Realization of three dimensional computer simulation of twill weave woven fabrics by developing three dimeensional geometrical models

This study was carried out to obtain computer simulations of the three dimensional geometric model of twill weave woven fabrics on the computer screen using certain fabric parameters. Warp and weft yarns of twill weave fabric structures stick out of the planes perpendicular to fabric because of being subjected to internal forces. Therefore a two dimensional model is not capable of defining the twill weave fabric geometry, a third dimensions is necessary to define the skewness. Warp and weft yarn skewness angles are the parameters which reflect this behaviour of twill weave fabrics. Yarn counts, yarn densities and fabric thickness are the other structural parameters used in the model. In constructing the model the path of yarns of twill weave fabric structure were determined first and then these paths were divided into small linear segments and finally a preliminary model was built up. Having determined the dimensions and direction angles of yarn central axis ?B-spline? method, which has been frequently used in the computer aided ships, planes, automobiles models and also of many other products in the recent years, was applied to convert yarn path to a smooth curve. For this purpose control points were determined in the linear model and a control polygon was defined. The curve obtained by B-spline method is formed inside this polygon as it will only pass through the initial and last control points. A three dimensional twill fabric model was obtained in 3D-SMAX computer programme by using the coordinates of the central axes of warp and weft yarns which were defined a B-spline curves and the coordinates of yarn cross sections. Consequently the accuracy of model was controlled by comparing the calculated crimp value and fabric weight values from theoretical model with the experimental data. Keywords: Twill weave fabric, B-spline, Geometric modelling