FABRIC DISTORTION AFTER WEAVING - AN APPROXIMATE THEORETICAL MODEL

The weft distortion represents an angular deformation of some fabrics after weaving, i.e. change in the original right angle between warp and weft. Here this problem is addressed by means of an approximate theoretical model. The proposed model is related to the fact that in case of diagonal weaving pattern, the fabric is an orthotropic material with the principal axes of elasticity other than warp and weft directions. Due to non-zero normal-shear coefficients, the unloading of warp pre-tension results in angular deformation. The theoretical model is simplified in the sense that the fabric is regarded as an assembly of stripes made of two different isotropic linear elastic materials. Following the principles of elastic homogenisation, global principal elastic moduli are derived in terms of individual elastic constants. Components of compliance tensor in warp weft directions, including normal-shear coefficients, are then derived from the rule of tensor transformation for rotated coordinate axes.