Abstract
In previous papers, the tensile strength and the deformation of fabric structure under extension were investigated on both the twistless and twisted yarn fabrics.
In this paper, the relationship between the tensile properties of the fabric and the yarn deformation in the fabric is discussed. The tensile load-elongation curves of the twistless yarn fabrics (Twl-R) and twisted ones (N-R) are plotted on log scale. It seems that these curves are composed of the initial curved line and straight line, except high extension. The elongation at the cross-point of the initial curved line and the straight line is termed Iε. From the microphotographs of the yarn cross-section in the fabric under extension, the yarn packing factor (1-ε) and the yarn crimp angle (θ) were measured.
The results are summarized as follows. In the region where the elongation is smaller than Iε, the removal of the yarn crimp in the fabric takes place mainly, and in the rest region, the elongation of yarn in the fabric takes place in the tensile direction. At the points of Iε in Twl-R and N-R fabrics, the yarn crimp angles (θ) and the yarn packing factor (1-ε) are almost the same value in all samples, independent of twist existence and the fabric density.
