Billie J. Collier

Drape Prediction by Means of Finite-element Analysis

The draping behaviour of fabric treated as an orthotropic shell membrane is predicted by using a geometric non-linear finite-element method, and the results are compared with actual behaviour. A drape tester employing photovoltaic cells was designed and constructed to determine the drape coefficient of fabric specimens of 10-in. diameter. The warp- and weft-direction tensile moduli of these samples were determined by using a Kawahata Tensile and Shear Tester, and literature values of Poissons ratio were obtained. With this approach, excellent agreement between experimental and predicted drape coefficients resulted. For a 100% cotton plain-weave fabric, a drape coefficient of 68.4% was experimentally determined as compared with a predicted value of 71.0%.

Measurement of Fabric Drape and Its Relation to Fabric Mechanical Properties and Subjective Evaluation

Fabric drape of a number of fabrics was measured using a digital Drape Tester and was found to be significantly correlated with the subjective evaluation of drape. Fabrics were draped on two different-sized pedestal plates, and differences in draping behavior between plates and among fabrics were determined Composite drape values measured on the Drape Tester differentiated the draping behavior of the different fabrics. Drape was also correlated with mechanical properties of the fabrics. The mechanical property values were used to formulate predictive equations for fabric drape. Shear hysteresis and bending resistance were found to be most closely associated with fabric drape.

Characterizing Polyester Fabrics Treated in Electrical Discharges of Radio-Frequency Plasma

Polyester (PET) swatches are treated with an electrical discharge plasma of a reactive atmosphere (tetrachlorosilane) to graft chlorosilane groups, subsequently hydrolyzed to very hydrophilic hydroxysilane groups. The Kawabata evaluation system for fabrics (KES-FB), high resolution microscopy, and surface tension measurements are used to investigate the physical properties of the fabrics before and after plasma exposure. The results show that the surface parameters are considerably modified by the treatment.

Cellulosic reinforcement in reactive composite systems

The two reactive systems using cellulosic fiber reinforcement emphasized in this article are twin screw extrusion maleation of polypropylene (PP) and structural reaction injection molding (SRIM). Both simultaneous and sequential compounding of sweet gum wood fiber (WF) with maleation were studied. Similar PP/WF mechanical properties are observed for simultaneous and sequential compounding. However, the melt viscosity of the simultaneous compounding and maleation deceases initially compared to neat polypropylene, whereas the sequential process does not have an initial decrease. After the initial response, the melt viscosity and shear thinning characteristics in both systems increase with WF content compared to their respective low WF behavior. The cellulosic reinforcement in the SRIM studies include: cheesecloth; and nonwoven mats formed separately from fiber bundles of sugar cane rind, kenaf, and sweet gum wood. In the SRIM system the modulus and tensile strength of the neat polyurea/urethane increases with cellulose content, independent of cellulosic source; the modulus doubles with only 4% cellulose, and the tensile strength doubles with only 7% cellulose. However, the elongation to break decreases from 300 to 30% with only 4% cellulose. Cellulose is as reactive with isocyanate in SRIM as are the commercial polyols.

CAD/CAM in the Textile and Apparel Industry

CAD/CAM technology is becoming increasingly apparent in the textile and apparel industries in the U.S. These applications are reviewed, and integration of CAD/CAM technology throughout the production and marketing chain is emphasized and explored. Adoption of voluntary standards of electronic data usage is central to such integration. Training of students in textiles and clothing in the importance of electronic communication, as well as in the software and hardware involved, is an important task of textile and clothing educators. Additionally, the linkages between textile and apparel production and distribution should be emphasized, and the facilitation of these linkages is suggested as an important research focus.

Objective Evaluation of Fabric Softness

The method of fuzzy comprehensive evaluation is used to solve the problem of grading fabric softness. Fabric mechanical properties that are regarded as determining fabric softness are measured with the KES-FB instruments. Statistical methods of ANOVA and factor analysis are suggested to determine the weighting-factor vector A, and the fuzzy conversion matrix U is formed on an assumption of linear membership function. Corre lation of fuzzy evaluation, subjective evaluation, and the Kawabata primary hand evalu ation is estimated statistically. The established fuzzy models focus particularly on for pure cotton and 50/50 cotton/polyester blended fabrics, and the results encourage further investigation for industrial implementation.

Prediction of Fabric End-use Using a Neural Network Technique

A neural network computing technique was proposed to predict fabric end-use. One hundred samples of apparel fabrics were selected and measured using the Kawabata KES-FB instruments. Instrumental data of the fabric properties and information on fabric end-uses, suitings shirts, and blouses, were input into a neural network software to train a multilayer perceptron model. The prediction error rate from the established neural network model was estimated by using a cross-validation method.

Kinetics modeling of dynamic pyrolysis of bagasse fibers.

The thermal decomposition mechanism of raw and treated bagasse fibers was modeled with three parallel independent first-order reactions. The kinetic parameters and pseudo components which best fit the experimental dynamic pyrolysis rate of bagasse was determined by means of the Matlab program using the least-square method. The calculated rate of thermal decomposition for each bagasse sample was consistent with experimental pyrolysis rate very well. A method was adopted to calculate the contents of cellulose, hemicelluloses, and lignin for bagasse fiber based on the dynamic pyrolysis model. The calculated contents of the untreated bagasse fiber agreed very well with some reported values from the literature. The effect of treatment conditions on the bagasse fiber compositions was also studied. From the three-dimensional plot for each of the three components, it could be observed that bagasse fibers treated under the intermediate alkaline condition could achieve the higher content of cellulose.

Extraction and Evaluation of Fibers from Sugar Cane

Sugar cane fiber bundles were extracted from the separated rind of cane stalks using alkaline treatments. The amount of lignin removed depended on alkaline concentration and time and pressure of treatment; agitation and vigorous boiling also affected the lignin removal. A severity factor R was calculated to compare the delignification conditions. Alkali concentration significantly affected the mechanical properties of the fiber bundles. Tenacity, toughness, and linear density were higher for the fibers extracted at the lower concentration, as were bending rigidity and hysteresis.

Characterizing Fabric End-Use by Fabric Physical Properties

This paper introduces a statistical approach to predicting fabric end-use based on Kawabata kes-fb data determining fabric physical properties. The classification theory zbasis of discriminant analysis is discussed, and a way to establish classification criteria to characterize fabrics for clothing uses is demonstrated. The mathematical prediction model is described by a quadratic discriminant function that successfully classifies fabrics appropriate for suiting, blouses, and shirts.