Experimental determination of yarn pull-out properties of para-aramid (Kevlar®) woven fabric

The aim of this study was to determine the pull-out properties of the para-aramid woven fabrics. Para-aramid Kevlar 29A (K29) and Kevlar 129A (K129) woven fabrics were used to conduct the pull-out tests. K29 and K129 woven fabrics had high and low fabric densities, respectively. For this reason, yarn pull-out fixture was developed to test various K29 and K129 fabric sample dimensions. Data generated from single and multiple yarn pull-out tests in various dimensions of K29 and K129 woven fabrics included fabric pull-out forces, yarn crimp extensions in the fabrics, and fabric displacements. Yarn pull-out forces depended on fabric density, fabric sample dimensions, and the number of pulled ends in the fabric. Multiple yarn pull-out force was higher than single yarn pull-out force. Single- and multiple-yarn pull-out forces in K29 (tight fabric) were higher than those of K129 (loose fabric). Yarn crimp extension in K29 and K129 fabrics depended on crimp ratio in the fabrics and fabric density. High crimp ratio fabrics showed high yarn crimp extension compared to that of the low crimp ratio fabrics. Long fabric samples also showed high yarn crimp extension compared to that of the short fabrics. Fabric displacement in K29 and K129 fabrics depended on fabric sample dimensions and the number of pulled yarns. Long fabric samples showed high fabric displacement compared to that of short fabric samples. Fabric displacement from multiple yarn pull-out test was also higher than that of the single yarn pull-out test. It was considered that fabric pull-out properties can play important roles for absorption of impact load due to the yarn frictions in the fabric structures.