (1962), Strength of Materials, Civil Engineering Book, Belgrade. Savast’yanova, A.G., Dronova, I.V. and Krainova, E.G. (1987), “Testing the wearing properties of flax and flax-blend woven fabrics”, Express Information, No. 16, pp. 11-24. Schwartz, P. (1982), “Bending properties of triaxially woven fabrics”, Textile Research Journal, Vol. 52 No. 9, pp. 604-6. Smuts, S. and Hunter, L. (1991), “The effect of fibre properties on the wrinkling of some wool and mohair suiting fabrics”, South African Journal of Science, Vol. 87 No. 8, pp. 378-80. Solov’ev, A.N. and Kiryukhin, S.M. (1974), Estimation of the Quality and Standardization of Textile Materials, Legkaya Industriya, Moscow. Stump, D.M. and Fraser, W.B. (1996), “A simplified model of fabric drape based on ring theory”, Textile Research Journal, Vol. 66 No. 8, pp. 506-14. Wortmann, F.J. (1985), “Aspects of the crease recovery of wool fabrics”, Melliand Textilberichte, Vol. 66 No. 1, pp. 78-80.
To purchase reprints of this article please e-mail:
[email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
An experimental study on fabric softness evaluation
Fabric softness evaluation
Peihua Zhang College of Textiles, Donghua University, Shanghai, People’s Republic of China, and
Xin Liu, Lijing Wang and Xungai Wang School of Engineering and Technology, Deakin University, Deakin, Australia
83 Received June 2005 Revised October 2005 Accepted October 2005
Abstract Purpose – To examine a simple testing method of measuring the force to pull a fabric through a series of parallel pins to determine the fabric softness property. Design/methodology/approach – A testing system was setup for fabric pulling force measurements and the testing parameters were experimentally determined. The specific pulling forces were compared with the fabric assurance by simple testing (FAST) parameters and subjective softness ranking. Their correlations were also statistically analyzed. Findings – The fabric pulling force reflects the physical and surface properties of the fabrics measured by the FAST instrument and its ability to rank fabric softness appears to be close to the human hand response on fabric softness. The pulling force method can also distinguish the difference of fabrics knitted with different wool fiber contents. Research limitations/implications – Only 21 woven and three knitted fabrics were used for this investigation. More fabrics with different structures and finishes may be evaluated before the testing method can be put in practice. Practical implications – The testing method could be used for objective assessment of fabric softness. Originality/value – The testing method reported in this paper is a new concept in fabric softness measurement. It can provide objective specifications for fabric softness, thus should be valuable to fabric community. Keywords Fabric testing, Force, Wool fabric Paper type Research paper
1. Introduction Fabric handle has been recognized as one of the most important performance attributes for apparel fabrics. It has been defined as a perceived overall fabric aesthetic quality that reflects the fabrics’ mechanical and physical properties (Kim and Slaten, 1999). In order to objectively quantify fabric hand properties, many researchers have focused on the development of testing instruments and methods since the 1970s. The most important instrumental approaches are kawabata evaluation system (KES) and fabric assurance by simple testing (FAST). These two methods are based on correlations between a number of subjective assessments of fabric handle (such as smoothness, This work was carried out under the Visiting Fellowship program of the China Australia Wool Innovation Network (CAWIN) project. Funding for this project was provided by Australian wool producers and the Australian Government through Australian Wool Innovation Limited.
International Journal of Clothing Science and Technology Vol. 18 No. 2, 2006 pp. 83-95 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610645748
IJCST 18,2
84
firmness, fullness, crispness and hardness) and corresponding mechanically measurable fabric properties (such as low mechanical stress, shearing, bending, compression and surface friction) (Kim and Slaten, 1999). These two systems have many merits, and the FAST system has been used by many leading worsted fabric manufacturers and end-users. The KES system is a comprehensive system that is relatively complex. The small-scale apparel and textile manufacturers and merchandisers may find these systems difficult to use (Kim and Slaten, 1999). Many researchers have put effort into developing a simple objective handle testing system. Since Alley’s patent (Alley, 1978) illustrated the nozzle extraction process and handle meter for measuring handle, Behery (1986) and Pan and Yen (1992) used Alley’s extraction hand measurement technique to evaluate the hand properties of various fabrics. The principle of this method is to employ a tensile tester to extract the fabric through a small half-cone shaped nozzle and to identify parameters from a force-displacement curve as the result of overall hand. Grover et al. (1993) developed a hand measurement device and the total hand results were determined from the maximum force of pulling fabric through a ring. Pan and Zeronian (1993) have suggested that all the property categories measured by the KES-FB system can be run on an Instron tensile tester when the proper attachments are provided. Yazdi (2003) has expressed a way of doing a concentrated loading method for measuring the basic low stress mechanical properties of woven fabrics and introduced the parameters which can indicate the mechanical properties of woven fabrics. Malathi et al. (1990) have proposed that the percentage compression of fabric measured at different pressure can be used for assessing the handle of fabric or softness of yarns. Knapton and Onions et al. (1967) have suggested a measure known as hardness to represent the handle of knitted fabrics. The lower the value of compression, the softer the fabric handle and vice versa. Recently, Liu et al. (2004a, b) introduced a simple method for evaluating fiber softness by pulling a bundle of parallel fibers through a series of pins. Their results suggest that pulling force measurements can reflect differences in fiber softness. Wang et al. (2004) presented a model to calculate the fiber pulling force theoretically. The modeling results further confirmed that the pulling force increases nonlinearly with the increase of the fiber diameter and coefficient of kinetic friction. The fiber pulling force can be an objective parameter for evaluating fiber softness. Based on the above pulling force technique, this paper examined the feasibility of objective evaluation of fabric softness by measuring the forces of pulling a fabric sample through a series of parallel pins. The fabric softness order ranked with pulling forces was compared to those ranked with values obtained from both FAST results and subjective softness assessments. Their correlation and regression analysis were also carried out. 2. Experimental 2.1 Sample selections The fabric specimens used in this study include wool and wool blend wovens of varying weave structures and plain knitted fabrics. Table I lists the general characteristics of 21 woven fabric samples. For knitted fabric samples, three types of knitting yarns with the same yarn count (Nm32/2) but different blend ratios of wool/polyacylonitrile (PAN) (100/0, 50/50, 30/70) were selected to knit the plain fabric samples on a lab knitter with the same machine settings. All samples were conditioned
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Fabric code
Fiber content (percent) 50/50 wool/polyester 45/55 wool/polyester 30/70 wool/polyester 30/70 wool/polyester 40/12/4/42 wool/nylon/cotton/flax 44/54/2 wool/polyester/Lycra 40/60 wool/polyester 96/4 wool/polyester 60/20/20 wool/polyester/soybean 50/50 wool/polyester 100 wool 100 wool 100 wool 100 wool 100 wool 100 wool 100 wool 100 wool 100 wool 100 wool 60/36/4 wool/polyester/elastic
Fabric structure
Fancy Plain Twill Plain Fancy Twill Twill Plain Fancy Plain Twill Twill Plain Twill Plain Plain Fancy Fancy Fancy Fancy Plain
67/2 63/2 51/2 42/2 88/2 £ 38/1 53/2 £ 51/2 51/2 98/2 £ 60/1 70/2 42/2 68/2 £ 50/1 52/2 70/2 28/2 35/2 30/2 30/2 25/2 þ 25/2 28/2 þ 28/2 30/2 þ 30/2 28/2
Yarn count (Nm) (warp £ filling) 310 £ 210 240 £ 220 300 £ 255 185 £ 170 360 £ 210 360 £ 240 310 £ 265 390 £ 370 360 £ 335 385 £ 365 410 £ 410 460 £ 230 180 £ 165 280 £ 230 225 £ 220 320 £ 275 430 £ 215 340 £ 270 420 £ 320 410 £ 330 270 £ 240
Picks per 10 cm (warp £ filling)
163.5 155.5 225.3 193.5 142.5 274.6 237.1 153.6 218.4 167.6 233.9 278 222.1 189.3 156.4 218.8 245.6 253.8 293.1 284.8 190.5
Fabric weight (g/m2)
Fabric softness evaluation
85
Table I. Woven fabric characteristics
IJCST 18,2
86
in the standard laboratory (temperature of 20 ^ 28C and relative humidity of 65 ^ 2 percent) for 24 h before testing. 2.2 Testing system for pulling force This pulling force testing system was designed for softness evaluation of animal fibres. The principle of the method was detailed in the previous publication (Liu, 2004a). The basic idea is that the force required to pull a fibre over a series of pins reflects the combined effect or fibre stiffness (fibre diameter) and surface smoothness, which in turn affect fibre softness. We were able to use the pulling force to differentiate the softness of fibres. In the current study, we have appied this technique to investigate the softness of fabrics. Figure 1 shows the pulling force testing set-up for woven (Figure 1(a)) and knitted fabrics (Figure 1(b)), respectively. Because of the different thickness of knitted fabrics from woven fabrics, two rigs were designed for measuring the pulling forces of woven and knitted fabrics, respectively. Details of the rig settings and the size of testing samples are given in Table II. We used a Lloyd material testing instrument (LR30K type) to test the pulling force. A load cell is attached to the cross head to sense the pulling force and the force signal is recorded by a computer system. 2.3 Pulling force measurements For woven fabric pulling force testing, each fabric sample was cut into 250 mm long and 25 mm wide test specimens. One end of each fabric specimen was held by an aluminum clamp and attached to the sensor of Lloyd instrument. The specimen was then mounted into the test rig with or without preload. Fabric sample No. 21 (Table I) was selected to determine an optimum test speed. Five measurements were done for each fabric at the same testing condition as the test results from the benchmark fabric
Figure 1. Pulling force measurement set-up
Table II. Rig settings and size of test samples
Parameters
Rig 1 settings
Distance between pins (mm) Pin diameter (mm) Number of pins Sample length (mm) Sample width (mm) Suitable fabrics
1.5 3 10 250 25 Woven fabrics
Rig 2 settings 15 5
12.5 10 7.5 10 12 500 90 Either knitted or heavy fabrics
No. 21 have a good repeatability. Three specimens (No. 5, No. 17 and No. 21), having subjective differences in fabric softness were selected for pulling force measurements with different preloads at a test speed of 400 mm/min. The optimum preload testing parameters were then determined. According to the optimized testing parameters, the specific pulling forces of all woven fabrics were measured in the warp direction. For knitted fabric pulling force testing, considering the curling/rolling tendency of knitted fabric samples, a double-layer of circular knitted fabric was used to measure the specific pulling force in the wale direction. Knitted specimens were 500 mm in length and finished with lock stitch on both edges.
Fabric softness evaluation
87
2.4 Illustration of the typical profile of pulling force Figure 2 shows a characteristic pulling force vs time (or load-displacement) curve. We calculate the average pulling force in between dotted lines (about 60 percent of the curve in Figure 2) as the pulling force for each fabric. We compute the specific pulling force (cN/ktex) by dividing the pulling force value by the linear density of each test specimen. 2.5 FAST testing In order to understand the specific pulling force characteristics and examine the feasibility of objective evaluation of fabric softness by using the pulling force method, we measured the woven fabric samples listed in Table I with the FAST testing system. The following FAST parameters were measured: E5, E20, E100: Fabric elongation measured at the pressure of 5, 20, 100 gf/cm2, respectively. EB5
Sidelong fabric elongation measured at the pressure of 5 gf/cm2.
W:
Fabric weight in gram per square meter.
C:
Fabric bending length.
B:
Fabric bending rigidity calculated from W and C.
F:
Fabric formability calculated from E20, E5 and B.
G:
Fabric shearing rigidity calculated from EB5.
Figure 2. Typical profile of a pulling force curve
IJCST 18,2
88
T2, T100:
Fabric thickness measured at the pressure of 20 and 100 gf/cm2, respectively.
ST:
Fabric surface thickness property equaled to the difference of T2 and T100.
The FAST testing results of mechanical and physical properties were then correlated with the specific pulling force results. 2.6 Subjective assessment of fabric softness We selected two groups of fabrics, plain (2, 4, 8, 10, 13, 15, 16, 21) and fancy structures (1, 5, 9, 17, 18), from Table I for subjective assessment of softness. The fabric size for handle assessment was 300 £ 300 mm. The softness order in each group of fabrics was ranked by 20 textile researchers. The smaller the order is, the softer the fabric is. We then used the SPSS statistical software to analyze the subjective assessment order. The softness ranking from the subjective assessment was compared with the specific pulling force ranking. 3. Results and discussion 3.1 Selection of pulling force testing parameters Figure 3 shows the specific pulling force results of Fabric No. 21 at different preloads and test speeds. Figure 3(a) shows that the specific pulling force increases as the
Figure 3. Selection of a test speed
preload increases, and the specific pulling force does not change too much as the testing speed varies. Figure 3(b) shows that the CV values at higher test speeds (400 and 500 mm/min) are lower than that at lower speeds (, 300 mm/min) for most specimens, therefore, the test speed of 400 mm/min was selected in this study. Figure 3(b) also shows that the CV value descends with increasing preload. Considering that the pulling force represents the sample’s frictional force and bending capability against the pins, the frictional force will contribute more to the pulling force than the bending force as the preload increases. Therefore, the bending force could be very small compared to the frictional force if the preload is too big. Since the bending capability affects fabric softness, we selected a smaller preload as a testing parameter in order to highlight the combination effect (i.e. pulling force) of fabric bending and frictional properties. Figure 4 shows the statistic results of the specific pulling forces of three specimens (No. 5, No. 17 and No. 21) measured with different preloads at 400 mm/min test speed. From Figure 4(a) we can see that the specific pulling force of these specimens increases as the preload increases. Figure 4(b) shows the CV values are relative lower at 12 and 17cN preloads than other preloads. As mentioned above, a small preload is preferred for pulling force measurements, we, therefore, selected 12cN preload as the reference preload parameter.
Fabric softness evaluation
89
Figure 4. Selection of a preload
IJCST 18,2
3.2 Pulling force testing results Figure 5 shows the results of specific pulling force of the woven specimens listed in Table I. It can be seen that the specific pulling force measured with a 12cN preload is higher than that measured with no-preload, and the preload does not affect the specific pulling force linearly.
90
3.3 Correlations between specific pulling force and selected FAST values This study uses 21 woven specimens ranging in weight from 142 to 293 g/m2. At the same rig setting and pin configurations, the specific pulling forces are strongly related to the fabric thickness and fabric weight. In order to compare fabric specific pulling forces of all fabrics, we divided 21 woven specimens into three groups according to their weights. Table III reports the correlations between specific pulling force indexes (Y) listed and selected FAST variables. The subscript of index Y has two figures. The first figure (i.e. 1 , 4) expresses the different transposed specific pulling force (AvF value). The second figure (“0” and “1”) represents the pulling force tested at no-preload and 12cN preload, respectively. For example, the index Y2-0 means AvF0/T2, and Y4-1 means AvF1/(T2 £ W). These results in Table III indicate that there are some strong positive correlations between the specific pulling force indexes and selected physical properties, such as fabric thickness (T2, T100), of FAST testing within the groups. Table III also shows strong correlations between specific pulling force indexes at no-preload and fabric bending length and bending rigidity from FAST testing when the fabric weight is less than 200 g/m2. However, as the fabric weight increases, the correlations are reduced and at a fabric weight greater than 250 g/m2, there is no significant correlation between specific pulling force indexes and fabric bending length and rigidity. As a thicker fabric has a large contact angle between the fabric and the pins, the pulling force results in this paper may not reflect the correlations between the heavy fabric and bending property. This suggests that both the pin diameter and the distance between pins should be adjustable to accommodate fabrics of different thickness. We also noted that there is no correlation between specific pulling force indexes and fabric bending property, but there is a strong positive correlation between specific pulling force indexes, fabric thickness and stretch properties when the fabric was tested with a preload of 12cN. It is clear that the method for measuring the pulling force without a preload is more suitable for softness assessment as the force reflects the fabric bending and rigidity property.
Figure 5. Specific pulling forces results of all fabrics
Weight (g/m2)
Index
Index meaning
140-200
Y1-0
AvF0
Y2-0
AvF0/T2
Y3-0
AvF0/W
Y4-0 Y1-1 Y2-1 Y3-1 Y4-1
AvF0/(T2 £ W) AvF1 AvF1/T2 AvF1/W AvF1/(T2 £ W)
Y1-0
AvF0
Y2-0
AvF0/T2
Y3-0
AvF0/W
Y4-0 Y1-1
AvF0/(T2 £ W) AvF1
Y2-1
AvF1/T2
Y3-1
AvF1/W
Y4-1 Y1-0 Y2-0 Y3-0 Y4-0 Y1-1 Y2-1 Y3-1 Y4-1
AvF1/(T2 £ W) AvF0 AvF0/T2 AvF0/W AvF0/(T2 £ W) AvF1 AvF1/T2 AvF1/W AvF1/(T2 £ W)
200-250
250-300
Correlations between pulling force indexes and selected FAST values E5-1 *, E20-1 * *, E100-1 * *, E100-2 *, C-1 * *, C-2 *, B-1 * *, B-2 * E5-1 *, E20-1 * *, E100-1 * *, E100-2 *, C-1 * *, B-1 * *, T2 * *, T100 * *, ST * E5-1 *, E20-1 * *, E20-2 *, E100-1 * *, E100-2 * *, EB5 *, C-1 * *, C2 * *, B-1 *, B2 * *, T2 *, T100 *, W * E5-1 *, E20-1 * *, E20-2 *, E100-1 * *, E100-2 * *, EB5 *, C-1 * *, C2 * *, B-1 * *, B2 *, G *, T2 * *, T100 * *, ST *, W** E20-1 *, E100-1 * *, T2 * *, T100 * *, W * * E20-1 *, E100-1 * *, T2 * *, T100 * *, ST *, W * * E20-1 *, E100-1 * *, T2 * *, T100 * *, W * * E20-1 *, E100-1 * *, T2 * *, T100 * *, W * * E5-1 *, E20-1 *, E100-1 *, C-1 *, T2 * *, T100 * *, ST *, W* E5-1 * *, E5-2 *, E20-1 * *, E20-2 * *, E100-1 * *, E100-2 *, C-1 *, B-1 *, T2 * *, T100 * *, ST * *, W * E5-1 * *, E20-1 * *, E100-1 *, T2 * *, T100 * *, ST * *, W** E5-1 * *, E5-2 *, E20-1 * *, E20-2 *, E100-1 * *, E100-2 *, C-1 *, B-1 *, T2 * *, T100 * *, ST * *, W * * E5-1 *, E20-1 *, E100-1 *, T2 * *, T100 * *, ST * *, W * * E5-1 * *, E5-2 * *, E20-1 * *, E20-2 * *, E100-1 * *, E100-2 * *, EB5 *, T2 * *, T100 * *, ST * *, W * * E5-1 *, E20-1 *, E20-2 *, E100-1 *, T2 * *, T100 * *, ST * *, W * E5-1 * *, E5-2 * *, E20-1 * *, E20-2 * *, E100-1 * *, E100-2 * *, T2 * *, T100 * *, ST * *, W * * T2 * *, T100 * *, ST * T2 * *, T100 * *, W * * T2 * *, T100 * *, ST *, W * * T2 * *, T100 * *, W * * EB5 *, T2 * *, T100 * * E5-2 *, T2 *, T100 *, W * * T2 * *, T100 * *, W * * E5-2 *, T2 *, T100 *, W * *
Notes: *Correlation is significant at the 0.05 level (two-tailed); * *correlation is significant at the 0.01 level (two-tailed); The postfix (21 or 22) of FAST parameters indicates the fabric direction of warp and weft, respectively
3.4 Regression analysis of specific pulling force index and selected FAST values We carried out a stepwise regression analysis for specific pulling force indexes (Y3 and Y4) as dependent variables, in order to understand how these individual properties from FAST testing are associated with the pulling forces. Table IV shows some significant regression equations. From Table IV we can see that strong correlation exists when the specific pulling force indexes are expressed as AvF/W (Y3) and AvF/(T2 £ W) (Y4). Some physical property variables tested by the FAST instrument, such as thickness (T2 or T100), bending length
Fabric softness evaluation
91
Table III. Correlations between specific pulling force indexes and selected FAST values
Table IV. Regression equations between specific pulling force index and selected FAST values
250 , W , 300
200 , W , 250
W , 200
Y4-0 ¼ 0.696C-1-0.354B-1 þ 0.061T2-0.183T100 þ 0.038E20-1-0.613E100-1 Y4-1 ¼ -0.621T100 þ 0.27T2-0.586W þ 0.165E100-1 Y4-0 ¼ 0.035C-1 þ 1.145T2-2.113T100-0.415W þ 0.352E100-1 Y4-1 ¼ 0.248E100-1 þ 0.361T2-1.261T100-0.418W Y3-0 ¼ 0.51E5-2 þ 0.214T2 þ 0.478T100 Y3-1 ¼ 0.597E5-2-0.513T2 þ 1.197T100
Regression equation
12.615 66.929 12.632 16.881 7.184 9.913
0.961 0.899 0.899 0.814 0.846
F
0.889
Correlation coefficients R
92
W (g/m2)
ANOVA
0.002
0.006
0.000
0.000
0.000
0.000
Sig.
IJCST 18,2
(C), bending rigidity (B), fabric weight (W) and fabric stretch properties (E5, E20 or E100), are the significant variables that contributed to the pulling force as a dependent variable. Their correlation coefficients (R) are higher than 0.8 ðP , 0:01Þ: In fact, these selected fabric properties are the most influential factors in determining fabric softness, therefore, the pulling force method can be a simple way to evaluate fabric softness.
Fabric softness evaluation
3.5 Fabric softness evaluation between pulling force and subjective assessment The details of fabric softness assessment results for both groups of plain and fancy woven specimens are shown in Figure 6, where the smaller the subjective assessment order value is, the softer the fabric handle. The length of the vertical lines indicates the frequency of the softness order. A longer line means more assessors gave the same softness order. From Figure 6, it can be seen that the variations of subjectively assessed orders among the assessors are very large. It is difficult for assessors to pick up a small difference in fabric softness. Table V shows the comparisons of mean rank and subjective order using non-parametric analysis of Kendall’s Related Model, where mean rank represents the mean rank values of 20 subjective assessment data and sub order is the order of mean ranks. It can be seen from Table V that, within Group 1, the Kendall’s correlation coefficient is too small, and there is less correlation, indicating that the handle of some
93
Figure 6. Subjective assessment results of selected fabrics
Group Group1 plain structure
Group2 fancy structure
Fabric no
Mean rank
Sub order
Kendall’s Wa
x2
2 4 8 10 13 15 16 21 1 5 9 17 18
5.70 6.75 2.70 4.85 2.05 4.30 5.20 4.45 2.20 4.60 4.40 1.15 2.65
7 8 2 5 1 3 6 4 2 5 4 1 3
0.390
54.667
0.871
69.640 Table V. Correlations among subjective assessment
IJCST 18,2
94
fabrics is very close. In contrast, there is a positive correlation among five specimens within Group 2 as the softness of fabric handle is quite different. Table VI illustrates the comparative results between the subjective assessment order and specific pulling force indexes order within Group 2, where fabric weights ranged from 142 to 254 g/m2. It shows a good correlation between the subjective assessment order and pulling force indexes. This result suggests that the pulling force method can be used to objectively evaluate the fabric softness. 3.6 Relationship between specific pulling force and wool content Figure 7 shows the relationship between specific pulling force and wool content of three knitted fabric samples, which had the same fabric stitch parameter and yarn count (32 Nm/2) but a different blend ratio of wool and PAN. It can be clearly seen that the specific pulling force value relates to the wool contents of these knitted fabric samples. The specific pulling force descends with the increase in wool content of knitted fabric. If the pin diameter increases, the specific pulling forces are also increased. Different pin diameters may be chosen for testing fabrics of different thickness. 4. Conclusions In this paper, we have examined a simple method of measuring the force to pull a fabric sample through a series of parallel pins to determine the fabric softness. Selected fabric properties tested using the FAST instrument, i.e. thickness, bending length, bending rigidity and fabric stretch characteristics are significantly correlated to the specific pulling force under the no preload testing condition. The pulling force testing results
Fabric no
Table VI. Comparative results between subjective assessment order and specific pulling force indexes order
Figure 7. Relationship between specific pulling forces and wool contents
1 5 9 17 18 Correlations (0.05 level)
Sub order
Y2-0
Pulling force order Y3-0
Y4-0
2 5 4 1 3
2 4 3 1 5 0.7
2 5 3 1 4 0.9 *
4 5 2 1 3 0.6
Note: *Correlation is significant at the 0.05 level (two-tailed)
have a good correlation with the fabric softness subjectively assessed. From experiments, we can draw the following conclusions: . The specific pulling force has good repeatability in test results, and simultaneously relates to the fabric thickness, bending and stretch properties. There is a good relationship between specific pulling force indexes and selected physical properties obtained from FAST testing. . Pulling force measurement without pre-load can be used to objectively evaluate fabric softness. The subjective assessment of fabric softness is consistent with specific pulling force indexes and there is a good correlation between subjective assessment and objective evaluations. . The specific pulling force also reflects the softness difference in otherwise similar wool/PAN knitted fabrics with a different wool content. References Alley, V.L. (1978), “Nozzle extraction process and handlemeter for measuring handle”, United States Patent 4, 103, 550, 1 August. Behery, H.M. (1986), “Comparison of fabric hand assessment in the United States and Japan”, Textile Res. J., Vol. 56, pp. 227-40. Grover, G., Sultan, M.A. and Spivak, S.M. (1993), “A screen technique for fabric handle”, J. Textile Ins., Vol. 84, pp. 1-9. Kim, J.O. and Slaten, B.L. (1999), “Objective evaluation of fabric hand, part 1: relationships of fabric hand by the extraction method and related physical and surface properties”, Textile Res. J., Vol. 69 No. 1, pp. 59-67. Liu, X., Wang, L. and Wang, X. (2004a), “Evaluating the softness of animal fibers”, Textile Res. J., Vol. 74 No. 6, pp. 535-8. Liu, X., Wang, L. and Wang, X. (2004b), “Resistance to compression behavior of alpaca and wool”, Textile Res. J., Vol. 74 No. 3, pp. 265-70. Malathi, V.S., Kumari, B.L.N. and Chandramohan, G. (1990), “A simple method of measuring the handle of fabrics and softness of yarns”, J. Textile Ins., Vol. 81 No. 1, pp. 94-6. Onions, W.J., Oxtoby, E. and Townend, P.P. (1967), “Factors affecting the thickness and compressibility of worsted-spun yarns”, J. Textile Ins., Vol. 58, pp. 293-315. Pan, N. and Yen, K.C. (1992), “Physical interpretations of curves obtained through the fabric extraction process for handle measurement”, Textile Res. J., Vol. 62, pp. 279-90. Pan, N. and Zeronian, S.H. (1993), “An alternative approach to the objective measurement of fabrics”, Textile Res. J., Vol. 63 No. 1, pp. 33-43. Wang, L., Gao, W. and Wang, X. (2004), “Modeling the force of pulling a fibre through a series of pin”, paper presented at World Textile Conference-4th AUTEX Conference, Roubaix. Yazdi, A.A. (2003), “Effective features of the concentrated loading curves (woven fabric objective measurement)”, International Journal of Engineering Transactions B: Application, Vol. 16 No. 2, pp. 197-208.
To purchase reprints of this article please e-mail:
[email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
Fabric softness evaluation
95
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
IJCST 18,2
An overview of smart technologies for clothing design and engineering
108
S. Lam Po Tang and G. K. Stylios
Received July 2005 Revised November 2005 Accepted November 2005
Heriot-Watt University, School of Textiles and Design, Selkirkshire, UK Abstract Purpose – The paper aims to provide an overview of the area of smart textiles. Design/methodology/approach – The paper describes and discusses new and developing materials and technologies used in the textile industries. Findings – Significant progress has been achieved in the area of technical textiles. Fibres, yarns, fabrics and other structures with added-value functionality have been successfully developed for technical and/or high performance end-uses. The basic building blocks are already in place in the field of smart textiles and clothing. Practical implications – As progress in science and engineering research advances, and as the gap between designers and scientists narrows, the area of smart clothing is likely to keep on expanding for the foreseeable future. Growth is predicted to occur in two distinct directions: performance-driven smart clothing and fashion-driven smart clothing. There are challenges that have to be addressed. Originality/value – The paper provides information of value to those interested in the future directions of the textile industry. Keywords Clothing, Garment industry, Textile technology, Fabric production processes Paper type General review
International Journal of Clothing Science and Technology Vol. 18 No. 2, 2006 pp. 108-128 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610645766
Introduction In recent years, significant progress has been achieved in the area of technical textiles. Fibres, yarns, fabrics and other structures with added-value functionality have been successfully developed for technical and/or high performance end-uses. Technical textiles were promoted as alternative materials for a limitless range of applications, including civil engineering, the automotive industry, aerospace and the medical industry. In the clothing sector, rapid progress in high performance materials attracted a lot of interest for the sports and protective clothing industry. Today, the limits of textiles are being stretched even further. The expertise gained from many years of technical textiles research is being more intimately married with expertise from other engineering, scientific and design sectors, giving rise to a new breed of smart technologies. The clothing industry although not the first to reap the benefits of these technologies, can potentially be revolutionised with the commercialisation of the latest “smart” textiles research. The term “smart” has been used to refer to materials that can sense and respond in a controlled or predicted manner to environmental stimuli, which can be delivered in mechanical, thermal, chemical, magnetic or other forms (Tao, 2001). The responses of smart materials differ. Visible direct responses include automatic changes in shape, colour, geometry, volume and other visible physical properties. Indirect responses may include, for example, changes at a molecular, magnetic or electrical level, which do not
necessarily become apparent to the naked eye, but are able to trigger other controlled reactions or functions. The degree of “smartness” also varies. In the simplest form, smart materials sense and react automatically to a stimulus. Dyes that change colour with the presence of UV lights are typical examples of simple smart materials. In more complex forms, smart structures can sense, react and activate a specific function. For example, in the case of wearable flexible electronics, signals can be detected by a sensor, analysed and evaluated by a processor, which in turn feed backs to actuators to perform a particular function. The relationship between the stimulus and components of the smart material becomes more multi-directional and more complex. Recently, the interest in smart and interactive textiles has grown exponentially. The global market for smart fabrics and intelligent textiles has been estimated at $300 million in 2003, and predicted to grow to $720 million by the year 2008 (Fitzpatrick, 2004)[1]. The US market alone was valued at $64 million in 2004, and is expected to reach $299 million in 2009, with an annual growth rate of 36 per cent (McWilliams, 2004). Growth is predicted to be high in the area of conductive materials, and in the military, biomedical and automotive industries. Unsurprisingly, the key players in the development of smart technologies are the US and Japan. The US expertise has been mostly geared towards military uses. In the 2004 Defence Spending Bill, for example, the US Government has invested at least $3 million on research on electronic textiles for monitoring of soldiers’ physiological conditions[2]. More recently, a $5.5 million contract has been approved on the research and development of combat casualty care fabrics[3]. Although driven by military applications, the US progress achieved in areas such as body armour, artificial muscles, protective clothing, physiological monitoring clothing and other wearable electronics for communication is immediately transferable to other civilian applications. Japan, the next contender in the race, has also made significant advances in smart and interactive textiles, notably with the support of the Japanese government, industry and academia. The Japanese investment in research and development is phenomenal. A new five year basic science and technology plan is set to be in the area of ¥24 trillion (Stylios, 2004); of this, a significant amount is likely to be allocated to the next generation technologies such as nano-electronics for smart and interactive materials. With the gradual reduction of component costs, the commercialisation of many of the smart technologies becomes achievable. The clothing and footwear industry has already started to innovate by incorporating the latest technologies. Photochromic T-shirts and swimwear are already established products and account for a significant part of the US smart and interactive textiles market. Adidas’s “1”, running shoe incorporates sensors, a microprocessor and motor to smartly adjust the level of cushioning during walking and running. The clothing and footwear industry have mostly embraced the embedded electronics innovation, perhaps because of the possibility to use cheap components within the smart clothing. However, other smart technologies are also showing signs of entering the commercial market, as is the case for shape memory materials in the USA. Shape memory materials Shape memory materials are materials that are able to return to a pre-programmed shape with the right stimuli, normally temperature. For example, if deformed
Smart technologies
109
IJCST 18,2
110
mechanically below the transformation temperature, they will be able to regain most if not all of their original shape back, once the temperature increases to above the transformation temperature. This transformation occurs because the material changes its internal structure with temperature. In the case of shape memory alloys (SMAs), for example, at a low temperature, the structure of the materials changes to a martensite phase, where they can be easily deformed. Upon heating, the structure changes to an austenite phase, and the programmed shape is recovered as the material “remembers” its original shape (Figure 1(a)). In the case of shape memory polymers (SMPs), the effect results from the polymer’s structure and morphology (Figure 1(b)), and the thermal transition temperature that triggers the effect may be a glass transition, or a melting point (Lendlein, 2003). SMPs and SMAs are the two most common forms of shape memory materials, but shape memory effects also occur in some ceramics, glasses and gels. Shape memory alloys The martensitic transformation that occurs in SMAs is a lattice-distortive, diffusionless and reversible structural change, as shown in Figure 1(a). The martensitic phase generally occurs at a lower temperature, but the parent, austenite phase, which is the shape that the alloy remembers, is usually a high temperature phase. It is also possible to remember a martensitic phase under certain conditions, hence achieving a two-way shape memory effect. In this case, the SMAs become actuators that can be trained to remember up to two shapes (Lane and Craig, 2003). The strains possible with alloys are much lower (up to 8 per cent) than those possible with SMPs; however, SMAs benefit from specific advantages, one of which being the ability to recover to 100 per cent of the original programmed shape. Nickel-titanium alloys are the most common SMAs, with good shape memory
Figure 1. Schematic diagram of shape memory effect in (a) alloys and (b) polymers
properties at relatively low transformation temperatures. Copper-based alloys are cheaper alternatives, with lower shape memory strains, but with transformation achievable over a broader temperature range. Other iron-based systems have been investigated, but found to perform less well with regards to shape recovery. Work on the aesthetic intelligence of SMAs has shown that after being “programmed” to take specific shapes, they can be spun in combination with traditional fibres to create bi-component yarns (Winchester and Stylios, 2003; Chan and Stylios, 2003). They can then be woven and knitted, both in their original wire form, and as bi-component yarns. Good aesthetic shape memory effects have been produced using SMAs, and some examples of SMA structures are shown in Figure 2. SMAs can be used for the clothing industry, with interesting “lively” effects on the garment, but incorporating excessive amounts of the alloy in a textile structure will have a detrimental effect on the handle and touch of the fabric. Challenges in the manufacturing and making-up processes, mostly caused by the lack of extensibility of the alloy during weaving or knitting, also need due consideration.
Smart technologies
111
Shape memory polymers SMPs, which have higher extensibility, superior processability, lower weight and a softer handle, can be considered more suitable for the clothing industry. Elasticity is an important prerequisite for the shape memory effect; the elastic polymer exhibits shape memory functionality if the deformation of the material is stabilised for the temperature range required (Lendlein, 2003). The shape memory behaviour of an SMP is defined by four temperatures (Gall et al., 2004). The glass transition temperature (Tg) is the reference point for thermomechanical deformation and recovery. The deformation temperature (Td) is the temperature at which the polymer is deformed into a temporary shape. This temperature can be defined to be higher or lower than Tg, depending on the response required. The storage temperature (Ts) is the temperature at which the deformed polymer is stable over time. Ts is less than or equal to Td. Finally, the recovery temperature (Tr) represents the temperature at which the material recovers to its original shape upon heating. SMPs have been categorised into four classes: chemically crosslinked glassy thermosets, chemically crosslinked semi-crystalline rubbers, physically crosslinked thermoplastics and physically crosslinked block copolymers (Liu et al., 2002). Typical examples of SMPs are segmented polyurethane-based ones, which have a wide range of shape recovery temperature, low manufacturing cost, and high recoverable strains
Figure 2. Examples of (a) spun, (b) woven and (c) knitted SMAs
IJCST 18,2
112
Figure 3. Schematic diagram of shape memory effect of structural opening and closing (a) at low temperature (closed structure), and (b) at high temperature (open structure)
(up to 400 per cent) (Yang et al., 2005). Other examples of SMP include crosslinked poly(cyclooctene) and poly(lactic acid) and poly(vinylacetate) blends (Liu et al., 2002). The SMPs can be engineered, extruded as fibres, programmed, used as filament yarns or spun as fancy yarns in blends with other fibres. They can then be knitted and woven with interesting shape-changing effects (Chan et al., 2002). However, depending on the level of deformation, type of structure, material structure, and so on, SMPs may not fully recover upon re-heating to above the transformation temperature. Under constraints, as in the case in a woven or knitted textile, the shape recovery of the SMP fibres is restrained due to the low modulus of the material. The shape memory effect also reduces with blending of the SMP with other polymers before extrusion in order to improve mechanical properties of the extruded fibres. The development of shape memory effects in membranes and coating materials has also been investigated with interesting results. By imparting an SMP finish on a fabric, it is possible to create a new generation of “non-iron” garments, where the fabric can return to its original shape when heated[4]. In another example, the Japanese made DiAPLEX membrane capitalises on the shape memory behaviour of the polymer to increase the comfort of the wearer. The ultra-thin non-porous SMP membrane has the ability to open up its microstructure when the temperature increases, to allow heat and water vapour molecules to escape through the membrane (Stylios, 2004). When temperatures drop, the microstructure closes, restricting the passage of heat and vapour and acting as an insulating layer. This mechanism is shown in Figure 3. Owing to their processability, there is potential for SMPs to be formed or moulded into specific shapes, other than fibres, membranes and films. Using biomimetics, structures such as those present in pine cones or stomata can be re-created to mimic nature and change shape or form to adapt with changes in moisture and temperature conditions (Dawson, 1999). In the case of mimicking pine cones, for example, scales on the surface of a fabric can be made to open and close in response to relative humidity or heat. Such a system has been pioneered through the development of a fabric with spike-like features that adapt to changing temperatures and moisture vapour (Catchpole, 2004). Although the use of shape memory materials is not compulsory for the design and engineering of such structures, by their nature, they make ideal materials for use.
The use of shape memory materials in the clothing industry opens up new horizons not only for fashion designers, but also for high performance garment engineers. As pioneered by the likes of Corpo Nove, the Italian fashion house based in Florence, the materials can be used to create innovative effects on individualised and customised fashions (Clowes, 2002). Corpo Nove’s shape memory shirt incorporates SMAs to cause the sleeves to shorten when the temperature increases. In the high performance garment area, SMAs and SMPs have attracted interest for use in medical pressure garments and sportswear. Phase change materials Smart sweaters that can absorb, store and release heat as required in order to keep the wearer at an optimum temperature are being designed and engineered for commercial purposes[5]. The smart and dynamic responsive ability of the sweaters is brought by the presence of microencapsulated phase change materials (PCMs), which are latent heat-storage materials. The technology of PCMs relies on their change in state, generally from solid to liquid and back, but also from liquid and gaseous states, solid and gaseous states and even solid to solid states. When the temperature increases and reaches the melting point of the PCM, the melted PCM absorbs heat, inhibiting the flow of thermal energy through the fabric, and maintaining its temperature constant (Ying et al., 2004; Hartmann, 2004). When the external conditions and the PCM cools down and solidifies, the reverse occurs, and heat is released to keep the wearer warm. This phenomenon only occurs over a specific temperature or temperature range for any specific PCM. When the latent heat of the PCM is fully absorbed or released (i.e. when the material is fully melted or fully solidified and crystallised in the case of solid-liquid phase changes), the thermoregulating effect stops. The material can be effectively “recharged” by a source of heat or cold (Hartmann, 2004). However, if temperatures keep on increasing, the material may undergo thermally induced decomposition, isomerization or oxidation (Hartmann, 2004). PCMs include hydrated salts, paraffin waxes, fatty acids and eutectics of organic and inorganic compounds (Farid et al., 2004). The most important PCMs for textile and clothing use are linear chain hydrocarbons, which include n-hexadecane, n-heptadecane, n-octadecane, n-eicosane and n-heneicosane (Zhang, 2003). More examples of PCMs are given in Table I. Using a mixture of two or more of the PCMs, the temperature stabilising range can be adjusted to suit specific applications. PCMs were originally developed for space suits, but although the technology was not applied to space travel, the potential has been exploited in various other applications where thermal regulation is required. PCM have been used for interior textiles, particularly bedding, but also for outdoor wear. It has been found that the heating effect of PCM clothing upon changing from warm indoor air to cold outdoor air lasts approximately 12.5-15 min on average, depending on the PCM content and environmental conditions (Ghali et al., 2004; Shim et al., 2001). PCMs therefore reduce body heat loss under these conditions. In a reverse phenomenon, PCMs can release heat when temperature drops and the material solidifies. In this circumstance, unless the clothing structure is carefully engineered, heat can be released to the cold outer environment rather than to the body (Shim et al., 2001). The first phase change fibres were produced by filling or impregnating hollow fibres with phase change materials such as hydrated inorganic salts or polyethylene
Smart technologies
113
IJCST 18,2
Group
Examples
Hydrated inorganic salts
Calcium chloride hexahydrate, sodium sulphate decahydrate, sodium sulphate decahydrate Straight chain alkanes or paraffinic hydrocarbons, branched-chain alkanes, unsaturated hydrocarbons, halogenated hydrocarbons, alicyclic hydrocarbons Paraffin examples include octadecane, nonadecane, hexadecane, etc. Stearic anhydride 2, 2-dimethyl-1, 3-propanediol, 2-hydroxymethyl-2-methyl-1, 3,-propanediol, ethylene glycol, PEG, pentaerythritol, dipentaerythrital, pentaglycerine, tetramethylol ethane, neopentyl glycol, tetramethylol propane, monoaminopentaerythritol, diaminopentaerythritol, tris(hydroxymethyl)acetic acid Polyethylene, PEG, polypropylene, polypropylene glycol, polytetramethylene glycol and co-polymers Waxes, oils, fatty acids, fatty acid esters, dibasic esters, 1-halides, primary alcohols, aromatic compounds, ethylene carbonate
Hydrocarbons
114 Anhydrides Polyhydric alcohols
Polymers Table I. Examples of phase change materials
Other
Source: Hartmann (2004) and Zhang (2003)
glycol (PEG) (Vigo and Frost, 1982; Vigo and Frost, 1983). Non-hollow phase change fibres can be produced by composite fibre-spinning with a PCM core and textile polymer sheath, by spinning a mixture of a PCM and polymer, or by embedding microcapsules in an extruded polymer (Zhang, 2003). Coating with PCMs has also been investigated with good results. This can be done using, for example, PEG, polyhydric alcohols or a binder containing microcapsules. Encapsulating the thermoregulating material is normally done by interfacial polymerisation, creating microcapsules of 20-40 mm in diameter, with walls of less than 1 mm thick (Nelson, 2002). This geometry creates a large surface area for heat transfer, resulting in rapid responses (Pause, 2000). The microcapsules can be deposited on the surface of the textiles in a coating layer, or incorporated in the spinning dope of man-made fibres, or in the structure of foams. The effect of having the PCM embedded in the polymer is more permanent and the fabric handle and drape properties are not as affected as with the coating process. Depending on the PCM properties, its incorporation in solvent-spun fibres such as acrylic has been less problematic than incorporating in melt-spun fibres, where processing temperatures and pressures may induce PCM degradation. This has been addressed with the addition of stabilizers. The PCM formulations or microcapsules typically contain between 80 and 99 per cent of PCM, with the remainder being additional components, such as antioxidants and thermal stabilisers (Hartmann, 2004; Nelson, 2002). The former, e.g. phenolic antioxidants, prevents or retards degradation in the presence of oxygen at temperatures and pressures encountered during polymer processing (Hartmann, 2004). The latter, which may be organic substances comprising phosphorus or phosphonites, are added to prevent or retard decomposition or isomerization of the PCM during polymer melt processing (Hartmann, 2004). The percentage of PCM added influences the thermoregulating effect. The magnitude of the thermoregulating effect increases as the number of PCM layers increases in the clothing assembly (Shim et al., 2001). It has also been found that when more PCM is present in a fabric, the duration of the phase change lengthens
(Ghali et al., 2004). In other words, the thermoregulating effect lasts longer. However, the addition of PCM microcapsules in fibres, fabrics or other textile materials affects other physical properties of the end product. For example, weight and stiffness increase, whereas strength and elongation decrease (Shim et al., 2001). Chromatic materials Fabrics dyed, printed or finished with chromatic dyes are able to change colour with a change in environmental stimuli such as heat (thermochromism), light (photochromism), chemical reactions (chemichromism), moisture (solvation chromism), pH (ionochromism), pressure (pieorochromism) and electrical currents (electrochromism). This response, apart from being of potential aesthetic interest to the fashion or mass-market garment industry, can be used as a detection and response mechanism in high performance garments. For example, in the medical field, garments that can detect and warn of the presence of infections, bacteria or viruses or any change in the physiological functions of the wearer can assist in support, diagnosis and treatment of patients. In the fire-fighting sector, thermochromic dyes have been engineered to change the protective clothing to white under extreme temperatures in order to reflect the heat away from the body (Hibbert, 2001). Thermochromic dyes Thermochromic dyes, which are by far the most popular chromatic dyes used in the textile industry, come in two types: “leuco” dye types, which exhibit a single colour change with a molecular re-arrangement, and liquid crystal types, which have a spectrum of colour changes. The thermochromism of the liquid crystal system results from the selective reflection of light by the liquid crystal, the molecular arrangement of which changes with temperature[6]. In the case of chiral nematic liquid crystals, the colour changes with the pitch length of the helix. The visual effect is normally a continuous change through a spectrum of colours. In use, thermochromic dyes are often encapsulated into microcapsules, and applied to a garment like a pigment in a resin binder. Physiochemical and chemical processes have been developed to encapsulate photochromic and thermochromic systems. Interfacial polymerisation techniques involving urea or melamine formaldehyde systems have been well accepted, as they result in satisfactory shelf life and durability (Nelson, 2002). In many cases, the chromatic system used on novelty printed textiles such as ski wear and promotional T-shirts consist of three components – a colour former, an acidic catalyst (developer) and a non-polar co-solvent medium. The thermochromic effect is caused by the interaction between the colour former and the developer in a low-melting hydrophobic medium within the microcapsules (Oda, 2005; Christie, 2001). When the colour former and developer composite is heated to above the melting point, the interaction between the two results in a colour change (Figure 4). Upon cooling and solidification, the composite returns to its original form and colour. Spiropyran dyes are an example of a typical class of dyes that can form a coloured merocyanine species upon exposure to heat, and turn back to a colourless spiro form spontaneously or after exposure to specific conditions (Keum et al., 1999). In another mechanism, as used in the Hypercolore T-shirts, two dyes and a temperature-sensitive salt work in combination in a suitable solvent to create the
Smart technologies
115
IJCST 18,2
116
colour changing effect (Bide, 1992). The system works on the principle that one of the dyes is an electron-donating compound, and the other an electron-accepting compound. As the temperature increases, the salt molecules dissociate, and interfere with interaction between the two colorants, changing the colour appearance of the fabric. The effect is enhanced by the solvent, which melts above 248C. In essence, the system behaves like a mixture in the solid state, but form coloured complexes in the liquid state (Sekar, 1998). Ionic compounds exhibiting thermochromism (e.g. pyridinium N-phenol betaines) change colour by a disorientation effect of the molecules which increases with heat. The change in colour is caused by a lowering of the ground state energy of betaine by polar attraction to the solvent molecules (Sekar, 1998). By comparison, colour changes in azo dyes and in dimmers are, respectively, caused by a cis-trans isomerisation and by dissociation of the dimmer into free radicals (Sekar, 1998). Examples of thermochromic dyes are given in Table II. The colour change can be repeated several times, however, one of the downfalls of thermochromic dyes is their poor light and wash fastness, which causes the colour
Figure 4. Example of interaction between a colour former (a) and an acid catalyst (developer) at high temperature to create a coloured compound (b)
Thermochromic
Photochromic
Spyropyran dyes
Spyropyran dyes (substituted indoline spiropyran, spirobenzopyrans, spirooxazines, spiro(benzothiazoline pyrans), benzodithzole spiropyrans, spiro (adamentane benzpyran)s, spyropyran carboxylic acid) Azo dyes (azo disperse, cationic azo, thio-indigo dyes) Chromenes (benzo and naphtopyrans)
Azo dyes (p-amino azo benzene derivatives) Heterocyclic dyes (oxazine dyes, cyanine dyes, merocyanine dyes, formazons of the benzazole series) Aromatic amines and substituted hindered aromatics Ionic compounds (pyrdinium N-phenol betaines) Dimers (triphenylimidazole) Table II. Examples of thermochromic and photochromic dyes
Source: Sekar (1998)
Diarylethenes Stilbene dyes Triphenyl methane and phthalein dyes Xanthene dyes Heterocyclic dyes (cyanine dyes) Miscellaneous dyes (fulgides, fulgimides, betaine dyes, organo-mercury dyes)
change effect to be only temporary (Oda, 2005). Microencapsulated thermochromatic dyes have been reported to survive up to 20 washes; wash durability is even lower if high temperature or bleaches are used (Nelson, 2002). Photochromic dyes Some dyes from the Spiropyran class of dyes mentioned above also react to visible and visible light, undergoing a reversible photochemical ring opening to form the metastable coloured photomerocyanine species (Brown, 1971). In other words, the dyes exhibit photochromism, i.e. they change colour after activation in visible or invisible light. Spirooxazines, the nitrogen containing analogues of spiropyrans, are also known to have good colour change upon photo-irradiation and good light fatigue resistance as well as being easy to synthesise (Christie, 2001; Lee et al., 2004). On exposure to light, they undergo a ring opening to form a merocyanine structure. When the light source is removed, the closed-ring structure is thermally re-formed. Diarylethylene derivatives have also been shown to exhibit photochromism, but the compounds show high fatigue resistance (Chen et al., 2000)[7]. More examples are given in Table II. The colour change occurs as a chemical process whereby a compound undergoes a reversible change between two states that have different absorption spectra (i.e. different colours). The change in state is generally brought by either molecular structural changes due to cleavage of bonds, cis-trans rearrangement or tautomerism (Sekar, 1998). For example, in the case of spirobenzopyrans, irradiation of the colourless compound causes heterolytic cleavage of the carbon-oxygen bond, thus forming an opened-ring coloured species[7] (Figure 5). To date, photochromism has been mostly used for optical switching data and imaging systems, and applications in the clothing industry have been very limited. Most textile applications involve pigment printing of the photochromic compounds rather than dyeing. Photochromic pigmented polymers have also been produced by extruding melted polymers such as polypropylene mixed with photochromic particles. Fulgides have been the class of dyes most used for textile applications, due to their good resistance to thermal fading. Other chromatic effects Solvation chromism, where a colour is developed when the fabric is wet or in contact with specific solvents, has been explored for the personal hygiene industry and has been used in novelty textile accessories (handkerchiefs) (Hibbert, 2001). Electrochromism could also of interest to the clothing industry, as the colour is here developed by stimulation with an electric current. Other chromatic dyes can be potentially used in fashion and high performance garments, but due to limitations – costs, durability, applicability, etc. there has been no report of successful commercialisation so far.
Smart technologies
117
Figure 5. Photochromism through ring opening mechanism (spiroindolinobenzopyran) (a) colourless compound, (b) coloured cis-, (c) coloured trans- and (d) coloured ortho-quinoidal forms
IJCST 18,2
118
Figure 6. Schematic diagram of drug release through stimuli-responsive hydrogels or membranes (a) before activated swelling and (b) after swelling
Stimuli-responsive hydrogels and membranes Three-dimensional polymer networks that can respond to external stimuli such as pH changes, electric field, temperature, ionic strength or other chemicals have attracted interest in the medical area. By swelling in response to a change in the stimuli, the so-called hydrogels are able to release drugs or other chemicals when required, hence acting like an actuator for a smart medical garment (Figure 6). Temperature dependent swelling effects are closely related to the temperature dependence of polymer-water and polymer-polymer interactions (Lee and Kim, 2003). The degree of swelling in the hydrogels can increase or decrease with temperature changes, thus releasing chemicals or other materials when swollen. In the case of pH-dependence, the acidic or basic components in hydrogels lead to reversible swelling and deswelling because of the change in state from ionised to non-ionised and back, in response to pH (Lee and Kim, 2003). Electrically responsive hydrogels are normally made of polyelectrolytes and an insoluble but swellable polymer network carrying cations or anions. Some examples of stimuli-responsive hydrogels are given in Table III. Membranes with similar stimuli-responsive properties have also been investigated. One example is the grafting of acrylic acid or N-isopropylacrylamide onto porous polymer membranes using plasma and UV radiation techniques (Lee and Shim, 2003). The membranes were found to be pH and temperature responsive, suitable for drug delivery or intelligent separation materials, but also for sensing and modulating external chemical signals. Although still at an early stage of development with regards to applications in the clothing industry, it can be speculated that such technologies, if engineered correctly, can be applied in the sports and medical clothing industry, releasing chemicals as and when the body requires (pH and temperature dependent hydrogels), or when manually stimulated (electric-current sensitive hydrogels).
Temperature
External stimuli pH dependent
Poly(acrylamide-co-butyl-methacrylate) Copolymer of hydroxyethyl and polyacrylic acid methacrylate and methacrylic acid or maleic anhydride Poly(N-isopropylacrylamide) Poly(N-isopropylacrylamide-co-vinyl terminated poly(dimethylsiloxane)-co-Aac) Poly(vinyl alcohol) and polyacrylic acid Poly(vinyl alcohol) and polyacrylic acid
Electric current
Smart technologies
Poly(vinyl alcohol) and polyacrylic acid Mixture of vinyl monomer, hyaluronic acid and crosslinker (Sutani et al., 2001) Poly (N-isopropylacrylamide) (Kato et al., 1998)
Source: Lee and Kim (2003)
Smart wearable electronics The wearable electronic industry has recently attracted a lot of attention. Gap kids and wild planet have already commercialised the “Hoodio”, a hooded jacket with in-built FM radio and controls on the sleeve. Infineon and Rosner have come up with a 128 Mb MP3 version, again with controls positioned on the sleeve. However, this type of wearable electronic is simply clever addition of electronic components to increase the functionality of garments. As such, they do not fall within the definition of “smart” textiles, where the material should be able to “sense” and “respond” to external stimuli. The materials described in the previous sections are inherently “smart” in that they can sense, and respond to stimuli such as heat, UV, electrical currents, and so on. Garments can be made “smart” not only by using such materials strategically, but also by incorporating smart wearable electronics that can perform the sensing and responding activities. Four key elements have to be considered: flexible electrical and data conductivity, flexible sensors and actuators, wireless communication, and power supply. Conductive materials Conductive fibres, yarns, fabrics and stitching or embroidery threads are essential components for wearable electronic technologies. The key is the degree of electrical conductivity, which makes them pathways for carrying electronic information or energy for a range of functions. Originally developed for dispersing static electricity, conductive materials are now in demand for applications such as flexible sensors, electromagnetic interference shielding, dust- and germ-free clothing, data transfer in clothing, camouflage and stealth technologies for military applications. Conductivity in textiles can be imparted with the addition of carbon, steel, nickel or silver, in wire form, fibre form or micro and nano particulate forms. Carbon fibres and carbon-filled fibres have good conductivity, but due to their colour, have potential aesthetic problems. Metal fibres (Figure 7), with diameters ranging from 1 to 80 mm are made by a bundle-drawing process, or by a shaving process during which fibres are shaved off the edge of a thin metal sheet (Meoli and May-Plumlee, 2002). The high conductivity of metal fibres and wires, which can be incorporated in fabric structures, is offset by their weight, cost and the potential damage that they can do to textile machinery. Metallic and galvanic coatings also produce highly conductive fibres, but
119
Table III. Examples of stimuli-responsive hydrogels
IJCST 18,2
120
Figure 7. Metal fibres for conductive textiles (a) spun metal and metal/polymer blended yarns, (b) woven spun metal yarns and (c) non-woven metal fibre fabric
have limitations with adhesion and corrosion resistance and with the suitability of substrate, respectively. Metallic salt coatings produce limited conductivities and poor wash resistance. The coatings are applied through various techniques, including evaporative deposition, sputtering and electroless plating (Meoli and May-Plumlee, 2002). Conductive polymers as such are still an area under active development. Difficulties encountered for the processing of the polymer are mainly due to the insolubility and infusibility of the material, which are caused by the strong intermolecular interactions (Kim et al., 2004). The electrical conductivity of these polymers is known to be caused by their conjugated double bond chain structure. p-conjugated polymers such as polyaniline, polypyrrole, polythiophene, etc., are examples of conductive polymers. Amongst them, polyaniline (PANI), which has attracted a lot of attention because of its good environmental, thermal and chemical stability. Polypyrrole (Ppyr) has also been successfully developed as a coated material for conductive polyester, nylon and acrylics (Kuhn and Kimbrell, 1989) and an embedding material on cellulose textiles (Dall’Acqua et al., 2004). The conductivity of the Ppyr polymer has been suggested to be caused by electron spins, or by bipolarons, believed to be the charge-carrying species in the molecule. Conductive polymers have been solvent spun, solvent casted, melt-spun as blends with conventional polymers, and used as coating materials, or embedding particles for fibres, yarns and fabrics. Melt-spinning of conventional polymers such as polypropylene and polyethylene with dispersed conductive polymers in the feedstock, although being a cost-effective and simple solution, have been found to create difficulties, because of the lack of homogeneity of the extruded material (Kim et al., 2004). By contrast, coating and polymerisation of conductive polymers on fibre surfaces have been found to produce better results (Kim et al., 2004; Dall’Acqua et al., 2004). Durability of the added conductive layers can be an issue, which may be possibly partially solved by additional protective coatings. Conductive inks are alternatives for adding conductivity to specific areas of a fabric or garment. By adding conductive particles such as carbon, copper, silver, nickel and gold to conventional printing inks, conductive patterns can be directly printed on traditional fabrics. For example, electric circuitry can be printed on conventional fabrics, and printed areas can be subsequently used as switches or pressure pads for the activation of circuits. This technique is supported by recent advances in digital printing, but further work on pre- and post-treatments, ink performance, agitation of the ink reservoir for an equal distribution of the conductive particles, drying, etc. is required (Meoli and May-Plumlee, 2002).
Flexible sensors Smart garments that do not derive their “smartness” from inherently responsive materials such as shape memory, phase change or chromatic materials require added sensors to detect any physical stimulus and process them into electrical signals. The simplest wearable electronic garments consist of conventional rigid sensors incorporated in the garment structure, and connected to batteries and other devices through cleverly positioned wires. Sensors that can continuously measure and monitor various physiological functions such as body temperature, blood pressure, heart beat, perspiration, and so on can be attached to various parts of the garment and be wirelessly connected to a central monitoring unit for control and feedback (Stylios and Luo, 2003). Advances in sensor technology are now such that size can be significantly reduced for comfortable applications in the medical, military and emergency services such as fire-fighting and rescue services. With the advent of micro and nanotechnologies, the potential for “invisible” sensors exists, particularly in areas where the size of the sensing area is not of prime importance. Where contact surface area is necessary, flexible sensors provide a solution. Fabrics coated with conductive polymers such as polypyrroles have been found to have remarkable properties of strain and temperature sensing (De Rossi et al., 1999). These fabrics compare well with sensitive strain gauge materials and inorganic thermistors, with the added bonus of being flexible, wearable, and also exhibiting electromechanical actuation properties. Nevertheless, it has been found that fabrics coated with conductive polymers may suffer from variations in time of the sensor resistance, and high response times (Engin et al., 2005). Commercially available flexible pressure sensors are based on various mechanisms. For instance, elasto resistive composites that reduce their electrical resistance when compressed can be used in combination with conductive fabrics[8]. A multi-layer structure consisting of two conductive fabrics separated by a meshed non-conductive one can also be used as a pressure sensor (Engin et al., 2005). The system here works by contact between the two conductive layers, when the material is pressed at points where there are holes in the non-conductive mesh. Another system consists of a three-layer structure, with a top conductive layer, a middle partially conductive layer that conducts locally when compressed, and a low resistance fabric with tracks to measure voltage[9]. When pressed, the flexible sensor can detect where the force is, and how much pressure has been applied, making it suitable for control interactive interfaces (fabric switching and sensing) or hazard sensing. Flexible fabric-based moisture sensors have also been developed as multi-layer structures consisting of a top cover layer that receives the moisture, a soaker layer to transmit the moisture to the sensor layer, a sensor layer made of a conductive fibre matrix that allows measurement of the change in resistance, and a final waterproof barrier layer[10]. Although developed for incontinence products in the healthcare market and for moisture detection in built environments, the technology is also applicable high performance sportswear or protective clothing. Fabric damage sensing can be monitored through plastic optical fibres, which can detect broken paths in the fabric and provide information about the degree of damage and location (Lind et al., 1997). This technology is applicable for protective clothing, providing information on bullet penetration, chemical, thermal, physical and biological attacks. The information can then be used swiftly to provide medical treatment in the event of injury.
Smart technologies
121
IJCST 18,2
122
Textile electrodes for the measurement of electrocardiograms have been made out of knitted stainless steel fibres, and incorporated into a belt to be worn around the thorax (Hertleer et al., 2004). The so-called “Textrodes” are in direct and close contact with the body. Tests have shown that they provide accurate signals, as compared with conventional electrodes, despite the presence of additional noise. The potential applications for this type of technology include monitoring of patients in clinical conditions and healthcare, of sportsmen during intense and extreme physical activities, of fire-fighters and soldiers in action, and so on. Smart textiles rely not only on a sensing device, but also on an actuating one, which will transform electric signals into a physical phenomenon, be it a simple display, a change in properties, colour or a shape memory effect, which have been discussed in previous sections. Electroactive polymer actuators for integration into fabrics and garments are being developed. Examples include conductive polymers, dielectric elastomers and carbon nanotubes (Engin et al., 2005). It has been shown that such materials are able to change properties, exert high forces and/or change in volume when ionic species are forced to penetrate inside their network by electro diffusion. For example, the dimensions and electrical conductivity of conductive polymers change significantly with a change in ionic doping in the polymer. In the case of carbon nanotubes, it is predicted that their superior mechanical and electrical properties will lead to superior actuating performance. As these flexible materials can “respond” by translating electrical signals into physical ones, they complement the flexible sensors required for smart garments. Wireless technology A link between various components of a smart garment system is essential for wearable electronics. This communication may be required between various sensors and actuators incorporated in the garment. Using traditional wire-based networks restrict the comfort of the wearer. Optical or conductive fibres used within the fabric structure are able to address this issue. The former has the advantage of being insensitive to electromagnetic radiation, and of not generating heat during data transfer. Conductive fibres benefit from being able to conduct electrical signals, unlike optical ones, where the signals have to be converted at some point. Communication outwith the garment, for example, between the garment and a central control unit, requires wireless technologies assisted by the presence of a flexible antenna on the textile material. The presence of wires will not only decrease the comfort of the wearer, but also restrict movement significantly. Wireless devices such as mobile phones and pagers are easily available and widely used. These devices use radio frequency local area networks (RF LANs), which unfortunately have a limited radio frequency spectrum. Personal area networks (PAN) have received significant interest for some types of smart clothing. Unlike LAN, which serves multiple users wirelessly, PAN is centred around one person, enabling the interconnection of information technology devices typically within a 10 m range, i.e. the range of an individual. This type of network only needs only a low power supply, which is a prerequisite for a portable and wearable system. As such, PAN is ideal for wearable technologies where digital communication is required with nearby computers, or between individuals. The concept of using PAN for digital information exchange between individuals is interesting. Using the electrical conductivity of the human body
or of people’s clothing as a data network, it is possible to transfer data from one person to the other via an intra-body contact such as a handshake, or via an intra-clothing contact[11]. Bluetooth technology within a PAN is being used for smart garments to wirelessly communicate, through radio frequency, to another device within a reasonable distance (10 m). The technology is affordable, and the devices can find each other and communicate with each other automatically, through a very small built-in radio module. Infrared technology is able to transmit data wirelessly on a “one-to-one” basis. However, the devices have to be aligned, which may not always be possible in the case of a wearable smart garment and a fixed computer. By contrast, Bluetooth enables communication even through walls, in any direction. Concerns, however, have been raised because of this (Hum, 2001), and the implications of radio frequency fields being emitted into the body are under debate. In response to these concerns, fabric area networks (FAN) have been investigated (Hum, 2001). FAN enables the radio frequency fields to be restricted to the fabric surface only, by enabling communications through nearfield inductive coupling of radio frequency fields. These radio frequency fields decay in strength with distance. The nature of the inductive coupling also localises the zones of communication to overlapping regions of the radio frequency antennas, thus preventing broadcast in any direction, as in Bluetooth technology. A multi-layer FAN prototype consisting of a network of fabric radio frequency links serving as wireless connectivity on the clothing and as portals to the various layers of the structure has been proposed and is claimed to be emission-safe, low-cost and easy to maintain (Hum, 2001). A front-end facilitates the interface of other peripherals to the FAN infrastructure.
Smart technologies
123
Alternative power sources Power sources for electronic components of a smart garment can be in the form of AC/DC charge interface, lithium ion polymer battery and/or solar cell interface. Power management can involve either or all of the three (or other power sources), as shown in Figure 8. A major disadvantage with charging devices is the necessity to be “wired”, which may not be suitable for some applications. A disadvantage with batteries is that they have only a limited lifespan, after which a new battery (or recharging) is required. These issues have led researchers to look into alternatives for traditional battery power. An area that has attracted a lot of interest is solar energy acquired through photovoltaic (PV) technology. PV technology is based on the energy that photons from sunlight can transfer to electrons in atoms of the PV cell. Typically, two types of technologies are used:
Figure 8. Power sources and power management in a smart garment
IJCST 18,2
124
crystalline silicon, or thin film materials. The former, which is the most common solar cell material for commercial application, suffers from being heavy, fragile, rigid, and costly to ship and handle. Thin film technology involves sequentially depositing thin layers of different materials into a very thin structure, enabling the production of flexible structures, which can be applied to textile end products. Commercially available flexible PV materials work on thin film technology, using amorphous silicon (A-Si) or Copper Indium Galium Diselenide (CIGS). A-Si PV thin films of 1 mm thick can absorb 90 per cent of usable solar energy, whereas CIGS can absorb 99 per cent of the energy. Recently CIGS thin film technology has been used in the development of a solar-powered jacket (Scottevest Inc., 2004)[12]. The detachable solar panels consist of thin film PV CIGS placed onto a thin stainless steel substrate. They convert energy from sunlight into a hidden battery pack, which in turn can be used to charge electronic devices. Charging time is reported to be in two to three hours in direct sunlight. Silicon-based thin films are also under investigation for use in woven military uniforms and other materials[13]. The substrate in this case is a thin (0.05 mm) flexible polymeric film, on which amorphous silicon is thinly layered. The sandwich-like structure is coated with a transparent top conductor to encapsulate and protect the material. Solar cells have also been developed using textile materials as substrates. One method is to deposit silicon from a gaseous compound as a nanocrystaline thin film on a woven or nonwoven textile substrate[14]. The technique has been used on polyester and glass textiles. Another method is to use PV polymer fibres directly to weave or knit textile fabrics[15]. One approach for this technology involves nanotechnology, whereby a dye is injected into titanium dioxide[16]. When applied to a flexible material, the dye absorbs energy from light; the energy travels through the titanium dioxide and a series of electrodes, and is converted into electrical energy. Using this approach, PV fibres can be produced, spun, woven, or knitted, or made into non-woven textiles. Titanium dioxide nanofibres produced by methods such as electrospinning have also been suggested to have potential for PV applications (Madhugiri et al., 2004). Another approach involves adapting the multi-layer thin film technology for cylindrical materials such as fibres (Graham-Rowe, 2001). PV fibres have been produced in this method by depositing a sandwich structure on the surface. As with thin film technology, the sandwich structure consists of amorphous silicon, sandwiched between a top electron-rich layer, and a bottom electron-poor layer. Photons hitting the surface layer displace the electrons in the top layer, which then flow through the middle and bottom layer and is converted to an electrical current. Conclusion The basic building blocks are already in place in the field of smart textiles and clothing. As progress in science and engineering research advances, and as the gap between designers and scientists narrows, the area of smart clothing is likely to keep on expanding for the foreseeable future. Growth is predicted to occur in two distinct directions: performance-driven smart clothing, such as continuous monitoring smart garments for patient rehabilitation or military use, and fashion-driven smart clothing, with more emphasis on the aesthetic and “effect” appeal. There are challenges that have to be addressed. For smart technologies to be used in the clothing industry, aesthetic properties such as the handle, drape and comfort of the fabric and garment
have to be acceptable. Weight, durability and launderability are always issues that are raised. The cost factor is also a primary challenge, which can limit the market size. However, a drop in prices has already been observed in a number of areas, including shape memory materials and electronic components. Finally, the successful and elegant integration of and interrelation between the various technologies is a new challenge for designers and scientists. Already, significant progress has been achieved in integrating technologies such as flexible sensors, conductive materials, solar power and wearable electronics. Further integration of technologies is likely to be achievable within this decade. The area of responsive stimulation of polymer networks is already receiving much attention for the development of the next generation of smart medical products and applications, including medical and clinical garments and clothing. Notes 1. Smart Fabrics and Interactive Textiles: Global Market Opportunity Assessment. 2003, Venture Development Corporation. 2. US Army Backs Electrotextiles, (2003), in Future Materials. 3. E-quipped for Battle, in Future Materials, (2005). 4. Scientists Unveil Shape-Memory Fabrics, (2004), in www.just-style.com. 2004. 5. Outlast, Bernette Spin Sweater with a Technical Twist, (2004), in www.just-style.com. 6. Chromic Materials. 7. Phenomena Involving a Reversible Colour Change, (2005), Royal Society of Chemists. 8. SOFTswitch Electronic Fabrics. 9. Eleksen, ElekTex Sensing. 10. Eleksen, Moisture Sensing. 11. Personal Area Network. 12. Solar Powered Style, in Future Materials. 2004. 13. Solar Fabrics Could be Used in Military Uniforms, (2004), available at: www.just-style.com. 14. Textiles Make Solar Cells that are Flexible and Lightweight, (2002), Technical Textiles International, 11(10), 5-6. 15. Konarka’s Nanotech Program to Make Photovoltaic Fabric with Ecole Polytechnique, (2005), Fibre 2 Fashion. 16. Konarka, Technology. References Bide, M. (1992), “Hot shirts”, ChemMatters, pp. 8-11. Brown, G.H. (1971), Photochromism, Wiley, New York, NY. Catchpole, H. (2004), “Pine cone inspired fabric to keep you cool”, A.S. Online. Chan, Y.Y.F. and Stylios, G.K. (2003), “Designing aesthetic attributes with shape memory alloy for woven interior textiles”, paper presented at INTEDEC 2003, Fibrous Assemblies at the Design and Engineering Interface, Research Institute for Flexible Materials, Edinburgh. Chan, Y.Y.F. et al. (2002), “The concept of aesthetic intelligence of textile fabrics and their application for interior and apparel”, paper presented at IFFTI 2002, Hong Kong.
Smart technologies
125
IJCST 18,2
126
Chen, Q. et al., (2000), “Optical and time evolution properties of a photochromic thin film”, Journal of Luminescence, Vol. 87-89, pp. 776-8. Christie, R.M. (2001), Colour Chemistry, Royal Society of Chemists, Cambridge. Clowes, S. (2002), “Smart shirt roll up its sleeves”, B. News. Dall’Acqua, L. et al., (2004), “Performances and properties of intrinsic conductive cellulose-polypyrrole textiles”, Synthetic Metals, Vol. 146, pp. 213-21. Dawson, C. (1999), “Science of extracting ideas for smart materials from nature”, Chemical Fibers International, Vol. 49 No. 5, pp. 394-7. De Rossi, D., Della Santa, A. and Mazzoldi, A. (1999), “Dressware: wearable hardware”, Materials Science and Engineering: C, Vol. 7, pp. 31-5. Engin, M. et al., (2005), “Recent developments and trends in biomedical sensors”, Measurement, Vol. 37, pp. 173-88. Farid, M.M. et al., (2004), “A review on phase change energy storage: materials and applications”, Energy Conservation and Management, Vol. 45, pp. 1597-615. Fitzpatrick, M. (2004), “Wired wear: intelligent clothing gets smarter”, available at: www. just-style.com (accessed August 2004). Gall, K. et al., (2004), “Internal stress storage in shape memory polymer nanocomposites”, Applied Physics Letter, Vol. 85 No. 2, pp. 290-2. Ghali, K. et al., (2004), “Experimental and numerical investigation of the effect of phase change materials on clothing during periodic ventilation”, Textile Research Journal, Vol. 74 No. 3, pp. 205-14. Graham-Rowe, D. (2001), “Photovoltaic fabrics combine cloth with solar cells”, New Scientist. Hartmann, M.H. (2004), Stable Phase Change Materials for Use in Temperature Regulating Fibers, Fabrics and Textiles, Outlast Technologies Inc., Boulder, CO. Hertleer, C. et al. (2004), “Towards a smart suit”, Wearable Electronic and Smart Textiles, Research Institute for Flexible Materials, Leeds. Hibbert, R. (2001), “Textile innovation traditional, modern and smart textiles”, Line. Hum, A.P.J. (2001), “Fabric area network – a new wireless communications infrastructure to enable ubiquitous networking and sensing on intelligent clothing”, Computer Networks, Vol. 35, pp. 391-9. Kato, N., Morito, T. and Takahashi, F. (1998), “An energy-saving method of heating for a chemomechanical poly(N-isopropylacrylamide) gel with Joule’s heat”, Materials Science and Engineering: C, Vol. 6 No. 1, pp. 27-31. Keum, S-R. et al., (1999), “Symmetric and unsymmetric indolinobenzospiropyran dimers: synthesis and characterization”, Dyes and Pigments, Vol. 41, pp. 41-7. Kim, B. et al., (2004), “Electrical and morphological properties of PP and PET conductive polymer fibers”, Synthetic Metals, Vol. 146, pp. 167-74. Kuhn, H.S. and Kimbrell, W.C.J. (1989), Method for Making Electrically Conductive Textile Materials, Milliken Research Corporation, Clemson, SC. Lane, R. and Craig, B. (2003), “Materials that sense and respond: an introduction to smart materials”, The AMPTIAC Quarterly, Vol. 7 No. 2, pp. 9-14. Lendlein, A. (2003), “Tailor-made intelligent polymers for biomedical applications”, in Tao, X. (Ed.), Smart Fibres, Fabrics and Clothing, Woodhead Publishing Ltd, Cambridge, pp. 278-90.
Lee, Y.M. and Kim, S.Y. (2003), “Stimuli-responsive interpenetrating polymer network hydrogels composed of poly(vinyl alcohol) and poly(acrylic acid)”, in Tao, X. (Ed.), Smart Fibres, Fabrics and Clothing, Woodhead Publishing Ltd, Cambridge, pp. 93-108. Lee, Y.M. and Shim, J.K. (2003), “Permeation control through stimuli-responsive polymer membrane prepared by plasma and radiation grafting techniques”, in Tao, X. (Ed.), Smart Fibres, Fabrics and Clothing, Woodhead Publishing Ltd, Cambridge, pp. 109-23. Lee, C-C., Wang, J-C. and Hu, A.T. (2004), “Microwave-assisted synthesis of photochromic spirooxazine dyes under solvent-free condition”, Materials Letters, Vol. 58, pp. 535-8. Lind, E.J. et al. (1997), “A sensate liner for personal monitoring applications”, paper presented at 1st International Symposium on Wearable Computers, Cambridge. Liu, C. et al. (2002), “Tailored shape memory polymers: not all SMPs are created equal”, paper presented at First World Congress on Biomimetics, Albuberque, NM. McWilliams, A. (2004), GB-309 Smart and Interactive Textiles, Business Communications Company Inc., Norwalk, CT. Madhugiri, S. et al., (2004), “Electrospun mesoporous titanium dioxide fibres”, Micoporous and Mesoporous Materials, Vol. 69, pp. 77-83. Meoli, D. and May-Plumlee, T. (2002), “Interactive electronic textile development”, Journal of Textile and Apparel, Technology and Management, Vol. 2 No. 2. Nelson, G. (2002), “Application of microencapsulation in textiles”, International Journal of Pharmaceutics, Vol. 242, pp. 55-62. Oda, H. (2005), “New developments in the stabilization of leuco dyes: effect of UV absorbers containing an amphoteric counter-ion moiety on the light fastness of color formers”, Dyes and Pigments, Vol. 66, pp. 103-8. Pause, B. (2000), “Measuring the thermal barrier function of phase change materials in textiles”, Technical Textiles International, Vol. 9 No. 3, pp. 20-1. Scottevest Inc. (2004), Global Solar Prepare Solar Jacket for Holidays, Scottevest Inc., Ketchum, ID. Sekar, N. (1998), “Photochromic and thermochromic dyes and their application. Part I”, Colourage, Vol. 45 No. 5, pp. 45-52. Shim, H., McCullough, E.A. and Jones, B.W. (2001), “Using phase change materials in clothing”, Textile Research Journal, Vol. 71 No. 6, pp. 495-502. DTI Stylios, G.K. (2004), “Interactive smart textiles: innovation and collaboration in Japan and South Korea”, Global Watch Mission Report, Heriot-Watt University. Stylios, G.K. and Luo, L. (2003), “The concept of interactive, wireless, smart fabrics for textiles and clothing”, paper presented at 4th International Conference Innovation and Modelling of Clothing Engineering Processes, IMCEP 2003, Maribor. Sutani, K., Kaetsu, I. and Uchida, K. (2001), “The synthesis and the electric-responsiveness of hydrogels entrapping natural polyelectrolyte”, Radiation Physics and Chemistry, Vol. 61 No. 1, pp. 49-54. Tao, X. (2001), Smart Fibres, Fabrics and Clothing, CRC Woodhead Publishing Ltd, Cambridge. Vigo, T.L. and Frost, C.M. (1982), “Temperature-sensitive hollow fibers containing phase change salts”, Textile Research Journal, Vol. 55 No. 10, pp. 633-7. Vigo, T.L. and Frost, C.M. (1983), “Temperature-adaptable hollow fibers containing polyethylene glycols”, Journal of Coated Fabrics, Vol. 12 No. 4, pp. 243-52. Winchester, R.C.C. and Stylios, G.K. (2003), “Designing knitted apparel by engineering the attributes of shape memory alloy”, International Journal of Clothing Science and Technology, Vol. 15 No. 5, pp. 359-66.
Smart technologies
127
IJCST 18,2
128
Yang, B., Huang, W.M., Li, C. and Chor, J.H. (2005), “Effects of moisture on the glass transition temperature of polyurethane shape memory polymer filled with nano-carbon powder”, European Polymer Journal, Vol. 41 No. 5, pp. 1123-8. Ying, B-A. et al., (2004), “Assessing the performance of textiles incorporating phase change materials”, Polymer Testing, Vol. 23, pp. 541-9. Zhang, X. (2003), “Heat-storage and thermo-regulated textiles and clothing”, in Tao, X. (Ed.), Smart Fibres, Fabrics and Clothing, Woodhead Publishing Ltd, Cambridge, pp. 34-57.
To purchase reprints of this article please e-mail:
[email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Discussing reflecting model of yarn
Discussing reflecting model of yarn
Jihong Liu and Itsuo Yamaura Faculty of Textile Science and Technology, Shinshu University, Ueda, Japan, and
129
Weidong Gao School of Textile and Garment, Southern Yangtze University, Wuxi, China
Received June 2004 Revised December 2004 Accepted December 2004
Abstract Purpose – This paper deals with the reflecting rays of yarn. Design/methodology/approach – The modeling, assuming that the fibers are arranged around the surface of elliptic yarn and reflecting rays of yarn are consisted of reflecting rays of fibers, is established using mathematical method. We can get a distributional curve of reflecting rays by this method. Findings – It was found that because resolution was an important parameter in measurement equipment, the result of modeling must be filtered. It gives fundamental theory for selecting resolution and we also provide other useful value for selecting equipment of image processing. Resolution is an important parameter for measurement equipment. We have provided the minimum resolution for yarn. When we do image processing for yarn, we can get correct information of yarn by image processing with the minimum resolution and over. Research limitations/implications – The result using different measurement equipment does not show the same result, therefore, the model must be filtered according to resolution. Orginality/value – Although previous researches have used the reflecting property of yarn, little work that analyzed the reflecting model of yarn and the relationship between resolution and reflecting property has been achieved. We present a method of analyzing reflection of yarn. Keywords Modelling, Fibric testing, Yarn, Image processing Paper type Research paper
1. Introduction Reflecting property of the yarn is reflecting foundation of fabric. In computer vision that means to get the appropriate representation of the meaningful objects in the image with specific properties of interest. Rovandi, etc. have used FFT method to analyze the property of fabric appearance. Lawrence, etc. have built the reflecting modeling of fibers. Motamedian, etc. have discussed the influence of dye. Although they have used reflecting property of yarn, all the above techniques considered geometric properties of the fibers and fabrics or tested by experiments, there was little work that analyzed the reflecting model of yarn and the relationship between resolution and reflecting property. We present a method of analyzing reflection of yarn. As a general model, the research assume that the fibers are arranged around the surface of elliptic yarn and reflecting rays of yarn are consisted of reflecting rays from fibers surface, therefore, we can calculate reflecting rays of yarn using mathematical method. In the model, retro-reflection of fibers is omitted. This method is basis of analyzing reflecting rays of fabric. The remainder of this paper is organized as follows. In Chapter 2, we will establish the reflecting model of yarn by the distribution and reflecting rays of the fibers.
International Journal of Clothing Science and Technology Vol. 18 No. 2, 2006 pp. 129-141 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610645775
IJCST 18,2
130
Experiments for yarns in fabric are illustrated in Chapter 3. Finally we will conclude in Chapter 4. In these chapters we will use Matlab 6.5 as software for calculating the result and use scanner of Artex to get the image for experiments. The resolution of scanner can reach to 8,000 dpi. 2. The reflecting model of yarn 2.1 The distribution of reflecting rays for fiber First, reflecting model of fiber is analyzed as follows. We will analyze reflecting rays on the surface of a single fiber with radius of Rf. Assume that there is a cylindrical fiber, which is located on a 3D plane defined by a global Cartesian coordinate system. Global coordinates XYZ is shown in Figure 1. Axis of a fiber is perpendicularly to XOY coordinate plane, and the coordinate of center of the fiber section is (Xf, Yf). A reflecting plane is perpendicularly to the axis of Y, which can be expressed as y ¼ H. Incident ray is parallel to y-axis and s is x-coordinate of incident rays in XOY plane. Let us assume that x is x-coordinate of intersection of reflecting ray and reflecting plane. The reason for these choices is that the supposed path of the rays is same as the path used scanner in fact. Incident rays, which are intercepted, are along the half circumference. The orientation of incident and reflecting rays corresponds to that used in the experimental work. From Figure 1, we can get: 8 s ¼ Rf cos u þ X f > > < x ¼ Rf cos u þ ðH 2 Y f 2 Rf sin uÞ tgðp 2 2uÞ þ X f ð1Þ > > : ¼ Rf cos u þ Rf sin utg2u 2 ðH 2 Y f Þtg 2u þ X f where u, as shown in Figure 1, which takes the ccw from the x-axis to intersection. Dot “M” is an intersection of incident ray and fiber’s surface. Some of reflecting rays
Figure 1.
that come from fiber cannot be received by reflecting plane. It is obvious that the range of u is: p 3p ,u, 4 4 Assume that the intensity vs angle of the reflecting rays is r. It is now possible to calculate separate intensity vs angle diagrams for incident rays that are reflected from parameter equation. From equation (1): 8 ds > > > < du ¼ 2Rf sin u ð2Þ dx > 2 2 > ¼ 2R sin u þ R cos u tg 2 u þ 2R sin u sec 2 u 2 2ðH 2 Y Þ sec 2 u > f f f f : du from equation (2): 8 ds 2Rf sin u >
: x ¼ Rf cos u þ Rf sin u tg 2u 2 ðH 2 Y f Þtg2u þ X f
Discussing reflecting model of yarn 131
ð3Þ
Assume that (Xf, Yf) is (230, 230) and Rf is 2, the result of the surface reflecting rays of the fibers is shown in Figure 2. From Figure 2, it is found that the reflection of fiber’s center is bigger than the other part of fiber. The curve for the cylindrical fiber in Figure 2 shows that there are some scattering at fiber axis between 220 and 240 and that is bigger than the radius of fiber. 2.2 The distribution of the yarn reflection Second, reflecting model of yarn is analyzed as following. As a general model for yarn, assume that the cross section of yarn is ellipse so that it can be used for yarn and fabric. Polar coordinates equation of yarn’s surface, as shown in Figure 3, is: R2y ¼
A2y B2y A2y sin 2 w þ B2y cos 2 w
ð4Þ
where Ay and By are the radius of the fiber’s long- and short-axis, respectively.
Figure 2.
IJCST 18,2
132
Figure 3.
We can get the result of radial coordinate for f ¼ b and f ¼ b þ g: R2y ¼
Ry 0 2 ¼
A2y B2y A2y sin 2 b þ B2y cos 2 b
A2y B2y A2y sin 2 ðb þ gÞ þ B2y cos 2 ðb þ gÞ
ð5Þ
ð6Þ
where b is polar angle, and g is the angle of two lines from the center of yarn to the fiber and the next fiber. And when f ¼ b the polar coordination of center of fiber is: (
X f ¼ Ry cos b þ X y Y f ¼ Ry sin b þ Y y
ð7Þ
where (Xy, Yy) denotes the coordination of the center of yarn section. Because the radius of fiber is very small than that of yarn, the distance of center of two neighbor fibers equal to the arc of yarn of two points. The next dormant equation about g can be get: ð4R2f 2 R2y Þ 2 Ry 0 2 þ 2Ry Ry 0 cos g ¼ 0
ð8Þ
Using numerical value method and the above equation, we can get the result of g for f ¼ b: Assume that (Xy, Yy) is (200, 200) and Ay is 10 and By is 8, the result of the surface reflecting rays of each fiber on the surface of yarn is shown in Figure 4. From the figure, it was found that the reflecting rays of fibers in the center of yarn are bigger than the other fibers.
Discussing reflecting model of yarn 133
Figure 4.
2.3 The distribution of the yarn reflection using numerical solution and considering cut off angle As the above intensity of each fiber’s reflection can be calculated, and there is no condition for the axis of incident rays and reflecting rays in fiber axis. But in fact reflection range of each fiber in yarn is different because each fiber will be influenced by its neighbor fibers. The incident rays or reflecting rays will be shelter from its neighbor fibers. We define cut-off angle a for each fiber in yarn. If the situation angle of fiber in yarn is b , 908; then reflecting range is 458 , u , a: Figures 5 and 6 show the size of a when b , 908: Figures 6 and 7 show the different situations for different size of fiber for b , 908: When:
Figure 5.
IJCST 18,2
134
Figure 6.
Figure 7.
Ry cos b . Ry cosðb þ gÞ þ Rf it is shown in Figure 6. By Figures 5 and 6, the a is calculated as following: a ¼ Ry sinðb þ gÞ 2 Ry sin b 2 Rf sin a
ð9Þ
b ¼ Ry cos b 2 Ry cosðb þ gÞ þ Rf cos a
ð10Þ
2a 2 when:
3 Rf a p þ arcsin pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi þ arctg ¼ 0 2 2 2 b a þb
ð11Þ
Ry cos b , Ry cosðb þ gÞ þ Rf it is shown in Figure 7. The coordinate O1 of fiber center is Ry cos(b, Ry sin b) and the coordinate O2 of fiber center is ðRy cosðb þ gÞ; Ry sinðb þ gÞÞ: By Figures 5 and 7, a is calculated as following:
a ¼ arctg
sinðb þ gÞ 2 sin b 1 þ p 2 arcsin 2 cosðb þ gÞ 2 cos b
ð12Þ
Discussing reflecting model of yarn 135
If the polar angle of fiber in yarn is b . 908; therefore, reflecting range is a , u , 1358: Figures 8 and 9 show the size of a when b . 908: Figures 9 and 10 show the different situations of different size of fiber when b . 908: When: 2Ry cosðb 2 gÞ þ Rf , 2Ry cos b it is shown in Figure 9. By Figures 8 and 9, a can be calculated as following: a ¼ Ry sinðb 2 gÞ 2 Ry sin b 2 Rf sin a
ð13Þ
b ¼ 2Ry cos b þ Ry cosðb 2 gÞ 2 Rf cos a
ð14Þ
p Rf a þ arcsin pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi þ arctg ¼ 0 2 2 b 2 a þb
ð15Þ
22a þ when:
Figure 8.
IJCST 18,2
136
Figure 9.
Figure 10.
2Ry cosðb 2 gÞ þ Rf . 2Ry cos b it is shown in Figure 10. The coordinate O1 of fiber center is (Ry cos b, Ry sin b) and the coordinate O2 of fiber center is (Ry cos(b 2 g), Ry sin(b 2 g)). By Figures 8 and 10, a can be calculated as following:
a ¼ arctg
sinðb 2 gÞ 2 sin b 1 þ arcsin 2 cosðb 2 gÞ 2 cos b
ð16Þ
Using numerical value method and equation above, we can get the result of a when f ¼ b: Considering the cut-off angle and assume (Xy, Yy) is (200, 200) and Ay is 10 and By is 8, Rf ¼ 2; the cut-off angle of each fiber according the order of b is 77, 97, 113, 130, 50 and 718. The result of the surface reflecting rays of each fiber on the surface of yarn is shown in Figure 11.
Discussing reflecting model of yarn 137
Figure 11.
2.4 The distribution of the fiber reflecting using numerical solution The distribution of the fiber reflection can be calculated with parameter equation: 8 ds 2Rf sin u > : fðuÞ ¼ Rf cos u þ Rf sin u tg 2u 2 ðH 2 Y f Þtg 2u þ X f 2 x ¼ 0 From equation (17), we can get the dormant equation:
rfi ¼ rfi ðxÞ ¼ 0
ð18Þ
Using numerical solution, from equation we can get r of different x. 2.5 The distribution of the yarn reflection using numerical solution Then, we use the numerical solution way to calculate the distribution of the yarn’s reflection. We add the number of each fiber in yarn and get their mean value. After that, we can get the distributing curve of yarn. Hence the yarn reflection is calculated with: n X ry ¼ rb ðxÞ ð19Þ i¼1
The result of the surface reflecting rays of yarn is shown in Figure 12. 3. Experimental methods and results 3.1 Equipment We use scanner of Artex to take the image of fabric. Resolution used in experiment is 5,080 dpi. 3.2 The diameter of familiar yarn Yarn count means 1,000 m long yarn weight in official regain, the thicker the yarn, the bigger the count is, to cotton yarn, yarn diameter d and count Ntex has relations as follows: pffiffiffiffiffiffiffiffiffi ð20Þ d ¼ 0:037 N tex ðmmÞ or:
IJCST 18,2
138
Figure 12.
2 d N tex ¼ ¼ 730:5 d2 ðtexÞ ð21Þ 0:037 Because of the existence of hairiness, projection of hairiness is included in yarn’s whole projection, considering filoplume coefficient of 1.08, yarn’s diameter d and projection diameter dy have relations given by: ð22Þ d y ¼ 1:08 d Hence we can get that relation of yarn’s count and yarn’s projection diameter dy by means of image processing, as follows: dy 2 ¼ 626:3dy ðtexÞ ð23Þ N tex ¼ 730:5 1:08 Therefore, we can calculate yarn’s dy from yarn’s fineness Ntex. In Table I, we have displayed the relationship of the count of familiar yarn and their dy, which is the projection diameter of yarn from image processing. According to Table I, the diameter of normal yarn is 0.1-0.4 mm, so when the resolution of scanner is 5,080 dpi, the number of dots will be 20-80 dots and when the resolution of scanner is 508 dpi, the number of dots will be 2-8 dots. When we want to get the information of yarn, we must get 5 dots for one yarn, which express the curve of reflecting rays. It is very important to select appropriate resolution according to the count of yarn. We advise the minimum resolution for different yarns. If the resolution of scanner is smaller than that shown in Table II, the result of image can only get some point of one yarn and we cannot get the correct information of yarn.
Table I.
Ne (s) Nt (tex) dy (mm)
Table II.
Ne Resolution
80 7.3 0.108
80 1,176
60 9.7 0.125
50 11.7 0.137
60 1,021
40 14.5 0.152
50 930
40 835
32 18.2 0.171
32 745
30 19.5 0.177
30 720
21 27.8 0.211
21 604
16 36.4 0.241
10 58.3 0.305
16 528
10 416
3.3 The especial situation for yarn reflection When we calculated the curve of reflecting rays, we used 100 dots for one yarn. Because the scanner cannot get so many dots for one yarn, the results are the average of many dots. Therefore, we must filter the result of the model. The result shown in Figure 13. In the figure, there are four lines, the solid line is the source line, and the “ þ ” line is the result of using 3 dots filter that means that resolution is change to 1/3 of the source, and the dashed line is the result of using 10 dots filter that means that resolution is change to 1/10 of the source, and the dash-dot line is the result of using 20 dots filter that means that resolution is change to 1/20 of the source. It is obvious the curves change into smooth curve by filter. If the number of filter dot is increased enough, the curve of yarn will be change to be line. The size of filter must be adapted to the resolution of scanner, e.g. if we select resolution as Table II, we must use 20 dots filter.
Discussing reflecting model of yarn 139
3.4 Experiment for yarn In this experiment, we made some yarns arrange on the surface of scanner and get the image of yarns with the count of 32s. Hence the diameter of yarn in projection will be 0.171 mm. The image, which is scanned with 5,080 dpi resolution, is shown in Figure 14. On this condition, the number of dots for yarn will be 34 dots. The dots’ brightness of yarns is calculated by: L ¼ 0:3R þ 0:59G þ 0:11B where L is the dots’ brightness of yarn, and R, G, B is tricolor. We calculate the result of only one line, which is under black line. The result is shown in Figure 15. There are 14 yarns in the image, and the image of one of the yarn has one corresponding wave crest. The result proves for predigesting yarns model.
Figure 13.
Figure 14.
IJCST 18,2
140
Figure 15.
Figure 16.
From Figure 15, it is found that there are some changes at the wave trough. That is the influence of reflection of filoplume of yarn. But when the resolution is on 51 dpi, the result is shown in Figure 16. From the figure, it is obvious that we cannot estimate the situation of yarn. 4. Conclusion . The modeling, assume that the fibers are arranged around the surface of elliptic yarn and reflecting rays of yarn are consisted of reflecting rays of fibers, is established by using mathematical method. We can get a curve of reflecting rays by this method. . Resolution is an important parameter for measurement equipment. We have provided the minimum resolution for yarn. When we do image processing for yarn, we can get correct information of yarn by image processing with the minimum resolution and over. . The result using different measurement equipment does not show the same result. Therefore, the model must be filtered according to resolution.
Further reading Inagaki, K. and Akagawa, N. (1969), “A discussion for reflecting properties of cylindrical fiber model”, J. Textile Mach. Soc., Vol. 25 No. 5, pp. 207-14. Lawrence, E.H. and Lester, P.B. (1963), “A study of the effect of cotton fiber structure on luster”, Textile Res. J., Vol. 33, pp. 205-17. Lewis, J., Dorrity, Z.F. and Carr, W.W. (2003), “Camera-based measurement of textile card web density”, Textile Res. J., Vol. 73, pp. 69-73. Motamedian, F. and Arthur, D.B. (2003), “Modeling the influence of dye distribution on the perceived color depth of a filament array”, Textile Res. J., Vol. 73, pp. 124-31. Ohta, K., Nonaka, Y., Lshii, T. and Okada, M. (1996), “Automatic analyzing of a fabric design with frequency components, part 1: automatic analyzing of a wearing design”, J. Textile Mach. Soc., Vol. 49, pp. 61-8. Rovandi, S.A.H. and Toriumi, K. (1995), “Fourier transform analysis of plain woven fabric appearance”, Textile Res. J., Vol. 65, pp. 678-83. Wood, E.J. (1990), “Applying Fourier and associated transforms to pattern characterization in textiles”, Textile Res. J., Vol. 60, pp. 212-20. Xu, B.G. (1996), “Identifying fabric structures with fast Fourier transform techniques”, Textile Res. J., Vol. 66, pp. 496-506. Zhang, H.Q., Gao, W.D. and Qiu, H. (2003), “Retro-reflection of round fibers”, Textile Res. J., Vol. 73, pp. 965-70.
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
Discussing reflecting model of yarn 141
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Digitizing and measuring of the human body for the clothing industry Ph. Guerlain and B. Durand Laboratoire de Physique et Me´canique Textiles, Ecole Nationale Supe´rieure de L’industrie Textile de Mulhouse, Mulhouse, France
Digitizing and measuring of the human body 151 Received October 2005 Accepted January 2006
Abstract Purpose – The paper aims to present several methods that were developed, evaluated and finally used as part of a 3D electronic tailor especially adapted to the clothing industry. Design/methodology/approach – An experimental top down approach taking care of building a system adapted to the constraints of the textile industry was used. The research was to the rapidity, the robustness and the comfort of the future system during the development cycle. Findings – A robust and efficient method for digitizing a human body in 3D that is usable for the measurement process with duration and accuracy adapted to the domain of textile industry. Research limitations/implications – The research is bound to many constraints. Some are expressed by the customers of the electronic tailor, some depend on the manufacturing process of the clothes and of course, some depend on economic requirements. Of course, the system is not fixed because it must be adapted and improved to be able to follow the evolution of the manufacturing process. Practical implications – This research permitted the creation of a marketed product improved for a few years by successfully measuring thousands of people. Originality/value – The paper demonstrates the usefulness of choosing a digitizing process. It shows the importance of keeping in mind the whole digitizing process for making the mesh generation and the measurements taken. The resulting mannequin proves that the process works well. Keywords Measuring instruments, Body regions, Clothing, Data analysis Paper type Research paper
1. Introduction Clothing sciences distinguish two main sorts of clothes: the ready-to-wear clothes and the made-to-measure clothes. Today, the clothes manufacturing process is largely automatized in particular for the operations of pattern design (Petrak and Rogale, 2001), pattern cutting and conveyer systems. In opposite, the measuring operations are still extremely frequently hand made even they are the starting point of the fabrication process for made-to-measure and of the distribution process for ready-to-wear. Nevertheless, the measuring operation has a big amount of disadvantages. First, it is a very long, tedious and anti-hygienic. Second, its accuracy depends on the habits and tiredness (or lassitude) of the operator. Third, this operation is expensive because of the needed human resource and because of the big amount of clothes return due to unsuitable sizes. A fast and automatic measuring system reduces or cancels most of these annoyances.
International Journal of Clothing Science and Technology Vol. 18 No. 3, 2006 pp. 151-165 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610657925
IJCST 18,3
152
The need of such an automatic and fast measuring system intensifies because of the emergence of new tendencies like mass-customization that corresponds to the possibility of personalizing a big amount of clothes for a low cost. To develop an automatic measuring system that is efficient for clothing industry it is essential to take into account the exigencies and to the constraints of the textile industry: . the existing measuring norms; . the clothes manufacturing or distribution process; and . the constraints expressed by the customers. 2. Taking measurements for the clothing industry The French norm NF 13402-1 (AFNOR G03-001) describes the manual measuring for clothing industry and particularly: . the different postures of the person to be measured; . the measuring points to be used; and . the way the measurements have to be taken. One of the most important instructions given by the norm is that the person has to be measured in the same attitude and with the same underwear than those used while wearing its new clothes. The new clothes are then best-fitting for those particular conditions. The measuring operation is mostly made while the customer stands erected (Figure 1) like it is frequently made in this domain, because a large part of the body surface is visible, and because the major measurements can be taken in that easiest position (Guerlain, 2002; Herve´, 1999; Brunsman et al., 1996). Nevertheless, even a majority of basis points like the waist (front view) or the breast (profile view) that are used by the norm are visually identifiable on the body surface, some reference points are localized on the skeleton and require being palpated. For examples, we can quote: the top extremity of the sternum used to position the neck perimeter, the acromion used to calculate the arm length and the apophysis of the wrist that are used to define the wrist perimeter.
Figure 1. Major measurements can be taken standing up
Once these landmarks are identified, it is relatively easy to take the measurements that are lengths taken from one point to one other following or not the body shape. Because the best-fitting of a garment is extremely subjective and depends on the customer wishes, it is necessary to have the possibility of manually place/move the measurement points. These manipulations may take a lot of time, and then, some of the benefits of using an automatic and rapid acquisition system are potentially lost. Of course, the big advantages of working with a fixed and hygienic acquired shape still remain. 3. The manufacturing or distribution process If the aim of the measuring system is to distribute ready-to-wear clothes, the measurements are used to select the best fitting garment size corresponding to the measurements. To do this, the measuring system must be completed with size prediction software working with size charts that store the geometrical characteristics of the clothes for each known sizes. The difficulty in that case is to be sure of the precision of the manufacturing process so that the size charts used to select the size effectively correspond to the distributed clothes. Ready-to-wear clothes correspond perfectly for mass clothing and the correct size is traditionally selected after a rapid measuring operation possibly followed by successive tryings on. Made-to-measure clothes can be manufactured according to the taken measurements by grading flat patterns or by modifying a 3D pattern with a 3D CAD system like it is described in Cho et al. (2003). In each case, specific rules have to be followed depending on the taken measurements, depending of the design of the final garment, depending of the mechanicals behaviour of the material (Provot, 1995; Louchet et al., 1995; Hutchinson, 1995) and possibly depending of specific alterations for disabled people, for example, Neuez (2000) and Tarfaoui and Akesbi (2001). Of course, made-to-measure clothes need more accurate measurements that are suitable to the manufacturing process and to the customer wishes concerning the best fitting of the garment. There is a particular context we will call partial made-to-measure. This kind of clothes are manufactured with a pattern selected like for ready-to-wear and deformed with special algorithms like those used for made-to-measure clothes. In that case, the size prediction software and a pattern design software are both required and the problems are, of course, cumulative. Whatever process is used to supply clientele with clothes, the best measuring system is to have a virtual 3D mannequin of the client available to take the measurements. This mannequin helps taken the measurements and allow the client to visually define the design of the clothes he will buy. In any case, compromises have to be accepted to respect at the same time the measuring norms and the constraints related to the chosen 3D body digitization process. For example, points that are normally palpated will be detected on the 3D digitized shape to assume there are no movements of the body during the measuring process. Of course, in this case, some inaccuracies may be induced because of muscular and fat volumes that cover the skeleton. 4. Choosing the digitizing process To obtain a marketable three-dimensional human body acquisition system, it is essential not to be mistaken while establishing the digitizing method. In order not to be
Digitizing and measuring of the human body 153
IJCST 18,3
154
mistaken, it is necessary to take into account the constraints related to the environment and the clientele. Environmental constraints are related to the system use. Especially, the digitization has not to be done in complete darkness and the process must be the less sensitive to ambient light as possible to enable the system being used in shops. Moreover, a considerable advantage is the minimal dimension and the mobility of the acquisition system. Clientele constraints concern essentially the duration of the whole measuring process. This duration has to be the shortest as possible particularly because of moving problems (Brunsman et al., 1996). The comfort of the customer is another legitimate reason too that implies a spacious system with ambient light and non-contacts. Clientele is very often afraid by the risk of being submitted to harmful radiation. Finally, of course, the cost must be the lowest as possible. To respect the constraints explained in the previous chapter concerning the absence of contact and of radiation, we decided to use a photo/video-based digitizing process without laser. 5. 2D measuring system Historically, the first system we tried consisted of photographing the client to be measured following the principle of the negatoscop. Two photographs were taken: one in front of the person, the others looking at the profile of the person. The edges of the body were extracted from the photographs and the measurements were taken on those edges. The Figure 2 shows two typical measurements that can be taken on the edges: the arm length and the height. This system was very simple but not very convenient. First, the measurements were altered by the posture of the person because the “pixel size” depended on the distance of the observed point to the camera. Second, some reference points taken on one edge needed to be connected to the other edge. One typical sample concerned the chest that can be located on the profile view, but must be measured on both profile and front view. Another big problem is the time needed to change the posture and the fact that the postures are not strictly the same. On the other hand, the acquisition during was only two snapshots long.
Figure 2. Typical measurements that can be taken on the edges
6. 2.5D measuring system The second system we tried was called 2.5D because it was a conjunction of 2D localization and 3D measurement. It consisted in inflating/deflating a generic mannequin according to 2D characteristic measurements taken on two images one from face and one from profile. The mannequin was deformed on the position where the 2D measurements where taken and the final 3D measurements where then taken on the deformed mannequin like it is shown in Figure 3. The acquisition duration still stand two snapshots long and the accuracy of the measurements was improved. But the problems of landmarks localization became more complicated, because it involved a 3D mannequin in conjunction with the 2D edges. Moreover, the accuracy varied according to the physiognomy of the photographed person. The more the morphology of the generic mannequin was different from the morphology of the person to be measured, the less the accuracy of the measurements was acceptable.
Digitizing and measuring of the human body 155
Figure 3. 3D measurements obtained with a 3D mannequin deformed according 2D measurements
IJCST 18,3
156
To go on in this way, it was necessary to classify the morphology of the measured people in order to select the appropriate generic mannequin. Moreover, even this method furnished a perfectly closed mannequin this mannequin was not aesthetically lifelike. So we preferred to digitize the whole 3D shape of the client, so that we can take measurements directly on the digitized shape without using any mannequin. 7. 3D measuring system In all the previous methods, the camera lost the depth information of the photographed objects while the photographs were taken. Because we wanted to keep a video process, we needed to set-up a video system that can recover the depth information. It exists four main possibilities to recover the depth information of a 3D object photographed with cameras to: (1) couple several cameras (typically two for making stereovision); (2) change the characteristics of the camera used (typically changing the focus); (3) move the camera (like a scanner); and (4) project a pattern on the object (a squares grid or fringes, for example). The making use of some of these methods is very delicate in the particular context of the digitization of a human body. It is typically the case of the stereovision methods that needs to find primitives on the human body to correlate the images (Horain, 1984; Vezien and Gagalowicz, 1991; Tarel, 1996). Indeed, it is extremely difficult to extract enough primitives on the human body to correlate them in the different taken images. The number of calculated points is not sufficient to reconstruct a complete 3D mannequin. Finally, specific methods like modifying the focus of the camera are limited for our usage and do not present a very good accuracy (Simon et al., 1991). So, among the really marketable methods, it is still possible to use those based on the projection of a pattern using one or multiple cameras. We tested stereovision but the very complex shape of the human body implies the use of multiple points of view to cover the major body surface. Despite of the number of cameras, some areas still stand inaccessible (armpits, crotch and all folds particularly for obese subjects). We compared the use of our cameras in stereovision (Herve´, 1999) and in monovision, and we concluded that inaccessible areas are more important with stereovision than with monovision. Then, in order to avoid a too big amount of cameras, we favoured the principle of monovision. After numerous trials, we established that two single views can be sufficient to offer a large coverage of the area to be digitized: one looking at the face, the other looking at the back of the person (Guerlain, 2002; Herve´, 1999). Of course, it is still possible to increase the quantity of cameras to ensure a good local reconstruction for some particular needs. Concerning the projected pattern, we first tried the use of a single pattern that permits an extremely fast acquisition (as fast as one snapshot) but that also implies two major problems. First, this method sometimes failed in uneven areas like under the breasts or the buttocks even the use of specific and complex home made algorithms (Figure 4). These identification failures lead to identified pattern defects and then breakages on the surfaces finally meshed.
Digitizing and measuring of the human body 157
Figure 4. Failure in fringe identification: one fringe seems to be split
Second, it is important that each element of the projected pattern is distinct and identifiable in the acquired images. Knowing that one identified element only permits the calculation of one 3D point, it is easy to understand that the biggest the elements of the pattern are, the less 3D points will be calculated. Moreover, the position of the elements of the pattern has to be determined in the image. This localization implies inaccuracy that is amplified by the 3D calculation. Figure 5 shows our first results obtained with the projection of a coloured grid (Guerlain, 2002; Herve´, 1999). It seems to be interesting to densify the projected pattern to increase the number of 3D acquired point. It is, of course, possible but respecting the physical limit imposed by
Figure 5. Surfaces acquired with a stereoscopic 3D reconstruction coupled to the projection of a coloured pattern
IJCST 18,3
158
the Shannon Nyquist theorem concerning the sampling systems. In our case, the sampler is the camera and the sampling step is the pixel size. According to the theorem, the projected pattern must present a period in the image that is more than 2 pixels to be identifiable. In practice, we determined that the observed period must not be less than 6 pixels and finally, the digitized 3D surface is not very dense (Figure 5). For avoiding these problems, of identification and localization, we decided to use a phase shifting method that required the projection of a fringes pattern (Bouhifd, 1998; De Groot, 1997). We added the projection of a binary code that separately identified each fringe of the pattern (Guerlain, 2002). With this method, each observed pixel can be uniquely identified without any doubt and without any localisation inaccuracy. Moreover, the number of calculable 3D points directly corresponds to the number of pixels present on the CCD sensor of the camera. 8. 3D points digitization For digitization in particular, we attempted to reconstruct by identification with a reference calibration alone but it was very difficult to explicitly calibrate our big working volume (2.3 m3). So, we privileged to establish the mathematical model of the cameras, even the use of such models implies a more delicate calibration that identify the optical behaviour of the cameras and of the objectives. The cameras are often assimilated to the well-known pinhole model shown in Figure 6 and applied, for example, in Ayache (1989). The resolution process of this model depends on the whished quality of the extrinsic parameters (Zhang, 1998; Gleicher and Witkin, 1992). The objective introduces a lot of defaults in the captured images. Some of them concern the focus of the taken images (depth of field, spherical aberrations . . .) and some others imply geometrical modification of the acquired images (field curvature, distortion). Tsaı¨ (1986) proposed one well-known mathematical model for correcting the distortion, which is normally the most disturbing default. We established that this model does not perfectly correspond to the behaviour of our objectives. Then, we preferred to design a specific optical device that allows us to establish a matrix assuming the correspondence between the 2D position of an original point and its 2D corrected position. Anyway the knowledge of the behaviour of the couple camera and objective has a big advantage due to the fact that it is more versatile especially for meshing the
Figure 6. The pinhole model of the camera
surfaces, for merging them and even for taking measurements on the reconstructed mannequin. Once, the optical defaults of the acquired images are corrected, the 3D coordinates of each point jointly seen by a camera, and its associated pattern projector can be calculated according the principle of triangulation (Figure 7). Thereby some points belonging to the digitization environment are calculated too and must be imperatively rejected. A posterior filtering of 3D points is possible in particular using the fiducial volume of calibration or applying a statistical analysis of the “quality” of the point. However, after experiments, we preferred a preliminary filtering based on the 2D points in the images which is possible because of the use of cameras. This is made by extracting the edge of the body in the taken photographs and by using this edge as a rejection mask during the 3D calculation of the image points.
Digitizing and measuring of the human body 159
9. Meshing the different views Once the points seen by the cameras are digitized, the surfaces of the body have to be meshed. We tried several triangulation methods based on heuristics or statistics and which require some criteria to be defined and respected (Bern and Eppstein, 1992; Lagarde et al., 2005). These methods were bound to fail by the extremely variable density of points on the digitized body. In fact, the human body morphology associated to the process of digitization supply a lot of points that frequently involve the creation of unsuitable meshes because: . two very close points are not necessarily joined (around crotch and armpits, for example); . two distant points are often joined (non observable areas that have to be closed like the sides, for example); and . two points that have to be joined are sometimes located on heavy slopes (neck/chin, underchest, . . .).
Figure 7. Triangulation with one camera and one projector
IJCST 18,3
160
Figure 8. One result obtained with the sculptor algorithm applied on the point cloud
A first algorithm so-called “sculptor” has been tried with an unenthusiastic success (Herve´, 1999; Dieval et al., 2001). The principle of this algorithm was to shift a sphere which size was judiciously determined accordingly to the resolution of the acquired point cloud. That sphere carved the convex envelop of the acquired volume layer-by-layer like a sculptor does revealing the surface corresponding to the point cloud. This algorithm worked well for naturally convex shapes (Figure 8), but it was slow and very sensitive to density variation in important slopes and above all, it failed when gaps were too big on the acquired surface. One important conclusion was that 3D information alone is not sufficient in our case to assume an automatic, robust and quick meshing process. While digitizing with a camera, it is easy to dispose of information about the organization of the points that is helpful for meshing the surface. In fact, it is enough to benefit from the natural order of the pixels of the camera used to do the acquisition. If two points are neighbours on the camera CCD they can be joined in the meshed surface if they correspond to the same projected pattern element (compatible fringe number). Taking care of keeping intact these relationships between image coordinates and three-dimensional coordinates resulting of the digitization, the meshing process can be done without using complex algorithms by judiciously taking advantage of the natural order of the points in the image. Acquired points are then naturally organized in a table for which the two entries are the fringe number and the image abscissa (if fringes are horizontal). This table contains the calculated ordinates in the image and the three-dimensional characteristics of the points and has, at the outside, a dimension equal to the image dimension. In Figure 9, some points are not determined. This means the points have not been 3D reconstructed in this image position because they have not been associated to a fringe number, or because the 3D calculation has failed. In all cases, they are not part of the surface to be reconstructed. These points could, for example, be located near the armpits or on the sides of the bust very near the edges. When a little group of points is missing in the middle of the meshed surface, it is conceivable to interpolate it with its reconstructed neighbours nevertheless it is not very interesting for the further use of the acquired surfaces.
Digitizing and measuring of the human body 161
Figure 9. Fringes before, during and after meshing
IJCST 18,3
162
Meshing the set of points consists of scanning the fringes from the first until the penultimate and then, for each fringe, it consists of scanning the columns from the first until penultimate. Like it is shown in Figure 9, the presence of a few neighbours has to be checked for each observed point (point 1) in the: . next column on the same fringe (point 2); . next column on the next fringe (point 3); and . same column on the next fringe (point 4). A very simple and quick case study determines how many meshes can be constructed and which ones if: . points 1,2,3 and 4 exist, a quadrangular mesh is composed with those points; . three out of the four points exist, a triangular mesh is composed; and . less than three points are available, it is not possible the make a mesh. Breakages are easily identified by evaluating the ratio distance2D/distance3D of two neighbour points. The final meshed surface can be locally completed and smoothed by evaluating the local value with an adapted 3D convolution kernel. A similar approach is shown in Karbacher et al. (2000), for example. We checked that this smoothing is efficient and does not deteriorate significantly the measurements taken on the digitized body surface. 10. Meshing the final mannequin In order to get a closed body, it is possible to use a correctly chosen mannequin and to deform it (Gurzki et al., 2001; Seo and Thalmann, 2004). This method is fully justified in virtual reality, but it is less interesting and too expensive in terms of resources within the context of the rapid human body measurement. We preferred to reconstruct a mannequin by ourselves using only the digitized surfaces. Whatever method is used to close the mannequin, the first step consists in distinguishing the different members of this body. At the minimum, legs, arms and bust have to be identified to avoid difficulties when meshing the gap in the junction areas (typically in the neighbourhood of armpits). Even if members can be identified in 3D (Ju et al., 2000), we have chosen to use the 2D edges of the body associated to the 2D/3D meshes for determining the kind of each point on the surface. This segmentation method is simple because the relationship 2D/3D is conserved during the whole meshing process (Figure 10).
Figure 10. Segmentation of members on surfaces using segmented edges
The segmentation makes the closing greatly facilitated because the job is done working separately on the different members of the body contrarily to the process presented in Boissonat and Geiger (1992), for example. The virtual mannequin is created by closing the members using NURBS (non-uniform-rational-B-splines) surfaces interpolation and the separately meshed members are ultimately joined using the neighbourhood relationships that exist in the initially acquired surfaces (Figure 11). Of course, it is no use making a complete merged mannequin if the only objective is to have an available acquisition suitable for taking standard measurements. In this case, a local closing into the cross-section plane can be enough (Peter, 1991; Guerlain, 2002), but the closing is then very sensitive on the edges of the cut (because of textile wrinkles, or because of digitization inaccuracy).
Digitizing and measuring of the human body 163
11. Conclusion The electronic tailor is the first chain link of the automatic attribution/fabrication of clothes and must respect the constraints involved in that domain. Among the numerous possible digitizing processes, we estimated that photo/video processes were the most adapted to the constraints of the textile industry in terms of security, comfort and rapidity. We started using a 2D measuring system and improved it progressively to obtain a full 3D system. This system does not forget the digitization method and moreover take advantage of that knowledge for filtering the points, meshing the surfaces, and closing the mannequin. For having a better coverage of the body surface, it is possible to increasing the number of acquisition heads. In this case, the mathematical model of the
Figure 11. Bust and members closed
IJCST 18,3
164
cameras and the duality 2D/3D kept during the whole treatment of the acquired points are useful again to merge the surfaces extracted from the different views. Now, our electronic tailor digitizes and measures a human body faster than 30 s for a digitized 3D mannequin that is composed of 300,000 usable points. It was successfully and comfortably tested on thousands of people. This big amount of measured people helps to continuously improve the system and to certify statistically that the measurements extracted are more precise and repeatable than those taken by a tailor. Anyway, this precision is easily enough comparing to the ease kept while dimensioning the pattern of the garments and comparing to the acceptability of error levels studied in Buxton et al. (2000). References Ayache, N. (1989), Vision Ste´re´oscopique et Perception Multisensorielle, InterEditions, Paris. Bern, M. and Eppstein, D. (1992), Mesh Generation and Optimal Triangulation, Xerox Corp., Palo Alto, CA, available at: www1.ics.uci.edu/ , eppstein/pubs/BerEpp-CEG-95.pdf Boissonat, J.D. and Geiger, B. (1992), “Three dimensional reconstruction of complex shapes based on the Delaunay triangulation”, rapport de Recherches de l’INRIA No. 1697. Bouhifd, M. (1998), “Conception d’un capteur interfe´rome´trique et sa caracte´ristique par imagerie nume´rique”, thesis, Universite´ L. Pasteur, Strasbourg. Brunsman, M., Daanen, H. and Files, P. (1996), “Earthquake in anthropometry: the view from the epicentre”, CSERIAC Gateway, Vol. 7 No. 2. Buxton, B., Dekker, L., Douros, I. and Vassilev, T. (2000), “Reconstruction and interpretation of 3D whole body surface images”, Proceedings of Scanning 2000, Paris. Cho, Y., Park, H., Takatera, M. and Kamijo, M. (2003), “Pattern remaking system of dress shirt using 3D shape measurement”, paper presented at the 6th Asian Design Conference. De Groot, P. (1997), “101-frames algorithm for phase shifting interferometry”, Europto, Preprint 3098-33, available at: www.zygo.com/papers/proc_3098_283.pdf Dieval, F., Mathieu, D., Herve´, K. and Durand, B. (2001), “Voluminal reconstruction of the bodies applied to the cloth trade”, International Journal of Clothing Science and Technology, Vol. 13 Nos 3/4. Gleicher, M. and Witkin, A. (1992), “Through-the-lens camera control”, Proceedings SIGGRAPH’92, pp. 331-40. Guerlain, Ph. (2002), “Contribution a` la me´trologie automatique tridimensionnelle du corps humain”, thesis, Universite´ de Haute-Alsace, Mulhouse. Gurzki, T., Hinderer, H. and Rotter, U. (2001), “A platform for fashion shopping with individualized avatars and personalized customer consulting”, Proceedings of the World Congress on Mass Customization and Personalization, Hong Kong. Herve´, K. (1999), “Contribution a` la me´trologie du corps humain pour le dimensionnement des veˆtements”, thesis, Universite´ de Haute-Alsace, Mulhouse. Horain, P. (1984), “Vision par ordinateur: extraction de primitives dans des images tridimensionnelles”, thesis, Institut National Polytechnique de Grenoble, Grenoble. Hutchinson, D. (1995), Adaptative Refinement for Mass/Spring Simulations, INRIA, Rocquencourt. Ju, X., Werghi, N. and Siebert, J.P. (2000), “Automatic segmentation of 3D human body scans”, Proceedings of International Conference on Computer Graphics and Imaging.
Karbacher, S., Seeger, S. and Ha¨usler, G. (2000), “A non-linear subdivision scheme for triangle meshes”, Proceedings of Vision, Modeling and Visualization 2000, pp. 163-70. Lagarde, J.M., Devy, M., Moreno, L., Lacroix, P., Le Coutaller, P. and Briot, M. (2005), “Projet body scan: mode´lisation corporelle par profilome´trie”, paper presented at the 14e`me Congre`s Francophone AFRIF-AFIA de Reconnaissance des Formes & Intelligence Artificielle (RFIA’2004), Toulouse,Vol. 2, pp. 883-92. Louchet, J., Provot, X. and Crochemore, D. (1995), Evolutionary Identification of Cloth Animation Models, ENSTA/INRIA, Rocquencourt. Neuez, G. (2000), Range Camera Imaging with Application to Human Body Measurements, Chalmers University of Technology, Go¨teborg. Peter, C. (1991), “Etude et re´alisation d’un appareil d’acquisition automatique de se´ries de contours tridimensionnels du patient: aide a` la radiothe´rapie et a` la chirurgie de reconstruction mammaire en cance´rologie”, thesis, Institut National Polytechnique de Lorraine, Hague. Petrak, S. and Rogale, D. (2001), “Methods of automatic computerised cutting pattern construction”, International Journal of Clothing Science and Technology, Vol. 13 Nos 3/4. Provot, X. (1995), Deformation Constraints in a Mass Spring Model to Describe Rigid Cloth Behaviour, INRIA, Rocquencourt. Simon, T., Heit, B. and Bremont, J. (1991), Appre´ciation de la Profondeur Depuis des Images Nettes et Floues en Vision 3D Passive, CRAN-LEA Universite´ de Nancy I. Seo, H. and Thalmann, N.M. (2004), “An example-based approach to human body manipulation”, Graphical Models, Vol. 66, available at: www.miralab.unige.ch/papers/24.pdf Tarel, J.P. (1996), “Reconstruction global et robuste de facettes 3D”, Rapport de recherche de l’INRIA No. 2813, Rocquencourt. Tarfaoui, M. and Akesbi, S. (2001), “Methods numerical study of the mechanical behaviour of textile structures”, International Journal of Clothing Science and Technology, Vol. 13 Nos 3/4. Tsaı¨, R.Y. (1986), “An efficient and accurate camera calibration technique for 3D-machine vision”, IEEE Proceedings International Conference on Computer Vision and Pattern Recognition, pp. 364-74. Vezien, J.M. and Gagalowicz, A. (1991), “Reconstruction 3D base´e sur une analyse en re´gion d’une paire d’images ste´re´oscopiques”, INRIA, Rocquencourt. Zhang, Z. (1998), “A flexible new technique for camera calibration”, available at: http://research. microsoft.com/ , zhang/Papers/TR98-71.pdf Further reading Carrere, C., Isstook, C., Little, T., Hong, H. and Plumlee, T. (2000), “Automated garment development from body scan data”, National Textile Center Annual Report I00-S15. Istook, C.L. and Hwang, S.J. (2001), “3D body scanning systems with application to the apparel industry”, Journal of Fashion Marketing & Management, Vol. 5, pp. 120-32. Corresponding author Ph. Guerlain can be contacted at: [email protected] To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
Digitizing and measuring of the human body 165
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
IJCST 18,3
Body scanning of dynamic posture Liu Chi and Richard Kennon
166
Textiles Unit, School of Materials, The University of Manchester, Manchester, UK
Received April 2005 Accepted December 2005
Abstract Purpose – Aims to check the validity of measurements of dynamic postures recorded by a body scanner. Design/methodology/approach – Measurements between various anatomical landmarks have been taken both manually and using a 3D body scanner so that the validity of the measurements might be assessed when dynamic postures are adopted. Mechanical measurements of changes in the body surface dimensions have been compared with figures produced by a body scanner for both the standard natural position and for five dynamic postures, which must be accommodated when designing high-performance garments. Findings – Although the 3D body scanner collects data almost instantaneously and without physical contact with the target surface, the readings taken in respect of dynamic poses showed significant variations from manually-taken measurements, with discrepancies as large as 6.8 cm over a 16 cm distance. Research limitations/implications – The research has only been carried out on a very limited number of subjects. However, significant differences between manual and automatic body measurements are clearly demonstrated. Practical implications – The research showed that as there are as yet no universally-accepted conventions for 3D scanner measurements, the results appear to be optimised for the natural anatomical position. Body-scanners are not well-suited to taking measurements of dynamic postures expected in sporting activities. Originality/value – Measurements of anthropometric landmarks for high-performance activities have not previously been assessed, and these results usefully indicate the limitations of current 3D scanning technology. Keywords Body regions, Measurement Paper type Research paper
International Journal of Clothing Science and Technology Vol. 18 No. 3, 2006 pp. 166-178 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610657934
Introduction The last decade of the twentieth century saw considerable developments in the science of anthropometry. The 3D body scanner was developed and is currently capable of taking a number of different anthropometric measurements from the human body, and it can accumulate very large quantities of information during each of its assessments. Compared with traditional manual methods of measurement, the taking of readings by 3D body scanner is fast and discreet. It can collect data almost instantaneously without mechanically contacting the target surface. Hence, such technology goes a long way towards the elimination of the greatest impediments to anthropometric surveying: the reproducibility of the process and the time necessary to collect the data accurately. Once created, the image files can be accessed repeatedly to extract various types of information. Most modern scanners utilise laser light reflection or projected silhouette images to capture x, y, and z data points from the surface of the human body
(Istook and Hwang, 2001; Staples et al., 1994). Once the data have been acquired, they are processed to form a 3D point cloud. This raw information is then processed, filtered, and compressed to generate reproducible data from which critical anthropometric measurements can be extracted. This scanning technology has given the apparel industry the capability of printing clothing patterns for an individual, thus revolutionising the cut, make and trim process, and making possible the delivery to a consumer of a bespoke tailored garment without the need for trial fittings (Heyd, 2003a, b, c). It has been reported (Simmons and Istook, 2003) that there is currently a lack of consistency in respect of the anthropometric measurements produced by 3D scanners based on a number of different measuring technologies. Whilst any one type of system or standard posture may produce reliable results, significant variation appears to occur because of the way in which each individual type of system captures specific body measurements. Until the measurements recorded by each data-capture process can be standardised, the clothing industry will not derive the maximum benefit from its introduction (Simmons and Istook, 2003). In order to check the validity of measurements of dynamic postures recorded by a 3D body scanner, changes to body surface dimensions have been investigated for the standard natural position and for five dynamic postures. Traditional anthropometric landmarks have been measured manually and have been compared with output from a 3D body scanner. The Vitus 3D body scanner uses laser light to capture the surface position of objects placed within its operating space. The machine takes 85 body measurements in 15 seconds and saves them on its computer following analysis of the raw data using the associated ScanWorX software package. Methodology Freedom of movement of the human body is inextricably linked with garment pattern design and construction. The complex nature of the body is compounded by the fact that each component part of the anatomy has its own particular type of joining mechanism, connective tissue and manipulative musculature, and hence exhibits an individual form of articulation. Research has shown that the seams that connect major sub-assemblies of a garment are important in the promotion of style and comfort. In a study of overalls worn for asbestos removal work, results from 80 per cent of the subjects indicated that the crotch area was prone to failure (Huck et al., 1997). Such major joints occur where the head and other extremities connect to the trunk. The degree of movement at these sub-assembly joints is much greater than in other areas of the body. For the upper body, the seams concentrate particularly around the shoulder and the armhole. With different degrees of movement of the upper limbs, the position of bones, muscles and joints changes significantly during periods of activity, and this makes the skin, the body surface, in different parts of the body extend or contract appreciably, which directly affects the fit and comfort of the clothing and can even change the shape of the whole upper garment. Therefore, in order to study the relationship between body movement and clothing patterns in the shoulder area, it is essential to study the body skin changes in this area for different postures. The human body is a complex anatomical system capable of great subtlety in type and direction of movement (Watkins, 1995). In order to explore the dimensional
Body scanning of dynamic posture
167
IJCST 18,3
168
Figure 1. Dynamic postures adopted by the upper limb
Figure 2. Anatomical landmarks on the human body
changes of the skin around the armhole and devise a relationship between arm movement and the ease that must be incorporated into the sleeve, the front and the back of a clothing pattern, it is important to take account of the required extent of arm articulation. It is therefore necessary to consider the arm and shoulder geometry when the upper limbs are placed in a number of different positions, such as when the arm is lifted overhead 1808 (L1808) from the natural position. The arm may also be moved in the horizontal plane through a horizontal angle of 608 (H608) to a horizontal position of 908 (H908), and from the horizontal angle of 1808 (H1808), back to horizontal 2108 (H2108). Differences in the shape of the upper torso may also be observed, caused by the arm being moved into different postures, as shown in Figure 1. The purpose of this study was to compare the body surface changes as dynamic postures were assumed, by using traditional methods of body measurement alongside those of certain 3D body scanning measurements. A total of nine measurements were selected that were considered critical to the design of patterns from which well-fitting garments were to be created for high-performance use involving these six pre-designated postures. The nine dimensions taken from the upper body focused on the shoulder and arm, and included the front and back of the body. Body surface change was then calculated as the body moved from the standard anthropometric (natural) posture to five other dynamic postures. Two healthy female subjects were selected, aged 32 and 35, respectively , with figures and body shapes that might be described as normal and within the average range. They wore only briefs during both the scanning process and whilst manual measurements were taken. Firstly, 13 standard anatomical points were located and marked on the body, as shown in Figure 2. Manual measurements of nine anatomical lengths were taken with a tape measure for each of the six reproducible postures already described. Then adhesive markers were applied to the two subjects to mark
their respective anatomical landmarks. They were then placed in the Vitus 3D scanner in the standard natural standing posture and subsequently in five dynamic postures, and were asked to breathe normally whilst the scanning took place. Each standard scanning process took about 15 seconds. During this period 85 pre-determined measurements were automatically taken by the associated computer, which bases its information extraction on the assumption that the subject is in the natural anatomical posture. For a subject who is not in the standard posture, some of the measurements may not necessarily be correct. Therefore, the accuracy with which a 3D scanner is able to collect measurement data from subjects adopting various dynamic postures, is not specified and this aspect of their performance has been studied. The ScanWorX software package has been designed to make available a number of tools which manipulate information from the Vitus scanner, one of which is a digital tape measure (Heyd, 2003a, b, c). This makes possible the measurement of displacement between selected body landmarks, providing that they are clearly defined prior to scanning.
Body scanning of dynamic posture
169
The manual measurement method Manual measurement becomes straightforward once all the anatomical landmarks have been located on the body surface. There are 13 prominent points on the human body used by clothing designers when creating patterns (Liu and Yuan, 2001), as shown in Figure 2. Anatomical descriptions of the landmarks are included in Table I as appropriate (Gray, 1918). In order to track dimensional changes in the body surface when particular poses were adopted, the anatomical landmarks on the front, shoulder, back and arm, were connected by drawing lines on the skin, as shown in Figure 3. For example, the centre front line was drawn from the supra sternal notch, the front neck point (FNP), to the front waist point (FWP). The line L1 was marked from the front armpit (FA), to a point located a quarter of the vertical distance down from the top of the centre front line and is close to horizontal. Lines were drawn between the FA, the shoulder point (SP) and to the back armpit (BA), these curved lines hence delineate the top part of the armhole curve. The front and the back upper armhole curves were each subdivided Anatomical landmark
Description
FNP SNP BNP SP FA BA AP FWP BWP SWP FEP SEP BEP
Front neck point (supra sternal notch) Side neck point Back neck point (seventh cervical vertibra) Shoulder point, crown of shoulder Front armpit Back armpit Armpit point Front waist point Back waist point, small of back Side waist point Front elbow point (ante cubital fossa) Side elbow point (lateral epicondyle) Back elbow point (olecranon)
Table I. Description of landmarks on the human body
IJCST 18,3
170
into two equal parts. The centre point of the front armhole curve was connected to FNP and labelled L2. Line L3 follows the line of the shoulder, from the crown of the shoulder to the lateral neck point. To the rear of the body, a centre back line was drawn from the nape of the neck, vertically down the spine to the small of the back, at the back waist point. A line was drawn from a point, which was beneath the nape of the neck by a distance equating to one eighth of the length of the centre back line. The line from this point crossed the scapula and joined the middle of the back arm curve (SP-BA), and was labelled L4. A second line, L5, connected a point one quarter of the way down the centre-back line to the BA point. Lines L4 and L5 describe two half back widths. Lines L6, L8 and L9 define the shape of the upper arm. L6 joined the crown of the shoulder to the side of the elbow joint (the lateral epicondyle), hence this line extended from the crown of the shoulder along the arm to the side of the elbow, with the palm facing downwards. Lines L8 and L9 were constructed along the back and front of the upper arm, respectively : from the BA to the olecranon, the point of the elbow (BA to BEP), and from the FA to the ante cubital fossa, the inside of the elbow, the front elbow point (FA to FEP). Line L7 connected the underside of the armpit to the side waist point and followed the line of the side seam. After setting the landmarks and lines on the body, manual measurements of the nine lengths (L1 to L9) were undertaken with the body in the natural anatomical posture, using a glass-fibre-backed tape measure. The measurements were repeated for the five dynamic postures: L180, H60, H90, H180 and H2108. Many factors including posture, precise identification of landmarks, and the pressure exerted by the fibre-glass tape must be taken into consideration during the measurement of human subjects, and can introduce inaccuracies (Meunier and Yin, 2000). Even for trained personnel, the whole process is painstaking in nature. During these experiments, the subjects and the measurers were highly trained experts who took approximately three hours preparing each subject and repeating the measurements to ensure that the figures were as precise as possible, in both the natural and the dynamic postures. Manual measurement results The results obtained by manual measurement of the subjects are shown in Figures 4 and 5. The measurement line, ML was taken along the anatomical lines described earlier. Surface length changes to the skin, SC1, SC2, SC3, SC4 and SC5 relate to variations in the length of the anatomical lines measured as each of the various dynamic postures was adopted. The line length taken in the natural posture has been subtracted from the length of the same anatomical line when measured in the dynamic pose.
Figure 3. Setting landmarks and lines on the body
Analysing each anatomical line, and comparing its length in a dynamic pose against its length when in the natural posture, the dimensional changes were clearly demonstrated using manual measurement. Analysis of experimental results of manual measurement . The most significant changes in anatomical length were for L7 and L3 when lifting the arm through 1808. When the arm was raised to L1808, the body surface extension along the underarm line (L7) was the greatest: 9.5 cm for subject 1, and 8.5 cm for subject 2. The shoulder line (L3) reduction was also considerable: 2 8 cm for subject 1 and 2 7 cm for subject 2. . Other significant length changes occurred along lines L2, L5 and L7, when adopting the horizontal arm pose H608. This demonstrates that moving the arm horizontally through 608 makes an extreme demand on arm flexibility; the greatest skin extensions for this posture were the back width (L5) and the underarm length extensions (L7) of 6.5 cm for subject 1 and 9 cm for subject 2. The greatest contraction was in chest width (L2): 2 6 cm for both subjects. . The adoption of the horizontal arm position H908 caused a back width (L5) change similar to H608, the skin extension being 6.5 cm for subject 1 and 8 cm for subject 2. . The greatest length changes during the adoption of pose H1808 was in the upper arm length (L6): from SP to SEP. It is straightforward to understand that when the arm is in the natural position, L6 is the longest distance between SP and SEP,
Body scanning of dynamic posture
171
Figure 4. Surface length changes in cm for subject 1 adopting various postures
Figure 5. Surface length changes in cm for subject 2 adopting various postures
IJCST 18,3 .
172
so when the arm moves to the horizontal 1808 pose, this dimension shrinks and becomes the shortest line. The length change was 2 8 cm for subject 1 and 2 4 cm for subject 2. H2108 involves another extreme movement of the arm, since when the arm is in the horizontal 2108 position, the skin stretches across the back width (L4 and L5) and contracts across the chest width (L1 and L2); diminution in the upper arm length (L6) also occurs. The greatest dimensional changes are in L2 and L4, which were measured to be 4.5 and 2 5 cm for subject 1, and 5.5 and 2 3.5 cm in the case of subject 2.
From this experimental work, it can be seen that the overall pattern of variation in the body surface changes of the two subjects is similar. From the point view of clothing design, the basic tenet for pattern design is: the greater the skin surface change, the more ease the clothes need to ensure a comfortable fit (Liu and Yuan, 2001). The experimental data indicate that the surface dimensional changes when various dynamic poses are adopted are less than 13 cm for any area of the skin. Hence, if there is no requirement other than to accommodate the dimensional changes of the skin surface, then the ease that must be designed into patterns for high-performance clothing will not exceed 13 cm for the largest length change (underarm-when lifting) in order to fit the body of a standard-sized subject. This will also determine the limitations in the general requirements for the design of clothing patterns. Three-dimensional body scanning measurement method It is relatively straightforward to take manual measurements of the human body, but it is a slow and laborious process. Hence, the use of automatic body-scanning equipment represents an important advance in that it offers a quick and simple process for performing this task. When the scanner is used to take body measurements, the standard output results do not include a display of colours, lines, points or markers by which the digital measurements taken may be related to anthropometric landmarks. Hence, this equipment is not well suited to taking automatic measurements of dynamic postures adopted by the human body. However, by applying physical markers to highlight specific anatomical landmarks, such points may be identified after scanning, and thus may be facilitated the computerised measurement of the nine lines that were described earlier. Highlight landmarks on the body In order to show up the required points, small projections were applied to appropriate anatomical points on the subjects. The markers were small tapered cones of approximately 0.5 cm diameter height and base and were applied to the primary anthropometric landmarks. The physical size of these points could introduce a measurement error of up to 1 cm. However, this potential imprecision is reduced by the skill with which the operator can position the ends of the digital tape measure exactly on the centre of each target point. The subjects were first scanned standing in the natural position, then the subject’s stance was changed and images were scanned in a total of six postures. The scanning range was limited and footmarks on the central platform of the equipment positioned the subjects for scanning in the natural posture. When scanning
an arm lift of 1808, the use of these footprints was still appropriate. However, it was found that for the remaining four dynamic stances, with the arm horizontal and extended to 60, 90, 180 and 2108, it was only possible to retrieve a scanned image of the arm by positioning the subject 10 cm to the side of the centre line of the scanner. Three-dimensional body scanning measurement result In order to accurately compare the results of 3D scanning with those derived by manual means, the six postures necessary for taking the nine length measurements between major landmarks were set-up in exactly the same way for both measurement methods. This was ensured by using positioning jigs to precisely arrange the limbs. This virtually removed this potential inconsistency as a source of anything but very minor errors. The scanning process was quick and easily-completed once all the projecting landmarks had been prepared. Different scanned views of subject 1 are shown in Figure 6. Using ScanWorX software, the scanned image may be freely rotated, and can be enlarged or reduced in size; it is also possible to take point-to-point measurements using an interactive digital measuring-tape facility, and this capability was exploited in the experimental work. To obtain useful readings once any of the five dynamic postures had been struck, it was necessary to interact manually with the computer’s scanned image. This intervention was performed carefully marking the various anatomical points between which digital measurement was to be invoked. The landmarks which had been carefully located earlier were clearly visible on the scanned images, so the nine fundamental measurements could be requested. These figures were then extracted by the ScanWorX software and could be compared with the manual measurements. The results of the skin length change of 3D scanner measurement of the subjects are shown in Figures 7 and 8.
Body scanning of dynamic posture
173
Analysis of experimental results of 3D measurement From the data shown in Figures 8 and 9, it may be seen that digital body measurements taken from postures L180, H60, H90, H180 and H2108 are similar, though not identical to those recorded using manual measurement. Detailed examination indicates that the lengths of the lines (L1 to L9) extracted from the scanned images differ significantly from those taken by manual measurement, shown in Figures 4 and 5.
Figure 6. 3D body scanning image
IJCST 18,3
174
Figure 7. Scanned surface length changes in cm for subject 1 adopting various postures
Figure 8. Scanned surface length changes in cm for subject 2 adopting various postures
Figure 9. Average errors between manual and scanned measurements of the two subjects, analysed by anatomical location
The most marked changes in anatomical length were for L7 and L3 when lifting the arm through 1808, and these values were the same as when measured manually. When the arm was raised to L1808, the body surface extension along the underarm line (L7) was the greatest: 13 cm for subject 1, and 9.5 cm for subject 2. The shoulder line (L3) reduction was also considerable: 2 6.2 cm for subject 1 and 2 6.5 cm for subject 2. Subject 1 demonstrated the greater change (2 12.2 cm) in line L6 when raising the arm to L1808. Other significant length changes, in order of magnitude, occurred along lines L6, L5 and L1, when adopting the horizontal arm poses H60 and H2108. Similar results were found with manual measurement. Although the floor space of the scanning booth was 225 £ 220 £ 285 cm; which defined the working range of the equipment, it has been reported that the usable scan
volume is only 100 £ 95 £ 200 cm (Heyd, 2003a, b, c). Hence, the subject was restricted with respect to the posture that may be adopted within the scanner if a full range of body measurements was to be accurately produced. In order to take measurements of dynamic poses, it was desirable to be able to measure from the top point of the raised arm down to the feet. This distance often exceeds 200 cm for a female subject, and scanning equipment cannot normally work over such an extended vertical range. Similarly, if the subject was located on the standard footprint in the centre of the working platform and it was required to measure the horizontal extension of the arm, approximately half of the arm extended beyond the working radius of the scanner. In an attempt to accommodate such dynamic postures, it was necessary for the subject to stand off-centre. However, even for a subject located about 10 cm to the side of the platform centre, still the arm could not be fully scanned and the out-of-range areas are depicted in black on the scanner image, as may be seen in Figures 6 and 10.
Body scanning of dynamic posture
175
Comparison the result of 3D body scanning with manual measurement of dynamic postures The average errors of measurement lines and postures between the manual and the scanned measurements of two subjects are shown in Figures 9 and 10. From Figures 9 and 10, it may be seen that subject 1 elicited greater average errors than subject 2 when the results are analysed either by anatomical location or by posture. The most significant errors occurred in line L1, which was found to demonstrate an average discrepancy of 5.18 cm for subject 1, and 3.87 cm for subject 2. The large average postural error occurred in the L1808 pose, and this was 2.41 cm for subject 1, and 1.71 cm for subject 2. Overall, the average discrepancy between manual and scanned measurement was acceptable, being 0.85 cm for subject 1 and 1.1 cm for subject 2. However, from analysis of individual errors in every line and posture for manual and scanned measurements, it may be seen that the results contain significant inconsistencies. For instance, the most significant error variation between scanned and manual measurement in the case of subject 1 was when adopting the H2108 posture, and this was 2 6.8 cm along line L5, and equated to an error of 2 43 per cent. If it is accepted that a maximum manual measurement error of 1 cm error might arise from imprecision caused by the physical dimensions of the markers applied to the body, this still leaves a residual error of 2 5.8 cm which equates to 2 36 per cent. Hence, the scanned figure is insufficiently accurate for use in garment pattern creation. Even the results recorded in the natural anatomical pose contained significant levels of disagreement. The maximal error between the manual and the scanned figures for
Figure 10. Average errors between the manual and the scanned measurements for the two subjects analysed by posture
IJCST 18,3
subject 1 in the standard natural posture was 6.9 cm along line L1, this equates to an error of 28 per cent in the manual measurement of L1. If reduced by the maximal 1 cm error caused due to the dimensions of the marks applied to the body, still there was a 5.9 cm error equating to an error of 24 per cent, and again this was too imprecise to be used.
176
Analysis of measurement errors The computer measuring-tape can be invoked through ScanWorX to extract measurements of the subject directly from the scanned image. However, as measurements are taken from the electronic image, rather than from the body of the subject, they are inevitably subject to any imprecision introduced by the scanning process. Further errors may be introduced by the fact that the software has to handle non-standard postures for which it was not specifically designed and for which it has not been optimised. A further source of error lies in the fact that the digital tape measure inevitably utilises geometrical algorithms to create a virtual skin surface in order to create its working images. There will be some discrepancy between the recreated body shape and the three-dimensional original. As the point-to-point distances recorded by the digital measuring-tape are consistently shorter than those obtained by manual measurement, the indication is that in recreating the surface of the virtual image to which the digital tape-measure is applied, it might be surmised that the convexity of the curvature has been underestimated. Although all the landmarks can be observed on the virtual image generated by the scanning software, significant uncertainty was introduced by the physical dimensions of the markers used to locate the required landmarks. Restrictions in the use of the digital tape-measurement facility result from the fact that it can only be used to measure points which project from the surface of the skin. When re-entrant curves defeat the scanner, they are indicated on the virtual image of the body by black areas. From inspection, the areas that have not scanned correctly appear to be locations where the horizontal positioning of the camera creates a scanning shadow, for example, when part of the target lies behind an obstruction or within a re-entrant body curve. In Figure 11 it may be seen that there is an unresolved black section around the shoulder that was not successfully located by the machine. It is important to avoid such indeterminate areas when applying the measurement line, as the readings appear to zigzag into and out of these problem areas; the consequence being that excessively long distances are recorded, and these are too inaccurate to be used. Additionally, constraints on measurements resulted from the
Figure 11. A shoulder image which shows unresolved scanning areas in black
scanning of concave surfaces of the body as these shadowed areas had to be avoided when positioning the digital measuring-tape. Conclusions The work involving the use of traditional manual methods to measure dimensional changes of the skin was very laborious for both subjects and measurers, especially when considering different dynamic postures. Manual identification of body landmarks was time-consuming and introduced further sources of imprecision. Hence, obtaining precise results with this procedure was painstaking. It also seriously intruded upon the privacy of the subject. Hence, the use of an advanced high-speed automatic scanner for taking the body measurements necessary for the design of high-performance clothing is initially appealing. However, the preparation and point selection on the body in order to capture results from the scanner was also very time-consuming, as the various landmarks had to be accurately located. Since, the scanning techniques and the associated analytical software have been optimised for specific, conventional body postures, all the 85 measurements provided automatically by a simple scanning cycle have been pre-designed for a model adopting a standard natural posture. By changing the posture, most of the measurement positions are changed. Hence, when scanners are used to take measurements of unusual anthropometric configurations, such as when a body assumes a dynamic posture, which might be required to assist in the design of clothing used in particular sporting activities, and then the measurements taken using a scanner are not necessarily from optimal locations. Even though only a minimal number of subjects have been measured, and no attempt has been made to produce a range of measurements representative of a large cross-section of the population, the results nonetheless serve to show that for what might reasonably be regarded as normal subjects, even specially-designed digital tape-measurement software fails to capture dynamically-posed body measurements with the required accuracy. The results for anything other than the standard natural posture are disappointing. The experimental results reinforce this view, as manual measurement yielded more useful and valid data on the shoulder area for various postures than did the 3D scanner. In addition, errors were introduced into the data through the lack of standardisation that currently exists for the scanning process. Furthermore, there has been limited research detailing the accuracy of scanned data since the introduction of this facility into the clothing industry. For dynamic postures, the 3D body scanner cannot yet supply fast and accurate results. In addition, the present generation of scanning equipment does not take readings with sufficient discrimination for body landmarks to be identified from the resulting image. Hence, if accurate location is required of particular points on the body, such as the olecranon, they must be specifically marked prior to commencement of the scanning procedure. If the 3D body scanner could be increased in resolution and could be made capable of capturing colour information, the measurement accuracy would be dramatically enhanced, as small surface dots could be used to indicate body landmarks and reorientation of points on the body caused by positional variation could be addressed. It would also assist in the development of software capable of automatically extracting measurements of dynamic postures.
Body scanning of dynamic posture
177
IJCST 18,3
178
Although the 3D body scanner embodies the most advanced technology currently in use for measuring the human body, it would appear that it is not well suited for use in studies of dynamic postures which underpin the development of high-performance clothing. This situation is not likely to change until larger machines are introduced with an increased volumetric capacity coupled with improved analytical software, so that dynamic postures may be scanned and accurate point-to-point surface measurements may be taken. Until scanning machines are developed further, measurements for use in the design of high-performance clothing will have to be taken manually. References Gray, H. (1918), Anatomy of the Human Body, Lea and Febiger, Philadelphia, PA, Bartleby.com, 2000. Heyd, J.L. (2003a), “3D body technology: made to measure solutions”, Lectra Strategic Project, Large accounts Brands & Retail, MCPC. Heyd, J.L. (2003b), “3D design process”, Lectra Strategic Project, Large accounts Brands & Retail. Heyd, J.L. (2003c), “3D body technology: size survey, size fitting, made to measure solutions, 3D design”, Lectra Strategic Project, MCPC. Huck, J., Oprah, M. and Younghee, K. (1997), “Protective overalls: evaluation of garment design and fit”, International Journal of Clothing Science and Technology, Vol. 9 No. 1, pp. 45-61. Istook, C. and Hwang, S.J. (2001), “3D body scanning systems with application to the apparel industry”, Journal of Fashion Marketing & Management, Vol. 5 No. 2, pp. 120-32. Liu, C. and Yuan, Y. (2001), Clothing Pattern Construction, China Light Industry Press, Beijing (in Chinese). Meunier, P. and Yin, S. (2000), “Performance of a 2D image-based anthropometric measurement and clothing sizing system”, Applied Ergonomics, Vol. 31 No. 5, pp. 445-51. Simmons, K.P. and Istook, C.L. (2003), “Body measurement techniques: comparing 3D body-scanning and anthropometric methods for apparel applications”, Journal of Fashion Marketing & Management, Vol. 7 No. 3, pp. 306-32. Staples, N., Pargas, R. and Davis, S. (1994), “Body scanning in the future”, Apparel Industry Magazine, Vol. 55 No. 10, pp. 48-55. Watkins, S.M. (1995), Clothing: The Portable Environment, 2nd ed., Iowa State University Press, Ames, IA. Further reading Huck, J. and Younghee, K. (1997), “Coveralls for grass fire fighting”, International Journal of Clothing Science and Technology, Vol. 9 No. 5, pp. 346-59. Mckinnon, L. and Istook, C.L. (2002), “Body scanning – the effects of subject respiration and foot positioning on the data integrity of scanned measurements”, Journal of Fashion Marketing & Management, Vol. 6 No. 2, pp. 103-21.
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Systematic representation and application of a 3D computer-aided garment construction method
Part I: 3D garment basic cut construction
Part I: 3D garment basic cut construction on a virtual body model
Received November 2005 Revised January 2006 Accepted January 2006
179
Slavenka Petrak and Dubravko Rogale Department of Clothing Technology, Faculty of Textile Technology, University of Zagreb, Zagreb, Croatia Abstract Purpose – To develop a new method for computer-based 3D construction of garment basic cut on a computer generated body model. Design/methodology/approach – The method has been developed on an example of a 3D garment basic cut construction on a virtual body model, determining the position of characteristic 3D points necessary for computer-based definition of 3D cutting pattern contour segments. Contour segments modelling, as well as the modelling of 3D cut surfaces has been done using the NURBS objects. Findings – A 3D garment cut has been constructed, such that matches physical characteristics of the body in question and offers the necessary comfort of the cut. The surface of the 3D cut has been divided into individual 3D cutting patterns. Research limitations/implications – The method has been developed on an example of a 3D garment basic cut construction of a single paper of clothing. However, the same principles can be applied and developed for any garment basic cut. Practical implications – The 3D garment cut constructed can be further transformed into a network of polygons. Introducing fabric physical-chemical properties fabric drape can be simulated, aiming at more realistic visualisation and further assessment of the garment fit. The 3D cutting patterns developed can be, applying computer-based application of the mathematical models, transformed into 2D cutting patterns. Originality/value – As compared to the methods developed by some previous investigations, the newly developed method offers the construction of garment 3D cut on a computer-generated body model, granting the necessary comfort of the cut, which also means garment fitted to individual body characteristics. The 3D cut constructed can also be used as a starting point to define 2D cutting patterns in the following step, which will be matched to the physical characteristics of the model body, in the same way as the initial 3D cut. Keywords Clothing, Computer aided design, Modelling Paper type Research paper
1. Introduction The purpose of the investigations, performed at the Department of Clothing Technology, Faculty of Textile Technology, University of Zagreb, is to develop a new method for computer-based 3D construction of garment basic cut on a computer
International Journal of Clothing Science and Technology Vol. 18 No. 3, 2006 pp. 179-187 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610657943
IJCST 18,3
180
generated body model, using no fabric parameters. The method has been developed on the example of a basic cut for a ladies’ dress, taking into account individual characteristics of the model body and the addition for comfort of wearing, which is characteristic for the newly developed method. Previously developed methods and systems for 3D visualisation of a garment on a virtual body model are mostly based on the following two approaches. The first includes developing various methods for computer-based 3D garment modelling, within the development of particular CAD systems (Stylios et al., 1996; Gong et al., 2001; Ro¨del et al., 2001). The methods involve determining physical-mechanical properties of the fabrics used, while the garment visualisation is obtained by applying the garment drape parameter onto the 2D cutting patterns previously designed, using a computer-based simulation of the garment model manufactured from fabric of different properties. The other approach tries to find solutions for the problem of constructing the garment cut in a virtual environment on the computer-generated body model. The methods and systems developed within the confines of this approach (Ro¨del et al., 2001; Chiricota et al., 2001), are mostly used in designing garment models made from elastic fabrics, fitting tightly to the body. After the surfaces simulating 3D cutting parts have been shaped, physical-mechanical properties of the fabrics used are again applied onto them. The procedure of transforming the 3D into 2D cutting parts is reversed, as compared to the methods included in the first approach. The newly developed method is characterised by the garment basic cut being constructed on a computer-generated body model in a virtual environment, as an alternative to the conventional development of paper basic cut, tested on a tailors dummy (Rissiek and Trieb, 2004). Virtual testing of the basic cut fitting offers the possibility to match and model the basic cut on the model body, which yields a 3D basic cut of high quality, following the measures and physical characteristics of the model body. The model used in this investigation has been developed using a CAD software package. However, it is also possible to use a model developed on a 3D set of points or a cloud of points, as a result of recording a person using a 3D body scanner. The transformation of the 3D cut constructed, i.e. of the separated 3D cutting patterns into 2D patterns, is done using the mathematical models developed for the purpose, on a computer platform (Petrak et al., 2005), not employing the fabric parameters. The shape of the 2D cutting patterns transformed reflects the bodily characteristics of the model for which the 3D garment cut has been initially constructed. 2. Analysis of the computer-generated body model The first step in the development of the new method of computer-aided 3D garment cut construction involves fulfilling the prerequisites for a precise and high-quality computer-aided garment cut construction development. A grid of auxiliary lines and surfaces is developed, with the purpose of cutting the computer-generated body model into segments, such as transversal cuts by planes in the area of the chest circumference, waist circumference and the hips, as can be seen in Figure 1. Likewise, the model is cut vertically through the central axis of the body, using the plane that divides the model into two completely symmetrical halves, which will ensure symmetrical garment cut in the phases to follow. The model is also cut vertically using the plane that divides it into the front and back part. Apart from the planes mentioned,
Part I: 3D garment basic cut construction 181
Figure 1. Cutting a computer-generated body model using planes
a grid of auxiliary lines is also developed, characteristic for the construction of the paper of clothing in question. The procedures described determine, partially or completely, particular starting points used to construct individual contour segments of the future 3D cutting patterns. Cutting the body with the help of the planes the 3D garment cut construction is reduced to constructing a half of the front and a half of the back part of a dress to be designed. The whole of the 3D cut is obtained by transforming the halves, i.e. by using their mirror symmetry in relation to the central axis of the body. The procedure described can be applied for the body model with no deformations resulting in body asymmetry. The data on possible deformations are known in advance, given by the body model analysis previously performed. If there is a deformation present on the body, which would require partly or completely asymmetric garment cut, it is necessary either to modify some of the segments on the pattern or to reconstruct the pattern completely (which is seldom the case). Analysis of the body posture has also previously shown that the model selected has a normal posture. However, the analysis has also shown that the seat of the body is slightly pushed backwards and lowered (Figure 2). 3. Constructing a 3D cut of a ladies’ dress The 3D cut of a ladies dress was constructed using the software Rhinoceros 2.0, under the Windows 2000 operative system. All the segments, excluding the shoulder seam and the vertical seams from the line of the hips to the cut length, were 3D, and were constructed using the NURBS (non-uniform rational B-spline) lines, which enable creating the curves using precisely defined points. Altering the values of the initial and final segment point coordinates, as well as the weight coefficients of the points determining the segment, the shape and the length of the curves were changed. Closed curves of the chest circumference, waist and hips circumference, previously determined by cutting the model with planes, can be used to construct the garment cut. Scaling them in three dimensions, i.e. changing the measures depending on the cut comfort aimed at, enlarged closed curves were determined at the cross section of the chest, waist and hips circumference. Partial modification of the shape of these curves
IJCST 18,3
182
Figure 2. The analysis of body posture and shape
resulted in new, auxiliary curves, defining the shape and the circumference of the dress cut in the areas of the chest, waist and hips circumferences (Figure 3). The curve at the hips circumference determines the dress circumference of the cut length as well, i.e. the dress will be cut straight from the hips to the dress cut length. 3.1 Determining the position of main points and shaping the segments of the 3D ladies’ dress cut contours Cutting the body model by a vertical plane that divides it into the front and back part, defines partially the position of the shoulder seam as well. It is moved by some 20 mm towards the back part from the vertical plane, while simultaneously being raised by only a few mm from the shoulder. The beginning and the end of the shoulder seam are defined by measurements taken on the model. The points 1 and 2 are determined and joined by a straight line (Figure 4). The same plane defines partly the position of the side seam on the dress as well, i.e. the starting point of the side seam 3 and the final point 6 are situated in the plane (Figure 4(a) and (c). As related to the starting point 3 and the vertical plane, the
Figure 3. Cutting the computer-generated body model by planes and defining the curves of cross-sections on the model and garment cutting pattern in the area of chest circumference, waist and hips circumference
side seam is moved forwards in the waist by 20 mm on the curve of the waist, with the potion of the point 4 defined. From the point 4 to 5, which is defined as a crossing point of the side seam curve and the auxiliary curve defining the circumference and the shape of the dress on the hips, the side seam curve is shaped so that it gradually changes its course towards the back part and cuts the vertical plane in the point 5. From the hips depth to the cut length, i.e. between the points 5 and 6, the side seam is straight, being positioned in the vertical plane. Additionally, the curves of the front and back dress cut centrals are partially defined by the vertical plane, which symmetrically divides the cut into the left and right halves. It means that the values of the x coordinates of all the points that defined these two curves are all in the plane defined. The distance between these curves and the model, describing the comfort of the cut, is determined by the values of the y coordinates of the points defining the curves of the front and back central. This distance has been predetermined between the curve in the area of the chest and hips circumference, i.e. between the points 8 and 10, by scaling the closed curves in the area of the chest, waist and hips circumference, as explained in the Chapter 3 of the paper. From the crossing points of the front/back central with the closed curve at the hips depth (points 8 at the front part and 15 at the back part) to the cut length, both front and back centrals are defined by a straight line. The curve of the front central ends in the point 7, while the curve of the back central ends in the point 16. From the crossing point of the front central and the closed curve in the area of the chest circumference in the point 10, all to the point 11, which defines the neckline depth, the front central curve is removed from the model by a few mm. Likewise, the curve of the back central is also shaped from the point 12, which defined the neckline depth at the back central, to the point 13. The neckline itself, i.e. the curves determining its shape at the front and the back part, is shaped using auxiliary points between the previously defined point 11 at the front part, the points 1 and 12 at the back part. Both curves are removed from the model by a few mm, while their final shape, which also means the shape of the front and back neckline, is determined interactively, i.e. by adapting the spatial position of the points that define the shape of the curve.
Part I: 3D garment basic cut construction 183
Figure 4. Computer-aided construction of a 3D ladies’ dress cut: (a) main points of the front half 3D contour segments; (b) front part contour segments; (c) contour segments of the front and back halves; (d) back part contour segments; (e) main points of the back half 3D contour segments
IJCST 18,3
184
Similar method is employed to shape the curves that define front and back armholes. Some of the auxiliary, previously defined, lines are used in the process, which makes it easier to construct the armhole curves of a satisfactory shape, following the rules of conventional garment construction. In the above manner all the curves defining the contours of the future front and back 3D cut of the ladies’ dress have been constructed and shaped. However, it is also necessary to construct and shape the curves that will define the vertical dividing seams on the front and back parts. The dividing seam curve on the front part is defined by five main points, from 17 to 21, as well as by a number of auxiliary points, most like the curves constructed before. The starting point of the front dividing seam is in the point 17, which divides the shoulder seam into halves. The crossing point of the front dividing seam curve and the closed curve in the area of the chest circumference 18 is determined by measuring half of the chest width from the front central curve, following the curve in the area of chest circumference, according to the rules of conventional garment construction. Between the points 17 and 18, the curve is also defined by a certain number of auxiliary points, which additionally define its shape and ensure the necessary distance from the model. The position of the point 19 is determined by measuring from the front central curve, following the curve in the area of waist circumference. The measured length equals 1/8 of the waist width. The curve of the front dividing seam is also defined by a few auxiliary points between the points 18 and 19. The following main point, 20, which determined the shape of the front dividing seam curve, is situated at the crossing with the closed curve in the area of the hips circumference. The position of the point is determined by measuring 1/8 of the hips circumference from the front central curve, following the closed curve in the area of the hips. Auxiliary points additionally define the curve between the points 19 and 20 as well. The end point of the front part dividing seam curve, 21, is situated at the crossing with the curve determining the cut length, and is determined by drawing a vertical from the point 20. The points used to construct and model the back part dividing seam curve, are defined similarly (Figure 4(d) and (e)). This curve is, similarly to the front dividing seam curve, also defined by five points (17-25) and some auxiliary points. Point 17 is the starting point of the curve, as is on the front part dividing seam curve. The point 22, in which the back part dividing seam curve cuts the closed curve in the area of the chest circumference, is determined by measuring half of the back width, from the back central curve. The crossing points of the points 23 and 24 with the curves in the area of the waist and hips circumference are determined similarly. The point 23 is determined by measuring 1/8 of the waist circumference from the back central curve, following the curve in the area of the waist circumference, while the point 24 is determined by measuring 1/8 of the hips circumference þ 20 mm from the back central curve, following the curve in the area of the hips circumference. The final point 25 of the back part dividing seam curve, is determined by drawing a vertical from the point 24 to the curve on the cut length. The shape of the back part dividing seam curve, as well as the shape of the front part dividing seam curve, is additionally defined by a number of auxiliary points as well. These points also ensure the necessary distance of the curve from the model. 3.2 Constructing and shaping auxiliary curves and forming the 3D cut surfaces The construction and shaping of the curves that define the contour segments of the future 3D cutting patterns is still insufficient to form the surfaces to approximate the
garment virtual cut. From the point of view of computer graphics, certain rules should be obeyed when constructing and shaping the grid of curves that will be used to form a surface. Likewise, it is necessary to obtain the form of the surface that will as close as possible simulate the real appearance of the garment in question on a computer-generated body model. Appropriate comfort should be ensured on all the segments of the cut, which makes the construction and shaping of the curves more complex at particular segments. Because of this it is necessary to construct and additionally model a number of transversal and horizontal curves, within the previously constructed grid of curves that define cutting pattern segment contours. Figure 5 shows a grid of constructed and completely modelled curves, which can be used to form the surfaces of the front and back parts of the dress. Through selective control of the curve network constructed it is necessary to establish whether the cutting points of the curves are adequate. It is a prerequisite of defining necessary parameters, which will determine the manner and, finally, the shape of the surfaces to be formed. As two separate surfaces will be formed to simulate the front and the back part of the dress, it is necessary to cut all the transversal closed curves, from the curve in the area of the chest circumference to the cut length. The cutting is performed on the contour segments that simulate the side seams. It is thus possible to separate all the curves from the grid of curves of the front part from the grid of curves of the back part. Border positions are also defined, i.e. contour segments that will close the surface to be formed (Figure 6).
Part I: 3D garment basic cut construction 185
Figure 5. Gridwork of curves necessary to form the surfaces that simulate the 3D cut of the ladies’ dress
Figure 6. Defining border positions in order to form the surfaces of the front part of the 3D cut
IJCST 18,3
186
Depending upon the required preciseness of the surface, as related to the curve grid of curves constructed, allowable margins of errors are defined, within which the surface can deviate from the grid of curves. The margins of error should be minimal (Figure 6). Provided all the conditions have been correctly set and follow the requirements of the software, the computer will automatically, in the next step, form the surfaces of a particular density, which depends upon the density of the grid of curves used to form the surfaces. Surface density also depends upon a number of other factors, which will be clearly seen in further processing of a particular object, e.g. performing a simulation using the object and the object animation. It is preferable to use lower surface density if such moves are to be taken, as it shortens the time necessary to calculate a simulation. 3.3 Separating the surfaces formed into 3D cutting patterns The following step includes separating the surfaces formed of the front and back parts of the 3D dress cut into 3D cutting patterns. As it is necessary to form two separate surfaces to simulate the front central and the front side part of the dress, the surface formed of the front part is cut by a curve that simulates the front central and by the curve of the front dividing seam. The surface formed of the back part of the dress is divided into the back central and the back side parts, being cut by the curves of the back central and the back dividing seam. 4. Results and discussion The visualization of a geometrical model offers a more realistic representation of an article of clothing (Figure 7(a) and (b)). After visualisation has been performed, it is also possible to transform the model surface formed into a gridwork of polygons and to simulate the material drape by introducing the parameters of the fabric to be used. The computer-generated body model can also be animated with the model of the garment on which the parameters of the have been applied. Separating the surfaces of the front and back parts, using the front and back central curves, as well as the curves of the front and back dividing seam, individual 3D cutting patterns of the dress can be obtained, constructed following the characteristics of the model body (Figure 7(c)).
Figure 7. Visualization the 3D cut of the dress with the textures applied: (a) visualization on a computer-generated body model; (b) representation of the 3D cut and the symmetry plane; (c) 3D cutting patterns separated
From the point of view of computer graphics, the 3D cut of the dress thus constructed is a geometrical model. The following step includes preparing individual 3D cutting patterns for a systematic sequence of spatial transformations to be performed on the contour segments, with the aim to transform the 3D cutting patterns constructed into 2D patterns.
Part I: 3D garment basic cut construction
5. Conclusion Developing the method of computer-aided 3D construction of a garment basic cut on a computer-generated body model offers the construction of a 3D cut following the measures and physical characteristics of a particular body. The 3D cut constructed can be later transformed into a 2D cut, employing the mathematical models developed for the purpose (Petrak et al., 2005). The 2D basic cut obtained is highly precise and matches the physical characteristics of the model body. The 3D cut transformed into a gridwork of polygons can also be used to simulate the fabric drape, in order to give a more real visualisation of a garment on the body model, as well as to enhance the fit of the paper of clothing in accordance with the type of the fabric simulated.
187
References Chiricota, Y., Cochaux, O. and Provost, A. (2001), “Geometrical modelling of garments”, International Journal of Clothing Science and Technology, Vol. 13 No. 1, pp. 38-52. Gong, D.X. et al., (2001), “Progress towards effective garment CAD”, International Journal of Clothing Science and Technology, Vol. 13 No. 1, pp. 12-22. Petrak, S. et al. (2005), “A mathematical model to transform 3D into 2D curves”, Proceedings of 5th World Textile Conference AUTEX 2005, June, Department of Textiles, Faculty of Mechanical Engineering, University of Maribor, Portorozˇ, pp. 658-63. Rissiek, A. and Trieb, R. (2004), “FIGURA – individual mannequin used to develop collection and ensure garment fit (in Croatian)”, Tekstil, Vol. 53 No. 12, pp. 651-5. ¨ Rodel, H. et al., (2001), “Links between design, pattern development and fabric behaviours for clothes and technical textiles”, International Journal of Clothing Science and Technology, Vol. 13 Nos 3/4, pp. 217-27. Stylios, G. et al., (1996), “Modelling the dynamic drape of garments on synthetic humans in a virtual fashion show”, International Journal of Clothing Science and Technology, Vol. 8 No. 3, pp. 95-112. Further reading Dai, X. et al. (2001), “Drape formation based on geometric constraints and its application to skirt modelling”, International Journal of Clothing Science and Technology, Vol. 13 No. 1, pp. 23-37.
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
IJCST 18,3
188 Received November 2005 Revised January 2006 Accepted January 2006
Systematic representation and application of a 3D computer-aided garment construction method Part II: spatial transformation of 3D garment cut segments Slavenka Petrak, Dubravko Rogale and Vinko Mandekic´-Botteri Department of Clothing Technology, Faculty of Textile Technology, University of Zagreb, Zagreb, Croatia Abstract Purpose – To establish a method of transforming the 3D cutting patterns constructed and modelled into 2D patterns, excluding the fabric parameters. Design/methodology/approach – Three methods have been developed for transforming 3D cutting part segments into 2D segments. They are based on the computer-based application of the mathematical models developed. The mathematical models differ in their concepts and the application in a particular manner of transforming the 3D segments. Complex spatial matrix transformations have also been developed and used to further transform the 2D segments into the plane of chained 2D cutting pattern segments. Findings – Two-dimensional cutting patterns have been defined for the 3D garment model, initially constructed on a computer-generated body model. Research limitations/implications – The method has been developed on an example of a 3D garment basic cut construction of a single article of clothing. However, the same principles can be applied and developed for any garment basic cut. Practical implications – The mathematical models developed can be used in a new computer-based application for the 3D garment construction and the development of the 2D cutting patterns, matched to individual physical characteristics. Originality/value – The most outstanding property of the method developed is the possibility of gradual transformation of 3D cuts into 2D ones, with no need to define physical-mechanical properties of the fabric used and no need to introduce fabric drape. The newly created 2D cutting patterns are of outstanding quality and preciseness. Keywords Computer aided design, Clothing, Garment industry Paper type Research paper
International Journal of Clothing Science and Technology Vol. 18 No. 3, 2006 pp. 188-199 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610657952
1. Introduction The development of the method of 3D garment construction on a computer-generated body model (Petrak and Rogale, 2005) makes possible to construct garment basic cuts that follow the measures and physical characteristics of the model bodies. The following step in the development of the method for the computer-aided 3D garment construction, included comprehensive investigations aimed at establishing the method to transform the 3D cutting patterns constructed and modelled into 2D patterns,
excluding the fabric parameters. The methods and systems developed before were mostly based on the simulation of fabric (Stylios and Wan, 1999; Stylios and Powell, 2003) in computer-aided fabric or garment model visualisation, or on the other hand, on the application of fabric parameters in transforming the 3D cutting patterns into 2D ones. The investigations performed in developing the new method of 3D garment construction, as well as comprehensive work on the segments and segment parts of the 3D cutting patterns modelled, resulted in the following three methods of transforming 3D curves, i.e. cutting pattern contour segments, into 2D segments: (1) the method of transforming by projecting the curve onto the plane defined with three points; (2) the method of transforming by projecting the curve on the plane defined by the Gaussian method of least squares; and (3) the method of transforming by projecting the curve on the plane defined according to the Gaussian method of least squares and associated function extreme. Each of these methods is based on the application of the mathematical models developed, verified through systematic transformations of a number of 3D cutting pattern contour segments, on a computer platform. The choice of a particular projection method for a particular curve depends upon a number of parameters, such as the spatial shape of the curve in question, the shape the curve is supposed to have when projected onto a plane, as well as the length of the curve projected. The key requirement to be fulfilled by the method applied is that the curve length deviates minimally from the spatial curve length, i.e.: l 1 2 5 # l 2 # l 1 þ 5;
ð1Þ
where, l1, is the spatial curve length (mm) and l2, is the length of the curve projected (mm). The following chapters give a review of the gradual development of the mathematical model for the second transformation method. This method was used in the experiment to develop a 2D approximation of the spatial curve of the front dividing seam. Additionally, all the three methods mentioned require the 3D cutting pattern contours to be prepared, i.e. to be decomposed into segments and, when necessary, into segment parts. It means that all the three methods can have two initial steps in common, provided the 3D segment is transformed in its entirety. Step 1. The spatial curve k should be divided into the m number of parts, or segments: k1 ; k2 ; . . . ; kj ; . . . ; km ; so that each part kj, j ¼ 1; 2; . . . ; m; is approximately straight, i.e. to approximate by its shape some indefinite plane in space. Step 2. For each segment kj, defined with the n number of points, the point Sj, is determined from the j-part, as a starting point of the perpendicular coordinate system in space. 2. The mathematical model for the second method of transforming curves The application of the second method for projecting a spatial curve into a plane one, enables the transformation of the 3D curves which require the condition of (1) to be fulfilled, while the 2D curves, created by projecting the points, can by its shape be
Part II: spatial transformation
189
IJCST 18,3
190
similar to the spatial curve, or completely modified, in cases when it is necessary to “unwrap”or to develop an irregular spatial curve into an almost straight line or a 2D curve. The method employs the same first two steps as the other methods, while the position of the projection plane rj can be determined into one of the following two ways. Step 3. The first includes determining the position of the plane rj so that the shape of the 2D curve projected k0j is by its shape similar to the initial 3D curve kj. The second is used in projecting 3D curves, or cutting pattern contour segments, which should be developed into an almost straight line or a 2D curve. The segment is divided into a number of approximately straight sub-segments; with a different projection plane rj being defined for each sub-segment. The number of sub-segments depends upon the curvature of the segment, i.e. the number of sub-segments is proportional to the segment degree of curvature. The segment projected k0j ; is obtained by linking a series of sub-segments projected into a single 2D segment. It is necessary that the requirement (equation (1)) from the previous chapter is fulfilled after linking the 2D sub-segments into the segment kj. This is where the Gaussian method of least squares is used, which selects, from all the planes parallel to the defined rj, the one for further processing in which the sum of the squares of the distances from the projected point T 0k to the point Tk is minimal. For the purpose, the plane rj is transformed from its general form into a normal form of the equation of the plane: A j x þ Bj y þ C j z r j . . . qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ¼ 0; A2j þ B2j þ C 2j
ð2Þ
where, Aj, Bj, Cj, are the scalar components of the normal vector n~ ; which can be expressed by the cosines of the angles a, b, g, which the normal vector n~ closes with the coordinate axes x, y and z: r j . . .x cos a þ y cos b þ z cos g ¼ 0:
ð3Þ
The unit normal vector is determined by the following expression: n~ 0 ¼ cos a~i þ cos b~j þ cos g~k:
ð4Þ
where the following requirement should be met: cos2 a þ cos2 b þ cos2 g ¼ 1:
ð5Þ
Step 4. The following step asks for defining the planes rjp, which are parallel to the plane rj, removed from the starting point by the length of p. The distance of the individual point Tk from the plane rjp in its normal form, is defined by the following expression: dk ¼ xk cos a þ yk cos b þ zk cos g 2 p:
ð6Þ
It is thus possible to determine the sum of the squares of the distances between the points T 0k and Tk: n X k¼1
d2k ¼
n X k¼1
ðxk cos a þ yk cos b þ zk cos g 2 pÞ2 ;
ð7Þ
where, Pn, is the number of points that define the 3D segment and where the condition is that nk¼1 d2k is minimal. The Pabove method can be linked with the Gaussian method of least squares. If nk¼1 d2k is defined as a function of F( p), which is described by the following expression: Fð pÞ ¼
n X
d2i ¼
k¼1
n X
ðxk cos a þ yk cos b þ zk cos g 2 pÞ2 ;
ð8Þ
k¼1
where, p, is an unknown parameter. It is necessary to meet the condition of the function extreme, which means that the derivation by the variable p equally zero. The above can be written in the following form: cos a
n X
xk þ cos b
k¼1
n X k¼1
yk þ cos g
n X k¼1
zk 2 p
n X
1 ¼ 0:
ð9Þ
k¼1
The equation (9) offers the expression to calculate the parameter p, i.e. the distance from the starting point of the plane rjp, which has the required property: " # r r r X X X 1 p ¼ cos a xk þ cos b yk þ cos g zk : ð10Þ r k¼1 k¼1 k¼1 The parameter p determined is marked as pg and included into the expression (6), and the final expression for the plane rjp is defined as follows: r jp . . .x cos a þ y cos b þ z cos g 2 pg ¼ 0:
ð11Þ
Step 5. The following step includes projecting all the points from the segment kj onto the plane rpj. This is why it is necessary to draw normals or verticals nj onto the plane rpj in all the points Tk of the segment kj: nj . . .
x 2 xk y 2 yk z 2 zk ¼ ¼ ¼ t: Aj Bj Cj
ð12Þ
Particular points projected T k0 are determined by puncturing the plane rjp, described by the equation (11), by the normals nj, which are, for this purpose only, transformed from the form (12) into the following form: 9 x ¼ Aj t þ x k ; > > = y ¼ Bj t þ yk ; ð13Þ > > ; z ¼ C j t þ zk : Substituting x, y and z, from the equation (13) into the equation of the plane (11), results in an expression that can be used to calculate the parameter t:
Part II: spatial transformation
191
IJCST 18,3
192
t¼2
Aj xk þ Bj yk þ C j zk A2j þ B2j þ C 2j
:
ð14Þ
To simplify the matter, the parameter t from the equation (14) is denoted as tjk, and is substituted into the equation (13), to be used in calculating the values of the coordinates xk0 , yk0 , zk0 from the projection T k0 of the point Tk onto the plane rj: 9 x0k ¼ Aj t jk þ xk ; > > = y0k ¼ Bj t jk þ yk ; ð15Þ > ; z0 ¼ C j tjk þ zk : > k
The points T i ; T 0i for i ¼ 1; 2; 3; as well as the points T 0k ; offer the required projection k0j of the segment kj. Step 6. The final step in the second projection method also involves checking whether the condition (1) from the Chapter 1 has been fulfilled, as well as checking the shape of the curve projected. Provided the conditions have been met, further procedures of spatial transformation are performed on the segment k0j : 3. Transforming 3D segments using a mathematical model developed The mathematical model for the second method of transforming the 3D segments into 2D ones is applied to transform the following four 3D contour segments of the ladies’ dress cut: front dividing seam, side seam, front and back parts of the armholes. Each of these four 3D segments is defined by a starting and end point, as well as by a number of auxiliary points, the spatial position of which defines the 3D form of each individual segment. Transformation of the 3D front dividing seam segment in its entirety will be performed using the second mathematical model, e.g. all the points belonging to the 3D segment will be projected onto a single projection plane. 3.1 Transformation of the front dividing seam 3D segment into the 2D segment The 3D segment of the front dividing seam is defined by 17 points (Figure 1). The initial point of the 3D segment is situated at the crossing point with the closed curve of the dress circumference at the hips, while the closing point is situated at the half-way length of the shoulder seam, as is the case with the back dividing seam. The values of point coordinates defining the segment can be seen in Table I. Since, the 3D segment transformation is done by projecting the segment as a whole, e.g. by projecting all of the 3D points onto a single projection plane, the Step 1, described in Chapter 1 of this paper, is omitted, as it is not necessary to divide the 3D segment into sub-segments. The Step 2 is performed, initially defining the starting point of the coordinate system on the 3D segment. The point 10 (Figure 1), has been selected as the initial point of the coordinate system. It is situated at the crossing point with the closed curve of the dress circumference at the breast. The plane that will be used as the basis for defining the plane of projection (Figure 1), has been defined by selecting the point 10 as the initial point of the coordinate system, as well as by selecting the closing point of the segment. Calculation of all the parameters necessary to define the plane of projection follows. Mathematical expressions are defined to be used in calculating the values of the 2D
Part II: spatial transformation
193
Figure 1. A 3D segment of the front dividing seam, together with the points that define it and the plane r
Point no.
xi (mm)
yi (mm)
zi (mm)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 P
2 16.151 2 15.786 2 15.422 2 15.057 2 12.536 2 7.497 2 5.492 2 3.898 2 2.248 0.000 7.191 13.007 19.078 27.526 35.609 39.862 41.645 89.831
29.315 31.686 34.056 36.426 33.328 26.138 23.498 17.448 6.023 0.000 20.305 49.661 79.836 112.608 142.716 165.751 177.858 986.653
2 379.630 2 316.725 2 253.820 2 190.915 2 158.948 2 95.049 2 69.299 2 50.697 2 27.122 0.000 24.838 46.114 74.151 105.751 133.842 144.535 147.633 2 865.341
¼
point coordinates in the plane of projection, which will define the newly created 2D segment. The calculation is done following previously determined steps, as described in the Chapter 2 of the paper. The values of the coordinates for all the 17 points that define the curve are calculated using a computer. The points determining the projection plane are selected and thus created prerequisites for a computer-based application of the mathematical model described in Chapter 2. Using the expressions developed, all the necessary
Table I. The value for point coordinates that define the shape of the 3D segment of the front dividing seam
IJCST 18,3
parameters are established and the following projection plane rj for all the n points of the segment k is defined: r j . . .0:9693x 2 0 · y 2 0:2459z þ 0:157 ¼ 0:
194
ð16Þ
The values of the coordinates for the points projected are determined using the following expression: 9 x0i ¼ 20:069xi þ 0:271zi 2 0:173 > > = y0i ¼ yi : ð17Þ > > 0 ; zi ¼ 20:271xi þ 1:069zi 2 0:044 3.2 Spatial rotations of the front dividing seam 2D segment Transformation of the 2D front dividing seam segment has been done using three subsequent matrices of the segment rotation around the coordinate axis, as well as by applying the total sum of the rotation matrices. Since, the rotation of the segment closing point around the segment transformation coordinate axes cannot be completed, the point T 02 (Figure 2) has been selected as the segment rotation point referral to proportional rotation of all the other points on the segment. By rotating the segment around the x-axis of the coordinate system, the segment point T 02 is transformed into the new position T 002 (Figure 2), with proportional rotation of all the other segment points, while the closing point of the segment is transformed into the (x, y) plane. Further rotation of the segment, i.e. rotation of the point T 002 ; around the y-axis of the coordinate system shifts its position into the ( y, z) plane, while the closing point of the
Figure 2. Spatial rotations of the front dividing seam 2D segment
segment shifts to the crossing point with the z-axis of the coordinate system. The whole of the segment is thus transformed into the ( y, z) plane, while the new position of the point T 002 is marked as T 000 2 (Figure 2). As the front dividing seam segment is, as are all the other segments, supposed to be transformed into the (x, z) plane, so as to chain-link them into cutting pattern contours, it is necessary to rotate the segments around the z-axis of the coordinate system. However, the closing point of the segment does not shift in the process. Segment rotation is done by rotating the point T 000 2 for the characteristic angle of 908. It is thus (Figure 2), while the whole of the segment, e.g. all the transformed into the position T IV 2 points that define it, is transformed into the (x, z) plane. This completes the 3D transformation of the front dividing seam segment, employing the three subsequent segment rotations. Since, the calculation of the values for the transformed point coordinates after each transformation performed is a time-consuming process, as it is based on applying the matrices of rotation around each coordinate axis, we have found the matrix of sum of transformations around the three coordinate axes. This makes the process much faster; while the calculation is performed for the same values of the transformed point coordinates as after the last rotation performed, employing the three subsequent rotations. The calculation of the values for the transformed point coordinates using the sum of the rotation matrices. The first step is to define the initial point of the coordinate system in the first point of the segment (Figure 2). After this, the following values are determined for the parameters necessary to calculate the values of the transformed point coordinates. The sum of the rotation matrices is used for the purpose: T 02 ¼ ð16:196; 227:060; 377:598; 1Þ a ¼ 15:8038 b ¼ 26:2878 g ¼ 100:0138 Multiplying the sum of rotation matrices determined above with the values of the point T 02 homogenous coordinates, represents a single-step determination of the value for the transformed point T IV 2 coordinates: h i 0 x0 y0 z0 h0 T IV 2 ¼ T 2 ·M ZRXYZ ¼ 2 cos b sin g sin b cos bcos g 6 6 2cos g sin a sin b 2 cos a sin g cos a cos g 2 sin a sin b sin g sin a cos b 6 6 6 6 2cos a cos g sin b þ sin a sin g 2cos g sin a 2 cos a sin b sin g cos a cos b 4 0 0 0
0
3
7 07 7 7: 7 07 5 1
4. Results and discussion The transformation of the front dividing seam 3D segment, as a part of the 3D cutting pattern contour, initially constructed on a computer-based body model, is done in two steps. The first includes the transformation from the 3D into the 2D form, while the second uses the sum of rotation matrices to perform a complex spatial rotation of the 2D segment. The purpose is to define the position of the segment in the plane of chain
Part II: spatial transformation
195
IJCST 18,3
196
Table II. Coordinate value of the points defining the shape of the 2D front dividing seam
Figure 3. 3D segment of the front dividing seam, planes r and rj, together with the 2D segment of the same curve
linking all the segments into closed 2D cutting pattern contours. The first step determines the coordinate values for the points Tk0 as shown in Table II, which define the shape of the transformed 2D segment in the plane of projection, as shown in Figure 3. The 2D segment has been exposed to the procedure of checking the segment length and verifying its shape. Length deviation of the 2D segment, as compared to the
Point no.
xi (mm)
yi (mm)
zi (mm)
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170
218.906 214.736 210.566 26.397 25.206 23.019 22.086 22.223 23.112 22.765 2.364 9.094 16.373 24.274 31.464 38.071 41.391
26.658 29.571 32.482 35.394 32.273 25.074 22.426 16.493 5.423 2 0.517 17.929 45.326 73.538 103.8290 131.586 160.720 176.589
2 377.215 2 314.519 2 251.824 2 189.128 2 157.453 2 94.149 2 68.635 2 50.258 2 26.987 2 0.157 24.396 45.581 73.498 104.854 132.706 146.967 149.137
Notes: l1 ¼ 624.574 mm; l2 ¼ 623.975 mm; D l ¼ 0.599 mm
original 3D segment, has been established as Dl ¼ 0:599 mm; which lies within the tolerance limits, according to the prerequisite (equation (1)). The 2D segment projected has a satisfactory shape, e.g. the shape of the 2D segment meets the rules of conventional garment construction. The application of the method for transforming the 3D segments into 2D ones, based on the application of the mathematical model developed and the usage of a computer platform, offers gradual transformation of a 3D garment cut, initially constructed on a 3D body model, into a 2D cut. The investigations described include transforming a basic cut of a 3D ladies dress. The mathematical model presented has been used to transform the 3D segments of the back armhole, front dividing seam and side seam as well. Each of the segments has been transformed onto its own projection plane. Through additional transformations, i.e. a systematic series of spatial and planar rotations and translations, all the 2D segments created through the application of one of the three methods of transformation described in the Chapter 1, are transformed from various projection planes into the plane (x, z), where all the 2D segments are linked into closed contours of individual 2D cutting patterns. A set condition is that the lengths of specific cross sections on the 2D cutting patterns do not deviate from the same lengths on the 3D cutting patterns. The deviation of the overall surface for each 2D cutting pattern should be within the following boundaries: P 3D 2 5 cm2 # P 2D # P 3D þ 5 cm2 : The transformation of the front dividing seam 2D segment into the chain-linking plane (x, z) is done using the sum of rotation matrices, including a complex spatial transformation around all the three coordinate axes simultaneously. By rotating the segment point T 02 ; from the plane of projection rj, by the value of previously defined angles, around the initial point of the coordinate system, the position of the transformed point T IV 2 is determined (Figure 2). The following coordinates of the transformed point are determined employing the sum of the rotation matrices: h i 131:471; 0; 355:373; 1 : T IV ¼ 2 Transforming the rest of the 3D segments into individual planes of projection, as well as the additional transformations, e.g. spatial rotations of the 2D segments defined into the common plane (x, z), means that the conditions for chain-linking of the 2D segments into individual 2D cutting patterns are fulfilled. When the chain-linking of the segments is over, an overall control of segment lengths and specific cross sections on 2D cutting patterns is performed (Figure 4). The purpose is to check possible deviations of individual lengths on the 2D cutting pattern, as compared to the lengths of the same segments on the initially constructed 3D cut. Computer-based calculation of the overall surface is also done for each 2D cutting pattern, as well as the comparison of the 2D cutting pattern surfaces with the corresponding surfaces of the 3D cutting patterns. 5. Conclusion The new method is developed and presented of transforming 3D curves, i.e. 3D cutting pattern contour segments, based on a systematic usage of a mathematical model developed, using computer software to transform the 3D cutting pattern contour
Part II: spatial transformation
197
IJCST 18,3
198
Figure 4. Comparison of characteristic lengths on the 3D and 2D cutting pattern, together with the control of the overall 2D cutting pattern surface
segments of a garment constructed on a computer-generated body model into the 2D segments. A systematic series of complex spatial rotations and translations is used to transform all the 2D segments from the individual planes of projection into the chain-linking plane (x, z) of the segments into the contours of individual 2D cutting patterns. Analysis and control of the length of the individual 3D and 2D segments show minimum deviation in length for all the 2D segments. They are due to the implementation of one of the three methods of transforming the 3D into 2D segments. Additionally, the analysis of the overall surfaces of the 3D and 2D cutting patterns shows deviations within the boundaries of the previously set conditions for such deviations. The most outstanding property of the method developed is the possibility of gradual transformation of 3D cuts into 2D ones, with no need to define physical-mechanical properties of the fabric used and no need to introduce fabric drape. The newly created 2D cutting patterns are of outstanding quality and preciseness. The 2D cutting patterns created in this way can be also used to model and develop cuts of new garment models on CAD systems used for construction preparation in garment industry. The modelled cutting patterns will be matched to the physical characteristics of the model body for which the initial computer-aided construction of the 3D garment basic cut has been done. References Petrak, S. and Rogale, D. (2005), “The method of computer-based 3D construction of garment basic cut”, Proceedings of 5th World Textile Conference AUTEX 2005, Department of Textiles, Faculty of Mechanical Engineering, University of Maribor, Portorozˇ, June, pp. 664-70.
Stylios, G.K. and Powell, N.J. (2003), “Engineering the drapeability of textile fabrics”, International Journal of Clothing Science & Technology, Vol. 15 No. 3, pp. 95-112. Stylios, G.K. and Wan, T.R. (1999), “The concept of virtual measurement: 3D fabric drapeability”, International Journal of Clothing Science & Technology, Vol. 11 No. 1, pp. 10-18. Corresponding author Slavenka Petrak can be contacted at: [email protected]
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
Part II: spatial transformation
199
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
IJCST 18,3
COMMUNICATIONS
Croatian anthropometric system meeting the European Union
200 Received November 2005 Revised January 2006 Accepted January 2006
Darko Ujevic´ and Dubravko Rogale Department of Clothing Technology, Faculta of Textile Technology of University of Zagreb, Zagreb, Croatia
Mirko Drenovac Faculty of Philosophy of University of Osijek, Zagreb, Croatia
Dinko Pezelj Textile Journal Tekstil, Zagreb, Croatia
Marijan Hrastinski Educational Instituton, Zabok, Croatia
Nina Smolej Narancˇic´ Department of Clothing Technology, Faculta of Textile Technology of University of Zagreb, Zagreb, Croatia
Zˇeljko Mimica Faculty of Medicine of University of Split, Split, Croatia, and
Renata Hrzˇenjak Department of Clothing Technology, Faculta of Textile Technology of University of Zagreb, Zagreb, Croatia Abstract
International Journal of Clothing Science and Technology Vol. 18 No. 3, 2006 pp. 200-218 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610657961
Purpose – Anthropometry as one of anthropology methods is concerned with the measurement of the human body and determining the relationship of the size and proportions of the human body. Aims to outline the main features of the Croatian anthropometric system (HAS). Design/methodology/approach – The paper provides a description of the major characteristics included in HAS, the STIRP project supported by the Ministry of Science, Education and Sports by means of the HITRA program. Findings – In its TEST subprogram, HAS includes the first systematic anthropometric measurement in all Croatian counties and in the city of Zagreb. The objective of HAS is to determine a proposal of the new size system of clothing and footwear. The paper describes major characteristics included: anthropometric measurements and target points, part of practical measurements, survey of measurements based on age groups and instruments used for these purposes, notes about field measurements and HAS users. Practical implications – The implementation of HAS has been harmonized with International Organization for Standardization and EN standards and represents a considerable contribution on the path to the EU.
Paper refers on Scientific-Professional Conference, Textile Days, 2005, Zagreb.
Originality/value – Provides information of value to those concerned with developments in the clothing and garment industries. Keywords Measurement, Clothing, Body regions Paper type Technical paper
1. Introduction In the conditions of manufacturing fashionable clothing and footwear the size system is extraordinarily important. In order to satisfy as many customers as possible, it is necessary to develop such systems that will facilitate an efficient choice of garment and footwear sizes applicable to individual and group needs (Ujevic´, 2004; Ujevic´ and Hrzˇenjak, 2004; Ujevic´ et al., 2004). Anthropometry as an anthropology method is concerned with the measurement and testing of the human body and the relationship of dimensions among its individual parts (Ujevic´, 2004; Ujevic´ and Hrzˇenjak, 2004; Ujevic´ et al., 2004; Hrastinski, 1996). In the production of fashionable clothing and footwear the anthropometric measurements are applied in the field of construction and modelling, and they are obtained by anthropometric measuring a representative sample of the specific population. The results of the anthropometric measurements of the sufficiently large sample of the population may be used to determine national systems of clothing and footwear sizes. The latest anthropometric measurement of the population of the former state was carried out in only one part using a smaller sample in 1961/1962 resulting in the system (JUS) still applied in the Republic of Croatia (HRN). On the other hand, the industrialized countries improve their standards each 10-15 years. Upon completion of comprehensive preparations, preliminary investigations and analysis of numerous international and European systems, a team of prominent experts of different profiles and constructors, technologists, anthropologists, industrial medicine specialists, paediatricians and statisticians prepared the comprehensive technology STIRP-project entitled “Croatian anthropometric system” encoded as 0117-012. The Faculty of Textile Technology of the University of Zagreb is in charge of the project in collaboration with Institute of Anthropology of Zagreb, School of National Health “Andrija Sˇtampar” (Faculty of Medicine of the University of Zagreb), Faculty of Medicine of the University of Split and Faculty of Philosophy of the University of Osijek (Figure 1). Within the scope of this project anthropometric measurements of the population are being taken in order to make a Croatian anthropometric system as a basis for sizing systems of clothing and footwear. The measurements include the population of 20 Croatian counties and the city of Zagreb which is proportionally represented according to the number of inhabitants in the Republic of Croatia. A total of 55 age classes including children up to five years, pre-school children, school children, adolescence and adult population ranging from 20 to 82 years are being measured. A team of measurers is taking anthropometric measurements and gathering data on social and economic conditions. The determination of body measurements is being carried out in conformity with ISO 8559 and ISO 3635 standards, respectively , meaning 56 (for males) and 59 (for females) anthropometric measurements per subject, and ISO 9407 standard for
Croatian anthropometric system 201
IJCST 18,3
202
Figure 1. Presentation of the participatory institutions in the project “Croatian anthropometric system”
footwear sizing systems. A total of 30,000 subjects will be measured within the scope of this project. The HITRA program and STIRP “Croatian anthropometric system” will contribute to the economic development, especially to the fashion industry of high-quality garments and footwear and the growth of export capabilities and desire of economic subjects to satisfy the needs of harmonizing International Organization for Standardization (ISO) and European standards from industrialized countries, respectively. 2. Anthropometric measurements Since, people have different body heights and level of development, it is necessary to become familiar with a human body of average construction. To make cuts, it is necessary to study a large number of proportions (Latin proportio – symmetry, harmony, ratio, relationship of parts to each other). By proportions or relations a correct interrelationship of individual body parts and individual measures may be established. Based on the proportions deviations of the body from its average physique and its deformations may be observed.
In addition to several industry branches (furniture industry, tool industry, mechanical engineering, road building, industry of personal protective equipment and safety at work equipment, automotive industry, etc.), the garment and footwear industry is particularly interested in the results of anthropometric measurements. Three groups of information essential for the production of clothing and footwear are determined by systematic mass measurements and statistical treatment, such as (Ujevic´, 2004): (1) systems of clothing and footwear designation; (2) standard and proportional measurements; and (3) share of individual clothing and footwear sizes. Garment and footwear designation systems (HRN) are of general interests for the manufacturers, consumers and the entire population. They prescribe garment and footwear sizes and determine methods of size designation. There are no unique world’s garment and footwear size labeling systems, but each country proscribes them based on anthropometric measurements taken. Measurements are taken every 10-15 years, being the basis of improving and promoting standards. This is necessary due to life style and conditions reflecting directly on human body measures. It is in the interest of consumers and manufacturers that garments and footwear are made according to specific standards and as many sizes as possible. In this manner it is possible to meet demands of unknown customers, and this is a desire of each manufacturer of the clothing and footwear industry. Standard or main body measurements (body height – TV, bust circumference – OG, waist circumference – OS, hip circumference – OB and neck circumference – OV) are integral parts of each standard (Ujevic´, 2004; Ujevic´ et al., 1999; Denovac et al., 2002; Knez et al., 1995; Slavicˇek, 1966). Proportional (auxiliary) measurements are essential to clothing designers because they along with the main measurements form the basis for garment designing. Based on proportional measures specific regularities (relationship between proportional and main measures) and expressions used for the calculation of proportional measures out of main measures are determined, respectively. Using these expressions, deviations of a human body from the average physique may be determined. As a result of anthropometric measurements the share of individual garment and footwear sizes in the population being measured will be obtained. It is very important for manufacturers to know the share of a certain size in the total number of products because they work for unknown customers, being one of the conditions for successful sales in the market. Consumers are able to buy articles of clothing and footwear of appropriate sizes. 2.1 Anthropometric points For precise measurement of the human body a set of anthropometric instruments, measuring tape and other specially designed devices is used. To make cuts, a large number of proportions should be studied. For this reason it is necessary to study the human body, i.e. body proportions. Proportions show the correctness of the interrelationship between individual bodily measures, deviations from the average physique, i.e. the possibility of a deformation essential for making cuts is determined.
Croatian anthropometric system 203
IJCST 18,3
204
Figure 2. Anthropometric points
Before anthropometric measurements it is essential to determine the accurate position of individual anthropometric points on the human body. Anthropometric points are divided into fixed and so-called virtual ones (Ujevic´, 2004; Buzina et al., 1984). Fixed anthropometric points are always on the same part of the body. They are clearly visible, and their positions are easily determined. Virtual anthropometric points are changeable in relation to the bodily posture. Sometimes their position directly depends on the bottom where the subject tested stands when taking measurements. The determination of their position depends on the qualification of the measurer. When determining the position of anthropometric points one should bear in mind that there are numerous individual variations of skeleton shapes (Figure 2) used to determine the position of individual points. If there is a marked curvature of the skeleton, its position cannot be always localized in the same place. In such cases the approximation of this rounded surface or edge is taken for anthropometric points. When taking anthropometric measurement, the position of a particular anthropometric point is determined and is marked with demographic pen or these characteristic points are labelled (made by HAS). The position of all anthropometric points is to be determined in the standard bodily posture or in standing posture, with the exception newborn babies and infants. If possible, the position of anthropometric points is marked on the right side of the body. After bringing the body into the standard posture and marking the position of individual anthropometric points, anthropometric measurements are taken,
positioning the parts of the measuring instrument on the body of the subject, i.e. on individual anthropometric points. 2.2 Measuring tools Anthropometric measurements are taken using the following tools (Ujevic´ and Hrzˇenjak, 2004; Ujevic´ et al., 2003, 2004; Smolej Narancˇic´ and Szirovicza, 1995; Buzina et al., 1984): . measuring tape (Figure 3); . calipers (Figure 3); . one-arm anthropometer (Figure 3); . two-arm anthropometer (Figure 3); . specially designed protractor; and . digital scales.
Croatian anthropometric system 205
3. Description of practical measurements The ISO issued, as a recommendation, a series of standards towards the end of the 1970s of the last century, constituting the basis of the unique system of clothing and footwear designation all over the world. At a later time by issuing ISO 3635, ISO 8559 and ISO 9407 standards the foundations of defining the human body for the purposes of the clothing and footwear industry as well as for the implementation of anthropometric measurements were laid (Ujevic´ et al., 2004) as follows: . ISO 3635 – Size designation of clothes – definitions and body measurement procedure. . ISO 8559 – Size designation of clothes – garment construction and anthropometric surveys – body dimensions.
Figure 3. Measuring tools
IJCST 18,3
206
ISO 9407 – Shoe sizes – mondopoint system of sizing and marking. ISO 3636 – Size designation of clothes – men’s and boys’ outerwear. . ISO 3637 – Size designation of clothes – women’s and girls’ outerwear garments. . ISO 3638 – Size designation of clothes – infants’ garments. . ISO 4415 – Size designation of clothes – men’s and boys’ underwear, nightwear and shirts. . ISO 4416 – Size designation of clothes – women’s and girls’ underwear, nightwear, foundation garments and shirts. . ISO 4417 – Size designation of clothes – headwear. . ISO 4418 – Size designation of clothes – gloves. . ISO 5971 – Size designation of clothes – pantyhose. . ISO 7070 – Size designation of clothes – stockings. . EN 13402 – Size designation of clothes – terms, definitions and body measurement procedure. 3.1 Garment and footwear measurements of adults Measurements taken by one-arm anthropometer: . 027 Stature (TV) . 029 Waist height (VST) . 030 Hip height (VBO) . 032 Knee height (VKO) . 034 Sitting trunk height (SVT) . 053 Crotch length (DKO) . Sitting height to top of head (SVTJ) . .
Measurements taken by two-arm anthropometer: . 028 Trunk length (DTR) . 031 Seat depth (DS) . 052 Inside upper leg length (UDK) Measurements taken by calipers: . 056 Foot width (SˇST) . 017 Hand length (DSˇA) . 025 Foot length (DST) . 033 Ankle joint height (VSZ) Measurements taken by protractor: . 054 Shoulder slope (KRA) Measurements taken by scales: . 055 Body mass (MAT)
Measurement taken by measuring tape: . 001 Head circumference (OGL) . 002 Neck circumference (OV) . 003 Neck base girth (OBV) . 004 Shoulder length (DRA) . 005 Shoulder width (SˇRA) . 006 Back width (SˇL) . 007 Bust girth (male) (OGM) . 008 Bust girth (female) (OGZˇ) . 009 Bust distance (RGR) . 010 Lower bust girth (female) (DOG) . 011 Waist circumference (OS) . 012 Hip circumference (OB) . 013 Upper arm girth (OND) . 014 Elbow girth (OLK) . 015 Wrist circumference (OZP) . 016 Hand girth (OSˇA) . 018 Upper leg circumference (GON) . 019 Average circumference of upper leg (SON) . 020 Knee circumference (OKO) . 021 Circumference under the knee (OIK) . 022 Lower leg circumference (OPK) . 023 Smallest leg circumference (NON) . 024 Ankle joint circumference (OSZ) . 026 Body length (children) (DTJ) . 035 Scye depth (DO) . 036 Back length (DL) . 037 Length: seventh cervical vertebra to knee (DDK) . 038 Length: seventh cervical vertebra to foot (DDS) . 039 Bust height (from seventh cervical vertebra) (female) (WG) . 040 Front part height (from seventh cervical vertebra) (WP) . 041 Bust height (without neckline) (female) (VG) . 042 Front part height (without neckline) (VP) . 043 Hip depth (DBO) . 044 Trunk circumference (OTR) . 045 Total seat length (UDS) . 046 Shoulder circumference (ORA)
Croatian anthropometric system 207
IJCST 18,3
. . . . .
208
. .
047 048 049 050 051 057 058
Upper arm length (DNA) Sleeve length (DR) Sleeve length from 7th cervical vertebra (DR7) Inside sleeve length (UDR) Trouser length (DHL) Foot circumference (OST) Instep circumference (ORI)
Two groups of children are measured, namely those to the age of 5.4 years for whom 15 characteristic measurements are foreseen with no differences in sex when measurements are taken, and for older children to the age of ten years with 30 measurements taking account of sex difference. Children older than ten years are measured in the same way as adults of both sexes. 3.2 Measurements of children to 5.4 years Measurements taken by one-arm anthropometer: . 053 Crotch length (DKO) Measurements taken by calipers: . 056 Foot width (SˇST) . 017 Hand length (DSˇA) . 025 Foot length (DST) Measurements taken by scales: . 055 Body mass (MAT) Measurements taken by measuring tape: . 001 Head circumference (OGL) . 002 Neck circumference (OV) . 007 Bust circumference (OG) . 011 Bust circumference (OS) . 012 Hip circumference (OB) . 016 Hand circumference (OSˇA) . 026 Body length (DTJ) . 036 Back length (DL) . 048 Sleeve length (DR) . 051 Trouser length (DHL) 3.3 Measurements of children from 5.5 to 10 years Measurements taken by one-arm anthropometer: . 027 Body height (TV) . 032 Knee height (VKO) . 053 Crotch length (DKO)
Measurements taken by two-arm anthropometer: . 028 Trunk length (DTR) . 031 Seat depth (DS) Measurements taken by calipers: . 056 Foot width (SˇST) . 017 Hand length (DSˇA) . 025 Foot length (DST) . 033 Ankle joint height (VSZ) Measurements taken by scales: . 055 Body mass (MAT) Measurements taken by measuring tape: . 001 Head circumference (OGL) . 002 Neck circumference (OV) . 003 Neck base circumference (OBV) . 005 Shoulder width (SˇRA) . 007 Bust circumference (OG) . 011 Waist circumference (OS) . 012 Hip circumference (OB) . 013 Upper arm circumference (OND) . 015 Wrist circumference (OZP) . 016 Hand circumference (OSˇA) . 019 Average circumference of upper leg (SON) . 020 Knee circumference (OKO) . 022 Lower leg circumference (OPK) . 024 Ankle joint circumference (OSZ) . 036 Shoulder length (DL) . 037 Length: seventh cervical vertebra – knee (DDK) . 040 Front part height (from seventh cervical vertebra) (WP) . 048 Sleeve length (DR) . 049 Sleeve length from seventh cervical vertebra (DR7) . 051 Trouser length (DHL) The total number of measurements is: . fifty-nine in women and girls; . fifty-six in men; . thirty measurements of children at the age from 5.5 to 10 years; and . fifteen measurements for children to the age of 5.4 years.
Croatian anthropometric system 209
IJCST 18,3
210
Four measurements and their description are given hereinafter. 3.4 Body height – standing height (TV) When measuring the body height, the subject tested should stand on the even bottom without shoes and socks, with heels brought together and fully erect. The shoulders are relaxed. By moving the processus mastoideus (the nipple-like projection of the petrous part of the temporal bone) slowly, the head position is adjusted in such a way that the “Frankfurt horizontal” is brought into a horizontal position. Along the horizontally placed tape measure a triangle is moved until it touches the top of the head and the obtained value is expressed to the nearest 0.1 cm (Figure 4). 3.5 Shoulder slope (KRA) The value of the angle of inclination expressed in degrees and measured by the especially designed protractor (serving the needs of HAS) that is placed on the shoulder and follows the line joining the top of the shoulder and the point joining the shoulder and neck (Figure 5). 3.6 Bust height (from the seventh cervical vertebra) (WG) The distance from the seventh cervical vertebra, round the neck base, to the nipple (Figure 6) is measured. 3.7 Foot circumference (OST) The measuring tape lies on a slant over the first thumb knuckle and the little finger (Figure 7).
Figure 4. Body height
Croatian anthropometric system 211
Figure 5. Shoulder slope
Figure 6. Bust circumference
IJCST 18,3
212 Figure 7. Foot circumference
4. HAS logo To serve the needs of HAS, Maja Vinkovic, full professor for costume design, created 20 logo concepts. One HAS logo was selected, containing HAS symbols, part of early Croatian three-strand pattern, child’s, man’s and woman’s body silhouettes. The logo was accepted by experts and is printed on all documents used within the scope of this project (Figure 8). 5. ISO and EN standards Around the world different systems of garment and footwear designation are used, creating dilemmas and difficulties in potential customers as well as in manufacturers. This becomes especially prominent when these products are sold in different markets where dilemmas are raised because it is hard to understand garment and footwear size designation. Customers are often very confused because they cannot recognize the size designation or it does not provide appropriate information. It happens very frequently that one product contains several similar labels, creating confusion. The customers can seldom recognize all information contained in the size label as it is usually known only to specialists. Each product is designed according to its characteristic specialties and contains different accessories to make them more comfortable and to achieve a special form. As a result customers become even more confused. Only in special cases, body measurement corresponds to the body measurement taken, and as a rule the basis for determining garment sizes is just body measurement. Thus, in many cases body measurement and the measurement taken on the garment differ considerably. For these reasons it is in the interest of customers and garment and footwear manufacturers agree upon a unique method of size labelling of clothing and footwear which could be valid on all markets and supply customers with clear and appropriate information and enable manufacturers to achieve potential better sales.
Figure 8. HAS (Croatian anthropometric system) logo
By updating ISO 3635 standard and by issuing ISO 8559 and ISO 9407 standards the foundations of the unique definition of human body measurements for the needs of the clothing and shoe making industry as well as for the implementation of anthropometric measurements and size labelling system (Knez et al., 1995; Buzina et al., 1984; Knez, 1994; Drenovac, 1986; Drenovac et al., 2000; Szirovicza et al., 2002a, b; Denovac et al., 2002; Szirovicza et al., 2003; Hermann, 1991; Centre of Strategic Investigations and Institute of Defense Studies and Development of the Ministry of Defense of the Republic of Croatia, 2002) have been laid. 5.1 Body measurement and size designation The ISO 3635 standard determined four fundamental starting points for measuring the human body and garment size designation, namely: (1) application of body measurements; (2) application of metric system; (3) application of 1-3 characteristic measurements; and (4) introduction of pictogram. Body measurements determine size label, and garment measurements are left to the manufacturer. In this manner fashion and individual design of garment or cut are not affected. The application of the pictogram and in addition characteristic measurements, what is determined by other ISO standards, it is completely clear for customers how clothing size designation is carried out. They should be able to assess whether an article of clothing is potentially acceptable according to the body measurements printed on the left (horizontal) and on the right (vertical) side of the pictogram which displays a human figure silhouette and the site of taking an individual measurement shown in Figure 9. Individual ISO standards prescribe which measurements will be written next to the pictogram, and it depends on types of articles of clothing. A possibility is introduced that garment size is marked as a list of measurements with pictograms where is more applicable. ISO 3635 standard gives a survey of sites and measuring procedure of 14 characteristic measurements. As a result of ISO 3635 standard a series of standards has been issued explaining it in more detail: . ISO 3636 – Size designation of clothes – men’s and boys’ outerwear garments. . ISO 3637 – size designation of clothes – Women’s and girls’ outerwear garments. . ISO 3638 – size designation of clothes – Infants’ garments. . ISO 4415 – Size designation of clothes – men’s and boys’ underwear, nightwear and shirts. . ISO 4416 – Size designation of clothes – women’s and girls’ underwear, nightwear, foundation garments and shirts. . ISO 4417 – Size designation of clothes – headwear. . ISO 4418 – Size designation of clothes – gloves. . ISO 5971 – Size designation of clothes – pantyhose.
Croatian anthropometric system 213
IJCST 18,3
214
Figure 9. Example of size designation of clothes
. .
. .
ISO 7070 – Size designation of clothes – stockings. ISO 8559 – Garment construction and anthropometric surveys – body dimensions. ISO 10652 – Standard sizing systems for clothes. ISO 9407 – Shoe sizes – mondopoint system of sizing and marking.
The complete anthropometric survey of measurements and method of their taking is given in ISO 8559 standard, namely: 26 horizontal measurements, 27 vertical and two special measurements (body mass and shoulder slope). ISO 9407 standard describes the basic properties of shoe sizes and is applied for all footwear types. The standard describes the method of measuring foot length and width. The shoe size designation is determined as foot length expressed in millimetres, and on demand as foot width which are separated by a horizontal or slash. European standards (EN) 13402 (13402-1, 13402-3) depend on the ISO standards to the full extent and have two annexes. The first annex refers to the unification of some characteristic body measurements and the other one includes the determination of common starting points for grading body height. The European standards were established based on the ISO standards and the existing systems of national sizes and anthropometric measurements taken over the last 25 years. As ISO designations are sometimes too long or too lengthy, abbreviated labels are introduced into EN standards, and they include bust circumference, body height, and level of stature development whereby foreseen colors and symbols are used.
Up to the present day no unique world’s size labelling systems of garment have been established, but essential actions have been taken along the lines. One of the greatest achievements in this direction is the issue of European standards of the series EN 13402 relying on the former ISO standards. They are mandatory for all EU countries and for those exporting to this huge market. The anthropometric measurement implemented within the scope of the project “Croatian anthropometric system” is in conformity with the ISO and EN standards to the full extent. Since, no comprehensive anthropometric measurements have been done in the Republic of Croatia, they will be a credible indication of the state of our population and harmony with the measurements of the European Union. 6. Characteristics of field investigations Data collection is of crucial importance for the total success of each research project. For an effective and rational implementation of the HAS project it is therefore necessary to prepare field measurements of anthropological characteristics of subjects tested. In a particular field the success of fieldwork mostly depends on skills of the local organizer of investigations (Drenovac et al., 2000, 2002; Szirovicza et al., 2003; Hermann, 1991; Centre of Strategic Investigations and Institute of Defense Studies and Development of the Ministry of Defense of the Republic of Croatia, 2002). To be successful and rational in field measurements and to obtain valid data, the following is of paramount importance: . qualification (competence) ant motivation of the field team (measurers); . animation, i.e. finding, selecting, asking and gathering of subjects to be tested; . readiness of the infrastructure of measuring sites (measuring location); . organization of appointments and treatments of subjects (reception and measurements); and . validity and reliability of measurement implementation. The task of the local organizer of investigation includes: . making contacts with relevant institutions (local authorities and institutions where larger groups of subjects are measured and media); . organization of invitation (animation) of subjects; . provision of appointments and preparation of the measuring site (preparation of the room and necessary infrastructure); and . permanent feedback with the main researcher or the coordinator of the fieldwork at the Faculty of Textile Technology. The team preparing and implementing the fieldwork is made up of: . local organizer; . central coordinator (consultant and controller of the course and accuracy of fieldwork); and . field team of licensed measurers formed from local collaborators trained in anthropometrics.
Croatian anthropometric system 215
IJCST 18,3
216
To facilitate search for and encouragement of subjects to be subjected to measuring, it is useful to mention potential sources of organized subject groups and point to institutions that should be interested in the results of this investigation. The largest number of subjects can be animated in organized groups such as: kindergartens, schools, faculties, business organizations (they are interested in these problems in terms of clothing and footwear production), mass consumers of uniforms (military, police, security services, fire fighting, health institutions, departments stores, catering industry, etc.). A larger number of subjects can be animated at health-service institutions where medical examinations of the population are carried out (pediatrics, school medicine, and industrial medicine) and at the Central Employment Office. Different kinds of announcements for the animation of subjects may be used in several countries, such as: . notices in newspapers and invitations (on notice boards at factories, institutions, department stores, etc.); . invitations via e-mail and internet; and . invitations via radio and local TV stations. Nonetheless, the response of subjects to this form of animation seldom fulfils the criterion of the representativeness of the population structure because it does not reach all age groups and social categories of the population. Yet, it is advantageous to apply as samples in combination with other forms of gathering in a particular place. The success of the implementation of field research is based on meeting several trivial criteria, such as: . space availability (waiting room, dressing room, discretion of the room where measurements are taken); . informing the subjects to be measured about the site and working time of taking measurements; and . organization of reception and polite treatment of the subjects before, during and after measuring. A special integral part of field research is to find, qualify and license local collaborators or measures. The quality of data collected by fieldwork is considerably dependent on the qualifications of the measurers and their motivation for accurate measurements. Education and giving license to field measurers is of great importance. They become familiar with the field of work, measuring equipment, anthropometric methods, training in taking measurements, verification of accurateness and reliability of measurements. 7. HAS in use The application of HAS will result in statistically interpreted data on the anthropometric measurements of the whole population of the Republic of Croatia that will be useful to the manufacturers of all types of clothing and footwear. The applicability of these results will be significant in defining the uniforms of the Croatian army, police, fire brigades and other employees in the institutions of the Republic of Croatia.
In the first phase of the project realization the measurement program embraces the employees of the Faculty of Textile Technology, schools, work organizations, hospitals, old people’s homes, and in the next phases the program will be realized according to the plans and in all counties of the Republic of Croatia (Ujevic´ et al., 2004). To realize HAS successfully, necessary organizational forms for the implementation of measurements in displaced measuring sites of the individual counties have been determined. The necessary media promotion (radio, TV and press) and the web site of the project inform the public and enable the application of possible or potential subjects to be measured. 8. Conclusion Most countries establish standards according to their own criteria, and size systems developed and established in different European countries differ from each other. Most of these systems are based on the figure type determined by body height and differences in bust, waist and hip circumference. Garment sizes are mainly labelled for two or three stature groups: short, medium and tall, and three anthropometric measurements were defined: by bust, waist and hip measurements. In the 1970s and 1980s, ISO developed a new size labelling system according to which the product label would contain body measurements of characteristic dimensions. As a result, several countries changed their size system adopting the system developed by ISO. It is most essential for customers to be able to find their appropriate garment size easily. Anthropometric measurements and determination of body sizes and garment size labelling system according to the recommendations of the ISO standards are necessary for the Republic of Croatia. HAS will help improve the quality of exported fashionable clothing and footwear as an important parameter for launching products to the international markets. References Buzina, R., Grgic´, Z., Kovacˇevic´, M., Maver, H., Momirovic´, K., Rudan, P., Schmutzer, Lj. and Sˇtampar-Plasaj, B. (1984), Morphologic and Functional Anthropometry, Praktikum biolosˇke Antropometrije, Zagreb. Centre of Strategic Investigations and Institute of Defense Studies and Development of the Ministry of Defense of the Republic of Croatia (2002), “Multidisciplinary investigation of human resources of the Croatian army”, Project of the Ministry of Defense of the Republic of Croatia. Denovac, M., Szirovicza, L. and Petri, N.M. (2002), Investigation of Morphological and Psychological Properties of Divers, Demolition Experts and Vessel Crews of the Croatian Navy, Study, Institute of Anthropology, Zagreb, p. 97. Drenovac, M. (1986), “Microorganization, analysis and labor evaluation”, Project of the Productivity Department, Zagreb. Drenovac, M., Szirovicza, L. and Zˇivicˇnjak, M. (2000), “Morphological status of cadets and pilots of the Croatian Air Force”, Investigation Results (p. 157), VTS MORH (1998), Studies (p. 171), IOSTIR-MORH. Hermann, W. (1991), “Unique garment size system of Europe”, Tekstil, Vol. 40 No. 8, pp. 377-8. Hrastinski, M. (1996), Garment Construction 1, Handbook, Textile Technical School Zabok, Zabok.
Croatian anthropometric system 217
IJCST 18,3
218
Knez, B. (1994), “International and new European garment size systems and size designation systems of clothes”, Tekstil, Vol. 43 No. 1, pp. 19-25. Knez, B., Milicˇic´, J., Rudan, P., Szirovicza, L., Taborsˇak, D. and Tucakovic´-Mujagic´, Lj. (1995), “Applied anthropometry for anthropology, biomedicine, ergonomics and standardizaiton”, Handbook for Fieldwork, Republic of Croatia, Ministry of Defense, Zagreb. Slavicek, J. (1966), Garment Construction, Zagreb. Smolej Narancic, N.S. and Szirovicza, L. (1995), Ergonomic Measurements. Investigation of the Anthropometric Status of Conscripts of the Croatian Army (Fistonic´, I), Centre of Strategic Investigations of the Ministry of Defense of the Republic of Croatia, Zagreb, pp. 99-102. Szirovicza, L., Kalebota, N. and Drenovac, M. (2003), “Investigation of foot morphology of recruits of the Croatian army”, Collegium Antropologicum, Vol. 27 No. 2, pp. 635-43. Szirovicza, L., Knez, B. and Drenovac, M. (2002a), Determination of Body Measurements and Proposal of Garment Size System of Conscripts of the Croatian Army, Presentation of Investigation Results, Institute of Anthropology, Zagreb, IOSTIR-MORH, p. 115. Szirovicza, L., Ujevic´, D. and Drenovac, M. (2002b), “The structure of body measurement for the determination of garment system for young Croatian men”, Collegium Antropologicum, Zagreb, pp. 187-197. Ujevic´, D. (2004), Croatian Anthropometric System – Situation, Demands and Perspective, Inovacijsko zˇarisˇte, Bilten MZOSˇ. Ujevic´, D. and Hrzˇenjak, R. (2004), “Croatian anthropometric system”, paper presented at First Congress of Ctoarian Scientists from Croatia and Abroad, Zagreb – Vukovar, November, 15-19. Ujevic´, D., Rogale, D. and Hrastinski, M. (1999), Garment Construction and Modelling, Faculty of Engineering of the University of Bihac´, Bihac´. Ujevic´, D., Rogale, D. and Hrastinski, M. (2004), Methods of Garment Designing and Modelling, Faculty of Textile Technology of University of Zagreb, Zagreb. Ujevic´, D., Szirovicza, L. and Dimec, M. (2003), “Presentation of investigation and comparison of garment size systems”, Tekstil, Vol. 52 No. 12, pp. 603-711. ´ Ujevic, D. et al. (2004), Croatian Anthropometric System – Path to Europe, Proceedings, 27 May.
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Regional microclimate humidity of clothing during light work as a result of the interaction between local sweat production and ventilation Hiroyuki Ueda
Regional microclimate humidity 225 Received October 2005 Revised January 2006 Accepted January 2006
Osaka Shin-Ai College, Osaka, Japan
Yoshimitsu Inoue Osaka International University, Osaka, Japan
Mitsuo Matsudaira Kanazawa University, Kanazawa, Japan
Tsutomu Araki Hyogo University of Teacher Education, Hyogo, Japan, and
George Havenith Department of Human Sciences, Loughborough University, Loughborough, UK Abstract Purpose – The aim of this study is to explore the influence of the clothing ventilation in three body regions on the humidity of the local clothing microclimates under five work-shirts immediately after the onset of sweating in light exercise. Design/methodology/approach – The clothing microclimate ventilations were measured at chest, back and upper arm using a manikin. Separate wear trials were performed to determine the sweat production and the humidity of the clothing microclimate at the same locations as where the ventilation was measured during light exercise. Findings – Every shirt shows the greatest value of ventilation index (VI) for the chest and the smallest one for the upper arm. The values of VI differ remarkably at the chest among the five shirts. Comfort sensation became gradually worse as the time passed after starting exercise. There was no significant difference among the clothing conditions in mean values of rectal temperature, local skin temperatures, microclimate temperatures, microclimate relative humidities and local sweat rates at three regions over 10 min after the onset of sweating. A relationship was observed between the ratio of the mean moisture concentration in the clothing microclimate to the mean sweat rate at the chest and the back and the VI. Originality/value – The results suggest that clothing ventilation should be measured in different body regions in response to sweat rates in corresponding regions. Keywords Humidity, Clothing, Air, Thermal testing Paper type Research paper
The authors thank their subjects for their cooperation. This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sport, Science and Technology of Japan (Grant No. 16500498).
International Journal of Clothing Science and Technology Vol. 18 No. 4, 2006 pp. 225-234 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610668473
IJCST 18,4
Nomenclature A B(0)
226
HR msw O2(t) R Rae
¼ atmospheric oxygen concentration (20.9 per cent) ¼ constant value giving the difference between A 2 OðtÞ at t ¼ 0 (per cent) ¼ heart rate (bts min2 1) ¼ local sweat rate (g min2 1m2) ¼ oxygen concentration at time t (per cent) ¼ air resistance of fabric (kPa sec m2 1) ¼ air exchange rate (min2 1)
RHm Tm Tsk Tre V VI _ 2 max VO
¼ relative humidity of clothing microclimate (per cent) ¼ temperature of clothing microclimate (8C) ¼ local skin temperature (8C) ¼ rectal temperature (8C) ¼ fixed flow rate for measuring air resistance of fabric (0.04 m3 m2 2 sec2 1) ¼ ventilation index (L min2 1) ¼ maximal O2 uptake (ml kg2 1min2 1)
Introduction Work clothing is manufactured in various shapes and from a range of fabrics, according to its purpose. When creating clothing to be worn in conditions in which the body temperature is raised, designers must focus on minimising heat stress. This includes the selection of the fabric. To maintain thermal comfort of the body, it is important to maintain skin temperature and moisture within the comfort range, also during early stages of heat stress (Fanger, 1970; Gagge et al., 1967). Air exchange between a clothing microclimate and an external environment has a significant effect on the wearer’s evaporative and dry heat loss (Havenith et al., 1990; Bouskill et al., 2002). If exercise causes sweating, it is important to facilitate moisture diffusion through garments in order to keep the wearer comfortable. It is established that an increase in air exchange through the fabric, and through a garment’s apertures, increases evaporative heat loss. Previous research has quantified the increase in clothing ventilation resulting from increases in fabric air permeability, and has examined the influence of apertures on clothing ventilation using work suits with identical design but different permeability (Ueda and Havenith, 2004). Based on these studies, an evaluation method was proposed, that uses a calculation of required ventilation: the ideal amount of ventilation by which all sweat produced could be removed from the skin to the outside of the clothes (Havenith et al., 2003), hence keeping skin moisture low and maintaining comfort. The steady rate of sweating differs from one region of the body to another, and there are also regional differences in the degree of increase in sweat rate caused by increasing exercise intensity (Inoue et al., 1991, 1995; Kondo et al., 1998). Determination of required clothing ventilation and comparison to actual ventilation requires knowledge about regional sweating characteristics and measurement of local ventilation rates. Use of this knowledge would allow better accuracy in evaluating clothing, and would allow collection of useful data for designing clothes with efficient diffusivity. The purpose of this study was to explore the effect of clothing ventilation in three body regions on humidity in the local clothing microclimates of several work shirts immediately after the onset of sweating during light exercise. For this purpose, firstly local clothing microclimate ventilation in three body regions was measured, and secondly separate wear trials were performed to determine sweat production and
humidity in the corresponding clothing microclimates, in the same conditions as the measurement of ventilation, during light exercise. Method Clothing Five long-sleeved shirts were chosen from commercially available samples, representing shirts that are typically worn by consumers in environmental conditions similar to those in this experiment. The shirt patterns were identical, but they were made of five different knits of cotton; Table I shows the characteristics of fabrics used in this experiment. The two sets of the five shirts were prepared, respectively, for each subject (a new shirt was used for each test). Each of them was kept in 258C 50 per cent rh until the test after being washed and dried beforehand.
Regional microclimate humidity 227
Clothing ventilation at the chest, back, and upper arm Clothing ventilation was determined by measuring the ventilation index (VI), a product of air exchange rate multiplied by microclimate volume: VI ðL · min21 Þ ¼ air exchange rate ðmin21 Þ £ microclimate volume ðLÞ: First, each of five shirts was placed on a manikin, and the microclimate volume was estimated by measuring the circumference of the undressed and clothed manikin body; this was approximated using a cylinder model (Lotens and Havenith, 1991). Subsequently, air exchange rates between the clothing microclimate and ambient air were measured at the three body regions of chest, back, and upper arm in a climatic chamber with an air velocity of less than 0.3 m s2 1 using a tracer gas technique (Birnbaum and Crockford, 1978; Bouskill et al., 2002). For this purpose, the concentration of oxygen was reduced from a natural level to approximately 10 per cent, by flushing 100 per cent nitrogen gas into the microclimate under the shirt using a distribution tube system fixed to the surface of the manikin. Nitrogen injection was performed very carefully to reduce concentrations in the three regions at the same rate and to the same level. Gas concentrations in three microclimate body regions were sampled separately using sampling tubes, also fixed to the surface of the manikin, and were sent to three corresponding oxygen analysers. After the nitrogen influx was halted, oxygen concentrations in the microclimate were monitored over an extended period of time while they returned to a natural environmental level (approximately 20.9 per cent) due
Sample
Structure
Yarn count (tex)
Fiber material: cotton 100 per cent 1 Plain knit 23.6, 14.8 2 Stockinet 18.2 3 Plain knit 14.8 4 Jacquard knit 14.8 5 Mesh knit 9.1
Knitting gauge
Thickness (mm)
Area density (g/m2)
Air resistance (kPa · s/m)
20 28 24 24 24
1.09 0.56 1.00 0.59 0.88
233 133 182 131 171
0.10 0.15 0.28 0.28 0.03
Note: Thickness is measured at the pressure 6 gf/cm2
Table I. Description of five shirts
IJCST 18,4
to ventilation of microclimate air with ambient air. During this time, the oxygen levels increased from 11 per cent to the natural level in the form of an exponential curve, and the resultant air exchange rates were calculated using the following equation: O2 ðtÞ ¼ A 2 Bð0Þ · e2Rae · t
228
where O2(t) is the oxygen concentration (per cent) at time t, A is the asymptotic value of oxygen concentration (20.9 per cent), B(0) is a constant giving the difference between A 2 O2 (t) at t ¼ 0; and Rae is the air exchange rate calculated using least squares analyses. Measurements for each shirt were repeated seven times. Wear trials To survey clothing microclimate humidity, wear trials were conducted using the five shirts in a neutral condition. Three healthy men served as subjects for the wear trials. The age of each three subjects was 36, 22, 32 years; height 172, 179, 176 cm; mass 72, 82 70 kg; and surface area-to-mass ratio 247, 239, 258 cm2 kg2 1, respectively. Each subject _ 2 max ; tested each shirt twice in two different workload conditions: 30 and 45 per cent VO in balanced order. Therefore, each shirt was tested in six different sweat rate conditions. Each subject wore one of the shirts, underwear, socks, and long cotton trousers and he sat on a cycle ergometer for at least 15 min in a climatic chamber at a temperature of 258C, a relative humidity of 50 per cent, and with an air velocity of less than 0.3 m s2 1 after the instruments were attached. The tests lasted until at least 15 min of sweating was observed. To maintain roughly equal microclimate volumes at the chest and back for the comparison of the different shirts on the same subject, subjects attempted to maintain an upright position. They were asked not to move the upper half of their bodies to reduce pumping effects, since an increase in pumping effect could change the airflow in and at the clothing surface. Clothing microclimate temperature (Tm [8C]) and relative humidity (RHm [per cent]) were continuously measured during exercise using temperature-humidity sensors (Shinei Kaisya THT-B) at the three regions of chest, back, and upper arm. Moisture concentration [g m2 3] was calculated using Tm and RHm at each site (Goff, 1965). Each minute during exercise, local skin temperature (Tsk [8C]) was measured using skin thermistors at the chest, back, and upper arm, and rectal temperature (Tre [8C]) was measured using a rectal probe. Local sweating rate (msw [g min2 1 m2 2]) was measured at the chest, back, and upper arm using the ventilated capsule method. Dry nitrogen gas was supplied to the capsules (area 9 cm2) at a flow rate of 1 L min2 1; humidity of nitrogen gas flowing out of the capsules was measured by capacitance hygrometry (Vaisala HMP133Y). Subjects were asked to declare their level of comfort (comfortable, slightly uncomfortable, uncomfortable, very uncomfortable), every 5 min immediately before exercise until it was completed. All trials were performed during winter. Subjects were asked to refrain from other physical activity before the trials, and they did not ingest food or water from two hours before trials began until they were completed. All subjects considered themselves to be in good health, were not under a physician’s care, and were not taking any medication. All subjects were given oral and written information about the procedures and possible _ 2 max [ml kg2 1min2 1]) was risks involved in the study. Maximal O2 uptake (VO estimated for each subject while he exercised at a sub-maximal level; each subject pedalled on a cycle ergometer at a constant frequency of 50 rpm for 5 min at
four different exercise intensities. Heart rate (HR [bts min2 1]) and O2 uptake were _ 2 max measured during the final minute of each exercise period. For each subject, VO was estimated by extrapolating the relationship between HR and O2 uptake to an estimated maximal HR for each subject. Data analysis and statistics All data are expressed as mean ^ SD: A one-way analysis of variance (ANOVA) was used to assess the statistical significance of differences in VI among five shirts and a one-way repeated-measures ANOVA was used to analyse differences in Tsk, Tm, RHm at the three body regions, Tre, and level of comfort among the five shirts. A two-way repeated-measures ANOVA was used to assess the statistical significance of differences in msw in the two within-subjects factors: the five shirts and the three body regions. To compare the VI in two typical samples, a paired-t test was used. All statistical analyses were performed using commercially available software (SPSS version 11.5; SPSS). A value of p , 0:05 indicated statistical significance.
Regional microclimate humidity 229
Results Clothing ventilation at chest, back, and upper arm Because the five shirts were made from an identical pattern, microclimate volumes of shirts showed no significant difference when worn on the same subject [mean value: trunk 10.3, upper arm 2:0ð£103 cm3 Þ]. Because the subjects maintained an upright position during exercise, the microclimate volume at the chest or back were assumed to be half of the total value for the trunk. Figure 1 shows the mean VI at the chest, back, and upper arm for each of the five shirts. Coefficients of variation (CV ¼ SD/mean value (per cent)) ranged from 7 to 15 per cent. In each shirt, the chest had the greatest VI and the upper arm had the lowest VI. VI values at the chest and back differed significantly among the five shirts. Differences in VI at the back were unclear compared to differences at the chest, and at the upper arm they were hardly discriminated. Wear trials There were no significant differences in Tre, Tsk, or RHm among the shirts during the rest period; only chest Tm tended to show a lower temperature in sample 5 than in sample 4 (31:6 ^ 0:58C in sample 4 versus 30:7 ^ 0:68C in sample 5, p ¼ 0:05).
Figure 1. VI at the chest, back and upper arm
IJCST 18,4
230
Under all clothing conditions, each subject voted that he was comfortable during the rest period. After exercise began, Tsk rose, and in all tests sweating was observed after some time had passed; sweating was observed at the chest, back, and upper arm at about the same time. The onset of sweating varied among trials and ranged from 3 to _ 2 max : 7 ^ 2 min; 45 per cent VO _ 2 max : 10 min after exercise began (30 per cent VO 5 ^ 2 min). As time passed, the sweat rate gradually increased. For all subjects, the level of comfort decreased after exercise began, and after the onset of sweating there was a difference in the voted level of comfort among the shirts. When voted levels of comfort are compared between two typical samples of clothing ventilation, samples 2 and 4 (similar thickness and weight, but different air permeability; Figure 2), the level of comfort for sample 4 (lower air permeability) appeared worse than that for sample 2 after the onset of sweating in five of the six trials. Figure 3 shows the levels of comfort 10 min after exercise began. Ten minutes after beginning the exercise, when all subjects first or second voted their level of comfort after the onset of sweating in each trial, there were significant differences ð p , 0:05Þ in levels of comfort. There were no significant differences in Tre, Tsk at the back or upper arm, or RHm at the chest, back, or upper arm at the time. Only chest Tsk had a tendency to be lower in sample 2 than in sample 4 (34.88C in sample 2 versus 35.38C in sample 4, p ¼ 0:07). Figure 4 shows mean values for average sweat rates in different body regions in all sessions over 10 min after the onset of sweating. There were large variations in deviation due to individual differences and differences in the absolute intensity of exercise. Sweat rates were significantly greater at the chest and back than at the upper arm. There were no significant differences in sweat rate among clothing conditions and the clothing condition-body region interaction. After investigating average values over the 10 min after the onset of sweating, there were no significant differences among clothing conditions in Tre, Tsk, Tm, and RHm. To help clarify the interaction between sweat production, local ventilation, and resultant microclimate humidity, Figure 5 shows the relationship between the ratio of average moisture concentration in the clothing microclimate over the average sweat rate over 10 min after the onset of sweating, and the VI. There was a clear relationship between these two variables at the chest and back. Sample 2, with a high VI, demonstrated a lower ratio at the chest and back. On the other hand, sample 4, with an equal thickness and weight, but a lower air permeability fabric and a lower VI, demonstrated a higher ratio. Discussion The goal of this study was to explore the influence of clothing ventilation at the chest, back, and upper arm on humidity of clothing microclimates immediately after the onset of sweating when five permeable cotton shirts were worn during light exercise. This study was based on the hypothesis that increasing the amount of clothing ventilation would facilitate transport of produced sweat to the outside of clothes and hence, that clothing ventilation is an important factor during the initial stages of sweating to keep the wearer comfortable while working. During the measurement of ventilation, when permeable shirts were tested using a manikin under still air conditions, clothing ventilation was better at the trunk than at the upper arm. This demonstrates that clothing ventilation from a microclimate to the environment differs among regions of the body. Air exchange through fabric is
Regional microclimate humidity 231
Figure 2. Comfort sensations in Subj. 1, 2 and 3 wearing sample 2 and 4 during the exercise
IJCST 18,4
232 Figure 3. Comfort sensations at 10 min after starting the exercise
Figure 4. Average sweat rate at chest, back and upper arm over 10 min after the onset of sweating
Figure 5. Relationship between the ratio of average moisture concentration [g m2 3] to average sweat rate [g min2 2m2 2] and VI over 10 min after the onset of sweating
a complicated process affected by thermal ascending currents, air currents due to respiratory movement and/or body motion, a curved or waved fabric surface, a state of draping and other fabric properties. Clothing microclimate volumes directly affect clothing ventilation, and the thickness of air layers influence air currents in clothing microclimates. It is probable that these factors cause regional differences in clothing ventilation. Air penetrating through fabric has an obvious effect on clothing ventilation, but though some indication of an air permeability effect was present (sample 2 vs 4) there was no clear correlation between fabric air resistance and clothing ventilation over all five garments together. Air resistance (R), as an index of air permeability, is measured with flattened fabric samples using a substantial fixed airflow rate through the fabric (R ¼ DP=V ; where DP is the difference in pressure measured on both sides of a fabric, and V ¼ 0:04 m3 m22 sec21 ). Under normal wearing conditions, the expected airflow rate through fabric is much lower; this may lead to differences in air resistance and VI results. Factors such as fabric thickness, density, cover-factor, and surface characteristics may have different effects depending on test conditions. During actual wear, ventilation may also occur due to interactions among body regions; this cannot be observed during air permeability measurements. Investigation of clothing ventilation at various body regions will, therefore, lead to a more realistic evaluation of clothing than the simple examination of a fabric’s air permeability. Five cotton shirts of identical design were used in this experiment. Although they had different properties, there was no observed effect on the subjects’ thermoregulatory responses before exercise began. Only the mesh structure of sample 5 resulted in a slightly lower chest Tm at rest, and this was only relative to sample 4. This difference, however, did not have a large effect during exercise, as seen by the similar Tm for all samples. Given the low level of heat stress, the absence of a thermoregulatory effect is not surprising. However, all subjects reported reduced comfort in shirts with a lower VI compared to the shirts with a higher VI, comfort being a more sensitive parameter than the physiological responses in these conditions. Differences in comfort level were evident within 10 min after the onset of sweating in most trials. Average Tre, Tsk, Tm, and RHm values over the 10 min after the onset of sweating did not differ significantly among clothing conditions, so it is not possible to directly attribute observed differences in comfort levels to these parameters of thermoregulation. There was also no significant difference in average sweat rates over this period among the shirts, but there appeared to be a greater moisture concentration ratio in the clothing microclimate to sweat rate in shirts with a lower VI than in shirts with a higher VI. The difference in skin wettedness was probably considered to be the major cause of the differences in comfort levels over 10 min after the onset of sweating (Berglund et al., 1985). There appears to be a clear correlation between this ratio and VI, though it seems to vary among areas of the body. An increase in clothing ventilation may generally thin the diffusion zone, and therefore, improve evaporation efficiency. It is probable that the higher the ratio, the less the evaporative efficiency on the local skin surface, and that an increasing skin moisture concomitant with a lower evaporative efficiency reduces the level of comfort. This is confirmed when sample 2 is compared to sample 4 (equal thickness and weight, but different air permeability and VI). Figure 5 shows clear differences, which are reflected in the levels of comfort shown in Figure 3.
Regional microclimate humidity 233
IJCST 18,4
This experiment indicates that an increase in clothing ventilation is effective in keeping a wearer comfortable soon after the onset of sweating by preventing an increase in skin moisture concentration. The experiment also indicates that in order to design work wear or evaluate its conformability, clothing ventilation should be measured in different body regions in response to sweat rates in corresponding regions.
234
References Berglund, L.G., Gagge, A.P., Cunningham, D.J. and Oohori, T. (1985), “Vapor resistance of clothing, local skin wettedness and discomfort”, ASHRAE Transaction, Vol. 91, pp. 3-12. Birnbaum, R.R. and Crockford, G.W. (1978), “Measurement of clothing ventilation index”, Appl. Ergonomics, Vol. 9, pp. 197-200. Bouskill, L.M., Havenith, G., Kuklane, K., Parsons, K.C. and Withey, W.R. (2002), “Relationship between clothing ventilation and thermal insulation”, AIHA Journal, Vol. 63, pp. 262-8. Fanger, P.O. (1970), Thermal Comfort, McGraw-Hill, New York, NY. Gagge, A.P., Stolwijk, J.A.J. and Hasrdy, J.D. (1967), “Comfort and thermal sensations and associated physiological responses at various ambient temperatures”, Environmental Research, Vol. 1, pp. 1-20. Goff, J.A. (1965), “Saturation pressure of water on the new Kelvin”, in Wexler, A. (Ed.), Humidity and Moisture: Measurement and Control in Science and Industry, Reinhold Publishing, New York, NY, pp. 289-92. Havenith, G., Heus, R. and Lotens, W.A. (1990), “Clothing ventilation, vapour resistance and permeability index: changes due to posture, movement and wind”, Ergonomics, Vol. 33, pp. 67-84. Havenith, G., Ueda, H., Sari, H. and Inoue, Y. (2003), “Required clothing ventilation for different body regions in relation to local sweat rates”, in Rossi, R. (Ed.) paper presented at the 2nd European Conference on Protective Clothing, Montreux. Inoue, Y., Nakao, M., Araki, T. and Murakami, H. (1991), “Regional differences in the sweat responses of older and younger men”, J. Appl. Physiol., Vol. 71, pp. 2453-9. Inoue, Y., Nakao, M., Okudaira, S., Ueda, H. and Araki, T. (1995), “Seasonal variation in sweating responses of older and younger men”, Eur. J. Appl. Physiol., Vol. 70, pp. 6-12. Kondo, N., Takano, S., Aoki, K., Shibasaki, M., Tominaga, H. and Inoue, Y. (1998), “Regional differences in the effect of exercise intensity on thermoregulatory sweating and cataneous vasodilation”, Acta Physiol. Scand., Vol. 164, pp. 71-8. Lotens, W.A. and Havenith, G. (1991), “Calculation of clothing insulation and vapour resistance”, Ergonomics, Vol. 34, pp. 233-54. Ueda, H. and Havenith, G. (2004), “The effect of fabric air permeability on clothing ventilation”, in Tochihara, Y. and Ohnaka, T. (Eds), Environmental Ergonomics, Elsevier, London, pp. 343-6. Corresponding author Hiroyuki Ueda can be contacted at: [email protected]
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Influence of sewing parameters upon the tensile behavior of textile assembly Sabria Gribaa Laboratoire de ge´nie me´canique, Monastir, Tunisia
Sami Ben Amar
Influence of sewing parameters 235 Revised February 2006 Accepted February 2006
Laboratoire d’e´tudes des syste`mes thermiques et Energe´tique Ecole Nationale d’Inge´nieurs de Monastir, Monastir, Tunisia, and
Abdelwaheb Dogui Laboratoire de ge´nie me´canique, Monastir, Tunisia Abstract Purpose – The aim of this work is to check the influence of some sewing parameters upon the tensile behaviour of a textile assembly (assembly of two woven samples by a seam). Design/methodology/approach – This analysis was carried out according to the approach “experimental design”. The studied parameters are the sewing thread, the stitch type, the stitch density, the needle size and the edge of seam. The targeted answers are drawn from the tensile test on the assembly: breaking strength, breaking elongation and deformation energy. Findings – In order to highlight the behaviour of the seam, a load-extension curve for the stitch line is established: it represents, for a value of a given tensile effort, the difference between the displacement of the assembly and that of the fabric. From this curve, breaking elongation as well as the deformation energy are determined. Originality/value – An “experimental design” was carried out and analysed for two types of assembly (warp and weft). Linear models predicting each response were established. Keywords Textile industry, Assembly, Parametric measures, Tensile strength, Experimental design Paper type Research paper
Introduction Sewing a textile fabric is a very pointed operation which is governed by a broad spectrum of parameters like the type of sewing machine, the stitching velocity, the structure of sewing operation, the method and the ability of worker, the selection of stitching parameters, etc. seam appearance (straightness, proper stitches) and also seam tensile performance (strength, elasticity) is the result of combination of all this factors. In fact, many typical sewing problems occur such us skip stitches, thread breakage, fabric damage, faulty seam appearance (Inui and Yamanaka, 1998), needle damage, what reduces productivity and seam quality. The adjustment of all sewing parameters will be a must to ensure quality. Nevertheless, the lack of understanding of the rule of each factor, and primarily of the interaction impact between factors limit our ability to optimize right selection of sewing parameters. Therefore, we present an experimental study which aims to analyze and quantify the influence of some sewing parameters upon the tensile behaviour of a textile assembly. The investigation is carried out according to the approach
International Journal of Clothing Science and Technology Vol. 18 No. 4, 2006 pp. 235-246 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610668581
IJCST 18,4
236
“experimental design”. The experimental design will have to determine, among the chosen factors, those which have an influence on the result as well as the nature of these influences (direction and intensity) (Souvay,1995). The information available from such a study will allow us to understand and predict the behaviour of sewn fabric under uniaxial extension. Theoretical background Influenced parameters on tensile behaviour of textile assembly The object of this research is the assembly of two woven samples by a seam. Hence, any change in the tensile behaviour of textile assembly can be attributed essentially to: . The material to be assembled: during sewing process, the fabric is subjected to various mechanical solicitations (shear, compression, extension) (Postle,1998; Mahar et al., 1989), then fabric properties (composition, weave, thickness, strength) will govern its “sew ability” and also seam performance (Sauri et al., 1987). Stitch stability depends on the rigidity of material (Tartilaite and Vobolis, 2001a), the deformation of sewn fabric is a consequence of the internal frictions of fabric and of the relaxation process of cloth after the sewing process (Tartilaite and Vobolis, 2001b). It has also been proved that fabric bending property is an important factor influencing puckering of the seam (Lindberg et al., 1960). . The sewing thread: the use of a suitable sewing thread is fundamental to ensure the desired properties for the assembly. However, sewing thread properties (tensile performance, compactness, heat-resistance, abrasion resistance) are given by its structural parameters (thread type, twist, thread size). In fact, the type of thread determines the severity of abrasion (yarn-metal friction) which is crucial for seam durability. Additionally, during sewing, the elongation and the toughness of the thread reduces considerably, it was found that cotton threads exhibit higher strength loss than polyester threads (Sundaresan et al., 1997). The fineness of thread is expected to affect the strength of seam: the thicker thread provide a better seam strength, nevertheless it requires the use of a thicker needle which may damage the fabric. . The number of layers of the sewing material: the assembly is expected to be more resistant. Nevertheless, strength reduction in sewing thread grows with the augmentation of the number of layer of fabric since the thread suffers higher coefficient of friction (Sundaresan et al., 1998). . The geometry and the size of sewing needle: damage of the structure of the fabric occurs when the fabric is penetrated by the needle. The needle can penetrate at any point in the fabric, it can, therefore, deform the fabric loops or cause the fabric damage: the structure of the fabric can be deformed beyond its elastic limit or can literally be destroyed. The choice of the right needle (size, point) is fundamental to ensure assembly quality. However, fabric characteristics (tightness, weight, number of layer) and sewing thread properties (fibre type, fineness) are two crucial factors affecting the selection of the right needle. . The type of stitch and its density: there are a wide variety of stitches by which the use depends on the function of the seam and the place where it appears in the clothing part. The elongation and the strength of a sewn fabric can be affected by any change in the form of seam because of the difference of the interlacement of thread with fabric for each stitch geometry (over edge stitching, cover stitch
.
seams). The use of the most suitable stitch density depends on the material to be sewn and to the desired seam properties. Very high stitch densities do not always give a good results, they may bring with them the risks of damage of the structure and the puckered seam. The edge of seam: yarn in the fabric can pull out of the seam from the edge. The adjustment of this parameter is necessary to minimize seam slippage. However, this choice should take into account the fabric properties (smoothness, type of filaments), the sewing thread and the stitch parameters.
Experimental design The purpose of experimental design is to rule out the alternative causes, leaving only the actual factor that is the real cause. It is based on the principle of a factorial experimentation resting on the simultaneous variation of the factors. The treatment of the results is done using a multiple linear regression and the analysis of the variance. This strategy entails: . Definition of the targeted response. . Selection of the parameters susceptible to influence this response and the definition of theirs levels of variation which is crucial for the efficiency of the plan. The distance between levels should not be high to not dissimulate the existence of a non linearity’s but not very little what omit the influence of factor. The high level is generally noted (max þ 1) and the lower level (min 2 1). . Choice of kind of design: The complete factorial design which combines, in an exhaustive way, all levels of parameters; or the fractional plan (Taguchi method) which allows the reduction of the number of tests (Souvay, 1995). . Realization of the tests according to the combination of parameters and theirs levels given by the design plan (planned manipulation). . Treatment of results which consists of the determination of the effects (influences) using the principle of linear model as given in equation (1). The response is modelled by: X ai X i Y ¼ a0 þ ð1Þ i
where Y, the response; Xi, factor (parameters and interaction between them); ai, coefficients of model (effect of factor Xi) According to a student criterion (Demonsant, 1996), based on the evaluation of the variance of repeatability (which measures the experimental dispersion), the factors which the influence is of the order of the noise of measurement will be eliminated from the model. Load-extension curve for the stitch line The stitch line is expected to play an important role in the tensile behaviour of the assembly. In fact, the deformation of the assembly is a mixture of the deformation of the fabric and that of the seam. Then, in order to highlight the seam behaviour, we establish an extension-load curve for the stitch line by making the difference, for a given force, between the displacement of the assembly and that of the fabric. Consequently, tensile behaviour of the fabric before its sewing needs to be done.
Influence of sewing parameters 237
IJCST 18,4
238
Materials and methods In the present work, the investigation was carried out upon a plain weave fabric with the weight per square meter 109.72 gm2 2, the warp is a polyester textured filament (17 Tex, 24 Ends cm2 1) whereas the weft (16 Picks cm2 1) is composed alternatively by cotton spun yarns (33 Tex) and polyester spun yarns (50 Tex). Taking into account theses characteristics, the fineness of spun sewing threads was adjusted to 30 Tex and we choose a needle with small ball point shape. Then, five parameters have been researched: the needle size, the edge of seam, the stitch density, the stitch type and the sewing thread (fibre type). In order to reveal their influences, two levels were selected for each parameter, the details of these parameters are given in Table I. To avoid any dissimulation of the effects, we choose the complete design plan 25 (32 tests), this means that we do not neglect any interaction (the model include all parameters and all the interaction between them). Each test was repeated three times to take into account experimental dispersion. As far as seam was done following the two directions of fabric, we have established a design plan for each type of assembly: warp assembly (WRi code) and weft assembly (WFi code). In total we prepared 192 samples. In Table II we give the design plan for weft assembly which listed the samples which will be subjected to the tensile test. For example, WF 12 means that this is a weft assembly sample sewn following the combination of needle Nm 7O, edge of seam 5 mm, stitch density 6 stitches cm2 1, lockstitch, cotton spun sewing thread. The seams were made with one layer of fabric according to the international standard ISO 13935-1 (seam rupture using the strip method). A Brother industrial lockstitch machine (model SL 755-403-A) with Schmetz needle 134 SES (Nm70, Nm80) and a Brother chainstitch machine (model DT4-B 261) with Schmetz needle UY 128 GAS (Nm70, Nm80) were used for these trials. Before investigating assembled samples, a tensile test on fabric (in warp and weft direction) was carried out using the French norm NF G 07119 (strip test method). Results and discussion Analysis of rupture Experimentation reveals 4 types of assembly failure. In fact, in the vicinity of seam, a first visual analysis of the displacement of yarns made it possible to bring out two major phenomena occurring before the rupture of assembly: contracting of seam or seam slippage what is given, respectively, in Plate 1. We had found that the contracting of seam has always induced the breaking of the sewing thread (Type 1) without any damage of the sample, whereas when seam slippage occurs, the seam is still intact but yarns in the fabric pull out of the seam from the edge (Type 2), sewing thread has ruptured leaving holes due to yarn slippage (Type 3), damage of the fabric along the stitch line (Type 4). Plate 2 shows these types. For each test we have noted the type of assembly failure. The exam of results demonstrated a correlation between certain parameters and assembly breakage. In fact, Parameter Level A: needle size B: edge of seam C: stitch density D: stitch type
Table I. Considered parameters and their levels
High: þ1 Low: 2 1
Nm 70 Nm 80
10 mm 5 mm
6 stitches/cm 3 stitches/cm
E: sewing thread
Double Chainstitch Polyester Lockstitch Cotton
Sample code WF 1 WF 2 WF 3 WF 4 WF 5 WF 6 WF 7 WF 8 WF 9 WF 10 WF 11 WF 12 WF 13 WF 14 WF 15 WF 16 WF 17 WF 18 WF 19 WF 20 WF 21 WF 22 WF 23 WF 24 WF 25 WF 26 WF 27 WF 28 WF 29 WF 30 WF 31 WF 32
C 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21
Parameters level B 1 1 1 1 1 1 1 1 21 21 21 21 21 21 21 21 1 1 1 1 1 1 1 1 21 21 21 21 21 21 21 21
D
A
E
1 1 1 1 21 21 21 21 1 1 1 1 21 21 21 21 1 1 1 1 21 21 21 21 1 1 1 1 21 21 21 21
1 1 21 21 1 1 21 21 1 1 21 21 1 1 21 21 1 1 21 21 1 1 21 21 1 1 21 21 1 1 21 21
1 21 1 21 1 21 1 21 1 21 1 21 1 21 1 21 1 21 1 21 1 21 1 21 1 21 1 21 1 21 1 21
Influence of sewing parameters 239
Table II. Design plan for weft assembly
Plate 1. Major phenomena occurring before the rupture of assembly
IJCST 18,4
240
Plate 2. Types of assembly failure
when the stitch density level is low, the rupture type1 take place (32 samples: WF17-WF32 and WR17-WR32). When the stitch density level is high and the seam edge level is low the rupture type 2 occurs (16 samples: WF9-WF16 and WR9-WR16). Whereas, at the high level of both stitch density and the edge of seam, either the ruptures types 2, 3, or 4 have been proved to happen (16 samples: WF1-WF8 and WR1-WR8) as given in Table III. When the stitch density has its minimal value, a rupture of the sewing thread is constantly noted: the weak friction between the sample and the seam produces the contracting of the seam letting appear “holes” which progressively become more significant with the increase of the effort, the stitch line is prone to a longitudinal deformation which grows until its rupture. Whereas, when stitch density grows (high level), there is a strong adherence seam-sample, the stitch line piles up the weft of the sample and dice the small efforts, the warp has to slip from the edge (yarn slippage). Consequently, at the low level of the edge of seam, yarn in the fabric rapidly pull out of A: Needle size Nm 70 Nm 80 E: sewing thread E: sewing thread Polyester Cotton Polyester Cotton Warp/weft Warp/weft Warp/weft Warp/weft Table III. The rupture types 2, 3, and 4 of the assembly
D: stitch type Lockstitch Double chain stitch
3/3 2-3/4-3
3/3 2-3/4-3
2-3/2-3 2/4-3
3/3 3/4-3
the seam from the edge which produces rupture of the assembly by tearing of the sample (the warp and the weft of fabric are not interlaced any more). However, when it is at its high level, the edge of seam play the rule of inhibitor and the stitch line resist more to this slip what make it possible three ruptures: . Type 2: nevertheless by tearing of the sample, when the slip takes the top (depends on the size of needle, on the stitch geometry). . Type 3: yarn slippage is yet difficult, sewing thread breaks. . Type 4: the stitch line is more resistant than the sample; it is strongly opposed to this slip, what shear the sample at the level of seam and induce damage of the sample. We note sometimes a little rupture of the sewing thread.
Influence of sewing parameters 241
The variation in assembly failure is attested by the differences in the load-extension curves: abrupt rupture (type 1) of the curve and progressive isolated breakage due to seam slippage (type2, 3, 4) which is taken in Figure 1. It also reveals the influence of the stitch density and the edge of the seam upon the tensile behaviour of the assembly. Extension-load curve for the stitch line Figure 2 gives an example of an extension-load curve for stitch line (warp) by which we assess the differences in the seam behaviour: for assembly with low stitch density we find identical curves for the stitch line which prove correlation observed before. In addition, the influence of the edge of seam is revealed for high stitch density: before rupture, for a given force, displacement is more important at the low level of the edge of seam than at its high level which demonstrates that edge of seam inhibits yarn slippage. It is also clearly shown that, for a given force, seam is highly deformed at its low level density (undulation of seam) than at its high level one. Analysis of experimental designs For the analysis of experimental designs, we targeted five answers: from assembly load-extension curve we raise the breaking strength (Fmax), the breaking elongation (Almax) and the energy (W). To determine the most depending parameters upon the behaviour of the seam, we release from the extension-load curve for the stitch line, the
Figure 1. Different paces of load-extension curves for assembly
IJCST 18,4
242
Figure 2. Extension-load curves for stitch line
breaking elongation of the stitch line (Al Diff max) and the energy which was provided (WDiff). The found results show that some interactions (even until order 4) are more influential on the answer than some principal factors. Figure 3 gives two examples of warp assembly results relating, respectively, to the deformation of the stitch line (ALDiffmax) and to the breaking strength of assembly (Fmax), the digraph classes the effects by order of importance. The dotted line determines, according to the criterion of Student, the non influential effects (those which are on the left of the line). . Contrary to expectation, the stitch geometry does not have any influence on the breaking strength (Fmax), whereas it proves meaning on the deformation of the seam (ALDiffmax). In fact, the deformation of seam increases as the stitch passes from lock stitch to double chain stitch what is in conformity with the characteristics of these two stitches: the lock stitch pile up better seams whereas doublechain stitch gives more elasticity due to its way of formation. . The interaction density/edge of seam is also revealed to be a decisive parameter and has a crucial role on the behaviour of assembly: the effect of the variation of the stitch density is closely dependent on the level of the edge of seam; this result confirms the types of found ruptures. . The type of thread fibre is a very important parameter. Its fundamental influence upon either strength of assembly and slippage of the seam has been demonstrated. . The results found in warp assembly are similar to theirs of weft assembly. However, there are some differences which attest those influences of fabric construction: the differences between yarns (twist, size, yarn fibre, density) affect the frictional behaviour of seam (strength and slippage). In Table IV, we have recapitulated the three most significant effects relating to the five answers targeted.
Influence of sewing parameters 243
Figure 3. Classification of the effects of warp assembly
Warp assembly
B
E
Al max Fmax W Al Diff. max W Diff
2 1 1 2
1 2 3 1 1
AE
BC
CDE
3 3 2 3 3
2
Weft assembly
B
C
E
Al max Fmax W Al Diff. max W Diff
3
1 1 1
2 2 2 1 1
3
2
BC
CD
ADE
3
2
3 3
Table IV. The three most influential factors
IJCST 18,4
244
Figure 4. Models predicting the deformation energy of the stitch line
Linear models predicting the response Using the Student criterion, we could detect the factors of which the effect proved to be real and we eliminated the other factors from the model which influence is of the order of the noise of measurement. For each answer, a linear model is established and identified. We give in Figure 4 two examples of models predicting the deformation energy of the stitch line WDiff in the warp and in the weft direction. This figure, shows,
for each test (32 tests), the maximum experimental answer, the minimal experimental answer, the response of the complete model with 32 coefficient which takes into account all the factors and all the interactions and which coincides as well with the average of the experimental results, and finally the model with 12 coefficients obtained by eliminating the non significant effects. The exam of the curves demonstrates that the model given with the 12 significant coefficients presents a very little variation, compared to the complete model, and it makes it possible to give results included in the beach of the experimental values. Then, the models obtained by the experimental designs appear to predict well the tensile behaviour of our sewn fabric. Conclusion The focus of our study was the examination of the influence of selected sewing parameters upon the tensile behaviour (strip test method) of a fabric assembly. The investigation was carried out, upon a given fabric, using the approach of experimental design. Experimentation has revealed two major phenomena occurring before rupture (contracting of seam or seam slippage) and four standards of rupture of sewn samples. Analysing experimental designs for each type of assembly gives us very interesting results: it confirms the high influence of sewing thread (fibre type) and demonstrates as well the importance of interactions between factors, in particular, the interaction between stitch density and the edge of seam. Results in warp direction proved some differences with weft direction, then, fabric construction affects the behaviour of sewn fabrics. Linear models predicting each response were established by using significant factors, their confrontation with experimental results shows a very little fluctuation (in some points). This can be explained by the variation of the dispersion of experimental results which affects the calculus of the coefficients. References Demonsant, J. (1996), Comprendre et mener des plans d’expe´riences, Afnor, France. Inui, S. and Yamanaka, T. (1998), “Seam pucker simulation”, International Journal of Clothing Science and Technology, Vol. 10 No. 2, pp. 128-42. Lindberg, J., Westerberg, L. and Svenson, R. (1960), “Wool fabrics as garment construction materials”, Journal of the textile Institute, Vol. 51, pp. T1475-93. Mahar, T.J., Ajiki, I. and Postel, R. (1989), “Fabric mechanical properties relevant to clothing manufacture: part I- structural balance, breaking elongation and curvature of seams”, International Journal of Clothing Science and Technology, Vol. 1 No. 2, pp. 5-10. Postle, R. (1998), “Quelles caracte´ristiques le confectionneur va t – il exiger des tissus rec¸us”, Journe´e Kawabata Du, 16 mars. Sauri, R.M., Manich, A.M., Lloria, J. and Barella, A. (1987), “A factorial study of seam resistance: woven and knitted fabrics”, Indian Journal of Textile Research, Vol. 12, p. 188. Souvay, P. (1995), Les plans d’expe´riences me´thode Taguchi, Afnor, France. Sundaresan, G., Hari, P.K. and Salhotra, K.R. (1997), “Strength reduction of sewing threads during high speed sewing in an industrial lockstitch machine, Part I: Mechanism of thread strength reduction”, International Journal of Clothing Science and Technology, Vol. 9 No. 5, pp. 334-45. Sundaresan, G., Hari, P.K. and Salhotra, K.R. (1998), “Strength reduction of sewing threads during high speed sewing in an industrial lockstitch machine, Part II: Effect of thread and
Influence of sewing parameters 245
IJCST 18,4
fabric properties”, International Journal of Clothing Science and Technology, Vol. 10 No. 1, pp. 64-79. Tartilaite, M. and Vobolis, J. (2001a), “Effect of fabric tensile stiffness and of external friction to the sewing stitch length”, Materials Science, Vol. 7 No. 1. Tartilaite, M. and Vobolis, J. (2001b), “The investigation of fabrics internal friction and relaxation processes interaction in sewing garments”, Materials Science, Vol. 7 No. 3.
246 Corresponding author Sabria Gribaa can be contacted at: [email protected]
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Tearing and tensile strength behaviour of military khaki fabrics from grey to finished process
Tearing and tensile strength behaviour
Arunangshu Mukhopadhyay and Subrata Ghosh
Received October 2005 Revised February 2006 Accepted February 2006
Department of Textile Technology, National Institute of Technology, Jalandhar, India, and
247
Somes Bhaumik Sarla Fabric Pvt. Ltd,Ghaziabad, India Abstract Purpose – This paper seeks to report an experimental investigation on the tearing and tensile strength behaviour of military khaki fabrics from grey to finished process. Design/methodology/approach – Uses three different types of military fabric (3 up 1 down twill), differing in type of constituent yarns (ring/rotor) in order to test their tearing and testing strength behaviour. Findings – Tearing strength of fabric is found to be very much susceptible to change due to the process variation, while fabric tensile strength is relatively less sensitive. Ring spun yarn fabric shows higher tearing strength compared with rotor spun yarn fabric. However, the difference in their tearing strength reduces substantially as the process approaches towards the finished state. On the other hand, rotor spun yarn fabric exhibits higher tensile strength along the warp. Tearing strength along bias direction is in between warp and weft wise tearing strength; whereas tensile strength is lowest while tested along the bias direction. During the grey to finished process, tear strength falls at bleaching and dyeing, and particularly drops in strength is being more at the dyeing stage. Originality/value – This study has investigated the tearing and tensile strength behaviour of military khaki fabrics from grey to finished state, developing understanding of the impact of different processes on the tearing strength, so that fabric of the required tear strength can be developed with process modification. Keywords Finished goods, Tensile strength, Fabric testing, Armed forces Paper type Research paper
Introduction Military land forces in particular require to move, live, survive and fight in hostile environment; which often demands garments of high serviceability. In this regard, the tearing and tensile strength are considered to be very important parameters in designing military khaki fabrics. The strength of the fabric not only depends on the strength of constituent yarns, but also on the structure of yarn and fabrics, and many other factors (Morton, 1949; Realff et al., 1991). However, in service life of military garment, tear strength of the fabric is used to give a reasonable direct assessment of The authors wish to thank Sh Anand Bhargava for preparing samples used in this study.
International Journal of Clothing Science and Technology Vol. 18 No. 4, 2006 pp. 247-264 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610668482
IJCST 18,4
248
serviceability, and a fabric with low tearing strength is generally an inferior product. In contrast to the tensile strength, that involves the force required to break a large number of yarns simultaneously, and is relatively insensitive to yarn and fabric structural parameters, the tearing strength is considerably affected by changes in yarn and fabric geometry, the state of relaxation of constituent material and yarn frictional characteristics (Skelton, 1980). In a number of research papers (Harrison, 1960; Scelzo et al., 1994; Taylor, 1951), the effect of various factors such as testing method employed, type of yarn, thread spacing, crimp, weave and finishing treatment on tearing strength of woven fabric have been discussed. Different processes, after grey fabric manufacturing, can affect tearing strength by altering the single thread strength, ease of thread slippage, thread spacing and crimp. Although several workers have discussed the effects of common processes such as scouring and bleaching on tear strength of cotton fabrics, it has little relevance in present context. At present day scouring and bleaching can be performed simultaneously in a continuous operation under tension state. Under the said process, alkali depolymerizes cellulose chain and forms hydrocellulose, and with bleaching with peroxide, cellulose degrades by formation of oxycellulose (Freytag and Donze, 1983; Lewin, 1983), which coupled with the effect of tension may decrease yarn strength. On the other hand, swelling of cotton fibre due to alkali treatment improves fibre packing inside the yarn, which consequently tends to increase yarn tensile strength. Yarn also becomes harsh and hairy; all these factors along with the change in fabric constructional parameter can have significant influence on tensile and tearing strength of fabric. A several workers confirm that mercerization improve tearing strength of fabric (Morton and Turner, 1928; O’Brien and Weiner, 1954; Mazzeno et al., 1957; Reinhardt et al., 1958; Ziiffe et al., 1959). Mercerization of cotton usually results in increased single-thread strength, a reduction in yarn diameter, and a greater smoothness of the threads (Paul, 2003) – all these factors lead to an increased tearing strength. However, after mercerization, the impact of subsequent processes such as dyeing and sanforizing on cotton fabric are not known. In a study to investigate the impact of ring and rotor spun cotton yarn on the tearing strength of plain woven fabric, Scelzo et al. (1994) have observed that the rotor spun yarn fabric can also exhibit higher tearing strength depending on linear density of thread and direction of tearing. In case of fabric tensile strength, strength realization of rotor yarn in fabric is significantly higher than ring yarn fabric (Hari and Shankaranarayanan, 1984; Lord and Radhakrishnaiah, 1988). Present work is aimed at to investigate the tearing and tensile strength behaviour of military khaki fabrics from grey to finished state. This study is intended to develop understanding about the impact of different process on tearing strength, so that fabric of required tear strength can be developed with process modification. Further it is also important to investigate the impact of yarn structure (ring and rotor spun yarn), on the fabric tearing and tensile strength with the change of process. In this context, it is important to note that in most of the practical situation, the emphasis is given on the use of finish for the improvement of tearing strength of fabric. Experimental Three different types of military fabric (3 up 1 down twill) differing in type of constituent yarns (ring/rotor) are used for the present study. Fabrics are made in Sulzer
weaving machine under same set-up, using ring and rotor spun yarn of same linear density (37 Tex) with nominal twist of 7 twist/cm. The thread density at the loom state was 33.5 ends/cm (85 ends/inch) and 16.5 picks/cm (42 picks/inch) for all three types of fabric, viz., fabric composed of ring spun yarn as warp and weft, ring spun yarn as warp and rotor spun yarn as weft, and rotor spun yarn as warp and weft. The breaking strength, strain at fracture and force at 1 per cent strain of ring yarn are 6.73 N, 7.7 per cent, and 71.09 cN, respectively; whereas for rotor yarn the corresponding values are 4.93 N, 6.4 per cent and 50.03 cN (tested following ASTM D2256 88). The fabric specifications are given in Table I. The various steps of manufacturing finished fabric from grey stage are shown below. Grey fabric ! Desizing ! Scouring and bleaching ! Mercerization ! Dyeing ! Sanforizing The fabrics are processed in continuous manner under tension at different stages of processing (except desizing). Fabrics are desized in Osthoff Singe machine (Germany) with enzyme (Bactasol TK, BASF (India) Ltd) – 5 g/l, wetting agent (Kierlon MFB, BASF (India) Ltd) – 3 g/l and sequestering agent (Sirrix 2UDI, Clarient India Ltd) – 3 g/l. Desized fabrics are scoured with 40 g/l NaOH (988Tw), steaming at 958C for 20 min and simultaneously bleached with the recipe given below, in a continuous pretreatment range (PTR) machine (Benninger AG., Switzerland) followed by neutralisation with acetic acid. Bleaching recipe: NaOH (708 Tw) – 20 ml/kg H2O2 – 30 ml/kg (strength – 50 per cent w/w) Stabilizer – 11 ml/kg (Prestogen D, BASF (India) Ltd) Sequestering agent – 3.5 ml/kg (Invatex SA, Ciba Speciality Chemicals) Wetting agent – 3.5 ml/kg (Sandozine, Clarient India Ltd) The bleached fabrics are mercerized in Bendimenza (Benninger AG. Switzerland) with NaOH (488 Tw) at 278C followed by neutralization with acetic acid. The bleached fabrics are dyed with combination of Novelon brown R – 2.75 g/l and Solanthrene vat dyes (Yellow 3R – 0.65 g/l, Grey 2B – 0.19 g/l and Rubine 6B – 0.60 g/l) in Pad-Dry-Pad-Steam machine (Benninger AG. Switzerland) followed by neutralization with acetic acid. In the continuous process the dyed samples are sanforised in a sanforizing machine (Swastik, Ahmedabad, India). Tearing strength of fabric is measured using both Elmendorf tester and universal tester (ZWICK – model 1441). Elmendrof test is more traditional which measure the tearing strength of the specimen following impact loading (ASTM D 1424-96 (2004)). In case of measurement of tearing strength of fabric by the tongue procedure at ZWICK universal tester, the method based on (ASTM D 2261-96 (2002)) is followed, except the rate of extension level set at 1,000 mm/min. The above extension level was chosen since in most of the practical situation during military operation, fabric failure through tearing involves high level of extension rate. The tensile strength of fabrics are evaluated using ZWICK universal tester (model 1441) keeping fabric width and gauge length both are at 50 mm taking rectangular sample
Tearing and tensile strength behaviour 249
Table I. Dimensional and related properties of fabric (3/1 twill) 4.2 7.2 10.3 8.3 10.5 11.3
6.5 12.7 5.1 3.5 3.6 4.9 4.5 13.4 4 3.2 3.7 4.1
17.3 17.3 16.5 16.5 16.5 17.7
7.3 6.8 8.8 7.2 9.8 8.1
6.1 10.3 10.6 9.5 9.8 12
5.1 12.3 4.3 3.6 3.6 4.2
Crimp (per cent) Warp Weft
17.7 17.7 15.7 15.7 15.7 17.7 yarn as weft 17.7 18.1 16.9 16.9 16.9 18.6
Note: aCalculated without considering the weight of size material
Fabric composed of ring spun yarn as warp and weft Grey 35.4 Desized 39.8 Scoured and bleached 39.7 Mercerized 37 Dyed 38.6 Sanforized 38.6 Fabric composed of ring spun yarn as warp and rotor spun Grey 35.4 Desized 40.1 Scoured and bleached 40.5 Mercerized 38.1 Dyed 39.8 Sanforized 39.8 Fabric composed of rotor spun yarn as warp and weft Grey 35 Desized 40.1 Scoured and bleached 40.1 Mercerized 38.2 Dyed 40.1 Sanforized 40.1
Threads/unit length Ends/cm Picks/cm
243.8 237.9 221.5 210.6 221.9 225.8
236.7 236.3 225.6 215.7 220.2 230.9
230.4 238.9 216.2 206.2 210.5 220.1
204a 236.6 220.7 211.3 220.9 225.2
207.7a 239 226.5 213.6 221.7 231.1
207.1a 237.6 217.2 205.4 211.7 221.3
Fabric weight (g/m2) Actual Calculated
250
Type of fabric
IJCST 18,4
piece of 100 £ 50 mm: Lower gauge length than that of standard, and lower value of length to width ratio (1:1) is taken in view of smaller specimen dimension in case of tearing test and at the same time for avoiding necking phenomena during tensile testing. During loading at constant rate of extension, jaw speed up to the preload of 50 cN is set at 50 mm/min and thereafter speed of 1,000 mm/min is kept up to the breaking point. In the above test, higher rate of extension is kept for comparative assessment of the results with tear strength. For the measurement of tensile properties of yarn taken from fabric, gauge length and test speed are kept at 50 and 1,000 mm/min, respectively. Results and discussion The tearing and tensile strength of the fabric, whose dimensional properties are given in Table I, are presented in Tables III and IV and Figures 4-9. To analyse the strength behaviour of fabric in relation to yarn tensile properties, the latter properties are also investigated (Table II and Figures 1-3). The decrease in warp yarn strength due to desizing is expected. After desizing, yarn strength reduces at scouring and bleaching; the extent of reduction in strength being more for warp yarn. Under the said process, alkali depolymerizes cellulose chain and forms hydrocellulose, and with bleaching with peroxide, cellulose degrades by formation of oxycellulose. Since, during the above process fibre becomes weaker, higher level of yarn tension leads to further drop in strength as in the case of warp yarn. Higher warp yarn tension level also results in lower level of yarn crimp (Table I). In the subsequent operation after bleaching, the nature of change of force at fracture of warp and weft yarns is similar. On mercerization, strength of both warp and weft threads increase significantly; the change being large for rotor yarn strength as compared to ring yarn. At other stages following mercerization, the change in the above parameter is marginal. It is found that the influence of different process on yarn strain at fracture is different for warp and weft yarn, which can be attributed to the differences in tension level on the threads while processing the fabric at different stages. Yarn strain at fracture is highest for desized and mercerized process corresponding to warp and weft threads, respectively. Owing to scouring and bleaching, fall in yarn strain at fracture is expected and is more for warp yarn. Following the above process, mercerization at higher tension (on warp) and slack state (on weft) results in corresponding decrease and increase of strain at fracture. It may be noted that the ring spun yarn exhibits higher strain at fracture than rotor spun yarn. The behaviour of force required at 1 per cent strain (also indicate yarn modulus) for warp and weft threads with the change of process is similar, except substantial drop of the above parameter at desized state for warp yarn. At desizing process, removal of size material from the warp yarns makes them less stiff. The above initial yarn parameter is higher for bleached and dyed yarn, indicating that yarn become stiff due to the above processes. It may be noted that ring yarn exhibits little higher value of the said parameter as compared to rotor yarn in a specific direction. Further during processing of fabric since the longitudinal thread is subjected to greater tension, the warp yarn exhibit higher value of force at small extension. The impact of different process on tearing and tensile strength are discussed in the following sections, in relation to the change of tensile properties of yarn.
Tearing and tensile strength behaviour 251
Table II. Tensile properties of yarn taken from fabric
Fabric composed of ring spun yarn as warp and weft Grey 7.72 6.9 Desized 6.8 6.8 Scoured and bleached 6.0 6.5 Mercerized 7.7 7.8 Dyed 7.7 7.8 Sanforized 7.8 7.9 Fabric composed of ring spun yarn as warp and rotor spun yarn as weft Grey 7.8 4.3 Desized 6.2 4.5 Scoured and bleached 5.8 4.4 Mercerized 7.4 6.2 Dyed 7.3 6.4 Sanforized 7.4 6.4 Fabric composed of rotor spun yarn as warp and weft Grey 5.9 4 Desized 4.3 4.1 Scoured and bleached 3.8 3.9 Mercerized 5.8 5.9 Dyed 6 6.1 Sanforized 6.2 6.2
Force at fracture (N) Warp Weft 6.9 7.8 7.1 8.6 7.3 7.1 5 6.2 5.8 7.1 6.1 5.7 4.8 5.6 5.4 6.6 5.7 5.4
5.3 7.1 5.6 5.4 5.2 4.9 5.1 6.8 5.3 5.2 5.1 4.7 4.8 5.6 4.9 4.7 4.5 4.4
Strain at fracture (per cent) Warp Weft
97.6 58.8 65.7 57.8 70.2 71.1
115.3 61.3 79.2 68.7 84.5 80.8
129.4 68.1 89.4 70.5 88.8 83.5
30.8 30.5 40.3 31.6 53.8 52.1
32.7 31.4 42.2 32.6 56.3 57.1
37.6 42.6 49.2 35.6 60.3 61.2
Force at 1 per cent strain (cN) Warp Weft
252
Fabric type
IJCST 18,4
Tearing and tensile strength behaviour 253
Figure 1. Breaking strength of yarn taken from fabric
Effect of different process on fabric tearing strength It has been observed from Table III and Figures 4-6 that different process have significant impact on the fabric tearing strength. The tearing strength measured using two different method follows similar trend with the change of process. However, in all the cases, fabric tearing strength under impact loading (using Elmendorf tester) is higher than the evaluated strength under steady state of extension (using Universal tester). The trend of changing tearing strength is similar in warp, weft and bias direction and for three types of fabric (Table IV). At grey state difference in tearing strength among three types of fabrics is large, which reduces substantially on reaching dyed and sanforized state. However, after sanforizing process the fabric made out of ring spun yarn still shows higher tearing strength than the fabric composed of rotor spun yarn. The fabric made out of ring spun yarn as warp and rotor spun yarn as weft may have higher or lower
IJCST 18,4
254
Figure 2. Breaking elongation of yarn taken from fabric
tearing strength to that of rotor yarn fabric at different stages of processing and at different test direction. However, its tearing strength is always lower than the fabric composed of ring spun yarn. It is also noticed that fabric tearing strength is maximum along weft, while its value along bias direction is intermediate in between warp and weft way tearing strength. Higher value of tearing strength along weft can be attributed to much higher warp thread density than weft thread density (Table I). It is seen that the fabric tearing strength varies largely from grey to finished state. Owing to desizing, there is substantial improvement in tearing strength along warp. This is primarily due to increased yarn flexibility and a greater smoothness of warp yarns – both these factors lead to higher yarn mobility at the del zone during tear propagation. Consequently, a greater number of transverse yarns tend to share the load during tear which results in higher fabric tearing strength. The study also reveals that bleaching and dyeing process results in substantial drop in fabric tearing strength with some increase of the said parameter at the intermediate
Tearing and tensile strength behaviour 255
Figure 3. Force at 1 per cent strain of yarn taken from fabric
stage due to mercerization. The increase in tearing strength at mercerization is in agreement with the earlier findings (Morton and Turner, 1928; O’Brien and Weiner, 1954; Mazzeno et al., 1957; Reinhardt et al., 1958; Ziiffe et al., 1959). The drop in tearing strength due to scouring and bleaching can be attributed to fall in yarn strength (Table II) and increase in yarn rigidity (indicated by higher value of force at 1 per cent strain in Table II) and decrease in yarn smoothness. It is observed that particularly the fall in tearing strength due to dyeing is very large. During the dyeing process with vat dye, dyes form crystals inside the fibre, which in turn result in increased stiffness and decreased extensibility of fibrous assemblies. The yarn test results (Figure 3) also indicate higher yarn modulus after dyeing of fabric. It may be noted here that the yarn strength is not reduced after the dyeing process. Hence, fall in fabric tearing strength due to dyeing process may be attributed to increase in the value of yarn stiffness coupled with lower level of extensibility (Figure 2), and change in some undermined parameters such as yarn surface
Table III. Effect of fabric type on fabric tearing strength Tearing strength at impact (N) Weft
Fabric composed of ring spun yarn as warp and weft Grey 40.18 56.32 Desized 53.72 58.88 Scoured and bleached 43.63 51.45 Mercerized 50.23 55.05 Dyed 30.76 41.92 Sanforized 34.52 42.56 Fabric composed of ring spun yarn as warp and rotor spun yarn as weft Grey 32.62 52.04 Desized 42.9 56.32 Scoured and bleached 27.23 40.23 Mercerized 42.41 45.76 Dyed 20.23 36.78 Sanforized 27.51 37.76 Fabric composed of rotor spun yarn as warp and weft Grey 21.35 40.96 Desized 38.88 42.56 Scoured and bleached 25.74 37.76 Mercerized 37 50.56 Dyed 18.21 35.84 Sanforized 23.86 34.12
Warp 35.1 47.1 35.7 47.3 18.4 23.6 28.6 33.5 23.6 26.6 8.8 17.7 18.7 31.5 19.8 31.4 13.1 15.4
38.72 48.42 36.48 43.92 32.35 33.28 30.4 39.24 27.84 39.36 27.1 26.64
34.5 39.4 33.2 39.8 22.7 24.9
39.5 52.6 33.5 38.4 25.6 27.6
51.1 57.3 40.6 49.2 32.8 31.6
23 34.3 20.6 32.6 14.8 18
30.6 46.2 31.5 37.5 17.7 20.6
41.4 50.2 37.1 49.4 27.4 28.7
Tearing strength at steady speed (N) Warp Weft Bias
48.64 55.23 49.92 53.76 38.84 37.76
Bias
256
Properties Fabric type
IJCST 18,4
Tearing and tensile strength behaviour 257
Figure 4. Fabric tearing strength (along warp) results using
characteristics, yarn diameter and contact pressure between warp and weft, etc. At sanforizing process following dyeing, improvement in tearing strength is also noticed along warp. Effect of different process on fabric tensile strength The effect of different processes on fabric tensile strength at different direction can be seen from Figures 7-9. It has been observed that the warp way breaking strength of the fabric changes significantly as the process changes from grey to desized state. In spite of fall of warp yarn strength at desizing (Figure 1), the strength of fabric might increase due to the predominant effect of increased warp density due to
IJCST 18,4
258
Figure 5. Fabric tearing strength (along weft) results using
desizing. Owing to desizing, strength of rotor spun yarn fabric increases considerably, while fabric strength falls in case of ring spun yarn fabric. Tenacity value also show the similar feature indicating the greater strength realization (weaving assistance) for rotor spun yarn when made into fabric. At the end of the complete process, rotor spun yarn fabric exhibit much higher warp wise strength than ring yarn fabric. In the subsequent process after desizing, the change in fabric strength is relatively small. The change in fabric strength at different phases can be correlated primarily with the change in yarn strength and thread density, and onset of jamming condition (decide yarn configuration under stress and at breaking point). The interaction between warp and weft yarn also seems to be important, since the strength of fabric made out of ring spun warp yarn and rotor spun weft yarn is behaving typically (Figure 7) and become closer to rotor spun yarn fabric towards the end of the process. In all other direction ring yarn fabric is stronger than rotor yarn fabric at all stages of processing. Fabric made out of ring spun yarn as warp and rotor spun yarn as weft, when tested weft wise and along bias direction, exhibits similar strength to that of fabric made out of rotor spun yarn. With the change of the
Tearing and tensile strength behaviour 259
Figure 6. Fabric tearing strength (along biased) results using
process, the impact on absolute breaking strength and tenacity (along the above stated direction) is not much affected. It is also seen that the fabric strength along bias direction is lowest than the strength along other two direction (warp and weft wise). The above finding is primarily due to a major proportion of constituent yarn are not gripped by two jaws owing to their alignment and while stressing of fabric along bias direction, mainly inter-yarn friction influence the fabric strength. It is seen that in bias testing, the difference in strength between fabric made out of ring spun yarn and fabric composed of rotor spun yarn is lowest. Relative comparison between tear and tensile strength In a general observation, it can be stated that with the change in process variation, fabric tear strength is much more susceptible to change than fabric breaking strength. Further it is noticed that higher yarn strength may not necessarily lead to
Table IV. Effect of fabric type on fabric tensile properties Fabric breaking strength (kN/m) Weft
Fabric composed of ring spun yarn as warp and weft Grey 23.59 10.99 Desized 19.71 11.61 Scoured and bleached 17.12 10.04 Mercerized 17.65 12.15 Dyed 20.6 12.42 Sanforized 21.34 12.88 Fabric composed of ring spun yarn as warp and rotor spun yarn as weft Grey 19.36 8.28 Desized 21.48 7.81 Scoured and bleached 20.12 6.51 Mercerized 22.65 9.17 Dyed 23.78 8.59 Sanforized 24.1 9.1 Fabric composed of rotor spun yarn as warp and weft Grey 14.75 8.05 Desized 18.58 6.88 Scoured and bleached 17.34 6.08 Mercerized 20.24 8.68 Dyed 22.56 8.63 Sanforized 23.6 8.85
Warp 10.24 8.25 7.92 8.56 9.79 9.7 8.18 9.08 8.92 10.5 10.8 10.44 6.05 7.81 7.83 9.61 10.17 10.45
6.84 5.98 5.18 6.56 5.44 4.59 5.34 6.26 5.36 6.25 5.19 4.2
Warp
7.95 8.86 8.07 8.21 6.27 5.72
Bias
3.3 2.89 2.75 4.12 3.89 3.92
3.5 3.3 2.89 4.25 3.9 3.94
4.77 4.86 4.64 5.89 5.9 5.85
Tenacity (cN/tex) Weft
260
Properties Fabric type
2.19 2.63 2.42 2.97 2.34 1.86
2.89 2.53 2.30 3.04 2.47 1.99
3.45 3.71 3.73 3.98 2.98 2.6
Bias
IJCST 18,4
Tearing and tensile strength behaviour 261
Figure 7. Fabric strength (along warp)
higher tear strength. The drop of fabric tearing strength is very significant due to vat dyeing process. On the other hand changes in yarn and fabric tenacity are marginal due to the above process. Ring spun yarn/rotor spun yarn or their combination in fabric works differently for fabric tearing and tensile strength. Ring spun yarn fabric always exhibits higher value of tearing strength, while in case of fabric tensile testing; rotor yarn fabric might show higher strength. However, difference in tearing strength of three different fabrics is minimized towards the end of the process. Fabric tearing strength and tensile strength are maximum when tested the fabric along weft and warp direction, respectively. It has been also noticed that tearing along bias direction shows intermediate value to that of fabric tear strength along warp and weft; while in case of tensile testing, breaking strength of fabric is minimum along bias direction. Conclusions Tearing strength of military khaki fabrics vary widely with the change of process from grey to finished stage. On the other hand, under similar situation fabric
IJCST 18,4
262
Figure 8. Fabric strength (along weft)
tensile strength is relatively less sensitive. Ring spun yarn fabrics, although found to be superior for fabric tearing strength, but it possesses relatively lower tensile strength (along warp) than rotor spun yarn fabrics. Towards the end of the process, difference in tearing strength between ring and rotor spun yarn fabric reduced considerably. Tearing strength value, along bias direction, is in between warp and weft wise tearing strength, whereas tensile strength is lowest along the said direction. During the grey to finished process, tear strength falls at bleaching and dyeing; drop in strength being more at the latter stage. Further investigation is required for in depth analysis of the above phenomena. At the same time an alternative mode of dyeing should be evolved for developing military fabrics with improved tearing strength.
Tearing and tensile strength behaviour 263
Figure 9. Fabric strength (along bias)
References Freytag, R. and Donze, J-J. (1983), “Alkali treatment of cellulose fibres”, in Lewin, M. and Sello, S.B. (Eds), Handbook of Fibre Science and Technology: Vol I; Chemical Processing of Fabrics – Fundamental and Preparation; Part – A, Mercell Dekker Inc., New York, NY, pp. 91-121. Harrison, P.W. (1960), “The tearing strength of fabrics – A review of literature”, J. Textile Inst., Vol. 51, pp. T91-131. Hari, P.K. and Shankaranarayanan, G. (1984), “Comparison of physical and mechanical properties of ring and rotor spun yarn fabrics”, Indian J. of Textile Res., Vol. 9, pp. 85-9. Lewin, M. (1983), “Bleaching”, in Lewin, M. and Sello, S.B. (Eds), Handbook of Fibre Science and Technology: Vol I; Chemical Processing of Fabrics – Fundamental and Preparation; Part – B, Mercell Dekker Inc., New York, NY, pp. 93-165.
IJCST 18,4
264
Lord, P.R. and Radhakrishnaiah, R. (1988), “A comparison of various woven fabrics containing friction, rotor and ring spun cotton yarn fillings”, Textile Res. J., Vol. 58, pp. 354-62. Mazzeno, L.W., Reinhardt, R.M., Markezich, A.R. and Reid, J.D. (1957), “After mercerization of methylolmelamine resin treated cotton fabrics”, American Dyest. Rep., Vol. 46, pp. 719-24. Morton, W.E. (1949), “Some observation on fabric strength in relation to yarn properties and density of structure”, J. Textile Inst., Vol. 40, pp. 262-5. Morton, W.E. and Turner, A.J. (1928), “The influence of the degree of twist in yarns on the results of yarn mercerization, and on the properties of plain fabrics made from grey (or) mercerized cotton yarns, Part II: The results of various strength tests on the fabrics”, J. Textile Inst., Vol. 19, pp. T189-222. O’Brien, W.E. and Weiner, L.I. (1954), “A study of some factors affecting the tear- and water-resistance of lightweight clothing and tentage fabrics”, Textile Res. J., Vol. 24, pp. 241-50. Paul, R. (2003), “Role of swelling agents in cellulose modification”, Textile Technology, October, pp. 21-5. Realff, M.L., Seo, M., Boyace, M.C., Schwartz, P. and Barker, S. (1991), “Mechanical properties of fabric woven from yarn produced by different spinning technologies: yarn failure as a function of gauge length”, Textile Res. J., Vol. 61, pp. 517-30. Reinhardt, R.M., Kullman, R.M.H., Noore, H.B. and Reid, J.D. (1958), “After mercerisation of wrinkle resistant cottons for improved strength and abrasion resistance”, American Dyest. Rep., Vol. 47, pp. 758-64. Scelzo, W.A., Barker, S. and Boyce, M.C. (1994), “Mechanistic role of yarn and fabric structure in determining tear resistance of woven cloth, Part I: understanding tongue tear”, J. Textile Inst., Vol. 65, pp. 291-304. Skelton, J. (1980), “Tearing behaviour of woven fabrics”, in Hearle, J.W.S., Thwaites, J.J. and Amirbayat, J. (Eds), Mechanics of Flexible Fibre Assemblies, Sijthoff & Noordoff, Germantown, MD, pp. 243-53. Taylor, H.M. (1951), “Tensile and tearing strength of cotton cloths”, J Textile Inst., Vol. 42, pp. T161-188. Ziiffe, H.M., Eggerton, F.V. and Segal, L. (1959), “Comparison of mechanical properties of cotton yarns and fabric treated with anhydrous ethylamine and with mercerising caustic”, Textile Res. J., Vol. 29, pp. 13-20.
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
Textile and apparel supply chain management in Hong Kong
Apparel supply chain management
Jimmy K.C. Lam Institute of Textiles and Clothing, the Hong Kong Polytechnic University, Hunghom, Hong Kong, and
R. Postle Department of Textile, The University of New South Wales, Sydney, Australia
265 Received October 2004 Revised March 2006 Accepted March 2006
Abstract Purpose – This paper aims to review the concept of supply chain management. The typical problems facing with textile and apparel supply chain are short product cycle for fashion articles, long production lead-time and forecasting errors for fashion items. The Hong Kong textile and apparel supply chain faces additional problems of distance from customers in the US and European markets, long production lead-times and minimum batch sizes for production, and, recently, elimination of quota restriction in the US market, all of which force them to improve efficiency and enhance competitiveness through supply chain management. Seeks also to provide a selective bibliography for industrial practitioners with sources which can help them develop their supply chain strategies for the fashion market in Hong Kong. Design/methodology/approach – A range of recent published (1993-2005) works, which aim to provide practical advice are critiqued to aid the individual practitioner to manage its supply chain strategies in Hong Kong. These sources are sorted into sections: supply chain management in Hong Kong, textile and apparel supply chain management in Hong Kong, and problems faced by small and medium-sized enterprises for textile and apparel supply chain. Findings – The differentiation of product demands into functional and innovative products helps the supply chain company to employ different supply chain strategies for different products, namely responsive supply chain strategy for innovative products and efficiency supply chain strategy for functional products. These two supply chain strategies are focused on the downstream supply chain aiming at shortening the time to research the market and also to reduce the stock levels in the retailing industry. Research limitations/implications – This is not an exhaustive list and cases are mainly from the Hong Kong textile and apparel industry, which perhaps limits its usefulness elsewhere. Practical implications – A very useful source of information and impartial advice for industrial practitioners to develop their own supply chain strategies for the fashion market in Hong Kong. Especially recently with the elimination of quota to the US market, the management of the supply chain is critical. Originality/value – This paper fulfils an identified information/resources need and offers practical help to industrial practitioners on then supply chain management for the Hong Kong textile and apparel industry. Keywords Supply chain management, Textile industry, Hong Kong Paper type General review
1. Introduction In recent years, “world class” organizations purchase products, move and market goods and services on a global basis in order to meet customers’ needs on a timely basis, with relevant and high quality products produced and delivered in a cost effective manner.
International Journal of Clothing Science and Technology Vol. 18 No. 4, 2006 pp. 265-277 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610668491
IJCST 18,4
266
To achieve this goal, the concept of supply chain management (Cox et al., 1995) has proven to be of vital importance especially for the Hong Kong textile and garment industries. Hong Kong has become an important sourcing and control centre for the global garment industry with production plants in China, Indonesia, Thailand and India (Hong Kong Government Industry Department, 1995). Although billions of dollars of apparel business are conducted in Hong Kong, relatively little knowledge about the management of supply chains is reported in published research. The technologies of electronic data interchange (EDI), flexible manufacturing, automated warehousing and rapid logistics appear to achieve little improvement in the supply chain management (Fisher, 1997). New management concepts such as quick response, efficient consumer response, mass customization, lean manufacturing again fail to deliver the cost saving and performance improvements in the supply chain (Fisher, 1997). 2. Supply chain management Companies have traditionally viewed themselves as entities that exist independently and have to compete against each other in order to survive. However, such mindset cannot be sustained as no organization can operate alone in complete independence. Firms are finding that they can no longer compete effectively in isolation of their suppliers or other entities in the supply chain and are realizing the benefits of collaborative relationships within and beyond their own organization (Cox et al., 1995). The concept of the supply chain and its management are attracting increasing attention on behalf of both academic and industrial practitioners. 2.1 Definition of supply chain management Various definitions of a supply chain have been offered in recent years as the concept has gained popularity. The APIC dictionary (Cox et al., 1995) describes the supply chain as: . the process from the initial raw materials to the ultimate consumption of the finished product linking across supplier-user companies; and . the functions within and outside a company that enable the value chain to make products and provide services to the customers. The Supply Chain Council (1997) uses the definition: The supply chain – a term increasingly used by logistics professionals – encompasses every effort involved in producing and delivering a final product, from the supplier’s supplier to the customer’s customer. Four basic processes – plan, source, make, deliver – broadly define these efforts, which include managing supply and demand, sourcing raw materials and parts, manufacturing and assembly, warehousing and inventory tracking, order entry and order management, distribution across all channels and delivery to the customers.
Quinn (1997) defines the supply chain as: . . . all of those activities associated with moving goods from the raw materials stage through to the end-user. This includes sourcing and procurement, production scheduling, order processing, inventory management, transportation, warehousing and customer services. Importantly, it also embodies the information systems so necessary to monitor all of those activities.
In addition to defining the supply chain, several authors have further defined the concept of supply chain management. As defined by Ellram and Copper (1993), supply chain management is “an integrating philosophy to manage the total flow of a distribution channel from supplier to ultimate customer”. Monczka and Morgan (1997) state that:
Apparel supply chain management
. . . integrated supply chain is about going from the external customer and then managing all the processes that are needed to provide the customer with value in a horizontal way.
267
They believe that supply chains, not firms, compete and that those who will be the strongest competitors are those that: . . . can provide management and leadership to the fully integrated supply chain including external customer as well as prime suppliers, their suppliers, and their supplier’ suppliers.
From these definitions, a summary definition of the supply chain can be stated as: All the activities involved in delivering a product from raw material through to the customer including sourcing raw materials and parts, manufacturing and assembly, warehousing and inventory tracking, order entry and order management, distribution across all channels, delivery to the customer and the information systems necessary to monitor all of these activities.
Supply chain management coordinates and integrates all of these activities into a seamless process. It links all of the partners in the chain including departments within an organization and external partners including suppliers, carriers, third-party companies and information systems providers. Recently, a new type of supply chain is emerging in the industry, namely the late design responsive supply chain (Macedo, 2005). This supply chain combines the traditional supply chain and agile design-responsive supply chain together to eliminate product inventories and delivery times for fashion market. 2.2 Supply chain management in Hong Kong Two local supply chain management studies have been conducted in Hong Kong. The first study titled “Supply Chain Management, linkage to total industry benefits” was initiated by HKANA (1996) and commissioned by Coopers & Lybrand Consultants to access the impact of supply chain management on the domestic industry. The second study titled “Supply Chain Management in Global Trade” was again initiated by HKANA (1997) and commissioned by Kurt Salmon Associates to access the supply chain management for export industry. The first report identified the bottleneck to the implementation of supply chains in Hong Kong in terms of technology, information sharing, training and skill in understanding the supply chain management concept. Figure 1 shows that “no information sharing” is the major barrier to the implementation of supply chain management in Hong Kong. This may be due to the lack of trust amongst the trading partners and/or the lack of knowledge about the benefits of supply chain management. This issue was reported again by Borneman (2005) on his study in textile industry in US. Figure 2 shows that the awareness of supply chain management in Hong Kong is very low. Only 4 per cent of those surveyed indicated that they were “quite knowledgeable” about supply chain management. About 27 per cent of those surveyed
IJCST 18,4
268
Figure 1. Barriers to the implementation of SCM in Hong Kong
Figure 2. Awareness of SCM in Hong Kong
showed had “heard the term, but that’s all” and over 52 per cent mentioned that they had “never heard of it”. The low awareness of the supply chain management concept in the industry makes it difficult to share information amongst trading partners. The first report also benchmarked the supply chain performance of the Hong Kong manufacturers and retailers to the world average. Both are below the world average with the retailer supply chain performing slightly better than the manufacturer supply chain. As a result of this first Hong Kong report, the supply chain management resource centre was established by HKANA in 1998 to provide training and to increase the awareness of supply chain management for the Hong Kong industry. The second Hong Kong report by Kurt Salmon Associates (HKANA, 1997) identified that by implementation of supply chain management practices, Hong Kong’s export industries would save up to HK$9.2 billion (Australian $2.1 billion) on logistics and administration costs. The consultants concluded that the route for Hong Kong to excellence is to become the supply chain management thought-leader in global trade. The consultants further suggested that speed sourcing and replenishment are two key factors for Hong Kong to succeed in global supply chain management (HKANA, 1997). The two Hong Kong reports clearly show how important supply chain management is to the Hong Kong domestic and export industry. These reports indicate that the supply chain management practices in the Hong Kong industry are far below the world average.
3. Textile and apparel supply chain management in Hong Kong Although the two consultant reports show that Hong Kong industry in general is not well prepared for the supply chain management, the textile and apparel industry in Hong Kong, however, is quite different. A report on the techno-economic and market research study on Hong Kong’s textile, clothing and footwear industries (Trade and Industry Department, Hong Kong Government, 2000) shows that some supply chain management is already being undertaken by large enterprises in Hong Kong in response to demand from their buyers for supply chain co-ordination. The tactics includes: integration of supply chain through vendor partnership; streaming of supply chain through elimination of intermediaries; and focussing on core competency to gain competitive advantage, as shown in the following three examples. 3.1 Supply chain backward integration Fountain Set (Trade and Industry Department, Hong Kong Government, 2000) which is a major Hong Kong knitted fabric manufacturer, entered into agreements with several cotton yarn spinning mills in the Mainland of China to enhance control over the supply and quality of raw material. The manufacturer can reduce order lead-time as well as inventory levels. On the other hand, the spinning mills can receive a transfer of advanced production know-how to enhance their production efficiency. 3.2 Supply chain forward integration Textile Apparel Limited (TAL) (Trade and Industry Department, Hong Kong Government, 2000) is the major shirt manufacturer for the US market. It has partnered with J.C. Penney to monitor the weekly stock level of all its retail chain outlets and through its “SPEED” program, shirts can be manufactured and shipped to US within 48 h. Yue Yuen which is a Hong Kong-listed footwear manufacturer, has assisted Nike to source cheap but reliable raw material, manage inventories and deliver products, through a just-in-time system (Wall Street Journal, 2000). 3.3 Supply chain virtual integration As the biggest trading firm in Hong Kong, Li & Fung provides a “one-stop-shop” for its customers from product development, raw material sourcing, production planning and management, quality assurance, export documentation to shipping consolidation. As Li (Magretta, 1998) said: The policy of not owning any production facilities keeps the supply chain flexible and adaptable; encouraging the constant search for quality-conscious, cost-effective producers that can deliver to a deadline.
Li & Fung (Magretta, 1998) has been a pioneer in “dispersed manufacturing”. It performs the higher-value-added tasks such as design and quality control in Hong Kong and out sources the lower-value-added tasks to the best possible locations around the world. The result is a truly global product. To produce a garment, for example, the company might purchase yarn from Korea that will be woven and dyed in Taiwan, then shipped to Thailand for final assembly, where it will be matched with zippers from a Japanese company. For every order, the goal is to customize the value chain to meet the customer’s specific needs.
Apparel supply chain management 269
IJCST 18,4
270
3.3.1 Problems face by small and medium size enterprises for textile and apparel supply chain. Despite the success of the enterprises that have adopted the supply chain management concept in the textile and apparel industry, the industry members on the whole are still relatively small in order to take full advantage of the new concept. The success stories mentioned previously all involve large enterprises in Hong Kong. They are either the biggest trader (Li & Fung to 7,500 network producers) or the biggest manufacturer (TAL to J.C. Penny chain stores) or the biggest customer to suppliers (Fountain Set to China yarn suppliers) in the supply chain. However, most of the manufacturers in Hong Kong are small to medium scale and they lack the resources and bargaining power (unlike the big enterprises) in the supply chain. The findings from Hunter and Valention (1995) on the low success rate of quick response after a ten year period in US, may explain some problems facing supply chain management in the textile and apparel industry. Four problems were identified by Hunter and Valention (1995) on the failure of quick response in the apparel industry in USA. The following four problems were identified: (1) Too high expectations on behalf of the management from the program and the slow pace of changes in management practices and corporate culture. (2) Adversarial relationships between sectors change readily so partnerships do not remain: The major problem is that increase in profits coming from the practice of quick response goes to the retailer, while the up-stream participants take on most of the cost burden. Without some sharing of the benefits as well as the costs, partnerships are unlikely to develop. (3) The structural difference of the textile/apparel pipeline in industry: In sharp contrast to the automobile, appliance and electronic businesses, where the fabricator of the end-product dominates the smaller-parts suppliers and distributors, the apparel manufacturer is typically small with little influence over either the textile supplier or retailer. (4) The technical problems of standardization, communication and data accuracy in the industry: Although EDI has been used in industry for decades as a data exchange between different systems, no standard EDI format has been developed. Different vendors have their own EDI format and thus make the communication and data mapping difficult. The same is true for product identification and article numbering. It has been estimated that up to 70 per cent of EDI transactions, including barcodes, contain wrong or incomplete information (Hunter and Valention, 1995). The Hong Kong textile and apparel supply chain is faced with the similar situation to that described by Hunter and Valention (1995). Most garment manufacturers are small to medium scale not having the resources and power to negotiate with big players in the supply chain. An interview with one of the Hong Kong medium size sweater manufacturers (Ho, 2001) found that the company has to deploy three different EDI systems for its US buyers for its order and production monitoring system in the supply chain. In addition, since most of the sweater production is carried out in China and Bangladesh, the management must ensure that the three systems would work properly in a remote and under-developed area.
The elimination of quota restrictions to US market imposes another problem in the supply chain management. Major findings of the study “Opportunities and Challenges as the Garment Quota System Ends” conducted by Hong Kong Productivity Council (Chow, 2005) shows that 90 per cent of the interviewed manufacturers cut their price up to 25 per cent in the first half 2005. About 62 per cent of the total respondents agreed that US/EC customers tended to purchase more because of lower prices in the absence of quota cost. To improve the competition, 69 per cent of the respondents agreed to improve the efficiency and enhance competitiveness through supply chain management. 3.3.2 Fashion demand efficiency and responsive supply chain management Besides the technology and management issues in the supply chain, Fisher (1997) found that most companies failed in their supply chain management because of their mismatch between supply chain strategy and the nature of demand for their products. Based on the demand pattern, Fisher divided products into two categories in the supply chain: either primarily functional or primarily innovative. Functional products such as those obtained from grocery stores or patrol stations, normally do not change quickly with time; they have a stable and predictable demand and a long life cycle. However, their stability invites competition, which often leads to low profit margins. Innovative products like fashion apparel or personal computers, can enable companies to achieve higher profit margins. However, the very newness of innovative products makes demand unpredictable. In addition, their life cycle is short, usually just a few months, because as imitators erode the competition advantage that innovative product enjoy, companies are forced to introduce a steady stream of newer innovations. The short life cycles and the greater variety which are typical of these products further increase unpredictability. Table I shows the demand nature for functional and innovative products in the supply chain. With their high profit margins and volatile demand, innovative products require a fundamentally different supply chain than do stable, low-margin functional products. Fisher (1997) suggests that an efficiency supply chain strategy with focus on cost minimization should be used for functional products. A responsive supply chain strategy with focus on products availability, matching the marketplace with customer demands, should be used for innovative products. The failure of supply chain management is often due to mismatch between supply chain strategy and the nature of product demand.
Aspect of demand Product life cycle Contribution margin (per cent) Product variety Average forecast error (per cent) Average stock out rate (per cent) Average season markdown (per cent) Lead-time required for made-to-order products
Functional
Innovative
Predictable demand More than 2 years 5-20 Low (10-20 variants per catalogue) 10 1-2 0 6 months to 1 year
Unpredictable demand 3 months to 1 year 20-60 High (often millions of variants per catalogue) 40-100 10-40 10-25 1 day to 2 weeks
Apparel supply chain management 271
Table I. Demand for functional versus innovative products in the supply chain
IJCST 18,4
272
Table II. Efficiency supply chain and responsive supply chain processes
Table II shows the two different supply chain strategies used for functional and innovative products. As can be seen, the primary focus of the efficiency supply chain strategy is to minimize the overall production cost. The responsive supply chain strategy focuses on the maximum product availability to market, reduced stock out and forced markdowns. The problem with these two strategies is that the same product, for example apparel goods, can be both functional and innovative. A fashion garment in the early introduction stage can be an innovative product. However, at the end of the product life cycle, it becomes a functional product. It is therefore difficult for the companies to judge whether they should use responsive or efficiency supply chain strategies for each product in different stages of the life cycle. Nevertheless, Fisher provides a framework for the management to match the nature of the product with the supply chain strategy. Another problem with the textile and apparel supply chain is the product forecast and short life cycle for fashion and apparel goods. A fashion garment, by definition, is changing all the time and therefore, it is highly volatile and unpredictable. The challenge in managing the supply chain for fashion articles is to ensure product availability while keeping product obsolescence low. The ability to respond to market signals and to develop accurate demand forecasts (and to update them based on current information) is critical. Fisher and Raman (1994) developed an accurate response for women’s apparel sold by catalogue using the early sales data as an accurate predictor of life-cycle demand. He found that conventional forecasting based on a team of expert merchants has an average forecast error of 55 per cent. However, using the early sales data of the first two weeks of demand, the life-cycle forecasts for the same products developed by simple extrapolation can improve the average forecasting error by 8 per cent (Figure 3). Fisher and Raman (1994) also found out that if the committee has a strong agreement on the forecast, the forecast error would be reduced. Conversely, if the committee has a low agreement on the forecast, the error of forecasting would increase (Figure 4). This technique would improve the forecast error for high fashion articles and make the supply chain more responsive to the market demand. 3.3.3 Upstream supply chain management problems faced by Hong Kong textile and apparel industries. Considering the problems of the Hong Kong textile and apparel Efficiency supply chain process
Responsive supply chain process
Primary purpose
Supply predictable, demand efficiently at the lowest cost
Manufacturing focus Inventory strategy Lead-time focus
Maintain high average utilization rate
Respond quickly to unpredictable demand to minimum stock out and forced markdowns Deploy excess buffer capacity
Approach to suppliers Product design strategy
Generate high turns and minimize inventory throughout the chain Shorten lead-time as long as it does not increase cost Primary on cost and quality Maximum performance and minimize cost
Deploy significant buffer stocks of parts or finished goods Invest aggressively in ways to reduce lead-time Primary on speed, flexibility and quality Use modular design in order to postpone product differentiation
Apparel supply chain management 273
Figure 3. Accurate response to market signals
Figure 4. Forecast error and degree of agreement amongst the committee
supply chain, most garments produced in Hong Kong are intended for export and large amounts of the required materials are imported. Managing the international logistics therefore is crucial for the Hong Kong clothing industry. Moon (1999) surveyed 105 clothing manufacturing firms in Hong Kong with 25 companies for in-depth interview to understand the supply logistics for Hong Kong garment manufacturers. Results show that the overall logistics cost for in-coming fabrics, expressed as a percentage of total fabric cost, ranges from 1.5 to 8 per cent, with an average value of 3.7 per cent. Transportation consumes over 95 per cent of the overall logistics cost. Most surveyed firms, however, consider that the logistics are not important in their supply chain. This finding is rather contradictory to conventional thinking in the supply chain. Moon (1999) concluded that the Hong Kong clothing manufacturers like
IJCST 18,4
274
to focus on their core business function, for example sourcing, production, marketing, which are always regarded as the determinants of the firm’s existence. The clothing manufacturers therefore spent less effort on supply-side logistics and were not aware of the importance of developing logistics excellence in honing their competitive edge. Hong Kong has long been regarded as an important sourcing centre for clothing production in the Far East for the world market. Leung (1999) therefore, studied the Hong Kong textile and apparel supply chain from the supplier viewpoint. By analysis of the case study of a skiwear supply chain in Hong Kong (Hammond and Raman, 1995), Leung (1999) found that two reasons to limit the flexibility of the supply chain in Hong Kong were long production lead-time and large batch requirements for production, as shown in Table III. Leung found that the key issues that constrain the flexibility of the supply chain were: . little sharing of information amongst retailers, distributor and suppliers; and . fluctuation of fabric demand. For the suppliers, key constraints for the supply chain flexibility were: . batch size of greige goods; . quota restriction to US market; . lead-times; and . insufficient experience in managing demand. To increase the supply chain flexibility, Leung (1999) concluded that inventory-holding points should be located for the greige goods in the supply chain. This pre-positioning of greige fabric has enabled the skiwear company under study in the supply chain to react more quickly to the market demand for its distributor and trading partners in Hong Kong. They were able to print/dye the right pattern/colours for their styles, based on market information. The problems of information sharing and communication amongst the supply chain members are reported by Chen (2005) for his study on supply chain management in fashion industry between UK retailer shops and Chinese clothing manufacturers. He pointed out that “misunderstanding is a big issue in translating specifications from English into Chinese” and estimated that the manufacturers in China on average receive and understand 65.5 per cent of the retailer’s information (Chen, 2005).
Items
Table III. Lead-time and batch size in Hong Kong for skiwear production
Raw material information Greige fabric Dyeing of fabrics Garment Production Information Weekly output Line configuration Shipment information HK – Seattle – Denver
Lead-time
Minimum quantities
45-90 days 45-60 days
5,000-10,000 yards 1,000 yard per colour
12 parkas 40 people/line
1200 units in same style
42 days
4. Conclusion From definition, the supply chain involves all the activities in delivering product from raw material to the final customer. The supply chain activities span from internal organization to external trading partners of suppliers, carriers, third-party companies and information system providers. The management of the supply chain, therefore, is a complex process and involves trust; partnership and information sharing between the upstream and downstream supply chain partners. The consultancy reports on supply chain management surveys show that Hong Kong industry is generally not aware of the concept of supply chain management. The industrial benchmark for both manufacturing and retailing industries in Hong Kong for the supply chain performance is below the world average. Although some large enterprises in the textile and apparel industry in Hong Kong have adopted some forms of supply chain management with their US trading partners to streamline the supply chain management process, the real benefit of supply chain management is still largely restricted to big players in the industry. The typical problems facing with textile and apparel supply chain are short product cycle for fashion articles, long production lead-time and forecasting errors for fashion items. The Hong Kong textile and apparel supply chain faces additional problems of distance from customers in the US and European markets, long production lead-times and minimum batch sizes for production and recently, the elimination of quota restrictions in the US market; all these force the industry to maintain its competitiveness through supply chain management. The “Accurate Response” suggested by Fisher and Raman (1994) helps to improve the forecast for short cycle and high fashion apparel items and thus would be very useful to manage the supply chain in downstream retailing industry. The differentiation of product demands into functional and innovative products helps the supply chain company to employ different supply chain strategies for different products, namely responsive supply chain strategy for innovative products and efficiency supply chain strategy for functional products. Again, these two supply chain strategies are focussed on the downstream supply chain aiming at shortening the time to reach the market and also to reduce the stock levels in the retailing industry. The Hong Kong textile and apparel industry, however, is mainly an export-oriented industry. It occupies the upstream position in the textile and apparel supply chain. It focuses on design, material sourcing, sample making, dispersed manufacturing, co-ordination, transportation, documentation, quality assurance and testing in the supply chain. The strength of the Hong Kong textile and apparel supply chain lies in its close relationships with all suppliers in the chain. The geographical and cultural affinity to the Mainland of China further enhances the relationship between Hong Kong and its trading partners. Hong Kong, on the one hand, is able to access a pool of quality suppliers in the Mainland of China; on the other hand, Hong Kong can take advantages of its own leading position in sales, marketing and professional services to assist overseas buyers explore the China market, which has become the largest market in Asia. The supply chain in Hong Kong, therefore, instead of focussing on logistics, transportation, time to market and forecast demands, should focus on product
Apparel supply chain management 275
IJCST 18,4
design, material control, and production co-ordination. The Hong Kong supply chain activities should streamline the whole production process from fibres to yarn, knitting, weaving, dyeing and finishing, through to the garment manufacturing process.
276
References Borneman, J.M. (2005), “Trust: supply chain’s weakest link”, Textile World, Vol. 255 No. 9, p. 9. Chow, C.K. (2005), “Hong Kong, competitive supplier”, Textile Asia, Vol. 36 No. 9, pp. 11-12. Chen, Z. (2005), “Fashion clothing in supply chain management: Britain to China”, Textile Asia, Vol. 36 No. 9, pp. 53-6. Cox, J.F., Blackstone, J.H. and Spencer, M.S. (Eds) (1995), APICS Dictionary, 8th ed., American Production and Inventory Control Society, Falls Church, VA. Ellram, L. and Copper, M. (1993), “Characteristics of supply chain management and the implications for purchasing and logistics strategy”, International Journal of Logistics Management, Vol. 4 No. 2, pp. 1-10. Fisher, M. and Raman, A. (1994), “Making supply meet demand: in an uncertain world”, Harvard Business Review, Vol. 72 No. 3, pp. 83-94. Fisher, M.L. (1997), “What is the right supply chain for your product”, Harvard Business Review, Vol. 75 No. 2, pp. 105-16. Hammond, J.H. and Raman, A. (1995), Harvard Business School Case 695-022, revised 14 April 1995), The President and Fellows of Harvard College, Cambridge, MA. HKANA (1996), Hong Kong Supply Chain Road Map: Linkage to Total Industry Benefits, The Hong Kong Article Numbering Association, Hong Kong. HKANA (1997), Supply Chain Management in Global Trade – Made by Hong Kong, The Hong Kong Article Numbering Association, Hong Kong. Ho, K.K. (2001), “EDI systems for small to medium size factories in Hong Kong”, personal commnication, Hong Kong. Hong Kong Government Industry Department (1995), Techno-economic and Market Research on Hong Kong’s Textiles and Clothing Industries, Hong Kong Government Industry Department, Hong Kong. Hunter, N.A. and Valention, P. (1995), “Quick response – ten years later”, International Journal of Clothing Science and Technology, Vol. 7 No. 4, pp. 30-40. Leung, S.Y.S. (1999), “World-class apparel sourcing enterprises and the restructuring of existing global supply chains”, Journal of Textile Institute, Vol. 91 No. 2, Part 2, pp. 73-92. Macedo, J. (2005), “Emergence of late design responsive supply chain in the clothing industry”, Textile Asia, Vol. 36 No. 9, pp. 31-4. Magretta, J. (1988), “Fast, global and entrepreneurial: supply chain management, Hong Kong style”, Harvard Business Review, Vol. 76 No. 5, pp. 102-15. Monczka, R.M. and Morgan, J. (1997), “What’s wrong with supply chain management?”, Purchasing, Vol. 122 No. 1, pp. 69-73. Moon, K.L. (1999), “Supply-side logistics: managing in-coming materials by Hong Kong clothing manufacturers”, Journal of Textile Institute, Vol. 90 No. 2, Part 2, pp. 163-75. Quinn, F.J. (1997), “What’s the buzz?”, Logistics Management, Vol. 36 No. 2, pp. 43-7. Supply Chain Council (1997), available at: www.supply-chain.org
Trade and Industry Department (2000), Techno-economic and Market Research on Hong Kong’s Textiles and Clothing Industries, Trade and Industry Department, Hong Kong Government. Wall Street Journal (2000), “Overseas suppliers to US brands are thriving”, The Wall Street Journal, 10 March.
Apparel supply chain management
Further reading Lee, H., Padmanabhan, V. and Whang, S. (1997), “The bullwhip effect in supply chains”, Sloan Management Review, Spring, pp. 93-102.
277
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
IJCST 18,4
COMMUNICATIONS
The creative role of sources of inspiration in clothing design
278
Fatma Mete Department of Textile, Faculty of Fine Arts, University of Dokuz Eylul, Izmir, Turkey Abstract Purpose – To assess the creative role of sources of inspiration in visual clothing design. It aims to analyse simple, general accounts of observed design behaviour and early stages of the clothing design process, what is the nature of design inspiration, how sources of inspiration are gathered and how they affect the creativity and originality in clothing design. Design/methodology/approach – A progressive series of empirical studies looking at ready-to-wear clothing design has been undertaken; in situ observation, semi-structured interviews and constrained and semi-constrained design tasks. This empirical approach used ethnographic observational methods, which is effective in situations where conventional knowledge acquisition methods are insufficient, when broad understanding of an industry is needed, as in the fashion industry, not just a case study of a single individual or company. Findings – Identifies the major types of idea sources in clothing design and provides information about each source. Recognises that these sources of inspiration help designers to create design elements and principles of individual designs. In order to foster originality, sources of inspiration play a powerful role throughout the creative stage of design process, and also in the early stages of fashion research and strategic collection planning. Originality/value – This paper highlights the role of sources of inspiration and its effect in creativity and originality in the clothing design process. Offers practical help to clothing designers and design-led clothing companies. Keywords Fashion design, Clothing, Creative thinking, Design calculations, Design management Paper type Research paper
Introduction Sources of inspiration and its personal interpretation, visually and technically, play an important role in the design process, in increasing creativity. Clothing design studies and the creative role of design inspiration, during the early informal and actual clothing design processes is open to scientific investigation like aesthetically driven designs in other domains. Studying creative fashion design as process and product is seen more problematic than other design-led industries, as the interaction between the design elements and principles, material properties, adaptation and modification of design inspiration are International Journal of Clothing Science and Technology Vol. 18 No. 4, 2006 pp. 278-293 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610668509
This research was conducted at the Fashion Design Major, Department of Textile, Faculty of Fine Arts, Dokuz Eylul University in Izmir, Turkey and in four clothing retail and manufacturing companies. The author is grateful to the professional and student designers who acted as participants, and to his colleagues in Fashion Design Major, who assessed the qualities of the designs produced.
complex. Clothing design, as a variety of aesthetic and functional design processes, shares many characteristics of engineering design process. Research and observation are critically important in the fashion business. By researching and observing, designers gather background information for design, including studying current and future fashion trends and try to predict what the majority of their customers will want in the foreseeable future. In order to keep up with the changing world of fashion, fashion awareness should become second nature to every clothing designer. Appropriation, as a result of research and fashion awareness, is very important in the fashion industry. Designers must learn most of all to keep their eyes open, to develop their skills of observation, to absorb visual ideas, blend them and translate them into clothes that their customers will like. Exposure to beautiful things helps a designer distinguish genuine beauty and quality from fads and mediocrity (Frings, 2002). Design research defines the range of possibilities for designs within the scope of fashion and the intended target markets. It provides the sources of inspiration designs are based on, and enables designers to relate their designs to the context of fashion. The quality of designs depends not only on the designers’ talents but also on the quality of their design research. Only extensive research enables designers to stay fresh and keep up to date with developments (Eckert, 1997). This paper addresses the question of how originality and creativity can be improved through better support for the use of sources of inspiration. It gives an overview of the sources of inspiration in clothing design process and explains how they can be employed. The use of inspiration and its interpretation varies in different contexts, but some fundamental functions of sources of inspiration remain constant for fashion designers. The objective of this paper is to explain the vital importance of sources of inspiration in the clothing design process. Design and clothing as a visual and tactile sensory design It is well known that design is two things: process and product, as verb and noun. As design problem solution process, it is researching, setting the source of inspiration, planning, organizing to meet a goal, carrying out according to a particular purpose and creating. As product it is the end result, an intended arrangement that is the outcome of that process or plan. Clothing is an example of applied design, even the most exciting, original idea must show awareness of its practical purpose and environment. We realise that some art is pure, “art for art’s sake” but most creations in the daily world are for a practical purpose and use. Design as process is planning to meet a goal, and thus applies to everything intentionally created for a purpose. The steps and order of the process are essentially the same regardless of the end product. These steps are very similar to management as a planning process. Design as man made product and service falls into two major categories: sensory and behavioural. Sensory design is perceived through the senses, and is classified as visual, auditory, olfactory, tactile and gustatory. Behavioural design is planned action. Many products, however, include aspects of both, because design may be perceived through the senses and then interpreted behaviourally. A fashion show, for example, include both sensory and behavioural designs.
Sources of inspiration in clothing design 279
IJCST 18,4
280
Sensory design include those products experienced through the physical senses: sight, sound, taste, touch, smell. The main purpose of a sensory design product is the sensory experience itself. Many products are experienced/perceived through several senses at once. Sculptures are both seen and touched. Prepared dishes can be appetizing in flavour, attractive visually, and satisfying intouch. Clothing fabric is felt on the outside as well as on the inside against the skin and is also seen on the wearer. Occasionally it is also experienced as sound, as with the soft swoop of satin, the rustle of taffeta, the rubbing of curdory, crackling of leather, or the jangle of beads; or as smell, as in suede and leather goods or the fragrance of sandalwood beads. Many products involve several senses; but clothing as a sensory design product is most often and most importantly experienced as visual and tactile sensory design. Therefore, in clothing design, as a visuospatial design activity, sources of inspiration are perceived through one sense at once, thus visually, and are again interpreted through the same sense. This kind of “visuospatial thinking” has a salient role in the creative process of clothing designs. A different technique for creating new ideas in clothing design superimposes two transparencies on each other like a double exposure photograph and creates a new idea from the combination. Described as “homospatial process” it can also be applied using different senses (Davis, 1996). “Homospatial thinking” consists of actively conceiving two or more discrete entities occupying the same space, a conception leading to the articulation of new identities. Homospatial thinking has a very important role in the creative process in the following wide variety of fields: literature, the visual arts, music, science, and mathematics. This cognitive factor, helps to clarify the nature of creative thinking as a highly adaptive and primarily nonregressive form of functioning (Rothenberg, 1976). Another way of seeking inspiration in design might be called “cross-sensory” interpretation. In it, designs intended for one sense organ are interpreted through another: a flavour (olfactory and gustatory) inspires a poem (auditory); a satin fabric (tactile and visual) inspires a scent (olfactory); a song (auditory) inspires a picture (visual). This is a long used technique that has provided ideas for many artists. Walt Disney’s film “Fantasia” is a classic example of visualizing sound, so-called synesthesia. In it famous musical works are interpreted in line, colour, shape, light, and pattern in motion as music progress. Many words are used in both fashion design, music and art vocabularies, such as rhythm, balance, and harmony, or orchestral “colour” and “texture”. Musical compositions with titles like “Deep Purple” and “Rhapsody in Blue” suggest the close relationship between visual and auditory design (Davis, 1996). Briefly, in fashion design, mainly a visual and/or tactile source inspires a garment. Inspiration for apparel often comes from appreciation of qualities of the world around us. Designers must be open to inspirational sources and the different ways of seeking inspiration wherever they may lie. Research methodology and findings The importance of source of inspiration and their role in creative clothing design has been little understood and, therefore, rarely received attention in this industry. Eckert and Stacey (1998, 2000, 2003) studied knitwear design case, which shares many characteristics of complex engineering projects and as an example of “practical design” in a fast moving and highly competitive manufacturing industry. Their work included
a large ethnographic study of the knitwear industry, which produced a detailed design process model and an analysis of the causes of communication problems within design teams. Ma¨kirinne-Croft et al. (1996) tried to explain the fashion design process in terms of quantum mechanics and psychoanalysis and see design creativity as the ultimate mystery; their description of the design process is simplistic. The author has undertaken a progressive series of empirical studies, based on observation and interviews, looking at ready-to-wear (RTW) clothing design; in situ observation, semi-structured interviews and constrained and semi-constrained design tasks. This empiric approach combines ethnographic observational methods with the knowledge analysis techniques of artificial intelligence. It is effective in situations where conventional knowledge acquisition methods are insufficient, when broad understanding of an industry is needed as in the fashion industry, not just a case study of a single individual or company. In this research, the creative role of sources of inspiration in visual clothing design by novice and expert clothing designers was assessed through empirical research. As subjects, 16 talented clothing designers, 11 university-level fashion design students in Fashion Design Department at Dokuz Eylul University and five professional designers participated in the experiment carried out in this research. The first group of subjects included advanced fashion design students, seven talented students selected from the third and fourth year of undergraduate studies, and also four students of postgraduate studies, who also works as a free lance or part time assistant designers in the clothing industry. The second group was composed of five professional designers with a minimum of 5 years of experience in clothing industry. Subjects were assigned two types of design problem in order to assess early stages of the clothing design process and the creative role of sources of inspiration in clothing design process. In the first design problem, without given any source of inspiration designers were asked to design a small womenswear RTW collection, which consists of dresses. This experiment was performed to examine to see if designers use any specific sources of inspiration consciously in their designs and if they use whether they can identify it, thus which kind of sources of inspiration they use consciously in their visual design of dresses. With this aim, each of designers were asked, without any constraints, to produce three womenswear clothing designs in dress forms for RTW industry for a specific fashion season. At this stage, designers at work in industry and the fashion design department were observed and interviewed, with particular attention to designers’ source-gathering activities if there is any, and the simple general accounts of design behaviour and early stages of the clothing design process. In the second design problem, designers were given two sources of inspiration separately; images of a type of flower, as an example of sources of inspiration from nature, and another image of a historical garment, as an example of sources of inspiration from products-here previous garments. Again designers were asked to design two separate small womenswear RTW lines, using these sources of inspiration. This experiment was performed to examine the role of sources of inspiration in visual clothing design. Each of designers were asked to produce three clothing designs, namely women’s dresses, per source. Designers at work in industry and the fashion design department were observed and interviewed, with particular attention to the interpretation of design inspiration, adaptation activities, the simple general accounts of design behaviour of designers.
Sources of inspiration in clothing design 281
IJCST 18,4
282
Empirical data on early design processes, search for source of information and application of the inspiration to the design problems were obtained from these two phases of empirical study. The overall qualities of the designs produced, variety of aspects including creativity and the approaches applied were independently judged by three fashion design lecturers, including the author herself and one expert fashion designer from clothing industry. As predicted, from the empirical data, aspects of creativity in design related to the role of sources of information and the concept of originality have been identified. At the end of the first design problem, designers were asked about their conscious sources of inspiration and their personal interpretation of it, visually and technically. When asked about their conscious sources of inspiration, 75 per cent of the designers, 12 out of 16, reported several sources of inspiration. Four designers did not identify any conscious source of inspiration. Three major areas of inspiration sources were spontaneously mentioned; universe of products, universe of art and universe of nature. In the universe of products, designers mainly inspired by the previous fashion designs and fabrics. Secondly, they inspired by other products such as architectures, furnitures, telecommunications, food, etc. In the universe of arts, they mainly inspired by fibre art exhibitions, music, movies, paintings, drawings, graphic arts, sculpture and cartoons. In the universe of nature, they inspired by animals, felines, insects, vegetables, plants, flowers, minerals, stones and natural phenomenas. In the first experiment, mainly novice designers used a specific theme as a source of inspiration in their designs. In this phase, most of the experienced designers mainly did not use any specific source of inspiration in their designs, but used popular design elements and details of the current fashion context, with the constraint by “what would sell most”. It was not easy to identify a specific source in their collection. The reason for this can be expressed as they used to design for the mainstream manufacturing companies which they do not impose (push) the products to the market, but rather to extract (pull) them. It was identified that these designers’ approach is market oriented, rather than design oriented approach. At the end of the second design process, it is observed that designers extracted strong visual and tactile elements from the sources of inspiration supplied to them. Hence, in this design problem, thus in the case of given source of inspiration, designers performed better in terms of the overall qualities of the designs produced and the creativity level. They applied several adaptation methods to personally interpret them in visual and tactile elements of new designs. Experienced designers mainly were able to specify their materials for their designs in order to achieve the forms and lines in their designs. All these results indicate that using a source of inspiration increase the overall qualities of the designs produced and the originality and creativity. When a source of inspiration used effectively in a design problem, it also maintains collection unity. Otherwise, the pieces in the line were not seem related with each other. After selecting the source of inspiration, extensive research is also needed to gather detailed information about this specific source, in order to explore the new ways of looking at old things. Designers should be aware of everything in order for the design is appropriate, be more creative. Sources of inspiration in clothing design Where does the fashion designer get ideas and inspiration for new styles? The answer is everywhere and everything. Anything visual and tactile, in fact sensual,
can be a source of inspiration for a garment. Through television, the designer experiences all the wonders of the entertainment world. In films, the designer is exposed to the influences of all the arts, and lifestyles throughout the world. Because consumers are exposed to movies through international distribution, films prime their audiences to accept new fashions inspired by the costumes. Museum exhibits, art shows, world happenings, expositions, theatres, music, dance and world travel are all sources of design inspiration to fashion designers. The fashions of the past are also a rich source of design inspiration. While always alert to the new and exciting, fashion designers never lose sight of the past, they use old things in new ways (Stone, 2001). As stated the inspiration for a garment within a collection or for an entire collection can come from an infinite variety of sources. Sources of inspiration are often linked to the social “spirit of the times” also called the “zeitgeist”. Understanding the state of current fashion and searching for ideas and sources of inspiration involves looking at art objects and books, going on trips to places like Paris and Milan, visiting museums, watching people on streets and going on country walks. Designers are most creative when they are directly exposed to the sources of ideas. On the other hand, it has been observed in the fashion industry that there are two fundamental approaches in the creative clothing design processes: (1) material, thus fabric, inspired clothing design process; and (2) conceptual clothing design process, such as several themes originated from the universe of arts, nature or products. These design processes will be argued elsewhere in separate papers in details. It is known that the high-fashion “name” designers typically develop a concept, also called theme, for their collection in order to be more creative and original. The major types of idea sources in design-led industries are previous products, artifacts, natural objects and phenomena. In case of clothing design, garments, fabrics and trims as previous products, play an important role in sources of inspiration. Although, there is a broad recognition that much of the design proceeds by modification of previous ideas, in case of fabric inspired clothing design, designers search for new forms and styles with newly developed or invented materials. In this case a style often takes as its starting point the technical possibilities of materials. For example, the development of elasthen fabrics, such as Lycra, inspired designers to figure-hugging silhouettes. Garments and other products Clothing designers draw ideas from current and previous garments, such as couture or RTW designer garments, historic and ethnic garments, streetwear, etc. They attend catwalk shows, visit shops to absorb fashion trends, watch celebrities, identify the strong features of a new season, and study how the garments of market leaders and competitors are styled. Designers also study the photographs of garments from fashion magazines and trend publications to gain an overview of fashion. A photograph does not show technical details, but it communicates the mood of a design and the image of the target wear (Figure 1).
Sources of inspiration in clothing design 283
IJCST 18,4
284
Figure 1. Previous fashion designs (garments) as a source of inspiration
Historic and ethnic costumes Designers’ job is to find, just sort of feel the zeitgeist and to take an idea or a mood and turn it into something tangible, which often was something that had a history and a past. Designers often turn to the past (recent or historical) or to folk costumes for ideas and themes. Costume falls into two categories: historic costume, the fashion of a certain historical period; and folk or ethnic costume, traditional national or regional dress. Museum costume collections, historic films and books are excellent sources of costume references. Designers usually are sensitive to the combinations of design elements and principles in each historical period of costume. High-fashion/couture designers’ theme is often based on a historic or an ethnic inspiration. Fashion silhouettes or garment details popular during historic periods provide a source of design inspiration. For example, the empire silhouette recurs periodically throughout fashion history. Another example, the ruff collar or a sleeve detail from the renaissance period may inspire a collection. As an example of historic customs as a design inspiration, John Galliano’s spring/summer 2005 Dior couture collection can be given. He set the theme as “the age of empire” inspired by the images from the time of Napoleon, the emperor’s coat of arms, the image of a sensual woman such as Jose´phine de Beauharnais. In this collection he also interpreted this theme for wearable Napoleonic coats and Josephine gowns for RTW (Figure 2). Designers may be inspired by the clothing and accessory styles of other cultures. They find the same inspirational blend of colours, motifs, lines, shapes, and spaces in folk costumes. The global environment has increased interest in products from the far reaches of the world. Designers seek inspiration from “exotic” cultures whose clothing styles and fabrics are distinctly unique. Wearing clothing inspired from other cultures
Sources of inspiration in clothing design 285
Figure 2. Historic costumes (garments) as a source of inspiration
may provide a sense of adventure and vicarious enjoyment of that culture. Some designers travel to other locales to seek inspiration for a new line. Designers use of various national and ethnic groups and cultures as inspirations for their collections, such as Asia, Russia, the Austrian Hapsburgs, Africa, China, Spain, Persia, Gypsies, etc. inspirations. Apart from the current and previous garments, fashion designers are also influenced from other man made products, such as architecture, furnishing, electronics, food, etc. Inspired by architecture, Francisco Costa on his spring/summer 2006 Calvin Klein collection explained: It is about shape and it is about volume. The collection is very light, feminine and intricate. Architecture is still very important for us; there are layers of cotton, sometimes with circles applique´d on, sometimes squares. Very Bauhaus (www.style.com, 2005).
Artifacts The initial moment, the first idea for a collection is a very individual thing among fashion designers. Literature, movies, painting, sculpture, television, architecture, music and theatre can serve as inspiration for a fashion designer. Coco Channel, for example, was inspired Bauhaus and Picasso; Elsa Schiaparelli worshipped Francis Picabia, Jean Cocteau, and Salvador Dali. Yves Saint Laurent, strongly influenced by his friend Andy Warhol, created a pop art collection in 1966. Designers flock to large cities to soak up the creativity centered there. They are influenced by what other designers and artists are creating. Excitement about a new idea acts as a catalyst for more creativity. There is a growing desire for individuality in design and a desire for personality whether by accessorizing minimalism or mismatching lace, tweed, denim and print. Print was important to Schiaparelli’s surrealism and she collaborated with Salvador Dalı´ on a number of projects.
IJCST 18,4
286
One of their most famous pieces was a dress printed with a lobster, in reference to Dali’s sculpture Lobster Telephone. Dali’s art translated well into prints that were witty yet elegant and Schiaparelli’s interpretations of his surrealism, either hand-painted or freely embroidered, were strange yet pretty (Figure 3). Art exhibitions and movies often have an impact on design collections. Although the costume designers of contemporary films are influenced by current fashion, it also works the other way around. Clothing designers are also inspired by both new and old movies. Sometimes it is just a mood that captures their imagination, but most often it is the clothes. Olivier Theyskens on Rochas on his ss06 Rochas RTW collection, said, “I was very interested by the life of Monet, impressionism, cloudy-daylight colours, emotions and feelings. It is more ‘arty’ and I love the arty approach.” Music and the exposure that video gives celebrities have made a significant impact on young people. Teens look to see what rock stars are wearing, therefore junior designers emulate these entertainers so that their clothes will be popular with their customers. For his spring/summer 2006 RTW collection, Alessandro Dell’ Acqua explained, “Marilyn Monroe was the inspiration, but a very modern, very contemporary interpretation.” Natural objects and phenomena Designers take motifs, colour combinations and cultural connotations from nature in the same way as from man-made objects. Natural beauty also means that we are going to want more realistic renderings of some natural things. Sometimes the theme might be reflected in the colours of natural objects or phenomena, this is also called colour inspiration. For example, the colouration seen on a sunset view or flower bed might be an inspiration for a clothing line (Figure 4).
Figure 3. Artifacts as a source of inspiration – Salvador Dali’s Lobster Telephone as a source of inspiration for Elsa Schiaparelli’s lobster print dress
Sources of inspiration in clothing design 287
Figure 4. Flowers (nature) as a source of inspiration in Issey Miyake collection
Donatella Versace explained on her ss06 Versace collection, “The inspiration was palm springs. The colours are very desertlike and there is a lightness to the fabrics as well.” Materials (fabrics) While some designers research a specific time period or ethnic culture for inspiration, most designers of RTW mass market rely primarily on studying new fabric and texture trends. Visual and tactile characteristics of materials, an intriguing fabric texture or interesting print might serve as the design foundation for a collection. Several fabrics in prints, plaids, and solid colours and in smooth as well as textured surfaces might be combined to create an interesting collection. During this design stage of creation, some designers work with specific fabric ideas gathered at textile fairs or directly from textile manufacturers as they begin to sketch garment design ideas. Less frequently, designers might develop a design sketch, then seek the perfect fabric for it (Burns and Bryant, 1997). Fabrics themselves often inspire garment designs as shown in Figure 5 ss05 Versace RTW collection. The softness and drapability of a jersey might inspire gathers in a dress. Christian Dior wrote, “Many a dress of mine is born of the fabric alone.” In his spring/summer 2006 Fendi collection, Karl Lagerfeld, for example, reflected on his selection of design inspiration as material and technique, “Sometimes it is leather, sometimes it is pique, sometimes it is plastic, but it is all done with laser. You know, you could not do that before.” Another example for the use of fabric inspiration can be given from latest spring/summer 2006 RTW collections: Phoebe Philo on Chloe´ explained: I love all the couture fabrics. You know, boucle´s and gazards. It is wonderful to work with them. They are really lush and expensive and rich. But they are not versatile, you have to kind of respect them. You cannot do things that you can do with other fabrics, so it was an interesting process (www.style.com, 2005) (Figure 5).
IJCST 18,4
288
Although fabrics are the most important inspiration and resource for clothing designers, mainstream clothing designers are limited to the fabrics that are currently available in their price range. Designers shop at international textile fairs or fabric showrooms to see the current fabric collections. Special trims and findings are an important feature of some garment designs. A decorative detail, a unique trim can transform an ordinary or classic garment into a new look. For example, for childrenswear, special ribbons, trims, applique´s and accessories frequently “make” the design. A unique clasp or closure on a garment can increase its appeal, or special big buttons on a classic jacket may create a fresh look. Designers constantly seek interesting trims, findings and design details as a source of inspiration. Fashion research and forecasting Fashion is a reflection of the time and the lifestyle of the society from which and for which it is created. Trends today follow our shifting society and reflect what is happening in our world. They do not get invented only on runways. As they all influence trends, designers have to look at everything, economics, politics, weather, media, streets, celebrities, demographics, science, art, nature, etc. Several designers, working for a mainstream manufacturer, may use a similar fashion idea because they have been informed and inspired by common sources. It is not easy to design and make what people will want to buy in a future selling-season. Awareness, research and planning are needed for designers, manufacturers and retailers to design, make, buy and sell what consumers will want. Designers need to absorb a constant flow of information to anticipate change and consumer preferences. Donatella Versace explained, “You cannot live in an ivory tower and make fashion or anything artistic. . . You are to live in the real world.” Designer Karl Lagerfeld said “I want to be informed, to know everything, see everything, read everything. . . You mix all that, then forget about it and do it your way.” Ady Gluck-Frankel, owner and designer of Necessary Objects, explained, “It is the times that set the trends. We are all effected by the same issues: politics, ecology, economy, music, etc. We all just interpret them for our own markets.” Often, what seems to be intuition is actually clever assimilation and analysis of careful research (Frings, 2002).
Figure 5. Visual and tactile characteristics of materials as a source of inspiration – Versace dresses influenced by fabrics
Tracking the consumer mindset is vital to all creative industries and their design and product development team. Every designer in the fashion industry must be involved with research and analysis. They continuously study the life-styles of consumers, shop the market and read trend and design reports, fashion magazines and newspapers to understand consumers and what they might want to buy. Research and observation are critically important in the fashion business. By researching and observing consumer buying habits, watching couture and RTW designer collections, reading the most appropriate fashion publications, observing fashion trends and being aware of the arts, designers try to predict what the majority of their customers will want in the foreseeable future. In order to keep up with the changing world of fashion, fashion awareness should become second nature to every clothing designer (Frings, 2002). Fashion research and forecasting involve the following activities: . studying market conditions-how the consumer’s buying behaviour is influenced by society, economics, technology and the environment; . noting the life-styles of the customers; . researching sales statistics to establish sales trends; . visiting international fashion shows, exhibitions, conferences and trade fairs; . evaluating the popular designer collections to find fashions that suggest new directions or trends; . street research, absorbing street trends, photographing how people dress; . experiencing new retail concepts, observing competing stores to analyse their collections and design strategy; . photo and graphics research – everything from the colour of a building, the curves of a subway train, the sights in a vegetable market through to club flyers, advertising billboards, etc. . speaking to other designers and industry professionals; . surveying fashion publications, catalogs and design services around the world, trawling the internet, markets and bookshops; and . keeping up with current events, the arts, movies and the mood of the public. Fashion trends are the styling ideas that major collections have in common. They indicate the directions of colour, textiles and styling, in which fashion is moving. Designers look for the styles they think are prophetic, ideas that capture the mood of the times and signal a new fashion trend. Several designers may use a similar fashion idea because they have been inspired by common sources. The trend may appear in a fabrication, a silhouette or another design element that appears in several collections. Colour is usually the starting point of each season and often acts as a springboard for materials/fabric direction and trend research. In order to develop the colour themes, designers follow up influential material trade fairs, colour forecasting reports in fashion publications and/or work with external trend and colour consultants to come up with the seasonal palettes. Influential trade shows include the early Pitti Filati yarn fair in Italy, where forward-looking directions in colour and yarn from many major companies can be seen and the Premiere Vision European fabric fair held in Paris.
Sources of inspiration in clothing design 289
IJCST 18,4
290
At the end of the fashion trend research, inspiring visual moods either on actual mood boards or often in designer’s head are created, which can be used as a starting point for further development of colour palettes, textile directions, silhouettes and key shapes. Designers use them as a tool while they are creating and developing a new collection. The medium of the internet gives the designers the opportunity to constantly develop their initial ideas by adding, amending and refining the information. Designers need to do continuous research and collect likely sources of inspiration to absorb the zeitgeist and keep up with technical developments. They need to renew their stock of design elements, renew their awareness of the cultural and technical context, to continue to be creative. It is important for the clothing designers to keep up with design research and conceptual innovations in order to produce good ideas of their own. Originality and role of sources of inspiration Fashion research involves the collection of information from multiple sources on a continual basis. The designer does not create in a vacuum, but is influenced by everything she or he is exposed to. It is important to visit art museums, concerts, and movies and to participate in other activities that expose the designer to fashion-related trends. As fashion changes so quickly, before work on each new collection, every designer in the fashion industry is actively involved with fashion research. It becomes second nature to every designer and decision maker in the field of fashion. At this stage designers need to have something that’s recognizable so that they feel comfortable with it, so they can accept it quickly, but at the same time it feels new. So designers always try to put a new spin on old things. Sources of inspiration are used at the early stages of design and throughout the entire design process. Their roles can be summarised as follows: . Increasing originality and creativity. After doing careful research on the source of inspiration and gathering various visual images, materials and information about it, these sources can be translated into new designs by applying several adaptation techniques, depending on designer’s personal perception and interpretation. Applying various structural or surface visual analogies to the sources selected will increases the design quality of garments. . Making the design process easy. Designers will extract many ideas from the source of inspiration once they searched and understand the concept in detail. Instead of searching around for independent new design elements, designer will find them in front of themselves. . Deriving harmonious colour schemes directly. Designers often derive colour schemes directly from the source of inspiration. In case of fabric inspired clothing design approach, mostly they can have colours relating to current trend themes. . Maintaining harmony and uniformity of the collection. A consistent visual image of collection can be created by a well-developed theme. As the new designs will be related with the specified source of information, all the pieces in the collection will maintain a visual harmony.
.
.
.
.
Deriving technical acumen from products inspired, especially from previous garments. By studying other product’s and garments technical and design details and features, designers learn various new application techniques. Understanding the fashion appropriation of the season. Appropriation is very important in the fashion industry. By absorbing the constant flow of information to anticipate change and consumer preferences, designers will learn about the space of possible deigns. They would develop a feeling for what would look outdated, what captures the mood and what would look appropriate. Gaining this intuitive understanding is one of the most important skills of a fashion designer. Increasing aesthetic understanding of designers. Exposure to beautiful things helps a designer distinguish genuine beauty and quality from fads and mediocrity. Drawing the borders for the design framework. With the help of mood board for the specified source of inspiration, designers will know what to design and the best assortment of styles in the collection.
Although designers choose a marvellous source of inspiration, it gets nowhere if the designer cannot bring it to reality or interpret it appropriately. However, finding the right source of inspiration is not enough to be creative or not so often a matter of inventing something totally new. In order to increase designer’s originality and creativity, designers can seek new ways of seeing old and familiar things, new ways of using old, familiar media to increase their pool of ideas. Many people do not regard themselves as creative, but when they understand the nature of the product, technical acumen, sources of inspiration and the steps of the process, they can be creative. Practice in translating an idea into reality for any one product increases designers ability to realise other ideas (Davis, 1996). Conclusions Anything visual and tactile, in fact sensual, can be a source of inspiration in fashion design. Design ideas do not simply materialize out of thin air. First, the designer does careful research, but what makes a designer’s collection special and original is his or her unique interpretation of design sources. Therefore, in order to be more creative and original the sources of inspiration play an important role in clothing design. Research and awareness are the key to creativity. Designers must learn most of all to keep their eyes open, to develop their skills of observation, to absorb visual ideas, blend them and translate them into clothes that their customers will like. The design process shows that realistic observation of outside influences and needs, extensive research and awareness and logical thinking and order, remove a great deal of the supposed “mystery” of design or creativity. One who thoroughly understands design as product and process and has mastered the use of appropriate materials and adaptation techniques can be “creative” and can translate the source into reality as a successful fashion product. Sources of inspiration are used at the early stages of design and throughout the entire design process. From the findings of this research, the role of sources of inspiration in clothing design can be summarised as follows:
Sources of inspiration in clothing design 291
IJCST 18,4
. . . . .
292 . .
increasing originality and creativity; making the design process easy; deriving harmonious colour schemes directly; maintaining harmony and uniformity of the collection; deriving technical acumen from products inspired, especially from previous garments; understanding the fashion appropriation of the season; and drawing the borders for the design framework.
In fashion design, mainly a visual and/or tactile source inspires a garment. Inspiration for apparel often comes from appreciation of qualities of the world around us. In order to produce new and creative product ideas, designers have to continuously seek new sources of inspiration and new ways of interpret them and new ways of using old things, or seeing the familiar in a new light. However, finding relevant and intelligible sources of inspiration, as well as employing the inspiration in a manner which actually promotes the design quality of the garment is a complicated task in many clothing design cases. References Burns, L.D. and Bryant, N.O. (1997), The Business of Fashion; Designing, Manufacturing and Marketing, Fairchild Publications, New York, NY. Davis, M.L. (1996), Visual Design in Dress, 3rd ed., Prentice-Hall, Englewood cliffs, NJ. Eckert, C. (1997), “Design inspiration and design performance”, Proceedings of the 78th World Conference of the Textile Institute,Vol. 1, Textile Institute, Thessaloniki, pp. 359-77. Eckert, C. and Stacey, M. (1998), “Fortune favours only the prepared mind: why sources of inspiration are essential for continuing creativity”, Creativity and Innovation Management, Vol. 7 No. 1, pp. 9-16. Eckert, C. and Stacey, M. (2000), “Sources of inspiration: a language of design”, Design Studies, Vol. 21 No. 5, pp. 523-38. Eckert, C. and Stacey, M. (2003), “Adaptation of sources of inspiration in knitwear design”, Creativity Research Journal, Vol. 15 No. 4, pp. 355-84. Frings, G.S. (2002), Fashion: From Concept to Consumer, 7th ed., Prentice-Hall, Englewood Cliffs, NJ, pp. 72-84, 170-90. Ma¨kirinne-Croft, P., Godwin, W. and Saadat, S. (1996), “A conceptual model of the fashion design process”, Report for: EPSRC/DIP GR/H84475, Cheltenham and Gloucester College of Higher Education. Rothenberg, A. (1976), “Homospatial thinking in creativity”, Arch. Gen. Psychiatry, Vol. 33 No. 1, pp. 17-26. Stone, E. (2001), The Dynamics of Fashion, Fairchild Publications, New York, NY, pp. 82-3. Further reading Cross, N.G. (1989), Engineering Design Methods, Wiley, Chichester. Dorst, K. and Cross, N. (2001), “Creativity in the design process: co-evolution of problem-solution”, Design Studies, Vol. 22 No. 5, pp. 425-37.
Fiore, A.M. and Kimle, P.A. (1997), Understanding Aesthetics for the Merchandising and Design Professional, Fairchild Publications, New York, NY. Giere, R.N. (1988), Explaining Science, University of Chicago Press, Chicago, IL. Goldschmidt, G. and Tatsa, D. (2005), “How good are good ideas? Correlates of design creativity”, Design Studies, Vol. 26 No. 6, pp. 593-611. Johnson, M.J. and Moore, E.C. (2001), Apparel Product Development, Prentice-Hall, Englewood Cliffs, NJ, pp. 155-65. Lawson, B. (1990), How Designers Think, Academic Press, London. Wolfe, M.G. (1998), The World of Fashion Merchandising, The Goodheart-Willcox Company Inc., Tinley Park, IL, pp. 137-54. Corresponding author Fatma Mete can be contacted at: [email protected]
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
Sources of inspiration in clothing design 293
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
An improved analysis of bagging of textile fabrics. Part I: theoretical J. Amirbayat Centre of Excellence for Textiles, Amirkabir University of Technology, Tehran, Iran
Bagging of textile fabrics Part I 303 Received September 2005 Accepted February 2006
Abstract Purpose – Aims to analyse the stress distribution in a circular flexible sheet. Part I provides a theoretical approach to the analysis of the bagging deformation in textile fabrics. Design/methodology/approach – The investigation includes analysing the stress distribution in a circular flexible sheet clamped around its circumference under an externally applied force by a spherical object. Movement of the material normal to its original plane is then related to the external force and the elastic properties of the sheet, i.e. the elastic modulus and the Poisson’s ratio. The effects of the size of the force-applying object, relative to the sample radius, are also investigated. Findings – The relationship between the applied force on the centre of a flexible sheet material by a spherical object and the sag of the sheet was derived. Poisson’s ratio has an important role on the mechanism of deformation, restricting the extension of the sheet when it is high and intensifying the discontinuity of the strain at the interface. Research limitations/implications – The work could be expanded to industrial fabrics and to composite materials. Practical implications – The two papers provide a first step in an attempt for a better understanding of the stresses involved in bagging of a linear elastic sheet. They provide the basis for the development of fabrics that can withstand bagging problems. This research may also put forward improved methods of measuring bagginess. Some of the theoretical work may be used to predict bagginess of fabrics based on properties. Originality/value – The paper has two improvements on previous work: the inclusion of the effect of fabric Poisson ratio, and the suggestion of a better method of calculating the overall anisotropic properties. Keywords Fabric production processes, Textile technology, Deformation, Sheets Paper type Research paper
Introduction Generally speaking, bagging is the three dimensional deformation of a sheet under a force normal to its plane. In the field of clothing, however, the term is used for permanent deformations of certain parts of a garment such as the sleeves around the elbow and the trousers around the knee. A thorough study of the problem involves the analysis of stress distribution in addition to considering the complicated details of fabric behaviours such as non-linearity, irreversibility of the strain after a certain level of deformation, rate-dependence and fatigue. The present study, as the first step, is an attempt for a better understanding of the stresses involved in bagging of a linear elastic sheet.
International Journal of Clothing Science and Technology Vol. 18 No. 5, 2006 pp. 303-307 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610685221
IJCST 18,5
304
Background Applying a normal force by spherical object to the centre of a clamped sheet and studying the deformations, both theoretically and experimentally, has been performed by many researchers. Some of the available studies include the work by Kisilak(1999), Zhuang et al. (2000), Strazdiene and Gutauskas (2000) and most recently by Abghari et al. (2004) who investigated the contributions of in-plane fabric properties in fabric bagging experimentally. A comprehensive literature survey of the subject is given in a recent publication edited by Laton (2004). The present work is similar to the analysis by Zhang et al. with two significant differences. One is including the Poisson’s ratio, m, in the present analysis of the biaxial strains which they did not consider and the other is a better method of calculating the overall anisotropic properties, instead of measuring the properties in seven directions. The latter will be discussed in the second part of this work. Geometry of deformation Figure 1 shows a circular sheet of radius R deformed by a ball of radius r under a force F. The three-dimensionally deformed sheet consists of two different sections, a spherical cap in contact with the ball and a truncated cone. The following relations can be written between different dimensions:
d ¼ rð1 2 cos uÞ þ tan uðR 2 r sin uÞ R2x tan u ðR 2 r sin uÞ Lc ¼ 2 cos u Ls ¼ 2u · r: rc ¼
ð1aÞ ð1bÞ ð1cÞ ð1dÞ
During the following analysis quantities with dimension of length are normalized with respect of the sample radius R, e.g. d0 ¼ d=R; r 0 ¼ r=R and so on. Force-deformation analysis The problem is a simple case of membrane deformation of a sheet of thickness t where the bending rigidity is negligible, the stresses are expressed as force per unit width and the elastic modulus, E, is replaced by the membrane modulus, Y ¼ E £ t.
Figure 1. Deformation of a circular sheet under the external load
The analysis is also based on the state of plane stress for isotropic Hookean properties, but because of deforming the sample along all in-plane directions, the overall properties of anisotropic sheets can be used for this type of materials, with reasonable accuracy, as will be discussed in the next part. In the case of negligible friction, i.e. no shear, the tensile stress at the interface,s, which remains the same throughout the spherical portion in all directions can be found from the equilibrium equation at the interface: F ¼ 2pr sin u · s sin u F : 2pr · sin 2 u Strain at any point of the cap under the state of hydrostatic stress is: ð1 2 mÞ 1s ¼ s Y or: ð1 2 mÞ 1s ¼ F 0 0 2 r sin u where the dimensionless force is defined as:
s¼
F0 ¼
ð2Þ
ð3Þ
F : 2pRY
Strain in the conical section, which is under a longitudinal tension only, starts from s/Y at the interface and decreases with increasing its radius, rc[1]: r sin u s : 1c ¼ R 2 x=tan u Y Substitution for s and rearrangement gives: 1c ¼
F 0R ðR 2 x=tan uÞsin u
ð4Þ
The average strain between x ¼ 0 and x ¼ ð1=2ÞLc · sin u can be calculated from: Z Lc sin u 2 2 1c dx: 1a ¼ Lc · sin u 0 After substitution for Lc, and 1c and working out the integral we have: F0 1 · ln 0 1a ¼ : ð5Þ r sin u sin uð1 2 r 0 sin uÞ Compatibility If ls and lc were the original lengths which stretched to Ls and Lc under the action of the applied force, we have: l s þ l c ¼ 2R: Since, Lc ¼ l c ð1 þ 1a Þ and Ls ¼ l s ð1 þ 1s Þ; it follows that:
Bagging of textile fabrics Part I 305
IJCST 18,5
306
0
0
Lc Ls þ ¼ 2: 1 þ 1a 1 þ 1s Substitution for the lengths and the strains gives: 1 2 r 0 sin u u · r0 h iþ ¼ 1: 0 mÞ 0 F 1 1 þ Fr0ð12 cos u 1 þ sin uð12r 0 sin uÞ · ln r 0 sin u sin2 u
ð6Þ
Equation (6) has the form of: C1 C3 þ ¼1 1 þ C2 · F 0 1 þ C4 · F 0
ð7Þ
with: 1 2 r 0 sin u lnð1=r 0 sin uÞ 12m ; C 3 ¼ u · r 0 and C 4 ¼ 0 2 ; C2 ¼ 0 sin uð1 2 r sin uÞ cos u r sin u The positive root of the quadratic which results from equation (7), relates the dimensionless force, F0 to the angle of contact which determines all the four variables from equations (1a) to (1d). Figure 2 shows the computed force-deformation relationships for different values of r/R and the Poisson’s ratio. C1 ¼
Variations of the average strain with d0 The average strain of the whole sheet can be estimated by comparing the deformed length A to C with its original length, R: ðLc =2 þ Ls =2 2 RÞ : ð8Þ 1¼ R Substitution from equations (1c) and (1d) gives: ðu 2 tan uÞr 1 2 cos u þ 1¼ : ð9Þ R cos u The relationship between the strain and d0 is a weak function of r/R, as shown in Figure 3. This is because of its small coefficients in equations (1a) and (9) within the strain range involved.
Figure 2. Force-deformation relationship in dimensionless form. Right: effect of the Poisson’s ratio; left: effect of the relative size of the ball
Bagging of textile fabrics Part I 307 Figure 3. Values of strain at different levels of d0
Conclusions (1) The Poisson’s ratio, which was not included in the cited literature, has an important effect on the force-deformation relationship. Increasing the Poisson’s ratio restricts extension of the sheet within the spherical portion and requires a higher force for a given level of d0 . Higher Poisson’s ratios also intensify the discontinuity of the strain at the interface. (2) Increasing the relative size of the ball requires higher forces to deform the fabric to a given d0 due to the higher size of bi-axially deformed zone, but has negligible effect on the relationship between d0 and the strain. In the second part of the work, the theoretical analysis will be verified by experimental results. Note 1. It should be noted that the strain becomes discontinuous at the interface while the slope and the stress remain continuous. References Abghari, R., Sheikhzadeh Najar, S., Haghpanah, H. and Latifi, M. (2004), “Contribution of in-plane fabric properties in woven fabric bagging”, International Journal of Clothing Science and Technology, Vol. 16 No. 5. Kisilak, D. (1999), “A new method of evaluating spherical fabric deformation”, Textile Research Journal, Vol. 69 No. 12. Laton, J.M. (2004), Textile Progress, Vol. 36 No. 1. Strazdiene, S. and Gutauskas, M. (2000), “Behavior of stretchable textiles with spatial loading”, Textile Research Journal, Vol. 73 No. 6. Zhuang, X., Li, Y., Yeung, K.W., Miao, M.H. and Yao, M. (2000), “Fabric-bagging”, Journal of the Textile Institute, Vol. 91 No. 4. Corresponding author J. Amirbayat can be contacted at: [email protected]
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
IJCST 18,5
An improved analysis of bagging of textile fabrics. Part II: experimental work
308
J. Amirbayat and B. Namiranian Centre of Excellence for Textiles, Amirkabir University of Technology, Tehran, Iran Abstract Purpose – Aims to analyse the stress distribution in a circular flexible sheet. Part II verifies the theory with experimental work. Design/methodology/approach – The investigation includes analysing the stress distribution in a circular flexible sheet clamped around its circumference under an externally applied force by a spherical object. Movement of the material normal to its original plane is then related to the external force and the elastic properties of the sheet, i.e. the elastic modulus and the Poisson’s ratio. The effects of the size of the force-applying object, relative to the sample radius, are also investigated. Findings – The relationship between the applied force on the centre of a flexible sheet material by a spherical object and the sag of the sheet was derived. Poisson’s ratio has an important role on the mechanism of deformation, restricting the extension of the sheet when it is high and intensifying the discontinuity of the strain at the interface. Research limitations/implications – The work could be expanded to industrial fabrics and to composite materials. Practical implications – The two papers provide a first step in an attempt for a better understanding of the stresses involved in bagging of a linear elastic sheet. They provide the basis for the development of fabrics that can withstand bagging problems. This research may also put forward improved methods of measuring bagginess. Some of the theoretical work may be used to predict bagginess of fabrics based on properties. Originality/value – The paper has two improvements on previous work: the inclusion of the effect of fabric Poisson ratio, and the suggestion of a better method of calculating the overall anisotropic properties. Keywords Fabric production processes, Bagging, Textile technology, Deformation, Sheets Paper type Research paper
International Journal of Clothing Science and Technology Vol. 18 No. 5, 2006 pp. 308-313 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610685230
Materials and their properties A thin rubber sheet, a sheet of paper and four different clothing fabrics have been chosen for the experimental work. Including of the first two sheets was necessary for verification of the theoretical analysis which was based on the isotropic properties. Owing to the nonlinearity of the stress-strain curves, the membrane modulus of each fabric was measured at four different strain levels, 3, 5, 7 and 9 percents along three directions, warp, weft and 458 biases by a CRE tester at a rate of 1 cm/min. The overall modulus of each fabric at any of the four strain levels was calculated according to equation (1) of the appendix and then averaged. The Poisson’s ratios were estimated from equation (5) at each strain level and their average was used for the analysis.
Poisson’s ratio of the rubber was taken as 0.5 (Rodriguez, 1983) and for paper as 0.33, which is the value given by Brezinski et al. for biaxial loading quoted by Schulgasser (1983). Table I shows the properties of the samples tested.
Bagging of textile fabrics Part II
Bagging tests Fabric samples were tested by a rig shown in Figure 1(b). The sample and the ball diameters were 9 and 5 cm, respectively.
309
Results and discussions General There are two main sources of error which affect the stress analysis section in addition to using a mean value for the modulus. One is neglecting the friction and the other one is over estimation of the Poisson’s ratio for the textile fabrics. The first one results in smaller theoretical forces and the second one has an opposite effect due to restricting the area change within the cap which demands higher forces for stretching the sample. During the initial stages of deformation, the area of the cap which starts from zero is small and both sources of error, which affect this section only, have negligible effects but the theoretical curves show higher forces than the test results. This is due to using the average value of the modulus which is higher than the modulus at low strains. Upon further increase of deformation, the theoretical curves lag the experimental ones for two reasons. One is using the mean modulus, which unlike the earlier stages is lower than the actual value, and the other one is higher frictional forces due to increase in the size of the double curvature. Properties Materials Fabric I Fabric II Fabric III Fabric IV Rubber Paper
Wool- polyester Polyester Polyester-viscose Polyester 0.6 mm thick 80 g/m2
Modulus,Y (N/cm)
Poisson’s ratio, m
208 257 216 200 45 1,370
0.861 0.814 0.826 0.936 0.5 0.33
Table I. Properties of the materials
Figure 1. (a) Schematic presentation of the system; (b) the experimental rig
IJCST 18,5
Another point to be noticed is the sensitivity of the force, which is linearly proportional to the modulus, to the Poisson’s ratio when it is beyond 0.7 and approaches the unity. Figure 2 shows variations of the normalized force: F0 ¼
310
F 2pRY
with the Poisson’s ratio for three strain levels. For m ¼ 1, the portion of the sheet which comes into contact with the ball, cannot undergo in-plane strains in order to conform to the ball and requires infinite force from the beginning. Rubber and paper The agreement between the theory and the experimental results showed in Figure 3 supports the validity of the theoretical analysis. Quoting accurate Poisson’s ratios from the reliable sources, leaves neglecting the friction as the only source of error and as a result, the actual forces are either equal or higher than the predicted values. Textile fabrics The results for the fabrics, Figure 4, show good agreement between the theory and the experiment except for fabric I, which according to the experimental result started with an initial sag[1].The same problem, but in lesser extent, is involved in the case of fabric II. All the fabrics show the effect of over estimation of the Poison’s ratios at earlier stages before domination of the frictional force.
Figure 2. Effect of the Poisson’s ratio on bagging force
Figure 3. Force-deformation relationship for isotropic sheets
Bagging of textile fabrics Part II 311
Figure 4. Force-deformation relationship of textile fabrics
Conclusions . Agreement between the theoretical and experimental results for isotropic sheets, confirms the validity of the analysis in the first part. The difference between the theoretical and experimental forces, especially at higher levels of deformation, is due to neglecting the friction and using the mean modulus. . Replacing the isotropic elastic properties by average properties of the anisotropic sheets, makes the analysis applicable to a certain extent. In further studies of the subject, the following improvements will be considered: . involving the friction in the theoretical analysis; . including the overall stress-strain equations of the sheets along three directions in the computer program, instead of the mean values of the modulus; and . measuring the Poisson’s ratios by a suitable method instead of estimating them, as described in the appendix. Notes 1. Shifting the curve to the left, unlike in the case of uniaxial tests where the slack can be subtracted from the initial extension, does not help. A fabric with sag clamped around its circumference behaves stiffer than a flat one under a force normal to its plane. 2. When measurements by photographic method were not successful and no other method was available at the time, it was imperative to use an approximate equation.
IJCST 18,5
References Rodriguez, F. (1983), Principles of Polymer Systems, 2nd ed., McGraw-Hill, New York, NY. Schulgasser, K. (1983), “The in-plane Poisson’s ratio of the paper”, Fibre Science and Technology, Vol. 19.
312
Further reading Amirbayat, J. (1994), “A simple approach to the generalised properties of orthotropic sheets”, International Journal of Mechanical Engineering Education, Vol. 22 No. 4. Hearmon, R.F.S. (1961), An Introduction to Applied Anisotropic Elasticity, Oxford University Press, Oxford. Kilby, W.F. (1963), “Planar stress-strain relationships in woven fabrics”, Journal of the Textile Institute, Vol. 54, pp. T9-27. Appendix The membrane modulus, Y, and the Poisson’s ratio, in the form of m/Y, which vary with the 0 angle of bias from the principal directions,f, are known as the stiffness C11 and the compliance 0 2 S12 , respectively. Variations of these elastic constants have been studied by many researchers including Hearmon, Kilby and Amirbayat, who applied tensor transformations, applied mechanics, and energy method, respectively. The overall, values of any of the elastic variable constants, say K, between f ¼ 0 and f ¼ p/2 can be calculated from: Z 2 p=2 Kdf: K ¼ p 0 By substituting the proper equation for variation of the modulus given by any of the methods, integration and comparing the result with the value given by the equation for f ¼ 458 it can be seen that: 1 1 1 1 2 ð1Þ þ þ ¼ Y 4 Y 1 Y 2 Y 45 where Y1, Y2 and Y45 refer to the modulus along these directions. For estimation of the average Poisson’s ratios of the fabrics[2], one can use the equations for the compliances 1/Y and m/Y as given by the authors previously mentioned: 1 m4 n4 1 2m ð2Þ þ þ m2 · n2 2 ¼ Y1 Y2 Y G Y m ðm 4 þ n 4 Þm 1 1 1 ð3Þ ¼ 2 m2 · n2 þ 2 Y1 Y2 G Y Y ðm ¼ cos f and n ¼ sinfÞ: In the above equations, G is the principal sheer modulus, f is the angle of bias from direction one and m/Y ¼ m1/Y1 ¼ m2/Y2 because of the symmetry. Combining equations (2) and (3) gives:. 2 12m m n2 m þ 2 ¼ : Y Y1 Y2 Y The overall value of the expression between f ¼ 0 and f ¼ p/2 can be otained by a similar method applied for the modulus which gives:
12m 1 ð1 2 m1 Þ ð1 2 m2 Þ ¼ : þ 2 Y1 Y2 Y
For negligible Poisson’s ratios along the warp and weft directions: Y 1 1 : þ m < 1 2 2 Y1 Y2
ð4Þ
ð5Þ
The above expression can be used for estimation of the overall Poisson’s ratios of the fabrics and obviously the values calculated are over estimated.
Corresponding author J. Amirbayat can be contacted at: [email protected]
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
Bagging of textile fabrics Part II 313
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
IJCST 18,5
Comparison of hyperelastic material models in the analysis of fabrics
314
Manuel Julio Garcı´a Ruı´z and Leidy Yarime Sua´rez Gonza´lez
Received December 2005 Revised April 2006 Accepted April 2006
CAD/CAM/CAE Laboratory, EAFIT University, Medellı´n, Colombia Abstract Purpose – This work presents a review of the application of hyperelastic models to the analysis of fabrics using finite element analysis (FEA). Design/methodology/approach – In general, a combination of uniaxial tension (compression), biaxial tension, and simple shear is required for the characterization of a hyperelastic material. However, the use of these deformation tests to obtain the mechanical properties of a fabric may be complicated and also expensive. A methodology for characterizing the fabric employing a different experimental test is presented. The methodology consists of a comparison of the results of the fabric characterization with only a tensile test and the combination of shear, biaxial, and tension experimental tests by using FEA. Findings – Numerical results of the fabric behavior contribute to estimate the effects of experimental limitations in the material characterization and to select the best fit material model to modeling fabrics. Finally, a comparison of hyperelastic material models is illustrated through an example of a rigid body in contact with a hyperelastic fabric in 3D. Originality/value – Hyperelastic models are used to characterize textile materials. Keywords Textile testing, Elastic analysis, Finite element analysis Paper type Research paper
1. Introduction Linear elastic models assume a linear strain-stress relationship and small deformations. Materials with large elastic deformation (like rubber) need different constitutive models. Mooney (1940) presented a theory of large elastic deformation, Rivlin and Saunders (1951) studied large elastic deformations of rubber, in Blatz and Ko (1962) presented a new strain energy function to the deformation of rubbery materials, Yeoh (1993) proposed a strain-energy function for the characterization of carbon-black filled rubber vulcanizates in 1990 (Ogden, 1972), constructed an energy function for the characterization of rubber-like solids for nonlinear large elastic deformations based on strain energy density functions. Other constitutive relations are based on macromolecular network structure (Arruda and Boyce proposed a new constitutive model for the deformation of rubber materials, in 1992 (Arruda and Boyce, 1993). These models are characterized by a particular form of the strain energy function W. In each of these methods, a set of coefficients must be determined. International Journal of Clothing Science and Technology Vol. 18 No. 5, 2006 pp. 314-325 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610685249
Project financed by COLCIENCIAS and EAFIT University. The authors thank the following people and institutions for their collaboration for in this research. EAFIT University (Prof. Dr Eng. Oscar E. Ruiz and MSc Eng Carlos Eduardo Lo´pez Zapata), Colombian textile industrial – Leonisa S.A (Ing. Jose´ Fernando Duque), and the Colombian Council for Science and Technology – Colciencias.
The modeling and design of hyperelastic materials consists of the selection of an appropriate strain energy function W, and accurate determination of material constants for such a function. There is no literature about the application of hyperelastic models to the deformation analysis of fabric materials. This paper deals with the study of the deformation of fabrics using different hyperelastic models. The first section describes some of the most used hyperelastic materials models. The strain energy function for different materials is presented. The second section introduces a procedure to characterize hyperelastic fabric. Its advantages and disadvantages are evaluated and presented. 2. Hyperelastic models This section introduces the concept of hyperelasticity and mentions some important aspects about hyperelastic models. Hyperelasticity is the capability of a material to undergo large elastic strain due to small forces, without losing its original properties. A hyperelastic material has nonlinear behavior, which means that its deformation is not directly proportional to the load applied. An elastic material is hyperelastic, if there is a scalar function, denoted by W ¼ W(1):Rn£ n ! R called strain energy function (or stored energy function), such that: ›W ð1Þ ›W ð1Þ ¼2 ; ð1Þ S i;j ¼ ›1ij ›C ij where, Sij are the components of the second Piola-Kirchhoff stress tensor, W is the strain energy function per unit volume undeformed, 1ij are the components of the strain tensor, and 1ij are the components of the right Cauchy-Green strain tensor. Throughly algebraical manipulation, equation (1) can determinate the components of the Cauchy (true) stress tensor (s) ›W ð1Þ ›W ð1Þ 1 si;j ¼ 2pdij þ 2 C ij 2 2 ; ð2Þ ›I 1 ›I 2 C ij where I1 and I2 are the principal invariants of the [C] tensor. The three strain invariants of the strain tensor can be expressed as: I 1 ¼ l21 þ l22 þ l23 ;
I 2 ¼ l21 l22 þ l22 l23 þ l23 l21 ;
I 3 ¼ l21 l22 l23 :
The strain energy functions of hyperelastic constitutive models such as Mooney-Rivlin, neo-Hookean and Arruda-Boyce are given in the next subsections. They are expressed as a function of strain invariants I1, I2, I3 or in terms of the principal stretches l1, l2, l3 of strain tensor. In order to deduce the strain energy functions, it is assumed, unless indicated, that the material is isotropic and with constant volume (isometric deformation l1l2l3 ¼ 1). Also, unless indicated, hyperelastic materials are assumed to be nearly or purely incompressible. The most common functions of deformation energy are as follows: . Mooney-Rivlin model. Mooney and Rivlin proposed a strain energy function W as an infinite series in powers of (I1 2 3) and (I2 2 3) of the form: nX !1 W ðI 1 ; I 2 Þ ¼ cij ðI 1 2 3Þi ðI 2 2 3Þi ; ð3Þ ij¼0
where cij are constants. For example, the Mooney-Rivlin form with two parameters is:
Hyperelastic material models
315
IJCST 18,5
W ¼ c10 ðI 1 2 3Þ þ c01 ðI 2 2 3Þ: .
316
Neo-Hookean model. Equation (3) shows a series of powers which are usually truncated in the first terms. Then, taking only the first term of equation (3), the neo-Hookean model is obtained: W ðI 1 Þ ¼ c10 ðI 1 2 3Þ:
.
Ogden model. Ogden (1972) deduced a hyperelastic constitutive model for large deformations of incompressible rubber-like solids. The strain energy is expressed as a function of principal stretches as: W ðl1 ; l2 ; l3 Þ ¼
nX !1 r¼o
.
mr ar ðl þ la2 r þ la3 r 2 3Þ; ar 1
with mr and ar as material constants, which can be determined by experimental tests. Yeoh model. The Yeoh (1993) model depends only on the first strain invariant I1. The strain energy function W is obtained by W ðI 1 Þ ¼
i X
ci0 ðI 1 2 3Þi :
n¼1
.
.
It applies to the characterization of elastic properties of carbon-black filled rubber vulcanizates. Arruda-Boyce model. The constitutive model for the large stretch behavior of rubber elastic materials is presented by Arruda and Boyce (1993). Also sometimes called the eight-chain model because it was derived by idealizing a polymer as eight elastic chains inside a volume element. The strain stress function is based on an eight chain representation of the macromolecular structure of the rubber: 1 1 11 3 ðI 21 2 9Þ þ ðI 2 27Þ W ðI 1 Þ ¼ G ðI 1 2 3Þ þ 2 20N 1; 050N 2 1 19 519 4 5 þG ðI 2 81Þ þ ðI 2 243Þ þ · · · 7; 000N 3 1 673; 750N 4 1 where the module G ¼ nkQ, n is the chain density, k is Boltz-mann’s constant, N is the number of rigid links composing a single chain, and Q the temperature. Gent model. The strain energy density in the Gent model (Gent, 1996) is a simple logarithmic function of the first invariant I1, and involves two material constants, the shear modulus m and Im which measures a limiting value for I1 2 3. Gent proposed strain energy density as: 2m I1 2 3 I m ln 1 2 W ðI 1 Þ ¼ : Im 2
.
Blatz-Ko model. An application of finite elastic theory to the deformation of rub-bery materials is given in (Blatz and Ko, 1962). Incompressibility is not assumed. The strain energy function is cast in terms of the constants n, m and f, which can be determined experimentally: 1 2 2n n 22n=ð122nÞ21 o J1 2 3 þ J3 n o mð1 2 f Þ 1 2 2n n 2n=ð122nÞ J2 2 3 þ þ J3 21 2 n
mf W ðJ 1 ; J 2 ; J 3 Þ ¼ 2
Hyperelastic material models
317
where n is similar to the Poisson’s ratio, m is the shear modulus, andPf is a material constant. Also, a new set of invariants is defined by J 1 ¼ l2i ; P J 2 ¼ l22 i and J 3 ¼ Pli : Successful modeling and characterization of hyperelastic materials depend on the selection of an appropriate strain energy function, and the accurate determination of coefficients in the function. The next section describes the procedure used to identify the minimum number of standard tests needed to obtain a good characterization of a hyperelastic fabric. 3. Problem description The types of experimental tests to determine the constants of the hyperelastic model are: uniaxial tension, uniaxial compression, planar shear, biaxial tension, and volumetric test (Figure 1). However, the textile testing equipment utilized to measure these properties has a lot of features, unusual for general-purpose mechanical testing machines. Test method variations reported in the literature and proper interpretation of test results add to the uncertainty. In this section, we discuss standardization of three types of tests and the application of the results of these tests to the numerical modeling by finite element models (FEM). The simplest deformation mode from the experimental point-of-view, is the uniaxial tension. For this purpose, the norms ASTM 412 (ASTM D412 98a, 2002) for elastomer and rubbers and the norm ISO 527 (ISO 527-5, 1997) for plastics were used. Figure 2 shows the stress-strain curve of the hyperelastic fabric at 20, 80 and 1058C.
Figure 1. Stress-strain experimental curves for an elastomer
IJCST 18,5
318
Figure 2. Stress-strain curves for hyperelastic fabric at different temperatures
3.1 Methodology to determine the constants of the hyperelastic textile Different levels of experimental test can be used to characterize a hyperelastic fabric. The following procedure was developed to investigate the approximation error when only few of these tests are available. Also a computational experiment was designed to test the accuracy of the models. It consists of a rigid sphere in contact with a hyperelastic fabric as shown in Figure 3(a). The fabric is initially horizontal and it is fixed all around its edges. The solid sphere is then moved a distance towards the fabric.
Figure 3. Model of the fabric in contact with rigid body
The results of these analysis undertaken using different hyperelastic material models (Mooney-Rivlin, Ogden, Neo-Hookean, Yeoh, Blazt-Ko and Arruda-Boyce) were determined using input data determined from two different combinations of test data:
Hyperelastic material models
Case A only uniaxial tension data is employed. Case B shear, biaxial and tension test data are employed. An finite element analysis (FEA) is used to obtain the hyperelastic coefficients of fabric and apply them to the both cases A and B. The procedure that followed to analyze cases A and B is shown in Figure 4. First, the experimental data are introduced and a hyperelastic model is selected. A nonlinear regression routine is used to determine the
319
Figure 4. Methodology of the analysis hyperelastic materials
IJCST 18,5
coefficients of the selected model so as to obtain the model that best fits to the experimental data. The least-squares error to be minimized during data fitting can be based on absolute or relative errors and are defined as follows: X ½experimental dataði Þ 2 calculated data ði Þ2 absolute error ¼ i
320
relative error ¼
X i
experimental data ði Þ 12 Calculated dataði Þ
2
ð4Þ
The next step consists of comparing the residual of least squared error with an e value, if e is lower than least-squared error, then the constants are taken for modeling the hyperelastic material. Finally, the FEA is undertaken. The problem was solved by applying nonlinear analysis with FEM (Figure 3(b)). Although the hyperelastic model selected fit the strain-stress data, some models do not converge to the solution. Then, stability of the hyperelastic model was checked, i.e. the stretch ratio must be in a permissible range. If the material is deemed stable, then the strain-stress results for both cases A and B are stored for takes comparison. 3.2 Comparison of the results for the cases A and B (1) Case A. Determination of the properties of a hyperelastic material only using experimental data of uniaxial tension.The hyperelastic models analyzed in this case are shown in Table II. Models with a least squared error value greater than 1 ¼ 30 percent are not acceptable for this study. Acceptable error maximum between experimental and fitted data is assumed because this correlation represents few variations in the results of stress state of the fabric. The results of the Mooney-Rivlin and Yeoh models of higher order give the best fit with uniaxial tension. The Arruda-Boyce model also gives an acceptable result. However, the solution of the problem converges only for Yeoh and Arruda-Boyce. Figure 5 shows the results of fitting the hyperelastic constants using only the uniaxial tension test. (2) Case B. Determination of the properties of a hyperelastic material using experimental data of uniaxial tension, biaxial and shear tension. Hyperelastic models are compared in Table I. The Mooney-Rivlin model (with 9 parameters) best fits the experimental data. The strain-stress results are shown in Figure 6. Results obtained by using all three types of test data adjust exactly to the real problem. 3.3 Normalized error value Let the value of stress for case A be defined bysAi ; i ¼ 1, . . . ,n and n is the total number of nodes in the domain. Let sAi correspondingly be the stress value for case B. The normalized error value e can be calculated using the expression: max1#i#n sBi 2 sAi : e ¼ 100 max1#i#n sAi The error found when employing only the uniaxial tension test data is approximately 15 percent (Table II).
Hyperelastic material models
321
Figure 5. Comparison of material models case A
4. Hyperelastic constants to characterize the fabric Mooney-Rivlin (nine parameters), Yeoh (order 2 and 3), Arruda-Boyce and Ogden constitutive models of hyperelastic fabric have been established on the basis of uniaxial test results (Figure 7). The high-order Mooney-Rivlin and Yeoh models best fit the test data. The Arruda-Boyce and order 1 Ogden models also achieve an acceptable fit. In contrast, Ogden (order 2 and 3), neo-Hookean, Gent, Blazt-Ko, and the lower-order Mooney-Rivlin and Yeoh models show large differences between the numerical and test data.
IJCST 18,5
Hyperelastic model Mooney Rivlin
322
Ogden neo-Hookean Arruda-Boyce Gent Yeoh
Table I. Results of fitting using three tests data
Figure 6. Stress-strain fitting with Mooney-Rivlin (9 parameters, T ¼ 208C)
Blatz-Ko
2 parameters 3 parameters 5 parameters 9 parameters Order 1 Order 2 Order 3 – – – Order 1 Order 2 Order 3 –
Fit test data
Least squared error (percent)
– – Acceptable Good – –
96 95 30 18 180 – – 180 130 880 180 140 100 270
– – –
Hyperelastic model Mooney Rivlin
Ogden neo-Hookean Arruda Boyce Gent Yeoh Blatz-Ko
2 parameters 3 parameters 5 parameters 9 parameters Order 1 Order 2 Order 3 – Acceptable – Order 1 Order 2 Order 3 –
Fit test data
Least squared error
– Acceptable Good Best – – –
60 15 1 0.01 50 54 54 65 30 880 60 40 5 200
– – Good
5. Conclusions The derivation of models such as the Mooney-Rivlin and Gent is difficult because of the amount of experimental data required to obtain the model coefficients. To improve the accuracy of predictions, it is best to use experimental data from a range of experimental tests (uniaxial, biaxial, and planar tension). The Arruda-Boyce, neo-Hookean and Yeoh models offer a physical interpretation and provide a better description of general deformation modes when the parameters are based only on one test. In all cases, it is best to obtain experimental data over the range of strain of interest (this is especially true of the Ogden and polynomial models), and to select the model coefficients carefully to ensure stability. Two different combinations of input data were evaluated: uniaxial tension only and combined uniaxial, biaxial and planar tension, as described in Section 3.1. The normalized error calculated shows that there is little difference between the accuracy of pre-dictions made using uniaxial data only and those made using the combined uniaxial, biaxial, and planar tension data. Therefore, it appears that the biaxial and planar tests can be omitted with little effect on accuracy, thereby simplifying testing requirements. The use of only uniaxial test data will induce an error of 15 percent. In general, it is better to obtain data from several experiments involving different kinds of deformation. The range of deformation should be restricted to the interest of application, in order to determine the model coefficients. For example, the Ogden and Mooney-Rivlin models of higher order present some instabilities when only limited test data are available. Arruda-Boyce and Yeoh (order 3) models provide the best fit when the constants are calculated using only the uniaxial tension test. Numerical simulations of forming processes can be powerful tools for materials selection, tool design, and process optimization. A critical component of these simulations is the correct representation of the material response, as well as robust, standardized methods to characterize the materials and validate the simulations. It should be noted that the experimental and numerical approaches discussed here are applicable to the forming processes. For example, the behavior of a hyperelastic fabric in a thermoforming process could be simulated by a exact characterization, as is shown in Figure 8(b).
Hyperelastic material models
323
Table II. Results of fitting using uniaxial tension data
IJCST 18,5
324
Figure 7. Comparison of hyperelastic material models
Hyperelastic material models
325
Figure 8. Modeling of a thermoformed mold of hyperelastic fabrics
References Arruda, E.M. and Boyce, M.C. (1993), “A three-dimensional constitutive model for the large stretch behavior of rubber elastic materials”, Journal of the Mechanics and Physics of Solids, Vol. 41 No. 2, pp. 389-412. ASTM D412 98a (2002), “Standard test methods for vulcanized rubber and thermoplastic elastomers-tension”, Annual Book of ASTM Standards, December, pp. 1-14. Blatz, P.J. and Ko, W.L. (1962), “Application of finite elastic theory to the deformation of rubbery materials”, Transactions of the Society of Rheology, Vol. VI, pp. 223-52. Gent, A.N. (1996), “A new constitutive relation for rubber”, Rubber Chem. Technol., Vol. 69, pp. 59-61. ISO 527-5 (1997), “Plastics determination of tensile properties-part 5: test conditions for unidirectional fibre-reinforced plastic composites”, Annual Book of ASTM Standards, ISO, Geneva, pp. 1-9. Mooney, M. (1940), “A theory of large elastic deformation”, Journal of Applied Physics, Vol. 11, January, pp. 582-92. Ogden, R.W. (1972), “Large deformation isotropic elasticity on the correlation of theory and experiment for incompressible rubberlike solids”, Proc. R. Soc. Lond. A.. Rivlin, R.S. and Saunders, D.W. (1951), “Large elastic deformations of isotropic materials, VII, experiments on the deformation of rubber”, Transactions of the Royal Society of London. Series A (Mathematical and Physical Sciences),Vol. 243, pp. 251-88. Yeoh, O.H. (1993), “Some forms of the strain energy function for rubber”, Rubber Chem. Technol., Vol. 66, pp. 754-71. Corresponding author Manuel Julio Garcıa Ruız can be contacted at: [email protected]
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
IJCST 18,5
The evaluation of fabric treatment by Griff tester and sensory analysis
326
E. Strazdiene˙
Received November 2005 Revised April 2006 Accepted April 2006
Faculty of Design and Technologies, Kaunas University of Technology, Kaunas, Lithuania
S. Ben Saı¨d Laboratoire de Physique et Me´canique Textiles, Ecole Nationale Supe´rieure des Industries Textiles de Mulhouse, Mulhouse, France
M. Gutauskas Faculty of Design and Technologies, Kaunas University of Technology, Kaunas, Lithuania, and
L. Schacher and D.C. Adolphe Laboratoire de Physique et Me´canique Textiles, Ecole Nationale Supe´rieure des Industries Textiles de Mulhouse, Mulhouse, France Abstract Purpose – The aim of presented investigation was to test developed testing device Griff tester, created for the objective evaluation of textile hand and to compare the obtained data with sensory evaluation results of textiles, subjected to different final treatments. Design/methodology/approach – The effect of two finishing products, i.e. the crease-resistant finishing Knittexw “K” and the softener macro silicone Ultratexw “Ul” upon 100 per cent cotton plain weave fabric was studied by two methods – objective evaluation and sensory analysis. Objective evaluation was done using Griff tester device where disc shaped specimen was extracted through a rounded hole of the stand. Sensory analysis was performed by the panel of 11 trained persons. Findings – Investigations have shown that both treatments changed the hand of the fabric in the expected direction. Meantime, two experimental methods (objective and sensory approach) have shown their effectiveness to evaluate the textile touch, respectively. Practical implications – The obtained results proved that criterion Q can be used for sensitive and vivid detection of differences between fabrics, affected by different final treatment operations. The effects of finishing products’ concentrations were found to be in accordance with the manufacturer’s technical specifications and with the finishing industrialist’s expectations. Originality/value – Investigation results obtained by Griff tester revealed the possibility of fabric hand evaluation on the basis of one relative criterion Q. These results can be linked with some attribute issued of the sensory analysis applied to the characterisation of the tactile feeling. Keywords Textiles, Textile finishing, Sensory perception Paper type Research paper International Journal of Clothing Science and Technology Vol. 18 No. 5, 2006 pp. 326-334 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610685267
1. Introduction In order to confer a variety of looks and effects on fabrics, there are many new finishing products and treatments proposed by chemical suppliers. They can roughly be splitted
into two categories: easy-care and organoleptic. Among them numerous softeners have been proposed by suppliers (macro and micro silicone, fatty acid and polyethylene, etc.). They are now widely used in industry, but their effect is still difficult to quantify. Usually the effect of treatment in industry is evaluated subjectively. In some cases certain mechanical property variations due to finishing treatments can be tested using standard testing methods (ISO2313, 1992), but they are far away of representing human evaluation of tactile perception. Numerous researchers (Hearle and Amirbayat, 1987; Pan et al., 1988; Behera and Hari, 1994; Gong and Mukhopadhyay, 1993) have contributed to the science of objective measurement of fabric hand. Kawabata Evaluation System for Fabrics conceived in the 1970s, still remains the most complete set of device to measure the hand of fabrics (Kawabata and Niwa, 1980). However, hand evaluation is far more complex than tactile evaluation itself. Thus, this investigation was aimed to test developed testing device Griff tester created for the objective evaluation of textile hand (Martisˇiute˙ and Gutauskas, 2001). It was expected that with the help of this equipment the differences between fabric treatments technologies could be distinguished more evidently than it was done before. Furthermore, the aim of this research was to define the existing correlations between the results obtained thanks to this method and some attributes issued of the sensory evaluation of textile tactile feeling.
The evaluation of fabric treatment 327
2. Testing methods and materials We have investigated treatments performed on 100 per cent cotton plain weave fabric, 24 yarns/cm weft and warp, thickness – 0.97 mm, 160 g/m2, scoured and bleached. Two finishing products were studied: the crease-resistant finishing Knittexw “K” and the softener macro silicone Ultratexw “Ul”. (1) Knittexw FEL. A nonionic crosslinking resin based on a modified dimethyloldihydroxyethylene, allows to bring properties of anti-crease and anti-shrink to the fabric. (2) Ultratexw UM. Cationic emulsion of functional polydimethylsiloxane, allows to bring a very soft touch to the fabric. The products were processed using semi-industrial range and we have varied the concentrations of the two products as it is presented in Table I. Fabrics were tested and evaluated under controlled environmental conditions.
Product Non treated fabric Knittexw FEL “K” UltratexwUM “Ul”
Concentration (g/l) 0 20 50 80 5 20 40
Table I. Different finishing treatments
IJCST 18,5
328
Figure 1. Principal scheme of Griff tester device
Figure 2. Typical pulling through a hole curves obtained by Griff tester
The experimental part of the research was done using Griff tester device (Figure 1) according to the method described earlier (Strazdiene˙ et al., 2003a, b; Daukantiene˙ et al., 2003). Disc shaped specimen R ¼ 56.5 mm was extracted through a rounded hole r ¼ 10 mm of the stand. Distance between the limiting plates was selected to be h ¼ 1.6 mm. Values of r and h parameters depend on the thickness of tested material d ¼ 0.97 mm and are chosen taking into account not only specimen jamming conditions between the limiting plates and in pad’s hole, but also in respect to the sensitivity zone of this device (Strazdiene˙ et al., 2002; Strazdiene˙ and Gutauskas, 2005). Specimen pulling through a hole velocity was 100 mm/min. The number of specimens in each group of finishing treatment was 8. During testing, pulling curves H-P (pulling height – pulling force) were registered (Figure 2) on the basis of which three parameters were defined, i.e. maximal force Pmax,
slope angle of the initial part of the curve tga and pulling work A. On the basis of this data for each finishing treatment radial diagram was plotted and area S was calculated as it is shown in Figure 3. Relative criterion Q was determined as ratio S/S0, where S is the area of any finishing treatment, S0 is the area of non-treated specimen. Such relative criterion gives general characteristic of tested fabric from the standpoint of its deformability during pulling through a rounded hole, i.e. by providing the total evaluation for such fabric properties as bending, buckling, sharing, compression, friction, etc. In order to quantify tactile perceptions of fabrics, we have used a new method transposed from methodologies and standards already existing in food and cosmetic areas to textile goods (Philippe, 2002; Philippe et al., 2003, 2004). This method of “sensory profile” requires a group of trained persons, 11 in our case. These persons, called subjects, evaluate the products twice, in particular conditions, in order to avoid some bias due to other senses: the presentation of the fabrics is randomised and the evaluation is done without seeing using specially designed booth. Subjects use a set of 15 quantified attributes presented in Table II to build profile consisting of the descriptive, quantitative and objective analysis of the fabric. Quotation is performed on a non-structured scale of 0-10, as it was presented in previous studies (Philippe et al., 2003; Chollakup et al., 2004; Chollakup, 2004). Through implementation of rigorous procedures, i.e. exploratory procedures, samples presentation and data analysis, this methodology provides reliable descriptions of perceived quality of fabrics. The tested fabrics were less diversified than the fabrics usually tested by the panel and, consequently, some attributes might
The evaluation of fabric treatment 329
Figure 3. Method of S parameter determination
Bipolar attributes
Cold-warm Thin-thick Light-heavy Supple-rigid
Surface attributes Pilous Soft Granulous Sticky Grooved Greasy Slipping
Handle attributes
Falling Responsive Crumple-like Elastic
Table II. List of 15 attributes used for the sensory analysis
IJCST 18,5
330
Table III. The summary of fabric pulling through a hole parameters (r ¼ 10.0 mm; h ¼ 1.6 mm)
Figure 4. Variation of criterion Q versus finishing product concentration
not be pertinent for woven post-treated fabrics’ description. The pertinence of the attribute is checked a posterior using statistical tools. 3. Results and discussion 3.1 Objective evaluation by Griff tester As it was mentioned above, the initial data for the investigation was taken from H-P curves which are shown in Figure 2. The beginning of pulling curve corresponds to the specimen waving between the limiting plates up till the moment when sine curved waves are completely formed. So, this stage of pulling process is associated with fabric bending and is ended by Pmax value. When the waves start to obtain irregular shapes, i.e. they are pressed, compressed and start to break or to cover each other, H-P curve obtains pinked shape and P value more or less decreases. The second Pmax value is associated with fabric jamming in the hole of the stand. Figure 2 evidently shows that for the samples treated with macro silicone Ultratexw softener the second Pmax value is less expressed than in the case of samples after crease-resistant finishing Knittexw, because more soft and slippy specimens are more easily compressed and pass the hole with of the stand with less force. Also, it must be noted that in most cases highest Pmax value was located at the beginning of H-P curve. Average values of measured parameters and their standard errors are presented in Table III. Obtained results have proved that essential differences can be observed between different treatments of fabrics, because the difference between average values is greater than the sum of standard errors. Figure 4 shows the variation of the relative criterion Q according to the concentration of each finishing product. Finishing product
Concentration
Pmax, N
tga
A, N cm
Q ¼ S/S0
Non treated Knittexw FEL “K”
0 20 50 80 5 20 40
29.20 ^ 1.20 28.80 ^ 0.90 36.40 ^ 2.50 44.60 ^ 2.00 23.01 ^ 0.68 18.11 ^ 1.15 14.24 ^ 0.36
4.51 ^ 0.45 4.31 ^ 0.32 6.20 ^ 0.40 6.71 ^ 0.73 2.46 ^ 0.14 2.46 ^ 0.04 2.35 ^ 0.10
105.90 ^ 3.60 110.20 ^ 6.10 135.40 ^ 7.30 163.40 ^ 5.60 78.87 ^ 1.59 62.20 ^ 1.91 48.75 ^ 0.85
1.00 1.06 1.44 1.92 0.59 0.41 0.29
UltratexwUM “Ul”
3.2 The results of sensory analysis The results of sensory analysis are presented in Table IV. It shows the mean scores for the tested fabrics and for the seven pertinent attributes. For the silicone finishing, the “slipping” and “greasy” attributes change clearly with the concentration of the product. This result was expected as “Ul” treatment was known to soften the fabric and with the increase of concentration fabric becomes more “greasy” and “slipping”. It is also worth noting that the panel greatly perceived the modifications obtained by this treatment for the different concentrations. For the resin treatment it is expected to have more “nervous” and less “crumple-like” fabrics. This is confirmed by the results obtained, since fabrics treated with a high concentration of resin finishing were significantly more “nervous” and less “crumple-like” than the non-treated fabric. These results show that both treatments changed the hand-feel of the fabric in the expected direction and that the panel clearly perceived the modifications. Figure 5 shows the variation of sensory attributes according to the concentration of the finishing product.
The evaluation of fabric treatment 331
3.3 Correlation between the results obtained thanks to the two evaluation methods The analysis of the results presented for both methods shows that the evaluation of the fabrics is respected for the two types of treatment. The sensory evaluation ranges the treated fabrics as follows: (1) for the resin finishing in terms of “responsive” attribute we have: K80 , K50 , K20 , K0, while for the “crumple-like” attribute: K0 , K20 , K50 , K80; (2) for the silicone treatment “greasy” and “slipping” attributes are ranged in such a way: Ul0 , Ul5 , Ul20 , Ul40. The Griff tester evaluation ranges the fabrics into the same queue in respect to their treatment: for resin treatment “K” we have Q0 , Q20 , Q50 , Q80 and for the silicone “Ul” treated fabrics we have Q40 , Q20 , Q5 , Q0. By the comparison of the results of these two methods, we can clearly note that the criterion Q has the same pace as “greasy” and “slipping” attributes for the silicone treatment and the “responsive” attribute (so the opposite pace of the “crumple-like” attribute) for the resin treatment. This sustains the results obtained by the sensory analysis and indicates that the Q criterion can quantitatively describe the modifications assigned to the fabrics by the use of chemical finishing for different concentrations. Non treated Concentration Falling Rigid Slipping Soft Greasy Responsive Crumple-like
0 7.31 3.09 5.01 5.73 2.14 1.29 7.60
Knittexw FEL “K” 20 6.71 3.90 4.48 4.48 1.81 1.35 6.98
50 6.29 4.01 4.16 3.62 1.55 1.79 6.06
80 6.49 4.38 4.84 3.84 1.70 2.26 4.47
UltratexwUM “Ul” 5 7.34 3.18 5.73 5.28 2.98 2.00 7.32
20 7.37 2.78 6.77 5.83 4.77 2.77 7.67
40 7.26 2.99 7.67 6.65 5.52 2.84 7.40
Table IV. Mean values for sensory attributes
IJCST 18,5
332
Figure 5. Variation of the sensory attributes versus the finishing product concentration
In both cases of treatment Q varies in the same way as the affected attribute, these observations are confirmed by a mathematical correlation that shows a linear dependency between Q and the “responsive” and “crumple-like” attributes for the resin treatment and an exponential dependency between Q and “greasy” and “slippery” attributes for the macro-silicone finishing as it is shown in Figure 6. 4. Conclusions Investigation results obtained by Griff tester revealed the possibility of fabric hand evaluation on the basis of one relative criterion and that it could be associated to the sensory analysis data. Such objective criterion as Q can be used for sensitive and vivid detection of differences between fabrics effected by different final treatment operations. The effects of finishing products’ concentrations were found in accordance with the manufacturer’s technical specifications and with the finishing industrialist’s expectations. The evaluation of this effect was carried out by two different methods of tactile analysis: objective evaluation with Griff tester and sensory evaluation. The two methods are suitable to define the changes of textile material hand due to their final treatment peculiarities. These two methods have then shown their
The evaluation of fabric treatment 333
Figure 6. Correlation between criterion Q and different attributes of the sensory evaluation
effectiveness to evaluate the textile touch. Correlation between them was confirmed by the dependence of the sensory attributes to the objective criterion Q. Further investigations are still to be done to deeply analyse the effect of product concentration and determine the sensitiveness threshold and saturation. References Behera, B.K. and Hari, P.K. (1994), “Fabric quality evaluation by objective measurement”, Indian Journal of Fibre & Textile Research, Vol. 19 No. 3, p. 168. Chollakup, R. (2004), “Etude des me´langes soie-coton en filature fibres courtes: caracte´ristiques des fils et analyse sensorielle des tricots”, PhD thesis, Universite´ de Haute Alsace, Mulhouse. Chollakup, R., Sinoimeri, A., Philippe, F., Schacher, L. and Adolphe, D. (2004), “Tactile sensory analysis applied to silk/cotton knitted fabrics”, International Journal of Clothing Science and Technology, Vol. 16 Nos 1/2, pp. 132-40. Daukantiene˙, V., Papreckiene˙, L. and Gutauskas, M. (2003), “Simulation and application of pulling textile fabric through a central hole”, Fibres and Textiles in Eastern Europe, Vol. 11 No. 2, pp. 38-42. Gong, R.H. and Mukhopadhyay, S.K. (1993), “Fabric objective measurement: a comparative study of fabric characteristics”, Journal of the Textile Institute, Vol. 84 No. 2, pp. 192-8. Hearle, J.W.S. and Amirbayat, J. (1987), “Objective evaluation of fabric handle”, Textile Month, No. 1, 25, 27-8, 30. ISO2313 (1992), “Textile fabrics – determination of the recovery from creasing of a horizontally folded specimen by measuring the angle of recovery”, International Organisation of Standardisation, Geneva. Kawabata, S. and Niwa, M. (1980), The Standardisation and Analysis of Hand Evaluation, The Textile Machinery Society of Japan, Osaka. Martisˇiute˙, G. and Gutauskas, M. (2001), “A new approach to evaluation of fabric handle”, Materials Science, Vol. 7 No. 3, pp. 186-90.
IJCST 18,5
334
Pan, N., Yen, K.C., Zhao, S.J. and Yang, S.R. (1988), “New approach to the objective evaluation of fabric handle from mechanical properties. Part I: objective measure for total handle”, Textile Research Journal, Vol. 58 No. 8, pp. 438-44. Philippe, F. (2002), “Contribution a l’e´valuation tactile des produits textiles par analyse sensorielle”, PhD thesis, Universite´ de Haute Alsace, Mulhouse. Philippe, F., Schacher, L., Adolphe, D. and Dacremont, C. (2003), “The sensory panel applied to textile goods – a new marketing tool”, Journal of Fashion Marketing and Management, Vol. 7 No. 3, pp. 235-48. Philippe, F., Schacher, L., Adolphe, D. and Dacremont, C. (2004), “Tactile feeling: sensory analysis applied to textile goods”, Textile Research Journal, Vol. 74, pp. 1066-72. Philippe, F., Abreu, M., Schacher, L., Adolphe, D. and Cabeco Silva, M. (2003), “Influence of the sterilisation process on the tactile feeling of surgical gowns”, International Journal of Clothing Science and Technology, Vol. 15 Nos 3/4, pp. 268-75. Strazdiene˙, E. and Gutauskas, M. (2005), “New method fort he objective evaluation of textile hand”, Fibres and Textiles in Eastern Europe, Vol. 13 No. 2, pp. 35-8. Strazdiene˙, E., Daukantiene˙, V. and Gutauskas, M. (2003), “Bagging of thin polymer materials: geometry, resistance and applications”, Materials 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”, Proceedings of the 6th Dresden Textile Conference. Strazdiene˙, E., Martisˇiute˙, G., Gutauskas, M. and Papreckiene˙, L. (2003), “Textile hand: a new method for textile objective evaluation”, The Journal of the Textile Institute, Vol. 94 Nos 3/4, pp. 245-55. About the authors E. Strazdiene˙ is an Associate Professor at Faculty of Design and Technologies, Kaunas University of Technology, Kaunas, Lithuania. E. Strazdiene˙ is the corresponding author and can be contacted at: [email protected] S. Ben Saı¨d is a doctoral student at the Laboratoire de Physique et Me´canique Textiles, Ecole Nationale Supe´rieure des Industries Textiles de Mulhouse, Mulhouse Cedex; France, e-mail: s. [email protected] M. Gutauskas is a Professor at the Kaunas University of Technology, Faculty of Design and Technologies, Studentu str. 56; Kaunas, Lithuania, e-mail: [email protected]. L. Schacher is a Professor at the Laboratoire de Physique et Me´canique Textiles; Ecole Nationale Supe´rieure des Industries Textiles de Mulhouse; Mulhouse Cedex; France, e-mail: l. [email protected] D.C. Adolphe is a Professor at the Laboratoire de Physique et Me´canique Textiles, Ecole Nationale Supe´rieure des Industries Textiles de Mulhouse, Mulhouse Cedex; France, e-mail: d. [email protected]
To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0955-6222.htm
The influence of mechanical properties of sewing threads on seam pucker Vaida Dobilaite and Milda Juciene Faculty of Design and Technologies, Kaunas University of Technology, Kaunas, Lithuania
Sewing threads on seam pucker
335 Received March 2006 Revised May 2006 Accepted May 2006
Abstract Purpose – The paper aims to evaluate the influence of mechanical properties of sewing threads on the seam pucker. Design/methodology/approach – The mechanical properties of sewing thread were obtained performing tensile testing research. The seam pucker of lightweight fabric was evaluated after sewing, then after 24 h, after 48 h as well as after washing and drying. To determine dimension changes of fabric, the relaxation shrinkage was calculated. The results of thread properties and seam pucker were compared. Findings – In respect of seam pucker the best results were established sewing with polyester threads, the reversible strain of which were the least. After washing and drying, the highest pucker was typical of the specimens sewn with cotton sewing threads. It was noticed that increasing the amount of layers in sewing the influence of threads on seam pucker decreases. Washing and drying made considerably greater influence on the occurrence of pucker then time. Practical implications – This study has practical implications in the clothing and other nearly related industries. In the paper recommendations involved with application of sewing thread and evaluation of seam pucker are presented. Originality/value – In most cases the changes of sewn thread mechanical properties after sewing is analysed. This study is aimed to determine the influence of thread properties on seam pucker. Recommendations in the area of sewing thread and garment quality are based on the research. Keywords Clothing, Thread, Textiles, Textile testing Paper type Research paper
Introduction Quality of sewing garments is determined by many factors including puckering in the place of a seam. This defect is relevant to garments sewn of light textile materials, especially of lightweight fabrics. Seam pucker is influenced by different factors, as properties of sewing threads and fabrics, processes of needle penetration, stitch formation, sewing thread tension and fabric feeding, seam construction and various technological parameters, and other. Particular great attention is paid to fabric properties and factors of a sewing machine as well as to their compatibility in the process of sewing (Stylios and Lloyd, 1990; Stylios and Fan, 1991; Kawabata et al., 1991; Kawabata and Niwa, 1998; Mori et al., 1997; Park and Kang, 1997). The shrinkage of threads after sewing may have not inconsiderable influence on occurrence of this defect. However, studying properties of threads, the changes of mechanical properties after sewing is analysed in most cases (Mori and Niwa, 1994; Sundaresan et al., 1997, 1998; Zˇiliene˙ and Baltrusˇaitis, 2000; Rudolf and Gersˇak, 2001; Ajiki and Postle, 2003).
International Journal of Clothing Science and Technology Vol. 18 No. 5, 2006 pp. 335-345 q Emerald Group Publishing Limited 0955-6222 DOI 10.1108/09556220610685276
IJCST 18,5
336
The limited amount of researches analysing the influence of sewing thread properties on seam pucker have been reported (Schwartz, 1984; Behera and Chand, 1997; Fan and Leeuwner, 1998; Park and Kang, 1999). Seam pucker often is evaluated immediately after the sewing process or shortly after it. Thus, there is no possibility to evaluate relaxation processes of sewing garment fabrics manifesting themselves only after longer time passes from the sewing process. Particularly, it is relevant to sewing threads as in the process of sewing they undergo different loads, are stretched, flexed and otherwise deformed. Reversible deformations of threads may assert themselves only after some time, and this fact would also have influence on quality of a sewing garment as due to this deformation threads may crease seams, especially in the sewing garments of light fabrics. One of the factors relevant to seam puckering is the impact of humidity that is often left unconsidered. After sewing, seam quality may be acceptable, but under the impact of humidity seams may crease significantly as macromolecules of fibres in sewing garment fabrics become more mobile and return to their normal status. Thus, in order to asses the reasons of seam puckering in a complex manner it is necessary to consider the compatibility of sewing garment fabrics both in the process of sewing and when some time passes after sewing as well as in the course of operation. The aim of this paper is to evaluate the influence of mechanical properties of sewing threads on the seam pucker. Materials and methods Commercial polyester and cotton sewing threads having different structural, physical and mechanical properties were selected for the present study. The details of these threads are given in Table I. Defect of seam pucker is especially topical for lightweight fabrics of sewing garments. Therefore, in the research fabrics deigned for light garments were used, marked as A1 (100 per cent cotton), A2 (PES/cotton), A3 (100 per cent CV). Mechanical hysteresis of sewing threads was obtained using universal testing machine “ZWICK/Z005”. In the course of the analysis, load of 2 N was suddenly applied to tests specimens and eliminated immediately, returning the lower clamp to the initial position. Distance between clamps was 500 mm, their movement speed was 300 mm/min, with 1 load cycle performed. From the obtained curves of mechanical hysteresis, parameters of sewing threads, i.e. total strain et, per cent, elastic strain ee, per cent and remaining strain er, per cent were determined. Remaining strain er was determined by measuring on the axis of abscissas the distance from the origin point of coordinates to the end point of a return part of a hysteresis loop, whereas ee was determined by measuring on the same axis the distance from the end point of a return part of a hysteresis loop to the node of the axis of abscissas and a perpendicular drawn from the top of a hysteresis loop (Figure 1).
Table I. Properties of sewing threads
Thread code
Composition
A402 C452 M402
100 per cent PES 100 per cent PES 100 per cent cotton
Linear density, tex
Elongation at break, per cent
Breaking tenacity, cN/tex
14.8 £ 2 13.1 £ 2 14.8 £ 2
18.9 19.3 6.0
36.3 502 42.9
Sewing threads on seam pucker
337
Figure 1. The curve of mechanical hysteresis of sewing threads
Single-cycle tensile testing of sewing threads were also performed using “ZWICK/Z005” testing machine. When determining single-cycle tensile characteristics of sewing threads, length of a working part was 500 mm and speed was 300 mm/min. To test specimens, permanent load of 2 N was applied, whereas load and relax time was 5 minutes. From the obtained curves, total strain Et, per cent, reversible strain Erv, per cent and remaining strain Er, per cent were calculated. Seam pucker was evaluated by measuring length of test specimens sewn with the sewing threads chosen for research and calculating pucker coefficient W (per cent) (Kwong et al., 1997): Ls 2 L0 £ 100; ð1Þ W¼ L0 where L0 is initial length of specimen, Ls is length of specimen, stretched until puckers disappears. Length of specimens was measured immediately after sewing, then after 24 h, after 48 h as well as after washing and drying. To prepare the specimens for this investigation, the fabrics’ strips of 200 £ 30 mm dimensions were cut in the warp direction. Two such strips were sewn together across the centre line in longitudinal direction. The seam type was 1.01.01. Another part of test specimens was prepared grouping strips by three. “Juki” DLU 490 one-needle lockstitch sewing machine and “Schmetz” needle No. 90 were used, with stitch length of 2.5 mm. For each group of different sewing thread, optimum tension was selected, respectively. Other sewing conditions were chosen insomuch as to avoid the rest part of reasons determining pucker. After washing and drying, the specimens may shrink due to the shrinkage of sewing threads as well as the fabric. To determine dimension changes of fabrics,
IJCST 18,5
338
the investigation according FAST-4 testing technique was carried out. From A1, A2, A3 fabrics’ the specimens of 250 £ 250 mm dimensions were prepared. In these specimens initial sections with length L ¼ 200 mm were marked in the direction of warp and weft. In order to determine changes of dimensions, the specimen was dried up to humidity of 0 per cent (T ¼ 1058C) and lengths (L1) of its sections were measured. Then the specimen was soaked into water, left until saturation and removed. After that, its lengths (L2) were measured at humidity level of 100 per cent. After measurements, the specimen was dried again and its lengths (L3) were established at repeated humidity level of 0 per cent. Relaxation shrinkage RS was calculated such way: L1 2 L3 ð%Þ: ð2Þ RS ¼ 100 L1 Results and discussion Inherent and tension seam pucker is those who associated with the sewing thread. Inherent pucker is a result of fabric yarns displacement, when a needle penetrates the fabric and the upper and the lower threads loop insert within fabric. The fabric yarns are bent, stressed, and attempting to return to their original positions, but are prevented by the sewing threads. The fabric structural jamming is the most influenced by the sewing thread diameter alongside with other factors such as fabric properties, seam type, stitch density. The sewing threads chosen for this investigation are fine, furthermore, the used fabrics according to their structure are not sensitive for such kind of defect. On the basis on the above it can be concluded that sewing thread diameter not impact the seam quality. Tension pucker occurs when the over-stretched sewing thread shrinks to its original length and herewith gather up the fabric along the line of the seam. This defect due to sewing thread tension, uneven thread repartition and incorrect stitch length. In the study these factors were evaluated seeking to form well-balanced stitch, so it can be supposed the seam pucker was caused by sewing thread properties. Research results of mechanical hysteresis of the sewing threads are shown in Figure 2. It was noticed that hysteresis curves of the polyester sewing threads A402 and C452 chosen for research are similar by their nature. Nature of the hysteresis curve of cotton sewing threads M402 is a little bit different, but essential differences unobserved when comparing curves start-up zone of all investigated thread. Character of the beginning of a hysteresis curve depends very much on the thread structure, surface and crimp, which may be natural (wool threads) or artificial (textured threads). In this instance, when investigating threads that are folded and made up of two branches, beginning of the curve is similar in all cases. Further parts of hysteresis curves for polyester and cotton threads are different: a hysteresis curve of cotton threads is more upright and this means that extensibility and total strain of cotton threads is lower compared to the respective performances of polyester sewing threads. From the obtained curves of mechanical hysteresis (Figure 3) it was established that the lowest elastic strain is typical of cotton sewing threads M402, whereas elastic strain of polyester threads A402 and C452 are close. The highest remaining strain is characteristic to sewing threads C452, whereas this characteristic of other threads are close. The extent of remaining strain depends very much on intermolecular interaction of fibres. The stronger intermolecular interaction in fibres is the lower remaining deformation is observed.
Sewing threads on seam pucker
339
Figure 2. The curves of mechanical hysteresis of investigated sewing threads
Figure 3. The results of elastic ee and remaining strain er of sewing threads
After determining single-cycle tensile characteristics of the investigated sewing threads, it was obtained that the highest total strain is typical of polyester sewing threads C452 (1t ¼ 50.01 per cent) and polyester sewing threads A402 (1t ¼ 46.3 per cent) (Figure 4). It was obtained that reversible and remaining strain of threads A402 and C452 are
IJCST 18,5
340
Figure 4. The results of single-cycle tensile characteristics of investigated sewing threads
similar. Cotton sewing threads M402 feature the lowest total strain and rather high remaining strain, which in this case exceeds reversible strain almost by one third. Hence, according to the presented results it can be seen that sewing threads A402 and C452 attributed similar deformation properties both against a hysteresis curve and single-cycle tensile characteristics. In both cases, C452 feature the highest total strain and the highest reversible strain. Cotton sewing threads M402 feature the lowest extensibility and reversible strain values of these threads are moderate. The results of pucker coefficients W (per cent) of the different fabric specimens prepared by sewing two strips are shown in Figure 5. It was obtained, when the sewing conditions are the same the influence of sewing threads with different composition and mechanical properties on seam pucker is uneven after passing the time as well as washing and drying. Analysing the obtained results it was determined that when sewing by the threads chosen, seam pucker coefficient W is minor, does not exceed 2 per cent in most cases, and only specimens sewn of fabric A3 feature higher pucker (W amounted 4 per cent). It was obtained that after 24 and 48 h from the sewing, the value of seam pucker changes negligibly compared to the results of the measurements carried out immediately after sewing. The processes of washing and drying of specimens was impacted the change of seam pucker considerably greater compared to the influence made by the time factor. Analysis of the results has been shown that greater pucker is typical to the specimen sewn with corespun threads C452. As research of mechanical hysteresis of threads showed, these threads attributed the highest reversible strain among the investigated threads. In the process of sewing threads are stretched, flexed and otherwise deformed, and after sewing due to the relaxation processes in progress threads shrink and a seam creases. It is known, as in the process of manufacture sewing garment fabrics receive mechanical impacts, they become deformed. After manufacture processes, slowly vanishing elastic deformations are observed in fabrics and some stresses remains. Elastic deformation occurs, which due to the new intermolecular interaction may not vanish even over a long time. Under certain conditions (normal wear conditions), material is balanced. After affecting with humidity and warmth, kinetic energy of thermal movement in macromolecular segments increases. Materials having
Sewing threads on seam pucker
341
Figure 5. The results of seam pucker coefficient W (per cent) of specimens prepared by sewing two strips
experienced the impact of humidity and warmth during manufacture processes and in the course of wear return to their previous status. Hence, the greater is the deformation of fibres, threads or the material itself, the greater is the shrinkage observed later. Besides, under the impact of humidity and after penetration of water molecules into fibre macromolecules, interaction between macromolecules becomes weaker. Therefore, macromolecules in fibres become more mobile and return to their normal status. It is known that under the impact of warmth, macromolecules and their links assume kinetic energy and become more mobile (mobility of macromolecules increases). Thus, humidity together with warmth stimulates the process of shrinkage. This fact might explain why in all cases the greatest influence on seam creasing is made by the process of washing and drying. The results of seam pucker coefficients W (per cent) of the specimens prepared by sewing three fabric layers are shown in Figure 6. It was noticed that sewing three strips, the seam pucker defect assert itself weaker than sewing two strips: some 1 per cent in specimens of fabrics A1 and A2, and some 2 per cent in specimens of fabric A3. Decrease of the pucker coefficient could be influenced by the increase of thickness and rigidity of a
IJCST 18,5
342
Figure 6. The results of seam pucker coefficient W (per cent) of specimens prepared by sewing three strips
sewing: it is known that thicker and more rigid fabrics crease less. In most cases the tendency that threads with highest reversible strain determine greater pucker remain. However, depending on fabric properties the results of investigations can be close. This confirms the influence of fabric properties on seam pucker. Increase of pucker after washing and drying had greater influence in the specimens prepared sewing together three strips of fabric compared to the specimens with two ones. Seam pucker tendencies, however, remain similar as sewing together two layers; a little bit higher pucker coefficient is typical of sewing threads M402, but this value may be considered nonessential. Notwithstanding the value of seam pucker coefficient is moderate, but practically observed puckering is enough to determine downgrade a look of a final product sewing from lightweight fabric (Figure 7). Analysis of seam pucker results in all the investigated cases demonstrates that the lowest seam pucker coefficient is characteristic to the specimens sewn with universal sewing treads A402. It can be explain that elastic strain of these threads is negligible, whereas remaining strain is the lowest among all the threads investigated. Reversible elongation of cotton sewing threads is also negligible, however, according to the provided results it can be seen that particularly after washing and drying seam pucker is high, in some cases the highest among all the investigated
Sewing threads on seam pucker
343
Figure 7. The view of specimens after washing and drying
threads. Fibres of cotton threads absorb humidity and swell, therefore, their diameter increases. At the same time, thread diameter increases as well. Length of fibres, however, remains the same. As cotton sewing thread has twist, due to increase of cross-section outer windings are tensioned. However, they do not become longer, therefore thread becomes shorter. The higher is the twist, the greater is the shrinkage of thread. This fact may be used to explain why threads featuring low reversible deformation puckering seams rather strongly after washing and drying. In order to know whether considerable shortening of specimens after washing and drying is observed due to the shrinkage of sewing threads and not of fabrics, testing for determining the shrinkage of the latter was carried out. Results of relaxation shrinkage of warp and weft are shown in Figure 8. It was established that lengths of the investigated fabrics change neither in the direction of warp nor in the direction of weft while reducing humidity level to 0 per cent, whereas after soaking fabric into water and measuring its lengths (L2) at humidity level of 100 per cent, fabric lengths in the direction of warp become slightly longer, and fabric lengths in the direction of weft remain the same. When fabric is dried to humidity level of 0 per cent again, shrinkage increases and is the highest one. Changes of specimen dimension take place due to relaxation, when fabric threads are deformed by tensioning or compression. Relaxation takes place due to the impacts of humidity, pressing or water. Problems may arise, when shrinkage exceeds 3 per cent. Relaxation shrinkage of the investigated fabrics both in the direction of warp (RS ¼ 0.35 – 1 per cent) and in the direction of weft (RS ¼ 0.20 – 0.50 per cent) is
IJCST 18,5
344 Figure 8. The results of relaxation shrinkage RS (per cent)
negligible, therefore, it may be stated that after washing and drying sewing specimens become shorter not due to the shrinkage of fabric, but due to the shrinkage of sewing threads. Thus, as results of the performed investigations demonstrated evaluation of seam pucker is greatly influenced by mechanical properties of threads. The latter determine the behaviour of a sewing garment in the places of thready joins both in the process of sewing and when some time passes after sewing as well as during exploitation. Conclusions . The results of the investigation showed that sewing threads used for this research due to theirs structural and mechanical properties caused seam pucker, which pucker coefficient was some 2 per cent in most cases. Principle the value of this coefficient is not high, but for all practical purposes observed puckering determine downgrade a look of a final product sewing from lightweight fabric. . During the research inherent seam pucker was not stated, so the sewing thread diameter has not impact on structural jamming of fabric and a seam quality degradation from the point of view of seam puckering was conditioned by thread’s properties to return to their original position after deformation. . It was obtained, the best properties are characteristic of universal sewing threads, having the lowest reversible strain. After sewing specimens by these threads, the seam pucker defect is the least noticeable. These threads are recommended for sewing light fabrics. . It was established, that when some time passes after sewing the greatest crease to seams is made by corespun polyester sewing threads, the reversible strain whereof is the highest. In all investigated cases the highest seam pucker was observed after washing and drying, the time factor made considerably less influence on the occurrence of creases. After washing and drying, the highest pucker was typical of the specimens sewn with cotton sewing threads, due to yarn swelling. References Ajiki, I. and Postle, R. (2003), “Viscoelastic properties of threads before and after sewing”, International Journal of Clothing Science and Technology, Vol. 15 No. 1, pp. 16-27. Behera, B.K. and Chand, S. (1997), “Sewability of denim”, International Journal of Clothing Science and Technology, Vol. 9 No. 2, pp. 128-40.
Fan, J. and Leeuwner, W. (1998), “The performance of sewing threads with respect to seam appearance”, Journal of Textile Institute, Vol. 89 No. 1, pp. 142-54. 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. Kawabata, S., Niwa, M. and Ito, K. (1991), “Recent progress in the application of objective measurement to clothing manufacture”, Textile Objective Measurement and Automatization in Garment Manufacture, Ellis Harwood Limited, Chichester, pp. 81-105. Kwong, M. et al. (1997), “Development of judgment method for evaluation of overfeed seam in shape formation of jacket”, paper presented at the 78th World Conference of the Textile Institute, Greece, May, pp. 329-44. Mori, M. and Niwa, M. (1994), “Investigation of the performance of sewing thread”, International Journal of Clothing Science and Technology, Vol. 6 Nos 2/3, pp. 20-7. Mori, M., Niwa, M. and Kawabata, S. (1997), “Effect of thread tension on seam pucker”, Seni I Gakkaishi, Vol. 3 No. 6, pp. 217-25. Park, Ch.K. and Kang, T.J. (1997), “Objective rating of seam pucker using neural networks”, Textile Research Journal, Vol. 67 No. 7, pp. 494-502. Park, C.K. and Kang, T.J. (1999), “Objective evaluation of seam pucker using artificial intelligence part III: using the objective evaluation method to analyze the effects of sewing parameters on seam pucker”, Textile Research Journal, Vol. 69 No. 12, pp. 919-24. Rudolf, A. and Gersˇak, J. (2001), “Study of the relationship between deformation of the thread and built-in fibres”, International Journal of Clothing Science and Technology, Vol. 13 Nos 3/4, pp. 289-300. Schwartz, P. (1984), “Effect of jamming on seam pucker in plain woven fabrics”, Textile Research Journal, Vol. 69 No. 1, pp. 32-4. Stylios, G. and Fan, J. (1991), “An expert system for the prediction of fabric sewability and optimization of sewing and fabric conditions in garment manufacture (sewability system (SS))”, Textile Objective Measurement and Automatization in Garment Manufacture, Ellis Harwood Limited, Chichester, pp. 139-47. Stylios, G. and Lloyd, D.W. (1990), “Prediction of seam pucker in garments by measuring fabric mechanical properties and geometric relationship”, International Journal of Clothing Science and Technology, Vol. 2 No. 1, pp. 6-15. Sundaresan, G., Hari, P.K. and Salthotra, K.R. (1997), “Strength reduction on sewing threads during high speed sewing in an industrial lockstitch machine part I – mechanism of thread strength reduction”, International Journal of Clothing Science and Technology, Vol. 9 No. 5, pp. 334-45. Sundaresan, G., Hari, P.K. and Salthotra, K.R. (1998), “Strength reduction on sewing threads during high speed sewing in an industrial lockstitch machine part II – effect of thread and fabric properties”, International Journal of Clothing Science and Technology, Vol. 10 No. 1, pp. 64-79. Zˇiliene˙, L. and Baltrusˇaitis, J. (2000), “Investigation of sewing thread damage during sewing process”, Materials Science (Medzˇiagotyra), Vol. 6 No. 2, pp. 104-7. Corresponding author Vaida Dobilaite can be contacted at: [email protected] To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints
Sewing threads on seam pucker
345
International Journal of Clothing Science and Technology
ISSN 0955-6222 Volume 18 Number 6 2006
International textile and clothing research register Editor-in-Chief
Professer George K. Stylios
Access this journal online _________________________
2
Editorial advisory board __________________________
3
Editorial _________________________________________
4
Research register _________________________________
6
Research index by institution______________________
75
Research index by country ________________________
76
Research index by subject_________________________
77
Research index by principal investigator ___________
79
Awards for Excellence ____________________________
80
Access this journal electronically The current and past volumes of this journal are available at:
www.emeraldinsight.com/0955-6222.htm You can also search more than 100 additional Emerald journals in Emerald Fulltext (www.emeraldinsight.com/ft) See page following contents for full details of what your access includes.
CONTENTS
www.emeraldinsight.com/ijcst.htm As a subscriber to this journal, you can benefit from instant, electronic access to this title via Emerald Fulltext. Your access includes a variety of features that increase the value of your journal subscription.
How to access this journal electronically To benefit from electronic access to this journal, please contact [email protected] A set of login details will then be provided to you. Should you wish to access via IP, please provide these details in your e-mail. Once registration is completed, your institution will have instant access to all articles through the journal’s Table of Contents page at www.emeraldinsight.com/0955-6222.htm More information about the journal is also available at www.emeraldinsight.com/ ijcst.htm Our liberal institution-wide licence allows everyone within your institution to access your journal electronically, making your subscription more cost-effective. Our web site has been designed to provide you with a comprehensive, simple system that needs only minimum administration. Access is available via IP authentication or username and password.
Key features of Emerald electronic journals Automatic permission to make up to 25 copies of individual articles This facility can be used for training purposes, course notes, seminars etc. This only applies to articles of which Emerald owns copyright. For further details visit www.emeraldinsight.com/ copyright Online publishing and archiving As well as current volumes of the journal, you can also gain access to past volumes on the internet via Emerald Fulltext. You can browse or search these databases for relevant articles. Non-article content Material in our journals such as product information, industry trends, company news, conferences, etc. is available online and can be accessed by users. Reference linking Direct links from the journal article references to abstracts of the most influential articles cited. Where possible, this link is to the full text of the article. E-mail an article Allows users to e-mail links to relevant and interesting articles to another computer for later use, reference or printing purposes. Structured abstracts Emerald structured abstracts provide consistent, clear and informative summaries of the content of the articles, allowing faster evaluation of papers.
Additional complimentary services available Your access includes a variety of features that add to the functionality and value of your journal subscription: E-mail alert services These services allow you to be kept up to date with the latest additions to the journal via e-mail, as soon as new material enters the database. Further information about the services available can be found at www.emeraldinsight.com/alerts Connections An online meeting place for the research community where researchers present their own work and interests and seek other researchers for future projects. Register yourself or search our database of researchers at www.emeraldinsight.com/ connections Emerald online training services You can also access this journal online? Visit www.emeraldinsight.com/training and take an Emerald online tour to help you get the most from your subscription.
Choice of access Electronic access to this journal is available via a number of channels. Our web site www.emeraldinsight.com is the recommended means of electronic access, as it provides fully searchable and value added access to the complete content of the journal. However, you can also access and search the article content of this journal through the following journal delivery services: EBSCOHost Electronic Journals Service ejournals.ebsco.com Informatics J-Gate www.j-gate.informindia.co.in Ingenta www.ingenta.com Minerva Electronic Online Services www.minerva.at OCLC FirstSearch www.oclc.org/firstsearch SilverLinker www.ovid.com SwetsWise www.swetswise.com
Emerald Customer Support For customer support and technical help contact: E-mail [email protected] Web www.emeraldinsight.com/customercharter Tel +44 (0) 1274 785278 Fax +44 (0) 1274 785204
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
3
Professor Rosham Shishoo Swedish Institute for Fibre and Polymer Research, Mo¨lndal, 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 Ło´dz´ Technical University, Poland
Professor David Lloyd University of Bradford, Bradford, UK
International Journal of Clothing Science and Technology Vol. 18 No. 6, 2006 p. 3 # Emerald Group Publishing Limited 0955-6222
IJCST 18,6
4
International Journal of Clothing Science and Technology Vol. 18 No. 6, 2006 pp. 4-5 Emerald Group Publishing Limited 0955-6222
Editorial Championing the research efforts of the community The International Textile and Clothing Research Register (ITCRR) is in its 12th 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 and practice 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 re-invention 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. This year in particular we have welcome contributions from textile and clothing aesthetics, design and fashion. It is our view that in our field design and technology go hand-to-hand, and we predict that more exciting projects will come from this synergy. Consistent and extensive research and development in textile and clothing design and 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 seventeen 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 K. Stylios
The journal, now fully indexed in SCI 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 finally 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 Masako Niwa, Nara Women’s University . Professor Jachym Novak, Vysoka Skola Sronjni a Tectilffi . Professor Isaac Porat, UMIST . Professor Ron Postle, The University of New South Wales . Dr Taoruan Wan, University of Bradford . Professor David Lloyd, University of Bradford . Prof. G.A.V. Leaf, Heriot-Watt University . Dr David Brook, University of Leeds . Dr Jaffer Amirbayat, UMIST . Dr Norman Powell, Leeds Metropolitan University . Dr David Tyler, Manchester Metropolitan University . Professor Jintu Fan, Hong Kong Polytechnic University . Dr Lubas Hes, University of Minho . Dr Jelka Gersak, University of Maribor . Dr Han Fan, Heriot Watt University . Dr Hua Lin, Heriot Watt University . Dr Sharon Lam Po Tang, Heriot Watt University Thank you all subscribers, authors, editorial board members, referees, publishing team, colleagues, students for your support and especially Dr S. Lam Po Tang for her contribution. Correspondence address: Heriot-Watt University, School of Textiles, Netherdale, Galashiels, Selkirkshire, TD1 3HF, Scotland, UK. E-mail: [email protected] George K. Stylios Editor-in-Chief
Editorial
5
Research register
IJCST 18,6
Arad, Romania 6
Aurel Vlaicu University, Bd. Revolutiei 77, 310130 Arad, Romania, Tel*: +40 0257283010; Fax*: +40 0257280070; E-mail: [email protected] Principal Investigator(s): Prof.Dr Michaela Dina Stanescu Research Staff: Dr Magdalena Fogorasi, Dr Silvia Mihuta, Dr Dorina Chambre, Dr Dana Radu, PhD. student Mihaela Dochia
Biotreatments of textile waste Other Partners: Academic
Industrial
INCDTP Bucharest, LACECA Bucharest None Project started: 2004 Project ends: 2006 Project budget: e3000 Source of support: Ministry of Education and Research Keywords: Textile waste, Cotton, Cotton/PET blends The project deals with the analysis of different procedures for solid textile waste elimination for cotton based textiles. The biotreatments were chosen as ecological solution. The establishment of practical procedure for textile based on cotton degradation using enzymes was investigated. * Please include the full number, including the country and area codes.
Project aims and objectives To establish the reaction conditions for cotton biodegradation. . To choose the enzyme proper for such operation among the commercial products. .
To propose a technology for biodegradation of textile waste based on cotton
Research deliverables (academic and industrial) Technology for textile waste based on cotton biodegradation. Publications DWI Reports 2005 publication. Participation to Aachen Textile conference 2005 and ISEB-ESEB 2006- Leipzig
Athens, Greece Technological Education Institute of Piraeus (TEI), P. Ralli & Thivon 250, GR-12244, Athens, Greece, Tel*: +30 210 5381224; Fax*: +302105450965; E-mail:[email protected]
Principal Investigator(s): Prof. Maria Rangoussi, Prof. Christopher Provatidis, 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
National Technical University of Athens None Aristoteles University of Thessaloniki Project started: 1 January 2004 Project ends: 30 December 2006 Grant value: 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 combine finally the character of the textile fibres with the specific electrical conductivity. The electrical and mechanical properties of textile yarns made of man-made electrically conductive fibres will be studied taking in 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 in order to prove the suitability of the end products in various applications. * Please include the full number, including the country and area codes.
Project aims and objectives The project aim is to define the parameters for the production of electrically conductive fabrics dedicated for specific uses under controlled conditions to meet specific needs and standards. The objectives are the thorough study of the textile and electrical properties of the fibres, yarns and fabrics taking in account the changes of the behaviour 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 Not available.
Research register
7
IJCST 18,6
8
Athens, Greece TEI Piraeus, P. Ralli & Thivon 250, GR-12244, Athens, Greece, Tel*: +30 210 5381224; Fax*: +30 210 5450965; E-mail: [email protected] Principal Investigator(s): Lect. Savvas Vassiliadis, Prof. Christos Kotsios, Prof. Anthony Primentas Research Staff: Prof. Thanos Peppas, Argyro Kallivretaki
Strengthening the university – industry links in Uzbekistan Other Partners: Academic
Industrial
TechMinho (P), Logotech S.A. (GR) Tashkent Institute of Textile and Light Industry (UZ) Namangan Engineering and Economic Institute (UZ) Project started: 1 September 2005 Project ends: 31 August 2008 Grant value: e300,000 Source of support: European Commission Keywords: Textiles, Industrial liaison office, Distance learning During the three years long project the situation of the University – Industry links in Uzbekistan will be analysed. In parallel the need of the distance learning will be investigated taking in account the local conditions. After the first definition phase, the project foresees the development of structures serving the University – Industry links, like the liaison offices in the Universities and related actions. The distance learning activities will result in the operation of the necessary infrastructure and the creation of many modules for use between the Universities and the Industries. * Please include the full number, including the country and area codes.
Project aims and objectives The project aim is to analyse the current conditions in Uzbekistan and to develop structures and materials related to the strengthening of the university – Industry links and distance learning courses. The objective is to enhance the interaction between universities and industries using modern technological tools and methods.
Research deliverables (academic and industrial) Establishment of structures supporting the university – industry links in Uzbekistan and development of distance learning courses. Publications Not available.
Bolton, UK University of Bolton, Centre for Materials Research and Innovation, University of Bolton, Deane Road, Bolton BL3 5AB, UK, Tel*: +44 1204 903559; Fax*: +44 1204 399074; E-mail: [email protected] Principal Investigator(s): Dr S. Rajendran, Principal Investigator, Prof. S.C. Anand, Co-investigator Research Staff: Dr Alister Rigby
Design and development of novel compression therapy regimes for the treatment of venous leg ulcers Other Partners: Academic None
Industrial Vernon-Carus Ltd, Rossendale Combining Company Ltd Project ends: 23 October 2008
Project started: 24 October 2005 Project budget: £152,142 Source of support: EPSRC Keywords: Compression Therapy, Leg ulcers, Bandages
Venous leg ulcers are the most common type of ulcers and their prevalence increases with age. In the UK alone about 1% of the adult population suffers from active ulceration during their life time. The total cost to the National Health Service in the UK for venous leg ulcers treatment is about 650 million per annum, which is 1-2% of the total healthcare expenditure. Costs per patient have recently been estimated to be between 1200 and 1400. Venous leg ulcers are chronic and there is no medication or surgery to cure the disease other than the compression therapy. A sustained graduated compression mainly enhances the flow of blood back to the heart, improves the functioning of valves and calf muscle pumps, reduces oedema and prevents the swelling of veins. In the UK four layer bandaging system is widely used whilst in Europe and Australia the non-elastic two layer short stretch bandage regime is the standard treatment. Both the two layer and four layer systems require padding bandage that is applied next to the skin and underneath the short stretch or compression bandages. It is generally agreed by the clinicians that four layer bandages are too bulky for patients and the cost involved is high. A wide range of compression bandages is available in the Drug Tariff but each of them has different structure and properties and this influences the variation in performance and properties of bandages. The research carried out at the University of Bolton showed that there are significant variations in properties of commercial padding bandages, more importantly the commercial bandages did not distribute the pressure evenly at the ankle as well as the calf region. When pressure is applied using compression bandages, the structure of the nonwoven padding bandages collapsed and the bandages could not impart cushioning effect to the limb. In view of the above mentioned limitations and
Research register
9
IJCST 18,6
10
problems, it is vital that research and development work should be carried out to design, develop and characterise novel single layer bandages that would effectively fulfil the requirements of both padding and compression bandages. It is recognised that spacer is the right technology to produce novel compression bandages that meet the prerequisites of both ideal padding and compression bandages. In threedimensional (3D) spacer fabrics, two separate fabric layers are combined with an inner spacer yarn or yarns using either warp knitting or weft knitting route. It is possible to produce low modulus spacer fabrics by making use of elastic yarns. Elastic compression could be achieved by altering the structures. It should be mentioned that 3D structure allows greater control over elasticity and these structures can be engineered to be uni-directional, bi-directional and multidirectional. Uni-directional elasticity is one of the desired properties for compression bandages. The three-dimensional nature of spacer fabrics makes an ideal application next to the skin because they have desirable properties that are ideal for the human body. 3D fabrics are soft, have good resilience that provides cushioning effect to the body, breathable, ability to control heat and moisture transfer. For venous leg ulcer applications, such attributes together with improved elasticity and recovery promote faster healing. * Please include the full number, including the country and area codes.
Project aims and objectives .
To study in-depth the current practices and problems in managing venous leg ulcers.
.
To test and characterise the currently available commercial bandaging systems.
.
To design and develop single layer bandage that would replace the conventional multiplayer padding and compression bandages using warp knitting technology.
.
To design and develop single layer bandage that would replace the conventional multiplayer padding and compression bandages using weft knitting technology.
.
To study the feasibility of using environmentally and human skin friendly biodegradable fibres in designing the single layer bandage.
.
To test and characterise the properties of novel compression bandages and bandaging regimes.
.
To mathematically model and verify the performance and properties of the developed structures.
.
To quantify, predict and optimise the characteristics of the novel compression therapy regimes.
Research deliverables (academic and industrial) None Publications and outputs “Venous Leg Ulcer Treatment and Practice”, submitted to Journal of Wound Care.
Budapest, Hungary Budapest University of Technology and Economics, Budapest XI. Mu˝egyetem rkp. 3, Postal A., H-1521 Budapest, Hungary, Tel*: +36-1-463-1376; Fax*: +36-1-463-1376; E-mail: [email protected] Principal Investigator: Judit Borsa, Department of Plastics and Rubber Technology, Department of Physical Chemistry, Department of Chemical Technology
Modification of cellulose fiber for extension of its application Other partners: Academic
Industrial
Johan Be´la National Center for None Epidemiology, Inst. for Isotops and Surface Chemistry of the Hungarian Academy of Sciences, Johannes Kepler University, Linz, Austria, Dr Habil. Ildiko Tanczos Project started: 1 January 2005 Project ends: 31 December 2008 Finance/support: N/A Source of support: Hungarian National Research Fund (OTKA), Governmental Fund (GVOP) Keywords: Cellulose, Cotton, Hemp, Swelling, Chemical modification, Carboxymethylcellulose, Functional textile, Antimicrobial textile, Textile for hospital use Cellulosic fibers are modified by physical and chemical methods:
.
Interaction of cotton cellulose with quaternary ammonium hydroxide (tetramethylammonium hydroxide) is studied in comparison with sodium hydroxide. Cotton fiber is modified by slight carboxymethylation. Effect of technology parameters on the properties of the modified fiber, theoretical aspects of modification and some possible application of modified fiber (e.g. antibacterial textile for hospital use) are investigated.
.
Delignification and refinement of various kinds of Hungarian hemp are studied.
.
Research deliverables (academic and industrial) None Publication Borsa, J., La´za´r, K. and La´szlo´, K. (2005), “Antibacterial effect of carboxymethylated cotton fiber” Paper presented at The Fiber Society Spring Conference, St Gallen, May 2005.
Research register
11
IJCST 18,6
12
Budapest, Hungary ˝ egyetem rkp. Budapest University of Technology and Economics, MU 3-9, H-1111 Budapest, Hungary, Tel*: +36 1 4632495; Fax*: +36 1 4631689; E-mail: [email protected] Principal Investigator(s): Prof. Dr Ja´nos Somlo´, Dr Marianna Hala´sz, Dr Pe´ter Tama´s, Ga´bor Ambrus, Dr Be´la Bo˝di Research Staff: Dr La´szlo´ Monostori, Dr Petra Aradi, Dr Gyo¨rgy Lipovszki, Dr Kla´ra Zalatnaidr. Judit Barna, Lajos Szabo´, Bertalan To´th, Jekatyerina Kuzmina
RuhaRobot (ClothRobot) Other Partners: Academic
Industrial
AGA Informatics Ltd Budapest University of Technology and Economics, Budapest Tech Rejto˝ Sa´ndor National Osteoporosis Foundation Faculty of Light Industry, Institute of Leather, Textile and Garment Technology Project started: 1 January 2005 Project ends: 31 December 2007 Grant value: e327600 Source of support: National Development Plan – Structural Funds and the Cohesion Fund EU Keywords: 3D dress design, Model of human body, Visual robot, Wearing simulation, 3D drape tester There is a 3D dress designing system in the focus of the project. A parameterized body model is evaluated. The model is appropriate not only for the symmetric and asymmetric body modelling but for motion simulation too. The real sizes of the human body can be defined by a photo based on reduced measuring processes or by robotized 3D scanning using re-engineering. We are developing an integrated traditional scanner and a 6D KUKA robot for scanning the visible and masked body parts. Shape and sizes of clothparts are derived from the geometry of the human body model. Designers modify the model and shape of parts in space. The shape of patterns is calculated by direct laying out. The mechanical model of clothes is a multi mass-point flexible mechanical structure. A virtual mannequin wears the model dress. Draping and texture behaviour is real-time simulated by the mechanical model. There is a newly evaluated drape tester equipment. Tester scans the 3D shape of parts and material properties are defined by the same simulation as used for the virtual mannequin. * Please include the full number, including the country and area codes.
Project aims and objectives Real 3D Computer aided design for ready made clothes and for handicapped people. .
Usage of re-engineering techniques in body size measuring processes.
.
Development of a visual robot system and application in reg-trade.
.
Material parameter measuring for clothes simulation.
.
Special methods based on material simulation and the newly developed equipment.
Research deliverables (academic and industrial) Computer aided 3D dress design system for ready made clothes and handicapped people. . . .
3D drape tester equipment. Measuring results. Visual robot system
Publications Dr Tama´s Pe´ter, Dr Hala´sz Marianna (2003), “3D body modelling in clothing design”, IMCEP 2003, paper presented at the 4th International Conference, 9-11. Oktober, Maribor, Slovenia, ISBN 86-4350575-7, pp. 64-8. L. Kokas Palicska; J. Gersak; M. Hala´sz, (2005) “The impact of fabric structure and finishing on the drape behavior of textiles”, paper presented at AUTEX 2005, 5th World Textile Conference, Portorozˇ, Slovenia, 27-29 June, ISBN 86-435-0709-1, pp. 891-7. P. Tama´s; M. Hala´sz; J. Gra¨ff (2005), “3D dress design”, paper presented at AUTEX 2005, 5th World Textile Conference, Portorozˇ, Slovenia, 27-29 June, ISBN 86-435-0709-1, pp. 436-1. J. Kuzmina; P. Tama´s; M. Hala´sz, Gy. Gro´f (2005), “Image-based cloth capture and cloth simulation used for estimation cloth draping parameters”, paper presented at AUTEX 2005, 5th World Textile Conference, Portorozˇ, Slovenia, 27-29 June, ISBN 86-435-0709-1, pp. 904-9. L. Szabo´; M. Hala´sz (2005), “Automatic determination of body surface data”, paper presented at AUTEX 2005, 5th World Textile Conference, Portorozˇ, Slovenia, 27-29 June, ISBN 86-435-0709-1, pp. 715-20. L. Kokas Palicska; M. Hala´sz (2005), “Analysing of draping properties of textiles”, paper presented at IN-TECH-ED’05, 5th International Conference, 8-9. September, Budapest, ISBN 963 9397 06 7, pp. 133-8. O. Nagy Szabo´; P. Tama´s; M. Hala´sz, (2005) “Garment construction with a 3 dimension designing system”, paper presented at IN-TECH-ED’05, 5th International Conference, 8-9. September, Budapest, ISBN 963 9397 06 7, pp 248-357. J. Kuzmina; P. Tama´s; M. Hala´sz; Gy. Gro´f (2005), “Image-based cloth capture and cloth simulation used for estimation cloth draping parameters”, paper presented at IN-TECH-ED’05, 5th International Conference, 8-9. September, Budapest, ISBN 963 9397 06 7, P 358-65.
Dharwad, Karnataka, India University of Agricultural Sciences Dharwad Karnataka, Dr Geeta Mahale, Sr Scientist, Dept Textiles and apperal Designing, College of rural home science. UAS, Dharwad, Karnataka 580005. Tel*: 091-0836-2743190; Fax*: 091-0836-2448349; E-mail: [email protected]
Research register
13
IJCST 18,6
14
Principal Investigator(s): Dr Geeta Mahale, All India Co-ordinated Research Project on Clothing and Textiles Research Staff: Mrs Vanishree, S., and Mrs Iramma, G.
Value addition for agro and animal based fibres – (on-going project) Other Partners: Academic
Industrial
None None Project started: 26 September 1996 Project ends: continued project Grant value: 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 fibres are of several types such as cotton, wool and silk have developed as 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, wild silk, mestha.camel’s hair, hemp, agave, pina, etc. are yet to develop 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 take 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 a 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 certain extent. * Please include the full number, including the country and area codes.
Project aims and objectives .
To identify the resources – agro and animal based fibres, indigenous natural dyes etc. and related by-products and their present utilization.
.
To evolve the national profile of availability and trend of agro, animal based fibres and dyes.
.
To introduce intervention for improvement in the existing practices in processing fibres and dyes.
.
To develop new technologies through different techniques for cottage level adoption.
.
To assess the economic viability of the developed technologies.
Research register
Research deliverables (academic and industrial) Phase I (1996-98) – Identification of resources and utilization of agro and animal based fibres were studied Phase II (1998-99) – Optimization of Dyeing conditions using Arecanut and Marigold flowers. Dyeing Silk with Arecanut and Marigold Phase III (1999-2001) – Optimization of Dyeing conditions using Arecanut and Marigold flowers. Dyeing cotton with Arecanut and Marigold Phase IV (2001-2002) – Optimization of Dyeing conditions using Acalypha and Teak leaves. Dyeing cotton and silk with Acalypha and Teak. Preparation of value added products viz, saree.cushion covers, files, purses, macrame´ wall hangings.pouches, bags etc. using natural dye sources. Phase V (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. Phase VI (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 viz – Table cloth.deewan set. Dress material, pouches, greeting cards, cushion covers, files and handkerchief. Phase VII (2004-2005) – Dyeing cotton, silk and wool with mahaguny leaves, Optimization of dyeing conditions using mahaguny leaves extract and dyeing cotton, silk and wool with mahaguny leaves extract. Preparation of value added products using natural dye sources with dyeing and printing techniques. Publications Mahale, G., Sakshi 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., Sakshi and Sunanda, R.K. (2004), “Acalypha leaves, an eco dye for wool”, Textile Asia, Vol. 35, No. 4, pp. 39-43. Mahale, G., Sakshi and Sunanda, R.K. (2003), “Teak leaves, a dye source for cotton”, Textile Asia, Vol. XXXIV, No. 9. pp. 52-6. Mahale, G., Vanishree, S. and Iramma, G. (2005), “Natural colourant for silk”, Asia Textile and Apparel Journal, Vol. 15, No. 6, Hong Kong, pp. 42-3. Mahale, G., Sunanda, R.K. and Sakshi (2004), “Hedge plant – a natural colourant for wool” Textile India, September, pp. 31-2. Mahale, G., Sunanda, R.K. and Sakshi (2004), “Acalypha dyed wool-dyeing conditions”, Manmade Textiles in India, Vol. XLVII, No. 10, pp. 386-9. Mahale, G., Vanishree, S. and Sunanda, R.K. (2004), “Diversification of natural waste into dyestuff for textile material”, Indian Silk, Vol. 43 No. 3, p. 29. Mahale, G., Sunanda, R.K. and Sakshi. (2004), “Eco-dyed cotton with Marigold” International Dyer, Vol.’188 No. 4, pp. 46-8. Mahale, G., Sunanda, R.K. and Sakshi (2003), “Value addition – acalypha leaves extract”, paper presented at the seminar of “Natural seminar on Impact of New Economic policies on Rural Industrialization” National Institute of Rural Development, Hyderabad, 8-10 September.
15
IJCST 18,6
16
Mahale, G., Sakshi. and Sunanda, R.K. (2003), “Silk dyed with Acalypha (Acalypha wilkesiana) and its fastness”, Indian Journal of Fibre and Textile Research, Vol. 228, No.3, pp. 86-9. Mahale, G., Sakshi. and Sunanda, R.K. (2003), “Arecanut – a natural colourant for silk”, Manmade Textiles in India, Vol. 46, No. 4, pp. 136-41. Archana A., Mahale G. and Sakshi (2003), “Colour fastness of Parthenium dyed silk”, The Textile Industry and Trade Journal, Vol. 41, No. 1-2, pp. 49-50. Mahale, G., Sakshi. and Sunanda, R.K. (2002), “Printing with natural dyes – an enterprise. NIRD souvenir on strategies for rural industrialization through decentralized planning”, 24-25 October, pp. 1-8. Mahale, G., Sunanda, R.K., and Sakshi. (2002), “Colour fastness of eco dyed cotton with Marigold”, Textile Trends, Vol. 44, No. 10, pp. 35-9. Mahale, G., Sakshi and Sunanda, R.K. (2002), “Fastness properties of Acalypha on cotton”, International Dyer, Vol. 187, No. 9, pp. 39-41. Mudugal, S. and Mahale, G. (2002), “Fountain flower dyed UAS sheep breed wool – its colourfastness in acidic media”, Manmade Textiles in India, Vol. 45, No. 4, pp. 140-4. Mahale, G., Sunanda, R.K. and Sakshi. (2002), “Eco-dyeing – diversification of Teak leaves”. Proceedings of the International Conference on Eco-balance and Life Cycle Assessment in India, 13-15 February, pp. 76-9. Mahale, G., Sunanda, R.K. and Sakshi (2001), “Natural dyeing of silk with teak leaves and its fastness”. Proceedings of Convention on natural Dyes, IIT, New Delhi: pp. 111-6. Mahale, G., Sunanda, R.K. and Sakshi., (2001), “Eco-dyeing of cotton with teak and its fastness”, The Textile Industry and Trade Journal, Vol. 39, Nos 9/10, pp. 33-6. Mahale G., Sakshi. and Sunanda R.K. (2001), “Colour fastness of Arecanut dyed cotton”, ManMade Textiles in India, Vol. 44, No. 6, pp. 243-6. Mahale, G., Sunanda, R.K., Bhavani, K. and Sakshi (2000), “Colourfastness of Arecanut dye in acidic pH”, The Textile Industry and Trade Journal, Vol. 38, Nos 11/12, pp. 159-63. Neelima, G., Mahale, G. and Mulla, J. (2000), “Effect of reactive dyes on yarn properties of UAS sheep breed wool”, TextileTrend, Vol. 13 No. 8, pp. 39-40. Neelima G. and Mahale G. (2000), “Colourfastness of acid dyes-UAS sheep breed wool to washing, sunlight and hot pressing” Manmade Textiles in India, Vol. 43, No. 7, pp. 310-2. Neelima G. and Mahale G. (2000), “Colourfastness of UAS sheep breed wool to crocking”, Textile Industry of India, Vol. 39, No.4, pp.17-20. Neelima G. and Mahale G. (2000), “Effect of acid dyes on fibre properties of UAS sheep breed wool”, The Textile Industry and Trade Journal, Vol. 37, Nos. 3/4, p. 61. Mahle G., Sunanda R.K., Bhavani K. and Sakshi. (2000), “Optimization of dyeing condition for arecanut dye”, paper presented at the National seminar on Indian Natural Colouring Agent Beyond 2000 AD, 11-13 February, 2000:01. Neelima, G. and Mahale, G. (2000), “Effect of Reactive dyes on fibre properties of UAS sheep breed wool”, Manmade Textiles in India, Vol. 18, No. 2, pp. 73-4. Neelima, G. and Mahale, G. (1999), “Effect of acid dyes on yarn properties of UAS sheep breed wool”, New Cloth Market, Vol. 13, No. 12, pp. 59-60. Mahale, G., Bhavani, K., Sunanda, K. and Sakshi (1999), “Colour fastness properties of Areca Catechu in alkaline pH”. Indian Silk, Vol. 38, No. 7, pp. 18-21. Mahale, G., Bhavani, K., Sunanda, K. and Sakshi (1999), “Standardizing dyeing conditions for African Marigold”, Man-Made Textiles in India, Vol. 42, No. 11, pp. 453-8. Mahale, G., K., Bhavani, K., Sunanda and Sakshi. (1999), “Marigold – a natural colouring agent: assessment of its colourfastness”, Textile Industry of India, Vol. 38, No. 11, pp. 7-13. Neelima, G. and Mahale, G. (1999), “Dyeing of UAS sheep breed wool with reactive dyes”, Textile Industry of India, Vol. 38, No. 10, pp. 10-1.
Mahale, G., Sunanda, K., Bhavani, K. and Sakshi. (1999), “Tagetes Erecta: its colorfastness in acidic media”, Textile Trends, Vol. 42, No. 7, pp. 223-6. 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. et al. (1999), “Karantaka-woollen blanket weavers”, Indian Journal of Small Ruminants, Vol. 5, No. 1, pp. 39-42. Neelima, G. and Mahale, G. (1999), “Shrink proofing of wool”, Indian Textile Journal, Vol. 109, No. 7, pp. 56-8. Rashidabanu, U. and Mahale, G. (1999), “Pineapple leaf fibre (PALF)”, The Textile Industry & Trade Journal, Vol. 37, Nos. 1/2, pp. 27-9. Mahale G., Sunanda R.K. and Bhavani K. (1998), “Value addition – cotton yarns”, The Textile Industry & Trade Journal, Vol. 36 Nos. 11/12, pp. 75-9. Mahale, G., Bhavani, K. and Sunanda, R.K. (1998), “Bamboo (Bambusa arundinaca): immense possibilities”, Textile Industry of India, 12-4 November. Mahale, G. and Jayashree, Y. (1995), “Colour fastness of napthol dyed cotton fabric”, Textile dyer and printer, Vol. 28, No. 12, pp. 23-7.
Edinburgh, Scotland, UK Heriot-Watt University, School of Engineering and Physical Sciences, Riccarton, Edinburgh, Scotland, UK. EH14 4AS; Tel*: +44 131 451 3034; Fax*: +44 131 451 3473; E-mail: [email protected]; [email protected] Principal Investigator(s): Professor J.I.B. Wilson and Dr R.R. Mather
Solar cells in textiles Other Partners: Academic
Industrial
Being sought None Project started: 2001 Project ends: Ongoing Keywords: Thin film silicon, Solar energy, Photovoltaics We are developing thin-film silicon solar cells on low cost textile substrates, using chemical vapour deposition (CVD) technology, based on previous thin-film diamond expertise. The CVD technology employs a proprietary microwave plasma system (developed at Heriot-Watt University) with silane/hydrogen/dopant gas mixtures to produce the sequence of layers that forms the active part of these cells. We have shown that relatively low deposition temperatures of 200 C and the active plasma conditions of the process do not affect our textile substrates, whether of woven or non-woven construction. In addition, solutions have been determined to the problem of providing reliable electrical contacts over fibrous, flexible substrates, together with a conventional transparent conducting oxide as the top contact in the cell “sandwich” structure. Effective “first barrier” encapsulation may also use our deposition technology. * Please include the full number, including the country and area codes.
Research register
17
IJCST 18,6
Project aims and objectives Flexible solar cells for a variety of applications: e.g. building facades, use in remote areas, emergency use in disaster relief, camping/leisure industry, portable chargers.
Research deliverables (academic and industrial) Working prototype
18
Publications “Textiles make solar cells that are flexible and lightweight”, Technical Textiles International, December 2002, pp 5-6. “Solar textiles: production and distribution of electricity coming from solar radiation. Applications” in Intelligent Textiles and Clothing, ed. H. Mattila, Woodhead Publishing Limited, Cambridge, to be published in 2006.
Galashiels, UK Heriot-Watt University, Heriot-Watt University, Netherdale, Galashiels, TD1 3HF; Tel*: +44 1896 892234; Fax*: +44 1896 75 8965; E-mail: [email protected] Principal Investigator(s): Dr Lisa Macintyre Research Staff: Pippa Bell
“The measurement and control of mean pressure delivery exerted by pressure garments for the treatment of hypertrophic scars”. Academic partners
Industrial partners
None None Project started: September 2004 Project ends: September 2007 Source of support: EPSRC and Drapers Company Keywords: Pressure garment, Pressure measurement, Hypertrophic burn scars, Powernet fabric Pressure garments are the predominant treatment method for hypertrophic scars. They are constructed from elastic fabrics and are custom-made to suit individual treatment specifications. The properties of the elastic fabrics have an impact on the pressure delivery of the garments and ultimately determine treatment success. During this investigation 12 new pressure garment fabrics have been knitted using the powernet structure. Each fabric has a slightly different specification and by assessing certain fabric properties, the impact on pressure delivery of these fabrics can be established. The reduction factor, fabric tension and model circumference are the main properties that contribute to the pressure delivery of the fabrics; the relationships of which are being thoroughly investigated. The measurement of pressure delivery exerted by pressure garments to the wound site is very important. A mean pressure of 25mmHg has been regularly quoted as the optimum pressure required for treating hypertrophic scars. It has been established that
when assessing the extent of pressure delivery to the patient, there is no scientific method currently used by medical practitioners. Based on this information two sensor measurement systems are being developed and investigated for this project. The sensors are being used to measure the mean pressures exerted by pressure garment samples on cylinder models and have been incorporated into the construction of a pressure sensing mannequin which is a simulation of the male upper torso and left arm. Further measurements are to be taken from human volunteers and compared with the model analysis results. Throughout the investigation development work on a predictive equation for calculating pressure delivery of 25mmHg to small circumference limbs from pressure garments is being carried out. * Please include the full number, including the country and area codes.
Project aims and objectives .
.
.
.
Evaluate the pressures exerted to small circumference limbs and complex body shapes. Develop a pressure-sensing mannequin incorporating an accurate and reliable pressure measurement system to record pressures exerted by pressure garments. Evaluate the effectiveness of 3D modelling for investigation between fabric specifications and applied pressure. Establish relationships between powernet fabric construction variables and pressure delivery potential.
Research deliverables (academic and industrial) None Publications Not available.
Galashiels, Scotland, UK Heriot-Watt University, RIFleX, School of Textiles and Design, Netherdale, Galashiels TD1 3HF, UK; Tel*: +44 1896 89 2135; Fax*: +44 1896 75 8965; E-mail: [email protected] Principal Investigator(s): Prof. George K. Stylios Research Staff: Liang Luo
Interactive wireless and smart fabrics for textiles and clothing Other Partners: Academic
Industrial
None Project started: September 2002
None Project ends: September 2006
Research register
19
IJCST 18,6
20
Source of support: Worshipful Company of Weavers Keywords: Smart, Interactive, Textiles, Garment, Clothing, Sensors, Wireless The last few years have witnessed an increased interest in wearable technologies, smart fabrics and interactive garments. This has come about by certain technological innovations n the areas of sensor-based fabrics, micro devices, wire and wireless networks. In terms of textiles, most of current developments are towards the fashion markets and have resulted in glorifying garments as gimmicky gadgets. However, some efforts are also being directed in using the technology for improving the quality of life, or even for life saving purposes. Examples of such uses can be found in the military, healthcare, fire fighting, etc. This research project investigates new interdisciplinary technologies in fabrics, sensors and wireless computing, for the development of a prototype interactive garment for monitoring various functions of the wearer. * Please include the full number, including the country and area codes.
Project aims and objectives The general aim of the project is to develop technologies for use in interactive garments, which can provide monitoring functions for various applications such as the clinical or healthcare sector. More specifically, objectives are: .
Develop suitable wireless sensors for various measurements, including ECG, temperature, breathing, skin conductivity, mobility and movement, humidity, positioning, etc.
.
Develop a Personal Area Network and a Wireless Communication Centre.
.
Optimise suitable wireless technologies such as Bluetooth to enable communication between sensors and a central processing unit.
.
Conceptualise a smart multilayer fabric.
.
Integrate technologies.
Research deliverables (academic and industrial) .
Wireless sensors for physiological and other measurements.
.
Wireless communication centre for relaying information between sensors, wearers, central processing unit and Internet.
.
Conceptual multilayer fabric suitable for interactive garments.
Publications Stylios, G.K., Luo, L., “Investigating an Interactive Wireless Textile System for SMART Clothing”, 1st International Textile Design and Engineering Conference (INTEDEC 2003), Fibrous Assemblies at the Design and Engineering Interface, Edinburgh, UK, September 22-24, 2003. Stylios, G.K., Luo, L., “The Concept of Interactive, Wireless, Smart Fabrics for Textiles and Clothing”, paper presented at the 4th International Conference, Innovation and Modelling of Clothing Engineering Processes – IMCEP 2003, Maribor, Slovenia, October 9-11, 2003. Stylios, G.K, Luo, L., “A SMART Wireless Vest System for Patient Rehabilitation”, Wearable Electronic and Smart Textiles Seminar, Leeds, UK, June 11, 2004.
Stylios, G.K., Luo, L., Chan, Y.Y.F., Lam Po Tang, S., “The Concept of Smart Textiles at the Design/Technology Interface”, paper presented at the 5th International Istanbul Textile Conference, Recent Advances and Innovations in Textile and Clothing, Istanbul, Turkey, May 19-21, 2005.
Galashiels, Scotland, UK Heriot-Watt University, RIFleX, School of Textiles and Design, Netherdale, Galashiels TD1 3HF, UK; Tel*: +44 1896 89 2135; Fax*: +44 1896 75 8965; E-mail: [email protected] Principal Investigator(s): Prof. George K. Stylios Research Staff: Mohamed Basel Bazbouz
Investigating the spinning of yarn from electro-spun nanofibres Other Partners: Academic
Industrial
None None Project started: November 2004 Project ends: October 2008 Keywords: Electrospinning, Polymers, Nanofibre, Alignment, Yarn, Composite Our laboratory is using a process called electrospinning which has the ability to produce a wide variety of polymeric fibres with diameters from a couple of micrometer down to the nanometer scale. In this case different structures can be made from electrospun fibers to suit the needs of various industries. Electrospinning, a fibre spinning technique that relies on electrostatic forces to produce fibres in the nanometer to micron diameter range, has been extensively explored as a simple method to prepare fibres from polymer solutions or melts. Under the influence of the electrostatic field, a pendant droplet of the polymer solution at the spinneret is deformed into a conical shape (Taylor cone). If the voltage surpasses a threshold value, electrostatic forces overcome the surface tension, and a fine charged jet is ejected. As these electric static forces increase, the jet will elongate and accelerate by the electric forces. The jet undergoes a variety of instabilities, dries, and deposits on a substrate as a random nanofibre mat. In our work, nonwoven electrospun mats of nylon 6 produced from solutions with formic acid with different concentrations are examined. Each nonwoven mat with average fibre diameters from 200 to 1300 nm was prepared under controlled electrospinning process parameters. Effects of electric field and tip-to-collection plate distances of various nylon 6 concentrations in formic acid on fibre uniformity, morphology and diameters were measured. Processing parameters effects on the morphology such as fibre diameter and its uniformity of electrospun polymer nanofibres was investigated. A process optimization summarized the effects of solutions properties and processing parameters on the electrospun nanofibre morphology was issued. In our work, we Control the electrospinning process to move away from just collecting random fibre mesh to enabling the accurate deposit of fibres at any
Research register
21
IJCST 18,6
22
predetermined position. This will be by using a simple method of getting a fibres bundle made of aligned nanofibres between two known points. This collection process has been termed as the “gap method of alignment” involves grounding two circular disks from the spinneret. We have demonstrated that it is possible to produce continuous fiber yarn made out of electrospun nanofibres. The current process has the potential to spin nanofibre at a commercially viable rate. * Please include the full number, including the country and area codes.
Project aims and objectives .
Understanding of the electrospinning process.
.
Optimizing its process parameters to electrospin polymers into nanofibres with desired morphology.
.
Discussing the models proposed for jet forming, jet travel, processing instabilities.
.
Tensile testing of polymeric nanofibres.
.
Controlling the spatial alignment of electrospun fibres.
.
A technique for making continuous fibre bundle yarns from electrospun fibres.
.
Investigating the other methods for producing continuous fibre bundle yarns, Core-yarn and laminate composite consisting of aligned fibres in different Directions.
Research deliverables (academic and industrial) .
Nonwoven electrospun mats of nylon 6 produced from solutions with formic acid with different concentrations are examined.
.
Each nonwoven mat with average fibre diameters from 200 to 1300 nm was prepared under controlled electrospinning process parameters.
.
Effects of electric field and tip-to-collection plate distances of various nylon 6 concentrations in formic acid on fibre uniformity, morphology and diameters were measured.
.
Processing parameters effects on the morphology such as fibre diameter and its uniformity of electrospun polymer nanofibres were investigated.
.
A process optimization summarized the effects of solutions properties and processing parameters on the electrospun nanofibre morphology was issued.
.
The well-known Chauchy’s inequality is applied to prediction the velocity of the end of the jet in electrospinning.
.
A critical relationship between radius r of jet and the axial distance z from nozzle is obtained for the straight jet.
.
Draw ratio between the jet and the final fibres was predicted theoretically.
.
Manufacturing of aligned fibres array was easily achievable.
.
Processing parameters effects on the aligned fibres such as gap distance and collection time were investigated.
Research register
Publications In preparation: .
Systematic parameter study for ultra- fine nylon 6 fibre produced by electrospinning technique.
.
Electrospinning of aligned nanofibres with cotrolled deposition.
Conferences Paper and Poster: .
June 2006 (Electrospinning of nanofibres: potential scaffolds for medical applications) a presentation presented in Research in Support of Medicine, Health and Safety Conference, Edinburgh, UK.
.
June 2006 (Systematic parameter study for ultra- fine nylon 6 fibre produced by electrospinning technique), Poster presentation, Research in Support of Medicine, Health and Safety Conference, Edinburgh, UK.
Galashiels, Scotland, UK Heriot-Watt University, RIFleX, School of Textiles and Design, Netherdale, Galashiels TD1 3HF, UK, Tel*: +44 1896 89 2135; Fax*: +44 1896 75 8965; E-mail: [email protected] Principal Investigator(s): Prof. George K. Stylios Research Staff: Mohammad Mahfuzur Rahman Chowdhury
Investigating Nano Fibre production by the electrospinning process Other Partners: Academic
Industrial
None None Project started: July 2004 Project ends: July 2007 Project budget: N/A Source of support: N/A Keywords: Electrospinning, Electrospinning process, Parameters, Polymer, Nanofibre application Electrospinning is a unique way to produce novel polymer nanofibres with diameter typically in the range of 10 nm to 500 nm. Using this process, the polymer nanofibres can be made from a variety of polymer solutions or melt to produce fibres for a wide range of applications. Electrospinning occurs when the electrical force at the surface of a polymer solution or melt overcomes the surface tension and causes an electrically charged jet to be ejected. When the jet dries or solidifies, an electrically charged fibre remains. This charged fibre can be directed or collected or accelerated by electrical forces, then collected in sheets or other geometrical forms. This research project is an investigation of the electrospinning process and the effect of process variables on orientation, crystallinity, microstructure and mechanical properties of the nanofibres produced. Some of the polymeric parameters investigated
23
IJCST 18,6
are polymer type, solvent type, molecular weight, solution properties, viscosity, conductivity and surface tension. In the case of process parameters, the electric potential, flow rate, concentration, distance between capillary and collection screen, ambient parameters are important. * Please include the full number, including the country and area codes.
24
Project aims and objectives .
. .
To investigate process-structure-property relationships in polymer fibres with nanosize diameters produced by electrospinning. To innvestigate the morphology and properties of the polymer nanofibres. To produce fibres at uniform diameters.
Research deliverables (academic and industrial) .
Nanofibres of uniform diameter.
.
Defined mechanical and physical properties. Process-structure-property relationships.
. .
Detailed understanding of the electrospinning process.
.
Nanofibres suitable for applications such as air filtration, protective clothing, fibre reinforced support, and Biomedical.
Publications and outputs “Nano fibre and its medical application”, Poster presentation in Research in support of Medicine, Health and Safety” Conference, Heriot-Watt university, Scotland, UK.
Galashiels, Scotland, UK Heriot-Watt University, RIFleX, School of Textiles and Design, Netherdale, Galashiels TD1 3HF, UK, Tel*:+44 1896 89 2135; Fax*: +44 1896 75 8965; E-mail: [email protected] Principal Investigator(s): Prof. George K. Stylios Research Staff: Dr Taoyu Wan
Novel micro-channel membranes for controlled delivery of biopharmaceuticals Other Partners: Academic None
Project started: April 2006 Project budget: £650,000
Industrial Stryker UK Ltd, St James’s University Hospital, Leeds General Infirmary, Camira Fabrics Ltd, Dinsmore Textile Solutions Ltd Project ends: March 2009
Source of support: DTI Technology Programme Keywords: Micro-channel, Micro-porous, Membrane, Controlled delivery, Drug release This project, which stems out of research findings of an EPSRC-funded research, aims at developing micro channel structures (coatings, membranes, foams, etc.) with encapsulated biopharmaceuticals capable of controlled release by changes in temperature, pH, magnetic field or voltage. A technique for encapsulating biopharmaceuticals into micro-channels of a polymer matrix structure and controlling their subsequent release will be developed. Driven by the consortium, the technologies will be veered towards various pay-load bearing applications, e.g. in self-supporting materials for delivering bone growth hormones (INN eptotermin alpha) in bone fractures, or in coated textiles for the personal hygiene, healthcare, treatment and protective clothing industries. * Please include the full number, including the country and area codes.
Project aims and objectives The main objectives for the projects are to: . Establish criteria for channel size and distribution control; engineer the structure and morphology of the porous material to suit the encapsulation of biopharmaceuticals and their slow release. This involves both self-supported materials and coated textiles. .
Investigate UV-based techniques for the encapsulation of specific biopharmaceuticals, with particular reference to bone growth hormones.
.
Investigate strategies for the controlled release of the biomaterials from the channels within the developed membrane or coating. Characterise and test laboratory and pilot-scale samples – study release rates of the biopharmaceuticals, degradation/absorption rates and efficacy of the system. Investigate alternative exploitation routes as coated textiles with encapsulated biopharmaceuticals. The project will investigate possibilities both for implantable and nonimplantable pay-load bearing materials, both as self-supported materials, and as coatings or membranes supported by a base fabric. Research work on implantable applications will however only be performed in laboratory scale with the aim to prove the concepts.
.
.
.
Research deliverables (academic and industrial) Pilot-scale production of membranes, coatings, foams, or any other forms of channelcontaining materials with engineered, controllable and tailor-made channel sizes, shapes and distributions . .
Defined characteristics, properties and performance of the as-produced materials. A technique to encapsulate biopharmaceuticals within the membrane channels using a UV cross-linking technique, which eliminates the need to use high temperature treatments for encapsulation. This enables the biopharmaceuticals to maintain their effectiveness.
Research register
25
IJCST 18,6
26
.
The final expected result is the development of a system for activated release, e.g. following a change in stimuli or external conditions, such as temperature, pH, magnetic field or voltage. This will enable the controlled and targeted release of the biopharmaceutical as, when and where required for optimum treatments after fractures.
Publications and outputs Stylios, G. K., Giannoudis, P. V., Wan, T., “Applications of nanotechnologies in medical practice”, Injury, Vol. 36S, pp. S6-S13, 2005. Stylios, G. K., Wan, T., Giannoudis, P. V., “Present status and future potential in the enhancement of bone healing using nanotechnology”, Accepted for publication in Injury, 2006.
Galashiels, UK Heriot-Watt University, School of Textiles & Design, Netherdale, Galashiels, Scotland, TD1 3HF, UK, Tel*: +44 1896 892140; Fax*: +44 1896 758965; E-mail: [email protected] Principal Investigator(s): R H Wardman and R M Christie
Digital fast patterned microdisposal fluids for multifunctional protective textiles Other Partners: Academic
Industrial
9 universities across Europe 13 SMEs across Europe Project started: 1 May 2006 Project ends: 30 April 2010 Project budget: e12.7million Source of support: European Union Keywords: Protective textiles, Digital printing The project involves a consortium of 13 high tech and less RTD intensive SMEs across the enlarged European Union, together with 3 non-SMEs and 9 universities and research institutes. The project will involve the development of digital printing procedures and equipment to enable the disposing of fluids of various chemical agents to textile fabrics to impart functionalities geared towards protection. * Please include the full number, including the country and area codes.
Project aims and objectives The objective of the project is to develop breakthrough technology based on digitally microdisposing fluids on textiles, enabling high-speed protective functionalization, continuous processing and customised production. Digital microdisposal has the ability of exact localisation and patterning of functionalities in multilayer textile substrates, integrating advanced thermo- and hydro-regulation, sensorics, actuating and controlled release functions, based on nanotechnology and multifunctional materials.
Research deliverables (academic and industrial) Creation of new knowledge in mechatronics and micro-fluids, nanotechnology and multifunctional materials. Understanding the behaviour at nano-level of droplets on textile substrates. Technology breakthrough in textiles, enabling new functionalities; mass customisation and launching of new product services systems integrating the supply chain. New standards in personal protective equipment by enabling functionalities that empower the worker (sensorics and controlled release) to customise functionalities to specific uses. A shift from water-based processes, thereby achieving considerable savings in water, chemicals, and effluent. Publication Not available.
Ghent-Zwijnaarde, Belgium Department of Textiles, Ghent University, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium, Tel*: +32-9-2645735; Fax*: +32-9-2645846; E-mail: [email protected] Principal Investigator(s): Prof. Gustaaf Schoukens, Department of Textiles Research Staff: Prof. Paul Kiekens, Prof. Gustaaf Schoukens
Development of high performance artificial grass for football applications Other Partners: Academic CMSE Centre for Material Science and Engineering Project started: March 2004 Grant value: e435.704 Source of support: IWT Keyword: Artificial turf
Industrial Desso DLW Sports Systems Project ends: February 2007
This project wants to contribute to a breakthrough in the acceptance of artificial turf for football, having constant playing properties during the whole season. * Please include the full number, including the country and area codes.
Project aims and objectives The most important aims of the project are: . .
complete acceptance of artificial turf by sports men; guaranteed quality as to playing properties (sliding, ball roll, ball bounce,. . .).
Research register
27
IJCST 18,6
Research deliverables (academic and industrial): In order to meet these aims, the project involves: . research into an optimal stalk of artificial grass based on fixed required characteristics; .
research into and development of an alternative construction based on experimentally determined criteria and numerical simulation; and
.
research into and development of testing methods to translate intuitive aspects (e.g. sliding, ball contact,. . .) into objective criteria.
28
Publications Not available.
Ghent-Zwijnaarde, Belgium Department of Textiles, Ghent University, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium. Tel*: +32-9-2645735; Fax*: + 32-9-2645846; E-mail: [email protected] Principal Investigator(s): Carla Hertleer, Department of Textiles Research Staff: Prof. Lieva Van Langenhove
Application of smart textiles in clothing Other Partners: Academic IMEC Project started: September 2004 Grant value: e 65.120 Source of support: IWT TIS Keyword: Smart textiles
Industrial Centexbel Project ends: August 2006
The application of smart textiles in clothing provides on the one hand an answer to realistic needs relating to health, protection, communication, comfort, and safety of various users. On the other hand, this application creates new and economically interesting opportunities for the innovative textile entrepreneur. Moreover, smart clothes aim at a whole range of users, such as sportsmen, intervention teams, older people, disabled people, . . . The field of smart textiles practically has unlimited possibilities and what is more, it is to a large extent virgin territory. The time has come to instigate Flemish companies in the “clothing” value chain to take this innovative course. At the moment, too few textile companies in Flanders are familiar with the possibilities of the existing intelligent materials or with new technologies or textile materials enabling further product innovation. Through a dynamic networking between the players involved, the real possibilities with regard to the application and the maintenance of smart textiles will be made public,
demonstrable and negotiable. This action aims at encouraging Flemish companies to start company specific innovation projects, whether or not in co-operation with specialised technology providers and/or knowledge centres. * Please include the full number, including the country and area codes.
Research register
Project aims and objectives This project aims at promoting networking between all parties involved in the “clothing” value chain, the specialized knowledge centres and the technology providers in the framework of using smart textiles in clothing. Publications Not available.
Ghent-Zwijnaarde, Belgium Department of Textiles, Ghent University, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium. Tel*: +32-9-2645735; Fax*: +32-9-2645846; E-mail: [email protected] Principal Investigator(s): Dr Philippe Westbroek, Department of Textiles Research Staff: Dr Philippe Westbroek
Flexible Peltier elements based on textile structures Other Partners: Academic None Project started: March 2005 Grant value: e 140.079 Source of support: IWT
Industrial None Project ends: February 2007
Peltier elements are currently very successful given the possibility to use them as a cooling or heating system when applying an electrical current. Depending on the current direction, cooling or heating is obtained; when inverting the current direction, the cooling and heating effect will be inverted as well. This means that heating and cooling can be obtained at the same plane of the element by inverting the current which is sent through that element. However, Peltier elements have a rigid structure, which reduces their application possibilities. For that reason, the idea was put forward to develop flexible Peltier elements on the basis of textile structures. This means that fibres have to be available possessing the appropriate semi-conductor properties (such as Bi-Te) for an optimal Peltier effect. Alternative semi-conductor fibre structures have already been described, but they are less suitable for application in Peltier elements. * Please include the full number, including the country and area codes.
Project aims and objectives A first aim in this research project is to take a first step in that direction by conducting fundamental research into the electrochemical deposition of Bi-Te layers on different electrode materials and under varying circumstances and to study the properties of
29
IJCST 18,6
30
these layers with electrochemical and surface techniques. Gaining insight in the deposition and the properties of the deposited layer in view of the production of suitable semi-conductor properties is a second aim in this project. In a second project comprising more application-directed research, the aim is to deposit the semi-conductor layers with the most suitable properties on conductive metal wires, which are to be processed into a textile structure, suitable for the study of the Peltier effect. Publications Not available.
Ghent-Zwijnaarde, Belgium Department of Textiles, Ghent University, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium. Tel*: +32-9-2645735; Fax*: +32-9-2645846; E-mail: [email protected] Principal Investigator(s): Ing. Johanna Louwagie, Department of Textiles Research Staff: Prof. Paul Kiekens
Bilateral networking and quality training in textiles (NeQuaTex) Other Partners: Academic Technical University “Gh. Asachi” Iasi Romania
Industrial Center for Continuing Education and Training – Cetex Romania, S.C Filbac S.A Tg.Lapus Romania Project ends: January 2007
Project started: February 2005 Grant value: e 90.962 Source of support: Ministry Flemish Community
In their (attempts for) mutual cooperation, companies in the textile and clothing sector in Flanders and Romania encounter many practical problems. This project wants to deal with the most important ones: understanding and implementation of European quality standards, knowledge of EC regulations for CE marking, access to accredited laboratories, quality certification and management, mentality differences, efficiency, implementation of the latest technological developments. . . Other problems will be diagnosed in the initial phase of the project and incorporated in the work programme.
Research deliverables (academic and industrial) In both countries, training sessions, workshops and exchanges will be organised, revealing the basic principles of modern quality management in a free European market environment and new technological developments. Publications Not available.
Ghent-Zwijnaarde, Belgium Department of Textiles, Ghent University, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium. Tel*: +32-9-2645735; Fax*: +32-9-2645846; E-mail:[email protected] Principal Investigator(s): Ing. Johanna Louwagie, Department of textiles Research Staff: Prof. Paul Kiekens
T3-SQM – training in textile technology, standardisation and quality management Other Partners: Academic Technical University of Sofia Project started: January 2005 Grant value: e 99.988 Source of support: IWT
Industrial State Agency of Standardisation and Metrology (SATM) Project ends: December 2006
Over the last few years, the Bulgarian textile industry has made some progress in adapting itself to the free market economy. However there is still a long way to go. In order to come to a successful adaptation, the local textile companies – especially SMEs – and laboratories need assistance and training in the field of textile technology, standardisation and quality management. As a consequence, this project mainly focuses on the introduction and the implementation of standardisation and quality management systems according to EN and ISO standards in SMEs and testing laboratories. It will also help the local industrials and laboratories to get actively involved in the development of new testing methods and the implementation of EN and ISO standards.
Research deliverables (academic and industrial) In both countries training sessions for personnel will be organised, revealing the basic principles of modern quality management in a free market environment, standardisation and textile technology. In order to get a clear view of the local situation, at the project kick-off, a preparatory visit will be paid to the partners in Bulgaria. In consultation with the partners, training sessions will be developed in different modules (Product Quality, Standardisation, Quality management,. . .). At the beginning, these modules will be taught in English by UGENT-Tex to trainers from Bulgaria (training of trainers). The courses will be summarised into the local language. Subsequently, the training sessions will be repeated for a broader public, by a mixed team of trainers (training of trainees). Employees from the partner organisations and the local industry will also be invited to participate in short-term traineeships and workshops at the Department of Textiles of Ghent University, and possibly other laboratories and/or companies. This will give them the opportunity to experience how a modern and functional quality system in a laboratory and/or company works.
Research register
31
IJCST 18,6
32
Apart from basic subjects, this project also foresees in thematic training sessions that will reveal the latest developments in the field of technological quality management and textile testing. . At the end of the project, a training and consulting centre will be established at the Department of Textiles, Technical University of Sofia (Centre for Technological Quality Management). This centre will see to the further dissemination of the acquired knowledge long after the end of the project. Publications Not available.
Ghent-Zwijnaarde, Belgium Department of Textiles, Ghent University, Technologiepark 907, 9052 Ghent-Zwijnaarde, Belgium. Tel*: +32-9-2645735; Fax*: +32-9-2645846; E-mail: [email protected] Principal Investigator(s): Dr Philippe Westbroek, Department of Textiles Research Staff: Dr Philippe Westbroek
Development of nano-structured metallophthalocyaninebased surfaces for use in analysis of environmentally, medically and biologically important molecules Other Partners: Academic
Industrial
None Department of Chemistry, Rhodes University, South-Africa Project started: February 2005 Project ends: January 2007 Grant value: e 65.000 Source of support: Ghent University/VLIR There has been a growing interest in thiol-derivatized metallophthalocyanines (MPcs) in recent years for the fabrication of self-assembled monolayers (SAMs). SAMs are an incredibly versatile means of extending the functions of an electrode and have been known to offer greater advantages over films produced by other methods such as spin coating. However, our joint work on SAMs has shown limitations on the usable range for electrodes modified with SAMs. Thus in this proposal thiol-derivatized MPc complexes will be synthesized and deposited as nano and micro thin films by electrospinning. Electrospinning produces nano-fibres or sprays of thiol-derivatized MPc on conductive surfaces. The thiol-derivatized MPc complexes will also be deposited on surfaces modified by silane deposition. The catalytic activity as well as the stability and reproducibility of surfaces modified by the various methods (electrospinning, SAM and binding to silanes) towards the analysis of environmentally, medically and biologically important molecules will be evaluated and the results obtained compared. This work
will be an important step towards the development of electrochemical sensors for analysis of these molecules. The analytes chosen include environmentally important molecules (such as thiols and organohalides), biologically important molecules (such as cysteine and cysteinecontaining proteins) and medically important molecules (such as the neurotransmitters; serotonin and dopamine).
33
Publications Not available.
Huddersfield, UK University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, Tel*: +44 1484 472563; Fax*: +44 1484 472826; E-mail: [email protected] Principal Investigator(s): Paul Squires Research Staff: Cari Morton
Word4word Other Partners: Academic TEKO Centre – The Danish Academy of Design, Technology, Textile, Denmark, Handelsfagsskolen Business and Retail College, Denmark, Baronie College, Breda, Holland Project started: September 2004 Project budget: UK Budget: e53,000 Source of support: Leonardo Funds
Research register
Industrial Dansk Textil Union, Danish Retailers Organisation, Copenhagen, Denmark; IC Companies, Copenhagen, Denmark; ECCO Shoe, Areal, Portugal Project ends: December 2006
The textile/clothing, fashion and footwear industries in Denmark and in Europe are remarkable in experiencing an unsurpassed globalisation process and technological development and at the same time suffering from an educational backlog especially in terms of language competences and terminological knowledge, which often lead to costly mistakes and cross-cultural misunderstandings. Experience and reports from the industry show that the knowledge society and knowledge-based economy vigorously call for a larger degree of flexibility and readiness for innovation which can only be achieved through continuous competence building and the development of a common terminological platform. Consequently, companies and institutions of education will join forces in an International/European network to develop a common platform for knowledge-sharing by establishing a combined online terminology database and visual training system. The International/European dimension is needed in national training in companies and for students at textile/design schools who are to take up positions in companies
IJCST 18,6
34
operating worldwide. At production sites the database will provide an innovative teaching tool for competence building. The partners will involve the knowledge and competences of their own institutions in a collaboration where their expert knowledge within the various stages of the value chain from raw material to finished product will complement each other. Given the sheer scope and limited time span of the project and to ensure quality, the project will cover terminology in the stages from raw material to semi-finished product in English, German and Danish. Subsequent projects will extend the database from semi-manufactured to finished articles and extend the database into other languages. * Please include the full number, including the country and area codes.
Project aims and objectives Aims To develop an online terminology database in Danish, English and German for the textile/clothing, fashion and footwear industry. . To strengthen the students’ knowledge of the terminology used in the industry thus enhancing their skills and employability. Objectives .
. .
.
.
To provide a flexible, visual hands-on teaching tool. To provide companies with a tool to achieve consistency and homogeneity in vocabulary thus eliminating costly mistakes and preventing cultural misunderstandings. The work in the project will imply the implementation of a terminology bank for teachers, students and companies. To establish a lasting network between the partners and to strengthen and develop this further as the terminology database is to be extended into other languages. When this network has been firmly established, it will open up for all interested parties and countries in the EU.
.
To strengthen the industry’s ties to trade associations and other organisations.
.
To utilise the project results from the textile/clothing, fashion and footwear industry within other trades needing to obtain the same methodology for teaching and homogeneity in terminology.
Research deliverables (academic and industrial) .
An online database in English, Danish and German to strengthen consistency and homogeneity of the terminology used within the textile/clothing, fashion and footwear industry.
.
A database for visual teaching materials for teachers, thus introducting a new teaching methodology.
.
A web-platform for interactive information and exchange of information for teachers, students and companies. Consequently, the users can contribute to the contents of the database by using the link provided for suggestions.
.
A database and interactive tool for anyone taking an interest in terminology.
.
.
. .
Students at textile and design schools who are studying to become employees in the textile/clothing, fashion and footwear industry, be it as controllers, designers, purchasers or exporters. Teachers at textile and design schools who undertake special subject teaching within textile/clothing and footwear. Teachers who are trainers at production sites. Companies within the industry.
Publications and outputs The results of the project work will be disseminated in various ways: Internally in partner institutions: The companies will implement the database in their daily work in the mother company, subsidiaries and with their suppliers worldwide. The institutions of education will integrate the results in the curricula of the courses offered and place the results on their intranets. Teachers will use the templates as teaching materials. Externally: The partners will inform the public about the results by advertising in trade journals, participating in fairs and holding seminars and information meetings nationally. Local/national and international trade organisations, chambers of commerce and institutions of education will be informed of the results. A printed leaflet and a CD-Rom will be made about the possibilities for using the results of the project, besides information about the www.word4word.dk site will be given. This will ensure fast access to new knowledge for any interested person besides students, teachers and companies. The database will continuously be extended after the project period and expanded into other European languages. Once the project has been completed the database will become subject to commercialisation on a subscription basis to ensure continuous development and up-dating of the database.
Huddersfield, England University of Huddersfield, Department of Design, Queensgate Campus, Huddersfield, West Yorkshire HD1 3DH, Tel*: +44 1484 472928; Fax*: +44 1484 472826; E-mail: [email protected] Principal Investigator(s): Helen Woodget
How to realise complex textile craft techniques by cad and ink jet printing Other Partners: Academic
Industrial None
Dr R Annable, Dr J Pearson, Ms P Macbeth Project started: June 2005 Project ends: April 2007 Keywords: Ink Jet Printing, Craft, Colour Management, Simulation of craft techniques
Research register
35
IJCST 18,6
36
There are many techniques in textile crafts which are virtually impossible to produce commercially, for example hand and computer generated embroidered textiles and hand knotted woven fabrics. With the growing interest in the consumer market in the UK particular for textile craft products, it is becoming increasingly important to develop reproducible techniques to enable these products to be made to a commercially acceptable level. With the capability of ink jet printing being able to print at high resolution and in almost true colour, it is possible to simulate these techniques on fabric. In doing so, accurate colour representation must be achieved; the method of colour management used will be examined. This research describes the steps required to obtain identical images of the textile craft onto a CAD system, with the correct resolution, number of colours and size. This research is also pushing the boundaries of what is possible to print on using textile ink jet technology and pre-manipulated fabrics. Using a variety of fabrics that previously have not been able to print using ink jet technology; looking into custom treating and the possibility of fixing pigment inks. * Please include the full number, including the country and area codes.
Project aims and objectives The aim of this research is to achieve an accurate representation of hand-developed craft techniques using CAD software and textile ink jet technology, and to study the problems that may arise with this and to produce high quality printed fabric results. They will need to be commercially viable and in doing so the beginnings of a catalogue will be generated allowing for choice in custom made printed textiles. The process will be documented for future production of simulated craft techniques onto printed fabrics, resulting in the discussion of the use of colour management, CAD software and potential uses.
Research deliverables (academic and industrial) The outcomes of this research will be introduced into the teaching of these techniques into the under graduate courses; BA/BSc (Hons) Textile Design for Fashion and Interiors, BA (Hons)Textile Crafts, BA (Hons) Surface Design, BA (Hons) Costume with Textiles at the University of Huddersfield, and MSc in CAD in Textile Technolgy Publications and outputs The use of wide format ink jet printing for textile sampling, Paper presented at AUTEX Conference, July 2002, Bruges, Belgium. The use of embellishment techniques with ink jet printed repeated designs, Paper presented at INDETEC Conference Setember 2003, Edinborugh. ‘The commercial realistaion of complex textile craft techniques by cad and ink jet printing” Paper presented at Archtex Conference,September 2005, Krakow, Poland. “Craftily using ink jeT” Paper published in “Textiles” Journal Issue 33. no.2 pp.20-2.
IZMIR, Turkey DOKUZ EYLUL UNI., Deu Muhendislik fakUltesi Tekstil Muhendisligi Bol. Bornova Izmir Turkiye, Tel*: +902323882869; Fax*: +902323882867; E-mail: [email protected] Principal Investigator(s): Ass. Prof. Fatma Ceken Research Staff: Gulsah Pamuk (MSc in TExtile Eng)
Physical properties of automotive seat fabrics Other Partners: Academic
Industrial
Various Fabric Producers in Turkey None Project started: September 2005 Project ends: September 2007 Project budget:10000 USD Source of support: DOKUZ EYLUL UNI. and Turkish Fabric Producers Keywords: Automotive seat fabrics, Warp knitted fabric, Woven fabric, Velvet fabrics People spend more time in their cars with increased daily commuter distances to and from work, increased traffic density, more people work away from home and travel long distances by car at the weekends. For this reason the automobile manufacturers not only improve the technical and mechanical primary functions of the automobile but also improve the secondary parts that appeal to the senses, such as seats, door panels, carpets, etc. Seat covers is one of the most important factor for interior car design and for passenger’s comfort. The main fabric technologies used for seat covers are woven velour, jacquard woven, warp knit, warp knit pile sinker, warp knit double needle bar raschel velour, circular knit jacquard pile and spacers. The warp knitted fabrics have a structure that can be controlled and specific level of stretch and recovery. The major limitation of warp knitted fabrics is their relatively limited capability to produce large area of color and design effects. The spacer fabrics, when used in seat covers, provide temperature control, comfort and support. * Please include the full number, including the country and area codes.
Project aims and objectives In this study the aim is to compare the physical properties of automotive seat fabrics which are produced using different manufacturing techniques.
Research deliverables (academic and industrial) None Publications Not available.
Research register
37
IJCST 18,6
38
Jalandhar, India National Institute of Technology Jalandhar, Department of Textile Technology, Dr B.R Ambedkar National Institute of Technology, Jalandhar, G T Road Bye Pass, Jalandhar-144011, Punjab (India); Tel*: 91-0181-2690301,2690302; Fax*: 91-0181-2690932,2690320; E-mail: [email protected], [email protected] Principal Investigator(S): Vinay Kumar Midha
Development of needle punched nonwoven blanket fabric Other Partners: Academic
Industrial
Dr S. Ghosh None Project started: 1 April 2004 Project ends: 30 September 2007 Project budget: Rs 15 Lacs Source of support: Ministry of Human Resource Development, India Blankets are generally woven or knitted and are made from pure wool or blends of wool and acrylic fibres. Woven or Knitted fabric production is a lengthy, laborious and costly process. Whereas the needle punched fabric production is a short process and the manufacturing cost of needle punched nonwoven fabric is much lower. A nonwoven blanket is defined as a blanket produced by bonding or interlocking of fibres or both, accomplished by mechanical, chemical, thermal or solvent means or combination thereof. The important parameters, which affect the structure and properties in a needle punch nonwoven blanket, are the web parameters (type of fibre and fabric weight per unit area) and machine parameters (depth of needle penetration and needle punch density). The important requirements for end use performance of blankets are good handle, softness, good abrasion resistance, good thermal insulation in winter and good air permeability in summer. Fabric abrasion resistance increases linearly with the increase in needle punch density, but as the needle punch density is increased the other important properties like thermal resistance and handle are adversely affected. So a fabric with good thermal and handle properties will have poor abrasion resistance and vice- versa. So to design a blanket with good abrasion resistance without spoiling the softness and thermal properties, the machine parameters and web parameters are to be systematically optimized. * Please include the full number, including the country and area codes.
Project aims and objectives The objective of the project is to produce a cost effective nonwoven blanket by optimising the machine parameters to produce good thermal, softness and abrasive properties.
Research deliverables (academic and industrial) None
Research register
Publications Not available.
39
Jalandhar, India National Institute of Technology Jalandhar, Department of Textile Technology, National Institute of Technology, Jalandhar – 1440111, INDIA, Tel*: +91-181-2690301-2, 453; Fax*: +91-181-2690320,+91-181-2690932; E-mail: [email protected] Principal Investigator(S): Dr Arunangshu Mukhopadhyay Research Staff: Ms. Sunpreet Kaur
Designing nonwoven fabric for Pulse-jet Filtration Other Partners: Academic
Industrial
None None Project started: 31 March 2005 Project ends: 30 November 2008 Project budget: Rs. 15 Lacs Source of support: Ministry of Human Resource Development, Government of India Keywords: Dust particle, Nonwoven, Pulse-jet filtration Primary factors which determine the selection of a fabric for a particular application are state of aerosol medium (thermal and chemical condition, static charge on the particles, abrasive particles, moisture in the gas stream, etc.), filtration requirement (particle capturing efficiency, pressure drop and cleaning) and equipment consideration. The particle capturing mechanism by fabric filters based on reverse jet cleaning is well researched. A number of studies reveal the effect of fabric structural parameters on its filtration characteristics. Further a number of attempts have been made to improve filtration efficiency with reduced pressure drop and better cake release performance. However, it is worth mentioning that the above studies becoming rudimentary since pulse jet filter has become an attractive option of particulate collection utilities. Pulse jet cleaning is a technique whereby a short, periodic, high pressure burst of air is fired into the clean side of the fabric. The particles are dislodged and the pressure drop falls to an acceptable level. Pulse jet filtration can meet the stringent particulate emission limits regardless of variation in the operating conditions. The cleaning device is less expensive than other type of mechanism and requires considerable less space. Other merits of pulse jet fabric filters are high collection efficiency, on line cleaning application and outside collection which allows the bag maintenance in a clean and safe environment. The increasing adoption of pulse jet filters for control of process emissions and recovery of utility dusts has stimulated research on many aspects of their operation. Despite their
IJCST 18,6
40
wide applications, the functioning of fabric filters is poorly understood. The operating condition is usually specified by the manufacturer at the time of commission. In practice, however, the filtration process frequently undergoes changes in the operating condition caused by the disturbances due to the variation in the concentration of dirty air, variation in particle size, etc. Due to the complex characteristics inherent in the filtration and cleaning process of pulse jet bag houses, the proper understanding of the role of fabric construction on filtration is very important. Generation of such knowledge would represent an important first step towards designing fabric with improved barrier properties. * Please include the full number, including the country and area codes.
Project aims and objectives The separation of solids from fluids by textile filter media is an essential part of countless industrial process, contributing to purity of product, saving in energy, improvement in process efficiency, recovery of precious materials and general improvements in pollution control. The dust may create environmental pollution problems or other control difficulties caused by their toxicity, flammability and possible risk of explosion. The particles in question may simply require removal and be of no intrinsic value or alternatively may constitute part of a saleable product, for example, sugar or cement. Among several techniques, the most efficient and versatile is the fabric collector, especially when processing very fine particles. Fabric filtration under pulse jet situation becoming very common in industrial bag house filtration. However, there is lack of study on the role of fabric under the said circumstances. It is also important to develop the fabric suitable for pulse-jet filtration. Therefore, we are having the following objectives: .
Understanding the mechanism of filtration under pulse-jet situation.
.
Studing the effect of geometrical parameter of nonwoven fabric on filtration performance. Design and development of suitable nonwoven fabric under pulse-jet situation.
.
Research deliverables (academic and industrial) Initially the work will be concentrated on studying the impact of structural parameter of nonwoven fabric on its filtration performance in case of cement dust. This will lead to the development of suitable nonwoven fabric under pulse-jet situation in cement industry. At a later stage the work will be extended for optimising fabric design for other dust particles. Publications Not available.
Ksar-Hellal, Tunisia Institut Supe´rieur des Etudes Technologiques de Ksar-Hellal, b.p. 68, ISET de Ksar-Hellal, 5070 Ksar-Hellal, Tunisie, Tel*: +216 73 475900; Fax*: *+216 73 475163; E-mail: [email protected] Principal Investigator(s): Dr Ivelin Rahnev
A denim structural modification Other Partners: Academic
Research register
Industrial
ISET de Ksar-Hellal None Project started: 1 July 2005 Project ends: 31 January 2007 Project budget: N/A Source of support: N/A Keywords: Double weave, Rheological behaviour, Weaving optimisation The combination of two elementary twills in double woven fabric builds common weave structure of two layers. When the design provides work cloth, the first layer of the threedimensional weave texture has mostly aesthetical and protective purpose, while the inner layer gives the user’s physiological comfort. Independently of their function the autonomous layers give common mechanical reaction against the applied external forces. The need of equalizing the internal stresses and their homogenous diffusion over all the fabric elements makes the detailed description of the fabric mechanical behaviour extremely important, and that in the two directions: a long the warp and a long the weft. The detailed mechanical behaviour considers the current fabric reaction in the case of traction load with arbitrary intensity and duration. That is why the breaking characteristics cannot more be used as universal definitive criterion, obtained from the rheograms of the mechanical reaction when the fabric submits traction load. The project development passed by three stages. During the first stage the principal task consisted in the design of the weave and the determination of the technological parameters of the double fabric. The basic idea is to obtain the visible denim relief on the face, which means, that the elementary weave of the face is four-weave twill with weft effects-Tw(4)Z. In the square pattern composed of 14x14 warp and weft threads there are place for 4 denim rapports; there alternated as follows: 2 along the warp and 2 along the weft. Because the pattern rapport and the denim rapport are not multiples each to other the 7th and 8th warp and weft threads approach each to other in the middle of the whole weave. Thus, the denim is concentrated in the middle of the weave. In the square pattern remains 6x6 warp and weft threads; they are used to distribute the connecting points of the three-twill 4 rapports. On the common fabric back, i.e. on the inner layer face, we obtain twill with weft effect-Tw(3)Z; but in regard to the general pattern for the heald shafts movements this is equivalent to three-weave twill with warp effect-Tw(3)S. Thus, we have combined on the same fabric, two twills with orthogonal diagonals in order to equilibrate the common construction. During the firs half of the weft rapport (1st 4 7th picks) the loom weaves denim on the odds picks and three-weave twill on the pair picks. During the second half (8th 4 14th picks) the two elementary weaves alternate their places. The interconnections between the two fabrics are made by means of 4th and 11th ends; they rise alternatively as a common warp covering and attach the 1st and the 8th picks to the inner layer. Both the face and the back of the fabric show weft appearances. During the second stage the work was directed towards the execution of the experiment planned on the designed weave and the research detailed of the characteristic qualitative indices.
41
IJCST 18,6
42
The traction, or the feeding, of the warp as well as that of the weft density are the two controllable and functionally independent machine adjustments. They allow us to control the quantitative factors over a spherical experimentally field. The generalized nonlinear character of the textile materials rheological behaviour needs a model with at least 2nd degree surface response. In our experiment we want to verify the hypothesis of the viscoelastic reaction of the designed fabric. The working conditions allow us to choose the centrally composed rotatable experiment plan depending on two factors. Thus, the polynomial model for each mechanical criterion will be of second degree. The consolidated tests rheograms along warp and along weft show the differences in the mechanical properties of the warp and weft, as well the anisotropic behaviour changes in the specimens. The double fabric rheological behaviour does not change considerably with the experimental factors variation. The maximal resistance intensity remains approximately constant. The corresponding elongation decreases with the letoff traction increase and with the indirect increase of the warp tension when the take-up picks intensity increases. The reason is the preliminary elasticity consumption of the warp threads during weaving. The curvilinear character of the warp threads strain resistance is almost entirely transferred on the fabric along its warp. With the medium traction level of the let-off motion, we obtained the smoothest warp rheograms with the creep function linearizing trend. With the weft density increase, as well with the warp tension decrease, we observe a more nonlinear rheological reaction, because of the increased amplitude in warp threads crossing and the resulting structural displacements with the fabric traction. As the whole, the rheograms slope remains constant in the range of experimental plan. The weft rheological properties of the fabric are considerably more sensitive to the technological factors variations, especially to the take-up intensity, that is with the determining factor for the fabric strength along the weft. Of course, the increased weft threads relative number increases the maximal strength, and the rheograms really cease at. The fabric strength along weft follows the take-up increase, and shows its maximum for let-off motion medium load; when the warp is loose or overstressed, this fabric strength decreases. The elongation, which corresponds to the maximum force, also increases in the middle of the experimental field, but decreases at the factors extreme values. The double fabric rheograms consolidate the mechanical resistance of the weft threads in the two layers. As a matter of fact, the fabric strength along the weft as a function of the technological factors is represented by the creep curve and, especially by its slope. The creep function increases with the take-up intensity increase and reaches its maximum at a looser and at an overstressed warp during weaving. The contrasting in the rheological behaviour of the warp threads and the weft picks is explained by the common weave texture transformation into three thickened autonomous layers of threads: warp and two wefts. Both the warp and the weft relaxation rheograms show similar behaviour. The equal elongation levels kept constant for the time specified; result in different initial stress reaction. Thus, with low factor levels and low stresses, we find smaller differences between the initial and the final forces, which essentially is the difference in the relaxation function values. With the increase of the weft density and with the increase of the warp tension during weaving, the weave texture begins thicker and its strength increases, but it is due to the fibres and the threads elastic properties decrease.
We observe contradictory technological phenomenon, which suggest a search for an optimized fabric structure. It is difficult to evaluate by visual methods only, but we think, that the relaxation function does not show symmetrical changes with reference to the experimental centre. In other words, there is no linearity observed, neither with the elongation test level, nor with the weaving parameters. We believe, that the relaxation function variations averages cold be accepted as a primitive evaluation of the relaxation process, which satisfies the practical meaning of the derived criterion – the relaxation module. Similarly, we consider that the relaxation behaviour of the double fabric along weft has the same character as the relaxation behaviour along the warp. We note the simultaneous action of the let-off and the take-up motions, which, by the structural modifications in the double fabric influences the anisotropy of the product. In the experimental field there is a zone with minimal values of the studied technological criterion and which occupies the centre of the experiment. This fact means that for our weave and in dependence of concrete raw materials, there is only one texture, as a combination of the technological factors, which joins together the properties of the textile threads. It is characteristic, that in the periphery of the experiment; there, where the fabric is slackened and sparse, thus and there, where it is tight and dense, the initial characteristics of the warp threads and the weft picks appear individually. This is an index, that with the arbitrary weaving texture two disadvantage alternatives are possible: When the contact among the threads is not sufficient, they react in an autonomous way against the external forces and this fact reduces the common resistance of the fabric. When the threads are preliminary overloaded in the texture, each successive external force causes their abrupt and maximum reactions, which influences the increased anisotropy of the fabric. The existence of an experimental zone, where the criterion of the resistant divergence manifests minimal values, suggests us the possible technological combination of the weaving parameters, for which the designed fabric will acquire the optimal texture. In our case, it is the centre of the experiment, where the texture obtained equalizes the properties of the threads in a equilibrated rheological reaction balanced along the warp and along the weft. Above all, we note the coincidence of the zones of the experimental field, for which the relaxation modules have minimal values. In the same way, and in the two fabric directions, the rheological modules raise with the simultaneous increase of the take-up intensity and the warp tension. This fact shows, that thus derived technological criterion can give a relatively objective and universal evaluation for the viscoelastic properties of the studied fabric. The larger relaxation module corresponds to the increased fall of the threads stresses. This means that the stresses, generated from the applied constant strain, of their part cause the creeping in the medium of the fabric. In this case the mutual disposition and the preliminary strains of the threads allow the prevalent viscous character in the fabric rheological behaviour. In spite of the tenacity increased in the weft direction and the obviously tight and stable aspect, the fabric loses the capacity to restore its initial form and its dimensions. Conversely, the minimal relaxation module characterizes this fabric texture, for which the fabric is more elastic and lively; and has performed exploitation properties compared to the aesthetic aspect with a satisfactory tenacity.
Research register
43
IJCST 18,6
44
Finally, we arrive at the deduction, that among the possible machine adjustments of the weaving technology, we can choose that combination, which gives the optimal fabric texture. The properties of the fibres, the threads and the fabric have their optimal and natural state for each concrete case. By means of the applied rheological characteristics we can thoroughly explain the various phenomena of the weaving formation and by accessible criteria to develop the technological optimization as a final stage of the fabric design. During the third stage, which currently is in preparation, we complete the project of the double fabric by intermediary of technological optimization under the conditions of materials available. The machine mode of the weaving loom, provided by a dobby and an apparatus for weft change, represents the optimization subject. The technological factors of optimization are: the tension of the warp threads and the weft density which vary by the intermediary of the controllable machine adjustments of the let-off and the take-up motions. The optimization criteria correspond to intrinsic higher protection for the work cloths. We separated them with share in two groups. The first group of the mechanical qualitative indices: the tenacity of the traction load, the abrasion resistance and the bursting strength; represents the essential evaluations whose maximum values are sought. The second group of the hygienic and aesthetic indices: the surface mass, the drape and the air permeability; determines the limiting conditions for the model existence. The optimal solution is obtained by the scanning of the model polynomials in the experimental field. The final result of the technological optimization composes the technological chart of the designed fabric, including the prescriptions of the machine adjustments of the loom. * Please include the full number, including the country and area codes.
Project aims and objectives The double fabric of the type of cotton and intended for the work cloths with improved properties of exploitation is the objective of this project. The tasks of the development are directed towards: .
the composition of a weave suitable for double fabric and applicable in the conventional weaving technology;
.
the grouping of a multitude of the physical and mechanical qualitative indices, characterizing the high requirements of this woven fabric;
.
the technological optimization of the weaving mode and establishment of the machine adjustments for which the fabric acquires the desired properties.
Research deliverables (academic and industrial) The rheological properties, experimentally established, generalize the detailed description of the woven fabric mechanical behaviour in function of the weaving mode and constitute the principal factor of the technological optimization. The whole procedure of the double woven fabric conception has a methodological destination in the field of the textile specialists training of textile products design. The original weave of double fabric with the denim aspect as well as the optimized weaving technology can be applied into the industrial conditions of weaving.
Publications Rahnev I.,Work cloth weave metrological selection, “Textile and Garment”, ISSN1310-912X, (in press). Rahnev I.,Rheological behaviour of double woven fabric-cotton type, 6th Autex, poster presentation (ID128?), Raleigh, NC, 2006.
45
Lodz, Poland Technical Univerity of Lodz, Technical University of Lodz, Department of Clothing Technology, Zeromskiego 116 Str, 90-924 Lodz; Tel*: +48 042 631 33 21; Fax*: +48 042 631 33 20; E-mail: [email protected] Principal Investigator(s): Iwona Frydrych Research Staff: Renata Krasowska
Influence of work conditions of the disc take-up on characteristics of lockstitch Other Partners: Academic
Research register
Industrial
None None Project started: 20 May 2005 Project ends: 19 May 2008 Project budget: 49100 PLN Source of support: Ministry of Science and Higher Education Keywords: Lockstitch, Lockstitch machine formation zone (STS), Thread demand in STS, Thread feed by the take-up The project presents an elaboration of original model simulating a thread movement in the zone of stitch creation, on the basis of which a mechanism of take-up disc will be built. It will be evaluated in experimental research. The regulating point at this type of take-up will be presented as a novelty. According to this, reactions of the machine operator on the changes of sewing thread properties will be enabled and useful properties of lockstitch will be created. It requires elaborating the set of criteria assessing an action of this type of take-up disc. * Please include the full number, including the country and area codes.
Project aims and objectives The aim of the project is testing the working conditions of the disc take-up disc of the sewing thread taking into consideration the development of its construction of regulation points in the relation to existing solutions.
Research deliverables (academic and industrial) New construction of mechanism of take-up disc should create possibilities to adjust the parameters of its construction to thread sewing parameters and useful properties of the lockstitch.
IJCST 18,6
Publications 1. R. Krasowska, I. Frydrych: “Possibilities of modelling the control conditions of thread by the disc takeup in the lockstitch machine”. Fibres & Textiles in Eastern Europe, 1/2006. 2. R. Krasowska, I. Frydrych: “Formation of the thread control curve by the disc take-up in the lockstitch machine”. Research Journal of textile and Apparel, 2006.
46
Loughborough, UK Loughborough University, Environmental Ergonomics Research Centre; Dept. Human Sciences, Loughborough University, Loughborough, LE11 3TU, Tel*: +44 1509 223031; Fax*: +44 1509 223940; E-mail: [email protected] Principal Investigator(s): Prof. George Havenith Research Staff: A. Fogarty, X. Wang
“THERMPROTECT”, Assessment of thermal properties of Protective clothing and their use Other Partners: Academic
Industrial
None Lund University Sweden; EMPA, Switzerland; TNO, Netherlands; INRS, France; TU-Tampere, Finland; Ifado, Germany Project started: 2003 Project ends: 2006 Project budget: 700,000e Source of support: European Union Keywords: Clothing Heat & Mass Transfer; Radiation, Wet clothing, Energy use due to clothing, Wind This project focuses on effects of radiation, wind and wetting of clothing layers on the thermal strain experienced in Personal Protective Clothing (PPC) (Work Package 1 and WP2), on special issues with cold weather protective clothing (WP3), and on the impact of protective clothing on the energy consumption of workers (WP4). Heat transfer through PPC with different radiant and moisture transport properties is studied. First on material samples, followed by thermal manikin measurements and finally in a select number of conditions, in human wear trials. Data will be used to derive general models of either analytical (WP1, WP4) or conceptual (WP2) nature of heat transfer through PPC in relation to clothing material properties, climate, etc. * Please include the full number, including the country and area codes.
Project aims and objectives To improve the representation of clothing in ISO and EN heat and cold stress assessment standards.
Research deliverables (academic and industrial) Data that will be used by standard writers to update the available standards on thermal stress and strain in the workplace. Publications 1. Bro¨de, P., Candas, V., Kuklane, K., den Hartog, E., Havenith, G., Bro¨de, P., Candas, V., den Hartog, E., Griefahn, B., Havenith, G., Holme´r, I., Meinander, H., Nocker, W. and Richards, M., “Effects of heat radiation on the heat exchange with protective clothing – a thermal manikin study”, Central Institute for Labour Protection – National Research Institute, 3rd European Conference on Protective Clothing (ECPC), Poland, May 2006, ISBN: 83-7373-097-4. 2. Bro¨de, P., Kuklane, K., den Hartog, E. and Havenith, G., “Infrared radiation effects on heat loss measured by a thermal manikin wearing protective clothing”, Environmental Ergonomics XI, Proceedings of the 11th International Conference, Ystad, Sweden, May 2005, pp. 74-9. 3. Dorman, L. and Havenith, G., “The influence of clothing weight and bulk on metabolic rate when wearing protective clothing”, The Third International Conference on Human-Environmental System ICHES’ 05, Tokyo, Japan, September 2005, pp. 439-43. 4. Dorman, L., Havenith, G., Bro¨de, P., Candas, V., den Hartog, E., Havenith, G., Holme´r, I., Meinander, H., Nocker, W. and Richards, M., “Modelling the metabolic effects of protective clothing”, Central Institute for Labour Protection – National Research Institute, 3rd European Conference on Protective Clothing (ECPC), Poland, May 2006, ISBN: 83-7373-097-4. 5. Fukazawa, T., den Hartog, E.A., Daanen, H.A.M., Penders-van-Elk, N., Tochihara, Y. and Havenith, G., “Radiant heat transfer network in the simulated protective clothing system under high heat flux”, The Third International Conference on Human-Environment System ICHES’ 05, Tokyo, Japan, September 2005, pp. 435-8. 6. Fukazawa, T., den Hartog, E.A., Daanen, H.A.M., Tochihara, Y. and Havenith, G., “Water vapour transfer in the simulated protective clothing system with exposure to intensive solar radiation”, The Third International Conference on Human-Environment System ICHES’ 05, Tokyo, Japan, 2005, pp. 202-5. 7. Gao, C., Holme´r, I., Fan, J., Wan, X., Wu, J.Y.S. and Havenith, G., “The comparison of thermal properties of protective clothing using dry and sweating manikins”, Central Institute for Labour Protection – National Research Institute, 3rd European Conference on Protective Clothing, Poland, May 2006, ISBN: 83-7373-097-4. 8. Havenith G. (2005) Clothing Heat Exchange Models For Research and Application; The 11th International Conference On Environmental Ergonomics, Ystad, Sweden; Proceedings published as Environmental Ergonomics 2005. Editors I Holme´r, K Kuklane and C Gao. Lund University, Lund, Sweden, 2005.ISBN 91-631-7062-0, pp. 66-73. 9. Havenith, G., “Clothing heat exchange models for research and application”, Environmental Ergonomics XI, Proceedings of the 11th International Conference, Ystad, Sweden, May 2005, pp. 6673, ISSN 1650-9773. 10. Havenith, G., Wang, X, den Hartog, V.E., Griefahn, B., Holme´r, I., Meinander, H. and Richards, M., “Interaction effects of radiation and convection measured by a thermal manikin wearing protective clothing with different radiant properties”, The Third International Conference on HumanEnvironmental System ICHES 05, Tokyo, Japan, September 2005, pp. 47-50. 11. Havenith, G., Wang, X., Richards, M., Bro¨de, P., Candas, V., den Hartog, E., Holme´r, I., Meinander, H. and Nocker, W., “Evaporative cooling in protective clothing”, Central Institute for Labour Protection – National Research Institute, 3rd European Conference on Protective Clothing (ECPC), Poland, May 2006, ISBN: 83-7373-097-4. 12. Kuklane, K., Gao, C., Holme´r, I., Broede, P., Candas, V., den Hartog, E., Havenith, G., Holme´r, I., Meinander, H. and Richards, M., “Effects of natural solar radiation on manikin heat exchange”, Central Institute for Labour Protection – National Research Institute, 3rd European Conference on Protective Clothing (ECPC), Poland, May 2006, ISBN: 83-7373-097-4.
Research register
47
IJCST 18,6
48
13. Lucy Dorman, George Havenith and Thermprotect Network (2005) The Effects Of Protective Clothing On Metabolic Rate. The 11th International Conference On Environmental Ergonomics, Ystad, Sweden; Proceedings published as Environmental Ergonomics 2005. Editors I Holme´r, K Kuklane and C Gao. Lund University, Lund, Sweden, 2005.ISBN 91-631-7062-0, pp. 82-85. 14. Peter Bro¨de, Kalev Kuklane, Emiel Den Hartog, George Havenith And Thermprotect Network (2005) Infrared Radiation Effects On Heat Loss Measured By A Thermal Manikin Wearing Protective Clothing. The 11th International Conference On Environmental Ergonomics, Ystad, Sweden; Proceedings published as Environmental Ergonomics 2005. Editors I Holme´r, K Kuklane and C Gao. Lund University, Lund, Sweden, 2005.ISBN 91-6317062-0, pp. 74-78. 15. Richards, M., Rossi, R., Havenith, G., Richards, M., Candas, V., Meinander, H., Broede, P., Candas, V., den Hartog, E., Havenith, G., Holme´r, I., Meinander, H. and Nocker, W., “Dry and wet heat transfer through protective clothing dependent on the clothing properties and climatic conditions”, Central Institute for Labour Protection – National Research Institute, 3rd European Conference on Protective Clothing (ECPC), Poland, May 2006, ISBN: 83-7373-097-4. 16. van Es, E.M., den Hartog, E.A., Broede, P., Candas, V., Heus, R., Havenith, G., Holme´r, I., Meinander, H., Nocker, W. and Richards, M., “Effects of short wave radiation and radiation area on human heat strain in reflective and non-reflective protective clothing”, Central Institute for Labour Protection – National Research Institute, 3rd European Conference on Protective Clothing (ECPC), Poland, May 2006, ISBN: 83-7373-097-4.
Maribor, Slovenia Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, 2000 Maribor, Slovenia, Tel*: +386 2 220 7910; Fax*: +386 2 220 7990; E-mail: [email protected] Principal Investigator(s): Prof. Dr Alenka Majcen Le Marechal, Institute of textiles, Laboratory for chemistry, dyes and polymers Research Staff: Synthesis and modification of dyes and polyfunctional reagents, synthesis of active organic substances, Application of polyfunctional reagents in textile engineering, Introduction of nanoencapsulation in medical and hygienic textiles, Decoloration of textile waste water (H2O2/UV, H2O2/O3, H2O2/Fenton, H2O2/ultrasound), Development of sensors for monitoring of ecological parameters, Analytical methods in textile industry, Development of alternative methods for the determination of free formaldehyde
Advanced oxidation processes and biotreatments of water recycling in the textile industry (sixth framework programme) Other Partners: Academic Industrial Robert Blondel SA, TSP, Helios Intalquartz, DAMA, OBEM Project started: 1 January 2005
Industrial None Project ends: 31 December 2006
Grant value: 363.471 EUR Source of support: EC Keywords: Advance oxidation processes, UV-activated, Hydrogen peroxide, Thermal activated oxidation process, Decolouration, Bioflotation, ANN-based process control software The AdOPBio project aims to develop a decolouring and recycling treatment of the wastewaters in the textile finishing industry, based on two alternative methods: Advance Oxidation Processes (UV-activated photolysis of hydrogen peroxide and thermal activated oxidation process) for the decolouration of the spent bath, combined with a bioflotation process for the destruction of the residual organic load. The combination of these wastewater treatments is expected to achieve a complete decolourisation of the process waters for every type of wet process (finishing, bleaching, dyeing, etc.). The project will also develop and implement a process-control software based on artificial neural network and systems dynamics. Research centres in collaboration with textile finishing companies and suppliers of dyeing machines and wastewater treatment equipment will develop a prototype that will be tested and validated by the end-user companies (textile finishing companies) in order to accumulate experiences and improve the capability of the plant to match a wide range of industrial needs. The project includes all the steps in developing a wastewater treatment unit such as: . . . . .
modelling and laboratory investigations of AOP and bioflotation processes; design and manufacture of AOP and bioflotation reactors; design and manufacture of a dyeing machine, interfaced with both AOP reactors; implementation of an ANN-based process control software; and interfacing the dyeing machine with the bioflotation treatment plant tests of the plant in and industrial validation of the decolouring and recycling process.
* Please include the full number, including the country and area codes.
Project aims and objectives Today more than 4.000 compounds are used in the textile finishing process, which complicates design and setting up of a single cleaning up and recycling technology. The equipment used in decolouring and cleaning up processes is very hard to set and tune with the continuous variation in load and composition. Moreover, the pollutant charge can overload the capability of the cleaning plant, therefore failures are common and operational costs are prohibitive for SME companies. One of the purposes of the project will be to investigate different dyeing and finishing processes, drawing guidelines for the convenience of recycling water by this system. ADOPBIO will focus on a decolouring and cleaning up treatment for textile finishing wastewaters based on an UV-activated photolysis of the hydrogen peroxide (an targetted Advanced Oxidation Process, AOP) combined with a bioflotation treatment. The combination of these treatments can achieve a complete decolourization and recycling of the process waters for every type of wet process (finishing, bleaching, dyeing, etc.). ADOPBIO will also focus on the development and implementation of process control software, based on artificial neural network and systems dynamics.
Research register
49
IJCST 18,6
The textile finishing wastewater treatment is expected to achieve the following characteristics: Quality of the treated process water: .
full decolorization ( . 99% for interfering dyes; . 90% for other colour substances);
.
reduction of surfactants $ (99%) and toxic compounds (COD reduction $ 95%) if not recyclable;
.
recycling of at least 75% of the wastewaters.
50
Research deliverables (academic and industrial) Technical report on the end-users wet processes Economic impact report on the end-users wet processes End users specifications AOPs kinetic models Optimized laboratory AOP reactors AOPs and bioflotation scheme guidelines AdOPBio web-space (diagrams, run-time models, simulations) UV-activated AOP reactor scheme Thermal activated AOP reactor scheme Bioflotation reactor scheme Dyeing machine scheme ANN-based process control software Learning and operational simulation tools AOP simulated control panel UV- and thermal-activated AOP pilot reactors Bioflotation pilot reactor Dyeing machine prototype Integrated AdOPBio system of water treatment Industrial validation report Runnable models (predictive, sensitivity tests) Management tools (project calendar, reporting, cost follow up) Project quality indicator and milestone report Mid-term review Plan for using and disseminating the kowledge Publications Brodnjak-Voncˇina, D. and Majcen Le Marechal, A. (2003) “Reactive dye decolorization using combined ultrasound/H2O2” Dyes Pigm, Vol. 59, No. 2, pp. 173-9. Kurbus, T., Slokar, Y.M., Majcen Le Marechal, A. and Brodnjak-Voncˇina, D. (2003) “The use of experimental design for the evaluation of the influence of variables on the H2O2/UV treatment of model textile waste water” Dyes Pigm, Vol. 58, pp. 171-8. Kurbus, T., Majcen Le Marechal, A. and Brodnjak-Voncˇina, D. (2003) “Comparison of H2O2/UV, H2O2/O3 and H2O2/Fe2+ processes for the decolorisation of vinylsulphone reactive dyes” Dyes Pigm, Vol. 58, No. 3, pp. 245-52. Kurbus, T., Slokar, Y.M. and Majcen Le Marechal, A. (2002) “The study of the effects of the variables on H2O2/UV decoloration of vinylsulphone dye” Part II. Dyes Pigm, Vol. 54, pp. 67-78. Voncˇina, B., Bezek, D. and Majcen Le Marechal, A. (2002) “Eco-friendly durable press finishing of textile interlinings” Fibres Text. East. Eur, Vol. 10, No. 3, pp. 68-71.
Voncˇina, B., Majcen, N., Majcen Le Marechal, A., Brodnjak-Voncˇina, D. and Bezek, D. (2004) “Free formaldehyde determination using HPLC” Mater. Sci. Forum, Vols. 455/456, pp. 801-4. Voncˇina, B. and Majcen Le Marechal, A. (2005) “Grafting of cotton with [beta]-cyclodextrin via poly(carboxylic acid)” J. Appl. Polym. Sci, Vol. 96, No. 4, pp. 1323-8. Vajnhandl, S. and Majcen Le Marechal, A. (2005) “Ultrasound in textile dyeing an the decolouration/mineralization of textile dyes” Dyes Pigm., Vol. 65, No. 2, pp. 89-101.
Research register
51
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] Principal Investigator(s): Prof. Dr Sc. Jelka Gersˇak, Laboratory for Clothing Engineering, Physiology and Construction of Garments, Department of Textiles Research Staff: Research Unit Clothing Engineering, Research Unit Textile Technology
Clothing engineering and textile materials Other Partners: Academic
Industrial
None None Project started: 2004 Project ends: 2008 Grant value: 17.936.050 SIT or 74.890 ECU for 2004 Source of support: Ministry of Higher Education, Science and Technology Keywords: Clothing, Fabric, Fabric mechanics, Behaviour comfort, Prediction The research programme Clothing engineering and textile materials is based on complex research studies of fabric mechanics, structural properties of textile materials and their thermo-physiological comfort. The programme comprehends tree associated thematic parts: a) basic research on fabric mechanics with the emphasis on fabrics as complex textile structures, b) behaviour modelling of complex textile structures and c) characterisation of the parameters of thermo-physiological comfort. The important results of the research can be given in the form of the following achievements: .
It was established on the basis of the hysteresis behaviour of textile fabrics that such specific behaviour is caused by fabric’s structural parameters as well as by warp and weft friction properties. Fabric mechanical and physical properties, as well as relaxation are directly influenced by structural parameters of the fabric.
.
Textile fabrics must be treated as non-homogenous and anisotropic structures, and that is the reason why their mechanical characteristics such as tensile, shear, bending and compression properties are non-linear. That indicates that individual yarn and fibre movements within the fabric structure during deformation is rather complex. This is the reason that fabric’s mechanical properties should be regarded as a structural body instead of continuum.
IJCST 18,6
.
Elastic potential of textile fabrics is directly influenced by parameters of mechanical properties. Some fabrics show specific values of elastic potential. Responsible for that is raw material composition, type of weave and fabric’s structural parameters. Tensile elastic potential usually can increase with the increase in the work of deformation and is directly dependant on the ability of particular fabric to be relaxed as well as on its structural parameters and friction properties of warp and weft.
.
Multicomponents mechanical models can be stated as most appropriate models for proper description of relaxation phenomena in fabrics containing elastic components. Generally, according to the achieved results, it can be stated that with the increase of the share of elastic component, also relaxation time increases. That means that in fabrics with higher share of elastic component, because of relaxation of the tension at a constant deformation, the tension is slowly decreasing. After one or 24 hours relaxation it reaches higher values compared with the fabrics containing less elastic component.
.
The direct connection between the mechanical and physical properties of fabrics integrated into the garment, and finished garment appearance quality, which is defined on the basis of five criterions (garment fall, appropriate 3D shape of the garment, quality of garment fit, quality of the finished seams: seam puckering and flotation of seams, garment appearance as a whole) has been established. The results of the research work showed that different number of mechanical and physical fabric properties influence the garment appearance quality.
.
Human body thermoregulation as a system of heat exchange between the human body and garment and/or other textile product and environment is influenced by the garment type and its construction, as well as by fabric’s matter and thermal properties.
52
* Please include the full number, including the country and area codes.
Project aims and objectives The main objectives of this project are: .
definition of relationships between fabric mechanical properties and quality of a produced garment;
.
design of a model for prediction of garment appearance quality;
.
set-up of a model of fabric behaviour as shell; and
.
numerical simulation of heat exchange between the human body and garment system or other textiles products and environment.
Research deliverables (academic and industrial) Having realized the proposed research programme and gaining the knowledge about deformation and relaxation processes in fabrics, as well as by gained theoretical cognition and definition of interactions of mechanical and physical properties of fabrics and degree of garment appearance quality of the clothes to be made, the new knowledge has been developed. This new cognitions will be used for prediction of the non linear mechanical properties of fabrics in low loading area and simulation of fabric behaviour.
Furthermore, the theoretical cognition from this study area of interactions between matter properties of textile materials, heat exchange and humane thermoregulation will enable the development of the numerical simulation of heat exchange between the human body and garments or other textiles products and environment. Publications Gersˇak, J. (2003) “Investigation 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. 368-78. 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. 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. 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. Zavec Pavlinic´, D. and Gersˇak, J. (2004), “Vrednovanje kakvoc´e izgleda odjec´e”. Tekstil, Vol. 53, No. 10, pp. 497-509. Urbanija, V. and Gersˇak, J. (2004) “Impact of the mechanical properties of nappa clothing leather on the characteristics of its use”, J. Soc. Leather Technol. Chem., Vol. 88, No. 5, pp. 181-90. Kocik, M., Zurek, W., Krucinska, I., Gersˇak, J. and Jakubczyk, J. (2005) “Evaluating the bending rigidity of flat textiles with the use of an Instron tensile tester”, Fibres Text. East. Eur., Vol. 13, No. 2(50), pp. 31-4. (available at: http://www.fibtex.lodz. pl/50_09_31.pdf). Jevsˇnik, S., Gersˇak, J. and Gubensˇek, I. (2005) “The advance engineering methods to plan the behaviour of fused panel”, Int. J. Cloth. Sci. Technol., Vol. 17, Nos 3/4, pp. 161-70.
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] Principal Investigator(s): Prof. Dr Sc. Jelka Gersˇak, Department of Textiles, Laboratory for Clothing Engineering, Physiology and Construction of Garments Research Staff: Dr Sc. Jelka GERSˇAK, Dr Vili BUKOSˇEK, Dr Dunja SˇAJN, MSc. Rozalija BLEKACˇ
Study of the relationship between deformation and relaxation of fabrics containing elastane yarns in the spreading process Other Partners: Academic Faculty of Natural Sciences and Engineering, Department of Textiles, University of Ljubljana
Industrial ELKROJ, modna oblacˇila d.d., NAZARJE
Research register
53
IJCST 18,6
54
Project started: July 2004 Project ends: June 2007 Grant value: 4.051.470 SIT or 16.890 ECU for 2004 Source of support: Ministry of Higher Education, Science and Technology Keywords: Fabrics containing elastane yarns, Relaxation phenomena, Stress relaxation, Deformation, Spreading process The aim of the research project is to study the elastic behaviour of fabrics with elastane yarns taking into account the elastic potential, elastic deformations and relaxation ability based on the study of fabric mechanics, with the purpose to gain new cognition about the relationship between elastic deformations and relaxation phenomena in such fabric type. The main part of the research is focused on the study of elastic deformations and relaxation phenomena in fabrics with elastane yarns, where the influence of the parameters of tensional-elastic properties of such fabrics on elastic deformations and relaxation level will be investigated taking into account loading intensity. Special attention is given to the study of time dependence of relaxation phenomena in fabrics with elastane yarns and special relaxation conditions of such fabrics during spreading and laying into fabric layers, i.e. influence of the length, surface friction between fabric layers and number of layers. For this purpose the stress relaxation during witholding under constant deformations and the relaxation of fabrics after manually unwinding and spreading were studied. The relaxation of fabrics represents as elastic recovery and response of fabric as the result of loading during winding and spreading to form by lay. Based on given results of relaxation of fabric as the consequence of winding process was found that with higher percentage of containing elastane in the yarn grows the degree of deformation. * Please include the full number, including the country and area codes.
Project aims and objectives The main goal of the research is to find the correlation between the elastic deformation and relaxation level in fabrics with elastane yarns and to set up the model for predicting the relaxation of fabrics taking into account the parameters of fabric’s tensional-elastic properties, parameters of the spreading process, as well as the length and number of fabric layers. Publications Gersˇak, J., Sˇajn, D. and Bukosˇek, V. (2005) “A study of the relaxation phenomena in the fabrics containing elastane yarns”. Int. J. Cloth. Sci. technol., Vol. 17, Nos 3/4, pp. 188-99. Sˇajn, D. and Gersˇak, J. (2004) “ITMA 2003 – merilne naprave za merjenje nateznih obremenitev tekstilij ¼ ITMA 2003”, “Instruments for tension measuring of textile products during production process”. Tekstilec, Vol. 47, Nos 3/4, pp. 136-44. Sˇajn, D., Gersˇak, J. and Bukosˇek, V. (2004) “A study of the relaxation phenomena of fabrics containing elastane yarns”. Book of proceedings of 2nd International Textile, Clothing & Design Conference Faculty of Textile Technology, University of Zagreb, Dubrovnik, Croatia, Zagreb, pp. 605-10. Sˇajn, D., Gersˇak, J. and Bukosˇek, V. (2005) “Correlation between the relaxation and deformation of fabrics containing elastane yarn”, Proceedings of 5th World Textile Conference AUTEX 2005, Faculty of Mechanical Engineering, Department of Textiles, Maribor, Portorozˇ, Slovenia, pp. 406-11.
Manchester, UK Manchester Metropolitan University, Department of Clothing Design and Technology, Hollings Campus, Old Hall Lane, Manchester. M14 6HR, Tel*: +44 161 246 2676; Fax*: +44 161 247 6329; E-mail: [email protected] Principal Investigator(s): Dr Jess Power and Dr Rose Otieno Research Staff: T.B.C.
Anthropometrical data in knitted garments Other Partners: Academic
Industrial
MIRIAD T.B.C. Project starts: 30 September 2006 Project ends: 30 August 2007 Project budget:£36732 Source of support: MIRIAD/Department (internal funding) Keywords: Knitted garments Anthropometrical Knitted garments and the relating technologies have advanced immensely during the last decade especially in the areas of fully fashioning (integral shaping) and complete garment production. Various new techniques have become available in modern knitting machinery including microprocessor-controlled mechatronic systems for needle selection and fabric take down systems, as well as automated loop transferring. These technologies have enabled knitwear to be shaped three-dimensionally as not previously achievable through the sophisticated CAD software that generates pattern and control during knitting. Despite this advancement in programming software and electronic needle selection, garment development is still heavily reliant on the skill of the operator or designer to develop new shapes and manipulate this advanced technology into innovative knitwear. This advance in technology has opened up a large knowledge gap with regards to fit and styling within knitwear, and many questions have arisen; Do we really understand the relationship between anthropometrical data and knitwear sizing, styling and fit and do we utilise the knowledge effectively to enable predictions of fit to occur? In previous research it was found that many new knitwear developments are based on empirical knowledge utilising the trial and error approach to develop styles with good fit which conform to the human figure and the theoretical application is very much lacking. This suggests that there is a void caused by the lacking of theoretical data and a knowledge gap between the relationship of anthropometrics and knitwear development. It is vital to assist the industry by providing a sound theoretical understand in order to minimise time wasted utilising the trial and error approach which appears to be considered the current industry norm. In addition to the strong technical justification for the project investigation regarding the use of anthropometrical data in knitwear development, there is evidence that during resent years knitwear has become a key fashion item, a greater percentage of a clothing range in retail outlets are knitwear based. It has
Research register
55
IJCST 18,6
56
also been acknowledged that the individual knitwear manufacturers are placing much more emphasis on the development of new shapes that conform to the human form. However, there is an uncertainty regarding how much of this is derived from empirical development and the quantity that has a sound theoretical framework grounded in anthropometrical studies. * Please include the full number, including the country and area codes.
Project aims and objectives .
A thorough literature search to determine the key players; and establish knowledge gaps in relation to the use of anthropometrical data in knitwear sizing.
.
Intense market research collating knitwear sizing and anthropometrical data.
.
Through visits, interviews will be conducted with five key manufacturers to evaluate the current industry standards in relation to knitwear sizing and the usage of anthropometrical data.
.
Using laboratory based procedures analysis will occur by scientific evaluation into the current grading procedures in knitted garments, to determine the current industry standards.
.
Devise a database of anthropometrical information related to knitwear styles and sizing.
Research deliverables (academic and industrial) It is thus proposed to conduct investigation through a research project into the use and understanding of anthropometrical data in knitted garments. This will occur in the form of a study into the development and production of current knitted goods by primary research involving extensive practical observation by scientific means. This will result in the analysis of four basic stylelines in a variety of sizing codes. In addition it is proposed that five UK knitwear manufacturers will contribute information regarding their internal knowledge of the use of anthropometrical data within their current knitwear developments. The second part of the study will involve the collating of information gained from the scientific observation and the primary research from the knitwear manufacturers. A Research Assistant funded entirely by the project will conduct the extensive laboratory observational research to enable the research outputs to be achieved. Publications and outputs This research is grounded in previous postgraduate work and will expand on the department’s current research portfolio within anthropometrics and knitwear. The output will be in two phases: Phase I 1. Publication to outline the initial findings of the background study. 2. A conference presentation based on the findings of the primary investigation. Phase II 3. A framework for further research in the form of scholarly activity. 4. Development of a short course to relate the findings directly back to the industry.
Mulhouse, France Ecole Nationale Supe´rieure des Industries Textiles de Mulhouse, Universite´ de Haute-Alsace, 11 rue Alfred Werner, F 68093 Mulhouse, France, Tel*: +33389336320; Fax*: +33389336339; E-mail: [email protected] Principal Investigator(s): L. Schacher (ENSITM France), E. Strazdiene (KTU – Lithuania), Laboratoire de Physique et Me´canique Textiles FRE CNRS 2636 Research Staff: ensitm L. Schacher – D. Adolphe M. ISSA – S. BenSaid – JY.Dre´an, KTU E. Strazdiene – M. Gutauskas – L. Naujokaityle – L.Valatkiene
Handle and tactile evaluation of fabric by sensory evaluation and instrumental measurements Other Partners: Academic Department of Clothing and Polymer Products Technology (APGTK)
Industrial Faculty of Design and Technologies, Kaunas University of Technology (KTU), Donelaicˇio g. 73, LT 51424 Kaunas – Lithuania
Project started: January 2005 Project ends: December 2006 Source of support: Exchange programs “Gilibert” (PAI) between French and Lithuanian research laboratories Keywords: Sensory analysis, Griff tester, Tactile feeling Historically textile and clothing industries are producing products in appropriate qualities to satisfy consumer needs. In this regard handle is the most fundamental attribute that determines weather or not a particular fabric is suitable for a given enduse, ant that it often determines the commercial success or failure of textile manufacturing processes or products. Textiles can differently be evaluated and its sensory perception can be described by its mechanical properties. In this sense ENSITM (France) has a great experience in fabrics sensory (tactile) evaluation, while KTU (Lithuania) in creating testing devices which are much closer to real fabric loading conditions than most of the existing equipments. The aim of this research is to create reliable basis of textile hand evaluation and to lay foundation for its further standardisation. For this the following will be done: .
sensory evaluation of fabrics belonging to different categories; investigation of some parameters effect upon the variation of fabrics sensory properties;
.
investigation by the original devices of KTU;
.
Research register
57
IJCST 18,6
58
.
setting of relationships between measurements and sensory parameters; and
.
evaluation of sensitiveness threshold and saturation in the terms of touch.
It is evident that joint research will produce a scientific base for the control of fabric quality and performance as a result of new process and product development. This study will be valuable in the sense of economy, because it would allow to define the best fabric that the industries can use to get a specific effect in order to diminish the costs. * Please include the full number, including the country and area codes.
Project aims and objectives The aim of this research is to create reliable basis of textile hand evaluation by the joint research of two participating institutions and to lay foundation for its further standardisation. For this the following must be done: .
subjective evaluation of fabrics belonging to different categories of finishing, e.g. easy-care, anti-crease, etc.;
.
investigation of constructions parameters or of finishing treatment effect upon the variation of fabrics sensory properties;
.
investigation of fabrics of different categories of finishing by the original devices of biaxial loading i.e. by punching device and by KTU-Griff-Tester, which operates on the principle of specimen pulling through a rounded hole;
.
setting of relationships between fabrics objective characteristics obtained by KTU-Griff-Tester and between its subjective parameters obtained by sensory evaluation, e.g. between complex criterion and finishing; and
.
evaluation of sensitiveness threshold and saturation in the terms of touch.
Research deliverables (academic and industrial) .
new knowledge of textiles hand and its subjective evaluation that will be included in study programmes of master students;
.
it will provide new research themes for master and doctoral students of Universities;
.
it will extend the existing testing base of Universities laboratory by new testing methods and the interpretation of the obtained results; and
.
new knowledge of subjective evaluation will be disseminated for textile and clothing industries of Lithuania providing them new possibilities in their competitiveness, because the laboratory will be able to give qualified consultation services.
Besides all mentioned above, the results of joint research will be spread not only by the publications in the journals with the referee, but also in such well known scientific forums as European conferences organised by AUTEX (Association of Universities for Textiles) and Fibre Society conferences organised in US
Publications Philippe, F., Schacher, L., Adolphe, D. and Dacremont, C. (2003), “The sensory panel applied to textile goods: a new marketing tool”, Journal of Fashion Marketing and Management, Vol. 17, No. 3, pp. 235-48. Philippe, F., Abreu, M.J., Schacher, L., Adolphe, D. and Silva, M.E. (2003), “Influence of the sterilisation process on the tactile feeling of surgical gowns”, International Journal of Clothing Science and Technology, Vol. 15, Nos 3/4, pp. 268-75. Philippe, F., Schacher, L., Adolphe, D. and Dacremont, C. (2004), “Tactile feeling: sensory analysis applied to textile goods”, Textile Research Journal, Vol. 74, No. 12, pp.1066-72. Philippe, F., Schacher, L., Dacremont, C. and Adolphe, D. (2001), “Sensory analysis: state of art. Application to textile evaluation” International Textile Congress Fibres, yarns, fabrics, finishing, management, innovations, Terrassa (Espagne), Actes, 18-20 June, pp. 216-22. Philippe, F. Schacher, L. and Adolphe, D. (2003), “Characterisation of different finishing treatments using tactile sensory analysis” paper presented at The Fiber Society Spring 2003 Symposium, Loughborough University, Actes 30 June-2 July, pp.11-2. Philippe, F. (2001), “Contribution a` l’e´valuation tactile des produits textiles par analyse sensorielle”, the`se de doctorat en Sciences pour l’Inge´nieur, Universite´ de Haute Alsace, Mulhouse (France), January. Chollakup, R. (2003), “Me´langes soie-coton en filature fibres courtes: caracte´ristiques des fils et analyse sensorielle des tricots”. The`se de doctorat en Sciences pour l’Inge´nieur, Universite´ de Haute Alsace, Mulhouse (France), January. Strazdiene˘, E., Gutauskas, M. (2003), “Behaviour of stretchable textiles with spatial loading”, Textile Research Journal ISSN 0040-5175, 73(6): pp. 530-4. 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. Strazdiene˙, E., Daukantiene˙, V. and Gutauskas, M. (2003), “Bagging of thin polymer materials: geometry, resistance and application”, Materials Science (Medz˘iagotyra), Vol. 9 No. 3, pp. 262-5. Strazdiene˙, E., Domskiene˙, J. and Gutauskas, M. (2003), “New method for the evaluation of coated textiles performance properties”, Proceedings of the World Textile Conference, (Third AUTEX Conference). Gdansk, pp. 118-21.
Nottingham, UK University of Nottingham, School of Mechanical, Materials & Manufacturing Engineering, University Park, Nottingham, NG7 2RD, Tel*: 0115 9513779; Fax*: 0115 9513800; E-mail: [email protected] Principal Investigator(s): C D Rudd, A C Long, R Brooks, I A Jones, S J Pickering, N A Warrior, M J Clifford, C A Scotchford, G S Walker Research Staff: H Lin, L Harper, RRH Naqasha
Platform grant: processing and performance of textile composites Other Partners: Academic
Industrial
None
None
Research register
59
IJCST 18,6
Project started:1 February 2005 Project ends: 31 January 2009 Project budget: £445k Source of support: EPSRC Keywords: Textile Composites, Unit Cell Analysis, TexGen
60
Our current research portfolio is centred on the processing of polymer matrix composites with a growing emphasis on modelling and simulation. Given our high level of interest in textile-based composites and their growing importance in the field, we wish to introduce a common platform for our modelling studies based on our formalised textile generator (TexGen). Textile modelling provides a launchpad for downstream simulation of processing, damage mechanics and environmental performance. The functionality of our existing TexGen software will be extended and coupled to materials models for simulation of each of the above aspects of physical behaviour. Simulation of each of the physical processes will be enhanced by a common, interchangeable geometric definition of the textile structure within the rigid composite. This will enable a rapid understanding of fabric architecture effects to be built and the approach has excellent potential for application to other physical problems which relate to rigid and flexible composites or technical textiles. The platform grant application seeks continuity of support for key workers during the period of this development. Further details are available at: www.textiles.nottingham.ac.uk * Please include the full number, including the country and area codes.
Project aims and objectives Implement an approach based on textile modelling throughout our research portfolio, integrating the multiple streams of processing, energy management, biomedical applications and textile modelling; Develop a series of downstream models relating to: three-dimensional permeability, formability (including shear compliance), static mechanical properties, damage mechanics and residual property estimation, diffusion and environmental degradation. Exploit the potential of the platform grant to raise our international profile, develop strategic links with other leading groups, and enhance our technology transfer activities.
Research deliverables (academic and industrial) None Publications and outputs Not available.
Patras, Greece Robotics Group, Mechanical Engineering & Aeronautics Department, University of Patras, 26500, Rio, Patras, Tel*: +302610997268; Fax*: +302610997212; E-mail: [email protected] Principal Investigator(s): Prof. Nikos Aspragathos (Project Coordinator), Evangelos Dermatas (Associate Professor), Emmanouil Psarakis (Assistant Professor)
Research Staff: Panagiotis N. Koustoumpardis (Technical Researcher), George Zoumponos (PhD Student), Paraskevi Zacharia (PhD Student), Ioannis Mariolis (PhD Student), Ioannis Chatzis (PhD Student), George Evangelidis (PhD Student)
Research register
Handling of non-rigid materials with robots. Application in robotic sewing (XROMA)
61
Other Partners: Academic
Industrial
ELKEDE – Technology & Design Centre, Mechanical Engineering & Aeronautics Athens, Greece Department, University of Patras, Department of Electrical & Computer Engineering, University of Patras, Department of Computer Engineering & Informatics, University of Patras Project started: 26 May 2003 Project ends: 25 May 2007 Grant value: e220,103 Source of support: General Secretariat for Research and Technology, Hellenic Republic Ministry of Development Keywords: Fabric handling, Artificial intelligence, Intelligent control, Robotic handling for sewing, Robotic sewing, Fabric properties, Quality control, Seam quality, Color matching. The main concept and purpose of this project is the development of a robotic workcell for sewing fabrics. The research work deals with the handling and the quality control of fabrics and cloths in garment assembly. The project is focused in the fabric handling tasks: ply separation, translation, placement, folding, feeding and orientation for sewing. Sensor fusion, fuzzy logic, neural networks and machine learning techniques are used for controlling the robotic grippers and the applied forces for intelligent fabric handling. The quality control system is based on machine vision for detecting the fabric’s defects and color matching as well as for inspecting the seams’ quality. Each of the experimental stage sub-system devices are individually tested and at the end would be integrated to form a workcell. In addition, the project provides a new researchers training program, concerning the technology of automated handling of non-rigid materials and the technology of cloth making. The results will be demonstrated and disseminated to national cloth making industries – SME’s, and published to international journals. This is a joint project, where three Departments of the University of Patras and the ELKEDE – Technology & Design Centre are involved. Mechanical, Electrical and Computer Engineers are cooperated to integrate the automated handling and quality control system. * Please include the full number, including the country and area codes.
Project aims and objectives The main aim of this project is to develop new intelligent methods for the robotic handling of non-rigid materials, seam quality control and fabric color matching. The
IJCST 18,6
62
innovative approaches are based on sensor fusion and artificial intelligent techniques: Fuzzy Logic, Neural Networks and Genetic Algorithms. The objectives: .
Training new researchers in the technology of automated handling of non-rigid materials and the technology of the cloth making industry.
.
Development of intelligent algorithms for fabric handling strategies, color matching and seam quality.
.
Development of experimental intelligent mechatronic devices, for separatinghandling-translating-inspecting fabrics, in order to test the intelligent algorithms in laboratory conditions.
.
Development and test an integrated experimental system for the robotic sewing and the fabric quality control.
.
To demonstrate the results (acquired knowledge and experimental devices) in garment assembly.
Research deliverables (academic and industrial) Five PhD dissertations A laboratory prototype system of the robotic garment assembly Two Technical reports
Publications
Journals: Panagiotis, N. Koustoumpardis and Nikos A. Aspragathos (2003), “Fuzzy logic decision mechanism combined with a neuro-controller for fabric tension in robotized sewing process”, Journal of Intelligent and Robotics Systems, Vol. 36, No. 1, pp. 65-88. P.Th. Zacharia and N.A. Aspragathos (2005) “Optimal task scheduling based on genetic algorithms”, Robotics & Computer-Integrated Manufacturing, Vol. 21, No.1, pp. 67-79. Panagiotis N. Koustoumpardis, John S. Fourkiotis and Nikos A. Aspragathos, “Robotized measurement and intelligent evaluation of fabrics’ extensibility – tensile test”, submitted for publication to the International Journal of Clothing Science and Technology. I.G. Karybali, K. Berberidis, E.Z. Psarakis and G.D. Evangelidis, “An efficient spatial domain technique for subpixel image registration”, submitted for publication to the IEEE Transactions on Image Processing. G.T. Zoumponos and N.A. Aspragathos, “Fuzzy logic path planning for the robotic placement of fabrics on a work table”, submitted for publication to the Robotics & Computer-Integrated Manufacturing Journal. Furthermore, five papers are under preparation and will be submitted to international journals soon.
Conferences: P.Th. Zacharia and N.A. Aspragathos (2004), “Optimization of industrial manipulators cycle time based on genetic algorithms”, paper presented at 2nd IEEE International Conference on Industrial Informatics INDIN’04, 24-26 June, Berlin, Germany, pp. 517-22.
P. N. Koustoumpardis, N. A. Aspragathos (2004), “A review of gripping devices for fabric handling”, paper presented at International Conference on Intelligent Manipulation and Grasping IMG04, Genova, Italy, ISBN 88 900 426-1-3, July, pp. 229-34. Zoumponos, G.T. and Aspragathos N.A. (2004) “Design of a robotic air-jet gripper for destacking fabrics”, paper presented at IMG ’04, Genova, Italy, July, pp. 241-6. Ioannis, C. and Evangelos, D. (2004), “Semi blind gamma correction”, paper presented at 1st International Conference “From Scientific Computing to Computational Engineering”, Athens, 8-10 September. Mariolis, I, Dermatas, E. (2004), “Robust detection of seam lines using the radon transform”, paper presented at the 1st International Conference “From Scientific Computing to Computational Engineering”, Athens, 8-10 September. Zoumponos, G.T. and Aspragathos N.A. (2005) “A fuzzy robot controller for the placement of fabrics on a work table”, paper presented at IFAC World Congress, Prague, 4-8 July. P.Th. Zacharia, I.G. Mariolis, N.A. Aspragathos and E.S. Dermatas (2005), “Visual servoing of a robotic manipulator based on fuzzy logic control for handling fabric lying on a table”, paper presented at the 1st I*PROMS Virtual International Conference on Intelligent Production Machines and Systems, IPROMS 2005, 4-15 July, pp. 411-6. E.Z. Psarakis and G.D. Evangelidis (2005), “An enhanced correlation-based method for stereo correspondence with subpixel accuracy” paper presented at 10th IEEE Int. Conf. On Computer Vision, October, Beijing, China. I.G. Karybali, E.Z. Psarakis, K. Berberidis, and G.D. Evangelidis (2006), “Spatial domain for image registration with subpixel accuracy”, submitted to European Signal Processing Conf. (EUSIPCO), 2006 (accepted). Ioannis S. Chatzis, Evangelos S. Dermatas (2006), “Non-parametric estimation of camera response function”, paper presented at the 13th IEEE MELECON, 16-19 May (accepted in journal preselection). P.N. Koustoumpardis, G.T. Zoumponos, P.Th. Zacharia, I.G. Mariolis, I. Xatzis, G. Evagelidis, A. Zabetakis (2006) “Handling of non-rigid materials with robots (XROMA), application in robotic sewing”, paper presented at the 37th International Symposium on Novelties in Textiles, Ljubljana, Slovenia, 15-17 June. Mariolis, I. Dermatas, E., “Automated quality control of textile seams based on puckering evaluation”, paper presented at the 37th International Symposium on Novelties in Textiles, Ljubljana, Slovenia, 15-17 June. P.Th. Zacharia, I.G. Mariolis, N.A. Aspragathos and E.S. Dermatas (2006), “Visual servoing controller for robot handling fabrics of curved edges”, paper presented at I*PROMS NoE Virtual International Conference on Intelligent Production Machines and Systems, 3-14 July. Ioannis, C., Dimitris, G., Evangelos, D. (2006), “Spectral characterization of digital cameras using genetic algorithms”, paper presented at IPROMS 2006, 3-14 July. Ioannis S. Chatzis, Vasilios A. Kappatos, Evangelos S. Dermatas (2006), “Filter selection for multispectral image acquisition using the feature vector analysis method”, paper presented at IPROMS 2006, 3-14 July. Dimitris, G., Ioannis, S. Chatzis, Evangelos, D. (2006), “Detection of web denial-of-service attacks using decoy hyperlinks”, paper presented at Communication Systems, Networks and Digital Signal Processing (CSNDSP’06), 19-21 July, Patras Univ. Conference Centre, Patras, Greece. P.Th. Zacharia, I.G. Mariolis, N.A. Aspragathos and E.S. Dermatas (2006), “Polygonal approximation of fabrics with curved edges based on genetic algorithms for robot handling towards sewing”, to be presented in CIRP, 25-28 July, Ischia, Italy. P. Zacharia, G. Zoumponos, P. Koustoumpardis, A. Zampetakis, N. Aspragathos (2006), “Robot handling of non-rigid materials for the sewing process”, to be presented in ITCDC 2006, 8-11 October, Dubrovnik, Croatia.
Research register
63
IJCST 18,6
64
Pisa, Italy “E. Piaggio” Centre – University of Pisa, Via Diotisalvi, 2 56126 Pisa, Italy; Tel*: +39 0502217053; Fax*: +39 0502217051; E-mail: [email protected] Principal Investigator(s): Prof. Danilo De Rossi Research Staff: Prof. Roger Fuoco; Prof. Arti Ahluwalia; Dr Fabio DI Francesco; Dr Thoas Schafer
BIOTEX:Bio-sensingtextilestosupporthealthmanagement Other Partners: Academic
Industrial
CSEM Centre Suisse d’Electronique et de Microtechnique SA (Switzerland), CEA Commissariat a` l’Energie Atomique (France), Smartex s.r.l. (Italy), Thuasne (France), Penelope SpA (Italy), Sofileta (France) Project started: 1 September 2005 Project ends: 29 February 2008 Project budget: Total amount: e3.108.029 (eligible cost) – Requested EC Contribution: e1.900.000, University of Pisa quote: 255.750,00 Source of support: European Commission Dublin City University(Ireland), University of Pisa (Italy)
Integration of health monitoring tools into textiles brings the benefits of safety and comfort to the users. Instrumented clothes will provide remote monitoring of vitals signs, diagnostics to improve early illness detection and metabolic disorder and benefits to the reduction on medical social costs to the citizen. Ambulatory healthcare, isolated people, convalescent people and patients with chronic diseases are addressed. To date, developments in that field are mainly focused on physiological measurements (body temperature, electro-cardiogram, electromyogram, breath rhythm, etc.) with first applications targeting sport monitoring and prevention of cardiovascular risk. Biochemical measurements on body fluids will be needed to tackle very important health and safety issues. * Please include the full number, including the country and area codes.
Project aims and objectives The BIOTEX project aims at developing dedicated biochemical-sensing techniques compatible with integration into textile. This goal represents a complete breakthrough, which allows for the first time the monitoring of body fluids via sensors distributed on a textile substrate and performing biochemical measurements. BIOTEX is addressing the sensing part and its electrical or optical connection to a signal processor. The approach aims at developing sensing patches, adapted to different targeted body fluids and biological species to be monitored, where the textile itself is the sensor. The extension to whole garment and the integration with physiological monitors is part of the roadmap of the consortium.
Textiles for applications in health monitoring are becoming a major theme for the citizen’s healthcare and safety since they allow: .
simultaneously comfort and monitoring (for safety and/or health);
.
non-invasive measurements, no laboratory sampling; continuous monitoring during daily activity of the person;
.
possible multi-parameter analysis and monitoring; and . distributed sensing thanks to access to 90% of the body surface if integrated on clothing. Societal issues such as ambulatory healthcare, isolated elderly or disabled patient’s care may be tackled by these techniques. Moreover, non-invasive and continuous monitoring of people in a critical state is more and more needed, e.g. in emergency services, for heavily burnt patients and safety, e.g. exposed personnel like fire-fighters. At the present stage, health-monitoring systems using electronic textiles are mainly targeting applications based upon physiological parameter measurements, such as body movements or electro-cardiogram. To open a dramatically wider field of applications, biochemical measurements on body fluids (blood, sweat, urine) will be needed. At the present time, biochemical analysis systems compatible with integration into clothing are unfortunately lacking. This is a major drawback for instance in the case of sweat analysis which is potentially very rich in health related information. However, such analysis is hardly performed today because of the difficulty to sample sweat in sufficient quantity. Only a real textile sensor embedded in a garment through textile techniques will allow direct collection of sweat and a large body surface; moreover lower fabrication costs are expected. For blood analysis, the main interest will be to avoid invasive sampling and to allow continuous analysis. BIOTEX aims at the development of technologies to fulfil these needs. .
Research deliverables (academic and industrial) New textile integrated systems for biochemical parameters detection Publications Not available.
Pisa, Italy University of Pisa, Via Diotisalvi, 2 56126 Pisa Italy; Tel*: +39 0502217053; Fax*: +39 0502217051; E-mail: [email protected] Principal Investigator(s): Prof. Danilo De Rossi Research Staff: Post doc researchers, PhD students, post graduate students.
FLEXIFUNBAR Multifunctional barrier for flexible structure (textile, leather and paper)
Research register
65
IJCST 18,6
66
Other Partners: Academic
Industrial
Alan, Amkey Management, Annebergs, Arjo Wiggins, Basilius, Calsta, CEI, Centexbel, Centro Tecnologico do Calcado, Clotefi, Clubtex, CREPIM, Curtumes Aveneda, Devan, DG Tec, Duflot, ECCO, Gleittechnik, Europlasma, IFTH, IMP Comfort, INCA, IQAP, Lauffenmu¨hle, Linificio, Nabaltec, Nylstar, Patraiki, Procotex, Siamidis, Sinterama, Subrenat, Sveriges Provnings, Telice, Thrakika Ekkokistiria, Traitex, VTT, Wellman International. Project started: 1 October 2004 Project ends: 30 September 2008 Project budget: Total amount: e6,438,995 (University of Pisa: e343,000) Source of support: European Commission Keywords: Multifunctional, Barrier, Textile, Fiber, Flexible, Leather, Paper Brunel University, Pisa University, Centro Di Cultura per l’ingegneria delle Materie Pastiche, Ghent University, Queen’s University of Belfast, DWI – Aachen, Institut Pasteur de Lille, Institute of Natural Fibres – Poznan.
All citizens are permanently protected by flexible structures with barrier noise and thermal insulation, shield against electrostatic or electromagnetic phenomena, filtration of dust or insects. . . The application of flexible structure is very large thanks to their easy adapting properties and shape. Nevertheless, they will maximise the level of safety in building, transportation and to ensure the well-being of European citizens, The flexible structures, generally based on paper, leather or textile are usually treated to serve only one barrier effect.Ires a whole re-design of flexible structure functions that is the main purpose of FLEXIFUNBAR. For instance to prevent from all external aggressions in hazardous atmosphere, flexible structure must provide at least barrier effects. The ultimate goal of flexifunbar initiative is to develop innovative generation of hybrid multi barrier-effects materials, based on multi layer complex structures and functionalisation of micro and nanostructures.The development of such materials covers a large range of applications: .
Transportation: filter, thermal and acoustic insulation panel, pollutant detectors. . .
.
Home and building: wall covering, home furniture, carbon monoxide detectors, antibacterial mattress, electromagnetic insulation panels,. . .
.
Health: protection of people against insects, protective clothing for military and defense, hygiene mask, operation area.
* Please include the full number, including the country and area codes.
Project aims and objectives The innovation of Flexifunbar lies in the principle of associating in one same material several functionalities: Heat insulation, acoustic insulation, shielding against electromagnetic waves, anti odours, anti bacterial, flame retardancy. . . The objective of Flexifunbar is to develop and promote multi-functional flexible structure for use in many multisectorial industrial applications in the health field as well as in the building construction and transportation industries.
Research deliverables (academic and industrial) New fiber, textile, leather and paper samples with multifunctional barrier properties Publications Not available
Pisa, Italy University of Pisa, Via Diotisalvi, 2 56126 Pisa, Italy; Tel*: +39 0502217053; Fax*: +39 0502217051; E-mail: [email protected] Principal Investigator(s): Prof. Danilo De Rossi Research Staff: Prof. Luigi Landini, Ing. Enzo Pasquale Scilingo, Dr Federico Lorussi
MY HEART Cardiovascular Disease by preventive lifestyle & early diagnosis Other Partners: Academic University of Pisa, Universidad Politecnica de Madrid, Consorzio di Bioingegneria e Informatica Medica (CBIM), Politecnico di Milano, University of Padova, University of Firenze, University Clinic Aachen, Hospital Clinico San Carlos de Madrid Insalud, Fondazione Centro San Raffaele del Monte Tabor, University Pavia IRCCS/FSM, Universidad Politecnica de Valencia (Technical University of Valencia – Sports Center) Facludade de ciencias e technologia da universidade de Coimbra, Hospital de Unisersidate de Coimbra
Industrial 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, DrHein GMBH, Mind Media B.V., Medgate AG, CSEM Centre Suisse D’Electronique et de Microtechnique SA, Commissariat a l’energie Atomique (CEA-LETI), Eidgenossische Technische Hochschule Zurich
Research register
67
IJCST 18,6
(ETH Zurich), Instituto de Aplicaciones de las Tecnologı´as de la Informacio´n y de las Comunicaciones Avanzadas – Asociacio´n (ITACA), Mayo Clinic Rochester, Philips Electronics Nederland b.v. (Philips Research Labs Eindhoven), Lineapiu S.P.A.
68
Project started: December 2003 Project ends: September 2007 Project budget: University of Pisa: e976,168 Source of support: European Commission Cardio-vascular diseases (CVD) are the leading cause of death in the west. In Europe over 20% of all citizens suffer from a chronic CVD and 45% of all deaths are due to CVD. Europe spends annually hundreds billion Euros on CVD. With the upcoming aging population, it is a challenge for Europe to deliver its citizens healthcare at affordable costs. It is commonly accepted, that a healthy and preventive lifestyle as well as early diagnosis could systematically fight the origin of CVD and save millions of live-years. The MyHeart mission is to empower citizen to fight cardio-vascular diseases by preventive lifestyle and early diagnosis. The starting point is to gain knowledge on a citizen’s actual health status. To gain this info continuous monitoring of vital signs is mandatory. The approach is therefore to integrate system solutions into functional clothes with integrated textile sensors. The combination of functional clothes and integrated electronics and process them on-body, we define as intelligent biomedical clothes. The processing consists of making diagnoses, detecting trends and react on it. Together with feedback devices, able to interact with the user as well as with professional services, the MyHeart system is formed. This system is suitable for supporting citizens to fight major CVD risk factors and help to avoid heart attack, other acute events by personalized guidelines and giving feedback. It provides the necessary motivation the new life styles. MyHeart will demonstrate technical solutions. The outcome will open up a l new mass market for the European industry and it will help prevent the development of CVD, meanwhile reduce the overall EU healthcare costs. The consortium consists of 33 partners from 11 countries. It is a research effort of industrial, research institutes, academics and medical hospitals, covering the whole value chain from textile research, via fashion and electronic design, towards medical and home-based applications. * Please include the full number, including the country and area codes.
Project aims and objectives 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 5 different application areas. These application areas reflect the
main risks for developing a CVD and address the user need for early diagnose to limit the severity of an acute event.
Research register
Research deliverables (academic and industrial) Electronic systems embedded into functional clothes, functional clothes with integrated textile and non-textile sensors.Combination of functional clothes and integrated electronics will be intelligent biomedical clothes (IBC). Publications Not available.
Pisa, Italy University of Pisa, Via Diotisalvi, 2 56126 Pisa, Italy; Tel*: +39 0502217053; Fax*: +39 0502217051; E-mail: [email protected] Principal Investigator(s): Prof. Danilo De Rossi Research Staff: Prof. Bruno Neri; Ing. Alessandro Tognetti; Ing. Enzo Pasquale Scilingo; Ing. Federico Carpi; Ing. Antonio Lanata`
PROETEX: protection e-textiles: micronanostructured fibre systems for emergency-disaster wear Other Partners: Academic
Industrial
Smartex srl, Milior, Sofileta SAS, Thuasne, Consiglio Nazionale delle Ricerche – Commissariat a` l’Energie Atomique INFM, Technical University of Lodz, Ghent University – Department of Textiles, “CEA”,CSEM Centre Suisse University of PISA, Dublin City University, d’Electronique et de Microtechnique SA, Sensor Technology and Devices Ltd, Institut National des Sciences Steiger S.A.,Philips GmbH, Applique´es de Lyon Zweigniederlassung Forschungslaboratorien, Ciba Spezialita¨tenchemie AG, Diadora Invicta SpA, iXscient Ltd, Zarlink Semiconductor Limited, Brunet-Lion SAS, Brigade de Sappeurs Pompiers de Paris, European Centre for Research and Training in Earthquake Engineering, Direction de la De´fense et de la Se´curite´ Civiles Project started: February 2006 Project ends: January 2010 Project budget: University of Pisa: e780,443; Total: e 12,792,242 (Requested: e 8.100.000) Source of support: European Commission
69
IJCST 18,6
70
ProeTEX will develop integrated smart wearables for emergency disaster intervention personnel, improving their safety, coordination and efficiency and for injured civilians, optimising their survival management. This core application area, which is of significant societal importance in itself, will drive a wide range of key technology developments, building on current and past EU and national projects and the commercial activities of partners, to create micro-nano-engineering smart textile systems – integrated systems (fabrics, wearable garments) using specifically fibrebased micronano technologies. These are capable of being combined into diverse products addressing this core application area but also a wide range of other markets from extreme sports, through healthcare to transportation maintenance and building workers. The industrial partners can address these markets. Fiber systems can integrate sensors, actuators, conductors, power management, and the emergency disaster personnel smart garment will, within a wireless ambient planning and managing environment, progressively enhance and integrate fiber systems for: .
continuous monitoring of life signs (biopotentials, breathing movement, cardiac sounds);
.
continuous monitoring biosensors (sweat, dehydration, electrolytes, stress indicators);
.
pose and activity monitoring;
.
low power local wireless communications, including integrated fiber antennae;
.
active visibility enhancement, light emitting fibers;
.
internal temperature monitoring using fiber sensors;
.
external chemical detection, including toxic gases and vapours; and
.
power generation – photovoltaic and thermoelectric and power storage.
The technological base developed will concentrate on smart fibers/e-textiles, but the IP will combine these where appropriate with “conventional” microsystems (such as accelerometers, gyros, microcontrollers and wireless chips). * Please include the full number, including the country and area codes.
Project aims and objectives The central IP goal is to develop an integrated set of functional garments for emergency disaster personnel, such as firefighters and paramedics, plus systems for injured civilians. These will be produced using both enhanced and novel fibre based micronanosystems, whose development will extend the state of the art in this area. The project will roll out a sequence of progressively more capable integrated wearable systems for emergency disaster intervention personnel and injured civilians. Thus, overall the IP will: .
Progress the fundamentals of fibre-based sensor, processing, communications and power management systems.
.
Integrate these fibre-based capabilities into functional knitted or woven wearable garments.
.
Produce fully capable integrated communicating, sensor wearables, using additional “conventional” systems where necessary.
.
Test their match of user needs and requirements in a lab-based setting.
.
Demonstrate their function in a real-world application in a number of field trials.
Scientific objectives (1) Develop a multifunctional garment integrating an increasingly ambitious set of sensors and energy harvesting and storage which is reliable, robust, easy to wear and capable of manufacture. (2) Into this garment: Design, test and integrate a bioelectrical heart rate monitor into whole skin contact garment interface; Design, test and Integrate a cardiac sound monitor; Integrate sensor breathing monitor and ensure that signal conditioning and processing results in successful way. (3) Develop fibre and new textile based technological solutions, with reliable functionality, capable of integration into wearable garments covering the following set of technological area capabilities: . Monitor bioelectrical potential . .
Sensing breath movements Sensing posture and movement
.
Biochemical sensing, specifically determination of dehydration status
.
Sensing core temperature Acting as local communications antennae
. . .
Sensing external toxic gases/chemicals, including CO Generating local energy using thermoelectric generation
.
Generating local energy using photovoltaic processes
.
Storing energy using Li-Ion textile batteries
Technical objectives .
.
.
Develop and adapt textile manufacturing processes to these new active fibres and layers (weaving, knitting, coating, laminating) but also innovate in terms of clothes conception to optimise the assembly step regarding interconnection needs for e-textile garment. Develop and test a multifunctional (inner and outer) garment integrating an increasingly ambitious set of sensors and energy harvesting and storage which is reliable, robust, easy to wear and capable of manufacture for both intervention people and injured civilians. The inner and out garment will include an adapted set of functionalities based on the developed technologies. As example first inner garment could integrate bioelectrical heart rate monitor, cardiac sound monitor, strain sensor breathing monitor inner temperature measurement and ensure that signal conditioning and processing results in successful and robust physiological monitoring. Energy generated by the heat (thermoelectricity) and the movement (piezoelectricity) of
Research register
71
IJCST 18,6
the of the wearer. Outer garment will typically include toxic gas measurement, external temperature; motion and position monitoring, data transmission system, energy could be provided by photovoltaic external layer and textile Li-Ion batteries. .
72
Realize field trial of the instrumented garment for technological validation.
Research deliverables (academic and industrial) The key deliverables will be: (A) An inner garment for emergency disaster personnel, monitoring the health of the user through vital signs, biochemical parameters, activity and posture, generating and storing own power and communicating locally with other wearables and relaying through (D). (B) An outer garment for emergency disaster personnel, measuring potential environmental insults (temperature, CO, other toxic gases), sensing posture and movement of the wearer and offering improved visibility, generating and storing its own power communicating locally with other wearables and relaying through (D). (C) An under-garment jerkin or chest band for injured civilians (closely related to (A)) monitoring their health, generating and storing its own power and communicating locally, relaying information via (E). Victims monitoring measures will include: body temperature; cardiac pulse; respiration rate; ECG; percutaneous CO saturation; percutaneous O2. (D) A portable unit for the emergency disaster personnel, communicating with A, B & C, but offering additional “conventional” microsystem, providing both local and long range communication (acting as a relay for A, B and C), including some specific sensors not easily integrated into (B), plus accelerometers, gyros and GPS to enable high accuracy position and movement determination. This device should allow data entry and displays/alarms. (E) A portable unit for injured civilians, to include data relay capability and INS/GPS but no data entry or display. Some kind of integrated alarm or indicator to give the overall civilians health status. A simple user input, such as panic button, may be required. Publications Not available.
Shrewsbury, UK Rapra Technology Ltd, Shawbury, Shrewsbury, Shropshire SY4 4NR, Tel*: +44 1939250383; Fax*: +44 1939 251118; E-mail: [email protected] Principal Investigator(s): Chris Hare Research Staff: R Venables, S Wallace
New classes of composite engineering materials from renewable sources
Other Partners: Academic Upper Austria Research, Lulea University of Technology, Wroclaw University of Technology
Industrial Fraunhofer ICT, Risoe, Gaiker, Celabor, VTT, APC Composites, BAFA, Transfurans chemicals, PJH, Chemont, Tecnaro, MERL, Net composites, Tehnos, Griffner, MEDOP, Haidlmair, Fiedler, Ekotex, National Institute of wood Project ends: 1 October 2008
Project started: 1 April 2005 Project budget: e6.5 million Source of support: EU, Integrated Project, FP6
Future product design requires sustainable processes and eco-innovation in material development for engineering applications. The innovative approaches use new engineering materials – biocomposites and their development has to be knowledgebased, whereas predominant issues are resource saving, variability in properties and functionality, light weight, low costs and eco-efficiency in all stages of the product life cycle. The main objective of this project is to obtain a breakthrough for SMEs on the development and use of engineering thermoplastic and thermosetting materials mainly from natural resources, like lignin from the paper industry and from the High Pressure Hydrothermolyses (HPH) process, other biopolymers (here referred as biopolymers: e.g. Polylactide, Polyhydroxy-butyrate, Starch), furan resins, woven and non-woven cellulose fibres and fibre mats to final model products. The technical work programme will comprise the complete technical path from the input of natural raw materials (fibres, polymers and natural additives) to the output of final top quality engineering composite materials and model products (e.g. housings for electronic equipment, car front end interiors, glass frames, etc.) with an environmentally friendly life cycle. In parallel, there are activities concerning standardisation of characterisation and test procedures and quality control. Demonstration by the model products supporting the dissemination and the exploitation of results will exhibit the benefits of the materials and deliver a first input to material databases. An integrated concept of sustained skill and education of staff and students will provide routines and access to the material data. It includes the most interesting approaches of all current developments for engineering biocomposites. Innovative additives will provide flame retardancy and colouring. * Please include the full number, including the country and area codes.
Project aims and objectives To produce a range of “hi tech” composite panels using a variety of natural fibres and natural resins.
Research deliverables (academic and industrial) Many deliverables in the project, some of which are: Reports on: Raw material characterization, data and tolerances; Compounding of materials; Test data; Safety and emissions; Environmental Benefits; Economic Evaluation; Sample tools and parts; Demonstration Parts; Training, exploitation and dissemination.
Research register
73
IJCST 18,6
74
Publications Dr Tama´s Pe´ter – Dr Hala´sz Marianna, “3D body modelling in clothing design”, IMCEP 2003, 4th International Conference, 9-11. Oktober 2003, Maribor, Slovenia, ISBN 86-435-0575-7, pp. 64-8. L. Kokas Palicska; J. Gersak; M. Hala´sz, “The impact of fabric structure and finishing on the drape behavior of textiles”, AUTEX 2005, 5th World Textile Conference, Portorozˇ, Slovenia, 27-29 June 2005, ISBN 86-435-0709-1, pp. 891-7. P. Tama´s; M. Hala´sz; J. Gra¨ff, “3D dress design”, AUTEX 2005, 5th World Textile Conference, Portorozˇ, Slovenia, 27-29 June 2005, ISBN 86-435-0709-1, pp. 436-41. J. Kuzmina; P. Tama´s; M. Hala´sz, Gy. Gro´f, “Image-based cloth capture and cloth simulation used for estimation cloth draping parameters”, AUTEX 2005, 5th World Textile Conference, Portorozˇ, Slovenia, 27-29 June 2005, ISBN 86-435-0709-1, pp. 904-9. L. Szabo´; M. Hala´sz, “Automatic determination of body surface data”, AUTEX 2005, 5th World Textile Conference, Portorozˇ, Slovenia, 27-29 June 2005, ISBN 86-435-0709-1, pp. 715-20. L. Kokas Palicska; M. Hala´sz: “Analysing of draping properties of textiles”, IN-TECH-ED’05, 5th International Conference, 8-9. September 2005, Budapest, ISBN 963 9397 06 7, pp. 133-8. O. Nagy Szabo´; P. Tama´s; M. Hala´sz, “Garment construction with a 3 dimension designing system”, INTECH-ED’05, 5th International Conference, 8-9. September 2005, Budapest, ISBN 963 9397 06 7, pp. 348-57. J. Kuzmina; P. Tama´s; M. Hala´sz; Gy. Gro´f, “Image-Based Cloth Capture and Cloth Simulation Used for Estimation Cloth Draping Parameters”, IN-TECH-ED’05, 5th International Conference, 8-9. September 2005, Budapest, ISBN 963 9397 06 7, pp. 358-65.
Research index by institution Institution Aurel Vlaicu University Budapest University of Technology and Economics Dokuz Eylul University
Index by institution Page 6 11-12 37
Ecole Nationale Supe´rieure des Industries Textiles de Mulhouse
57-59
Ghent University
27-32
Heriot-Watt University
17-26
Institut Supe´rieur des Etudes Technologiques de Ksar-Hellal
40-45
Loughborough University
46-47
Manchester Metropolitan University
55-56
National Institute of Technology Jalandhar
38-39
Rapra Technology Ltd
72-74
Technical Univerity of Lodz
45-46
Technological Education Institute of Piraeus
6-8
University of Agricultural Sciences Dharwad Karnataka
13-17
University of Bolton
9-10
University of Huddersfield
33-36
University of Maribor
48-54
University of Nottingham
59-60
University of Patras
60-63
University of Pisa
64-72
75
Research index by country
IJCST 18,6
76
Country
Page
Belgium
27-33
France
57-59
Greece
6-8, 60-63
Hungary
11-13
India
13-17, 38-40
Italy
64-72
Poland
45-46
Romania
6
Slovenia
48-54
Tunisia
40-45
Turkey
37
UK
9-10, 17-27, 33-36, 46-48, 55-56, 59-60, 72-74
Research index by subject Subject
Page
3D Drape Tester Dress Design Human Body Modelling Spacer Fabrics Wearing Simulation
12 12 12 19 10 12
Anthropometric Data Antibacterial Artificial Intelligence Artificial Turf
55 11 61 27
Bandages Bioflotation Biopharmaceutical Biotreatment
9 49 24 6, 48
Cellulose 11 Chemical Modification 11 Clothing Engineering 51 Fit 55 Heat and Mass Transfer 46 Knitted 55 Medical 67 Protective 26, 46 Smart 28 Colour Control 61 Management 35 Comfort 51 Composite, 21. See Textile Composite Compression Pressure Garments 18 Therapy 9 Computer Aided Design 55 Craft 36
Conductive. See Textile Conductive Metal Wires Controlled-Delivery Cotton Cotton/PET Craft Database Decolouration Deformation Distance Learning Drape. See 3D Drug Delivery Dust Particles Dyeing Natural Elastic Potential Electrospinning Orientation, Crystallinity Enzyme Fabric Double Weave Handling Interactive, Smart Mechanics Properties Spreading Process Velvet Fibres, 66 Agro and Animal Alignment Nano Filtration
Index by subject
77 30 25 11 6 35 34 49 53 8 24 39 15 52 21, 23, 32 23 6 41 61 19 51 61 54 37 14 21 21, 23 39
Hand. See Handle Evaluation Handle Hemp
57 11
Industry
8
IJCST 18,6
78
Knowledge Transfer KTU Griff Tester
33 58
Lockstitch
45
Membrane Metallophthalocyanines Microporous Modelling TexGen
24 32 25 51 60
Nanotechnology
Network
23, 24, 27, 32, 69 30, 33
Oxidation Processes
49
Paper Peltier Elements Personal Area Network Plasma Polymer Pressure Measurement Printing Digital Ink Jet Process Control Properties Mechanical and Physical
66 29 20 17 21 18
52
Quality Quality Systems
61 31
Radiation Relaxation Rheology Robot Sewing Visual Sensor Biological Biosensors Ecology Electrochemical Healthcare Integrated Textiles Monitoring
26 35 49
46 53 41, 42
Pressure 19 Printed 26 Wireless 20 Sensory Evaluation. See Tactile Evaluation Sewing Thread 45 Simulation 60 Slow-Release 24 Solar Cells 17 Tactile Evaluation Terminology Textile Automotive Barrier Composite Conductive Energy. See Solar Cells Health Management Interactive, Wireless Knitted Materials Medical Multifunctional Nonwoven Processing and Performance Protective Renewable Sources Smart Structures Waste Woven Thin-Film Silicon Training
57 34 37 65 60, 72 7 46 64 20 10, 37 51 9, 18, 24 26, 65 10, 22, 38, 39 59 69 72 28, 70 29 6 37 17 30, 31
61 12
Ulcers Unit Cell Analysis UV-Activated
9 60 49
64 70 48 33 20 68 70
Value Addition
14
Water Recycling Weaving Optimisation Wind
48 41 46
Yarn Elastane
53
Research index by principal investigator
Index by principal investigator
Principal investigator
Page
Mukhopadhyay, A.
39-40
Ambrus, G.
12-13
Otieno, R.
55-56
Aspragathos, N.
60-63
Pickering, S.J.
59-60
Bo¨di, B.
12-13
Power, J.
55-56
Borsa, J.
11
Primentas, A.
59-60
Provatidis, C.
Brooks, R. Ceken, F. Christie, R.M.
37 26-27
Clifford, M.
59-60
De Rossi, D.
64-72
8 6-7
Psarakis, E.
60-63
Rahnev, I.
40-45
Rajendran, S.
9-10
Rangoussi, M.
6-7
Rudd, C.D.
59-60
Schacher, L.
57-59
Dermatas, E.
60-63
Frydrych, I.
45-46
Gersˇak, J.
51-54
Hala´sz, M.
12-13
Hare, C.
72-74
Havenith, G.
46-48
Stanescu, M.D.
6
Hertleer, C.
28-29
Strazdiene, E.
57-59
Jones, I.A.
59-60
Stylios, G.K.
19-26
Kotsios, C.
8
Tama´s, P.
12-13
Long, A.C.
59-60
Vassiliadis, S.
8
Louwagie, J.
30-31
Walker, G.S.
59-60
MacIntyre, L.
18-19
Wardman, R.H.
26-27
Mahale, G.
13-17
Warrior, N.A.
59-60
Majcen Le Marechal
48-51
Westbroek, P.
29-30, 32-33
Mather, R.R.
17-18
Wilson, J.I.B.
17-18
Midha, V.K.
38
Woodget, H.
35-36
Schoukens, G.
27-28
Scotchford, C.A.
59-60
Somlo´, J.
12-13
Squires, P.
33-35
79
Awards for Excellence Outstanding Paper Award International Journal of Clothing Science and Technology
‘‘An interactive body model for individual pattern making’’ Youngsook Cho, Naoko Okada, Masayuki Takatera Shigeru Inui and Yoshio Shimizu Shinshu University, Nagano-ken, Japan
Hyejun Park Korea Research Institute of Standards and Science, Daejon, South Korea Purpose – In order to mass-customize clothes, it is essential to consider individual body shape using computerized 3D body models. This paper describes the development of an interactive body model that can be altered with individual body shape for the purpose of computerized pattern making. Design/methodology/approach – For altering perimeter and length for contouring individual body shapes, a cross-sectional line model is proposed arranged at regular intervals. This model is easy for controlling body shape and also for calculating length and perimeters. Shape control lines (SCL) are used to modify the shape of the model in order to adjust the model to represent different body shapes. SCL are used to modify the perimeter of the cross-sectional line by scaling method with different center position and scaling ratio in a horizontal direction. Findings – In order to investigate whether virtual body models can be adequately substituted for real physical models, the perimeter and cross-section areas of SCL were compared, which resulted in an agreement ratio of over 93 percent. This fact supports the adaptability and potential usefulness of the body model. Originality/value – This research makes it possible for customers to modify the body model to match their own body shape during internet or catalogue shopping; it can also enable apparel manufacturers to communicate with their customers by describing the body model to fit on the screen while in the ordering process. Keywords Clothing, Computer applications, Human anatomy, Modelling, Physical testing, Shopping www.emeraldinsight.com/10.1108/09556220510581236 This article originally appeared in Volume 17 Number 2, 2005, pp. 91-9, of International Journal of Clothing Science and Technology, Editor: George Stylios
www.emeraldinsight.com/authors
