Characterization of Fabric Tensile Loading Curve in Nonlinear Region Related to Their Structure; Part I: Woven Fabric

This study focuses on the tensile modulus and Poisson’s ratio variations of woven fabric in nonlinear region of load-extension curve. This region of the curve can play as a control approach on the secondary modulus/primary modulus ratio. For this purpose, the fabric modulus and Poisson’s ratio were determined for three different weave structures (plain, 1/3 twill, and 1/7 twill) in the warp and weft directions. The experimental results were analysed statistically to obtain the primary and secondary linear regions and also the nonlinear region of fabrics moduli. The analysis explain that the geometry of fabric structures such as the float and diagonal parts of yarn and also the yarn crimp in both warp and weft yarns have important role on the modulus and Poisson’s ratio of fabrics in the nonlinear region. It was found that the greatest range of the nonlinear region in the warp direction is for plain then, 1/3 and 1/7 twill weaves, respectively, by reason of the increase of diagonal part of yarn and the decrease of float part of yarn in fabric structures, simultaneously. But, due to the buckling of the float part of yarn in the weft direction, the 1/7 twill weave has the greatest range of the nonlinear region and the plain weave has the least one.