Tensile properties and meso-scale mechanism of multi-axial warp-knitted fabrics of various structural designs

Abstract

Tensile properties tests of three kinds of multi-axial warp-knitted fabric, namely triaxial fabrics (-45^o/90^o /+45^o and -45^o /0^o /+45^o) and quadraxial fabric (-45^o /90^o /+45^o /0^o) have been studied along the orientations of 0^o, 45^o and 90^o. Stress-strain curves are obtained. The whole tension processing has been observed through high-speed camera and the series of images is picked up to analyze the meso-scale mechanism of the extension and displacement of tows on oriented layers. The results indicate that the tensile properties of MWK fabric are closely related to the orientations of the layers, and stitching yarns incarnate significant effects on deformation procedures of fabrics.