Single and multiple yarn pull-outs on aramid woven fabric structures

Abstract

The aim of this study was to understand the pull-out properties of para-aramid woven fabrics. Para-aramid Twaron CT714 and CT716 woven fabrics were used to conduct the pull-out tests. Twaron CT714 and CT716 woven fabrics have low and high fabric densities, respectively. A previously developed yarn pull-out fixture was improved to test various fabric sample dimensions. Data generated from the single and multiple yarn pull-out tests using various dimensions of CT714 and CT716 woven fabrics included fabric pull-out forces, yarn crimp extensions in the fabrics and fabric displacements. Yarn pull-out forces depend on fabric density, fabric sample dimensions and number of pulled ends in the fabric. Results showed that the multiple yarn pull-out force was higher than that of the single yarn pull-out test. Single and multiple yarn pull-out forces in Twaron CT716 (tight fabric) were higher than those of Twaron CT714 (loose fabric). Yarn crimp extension in Twaron CT714 and CT716 fabrics depends on crimp ratios in the warp and weft directions in the fabrics and on fabric density. High crimp ratio fabrics showed high yarn crimp extension in the fabric compared to that of low crimp ratio fabrics. Wide and long fabric samples also showed high yarn crimp extension compared to that of the narrow and short fabric samples. Fabric displacement in Twaron CT714 and CT718 fabrics depends on fabric sample dimensions and the number of pulled yarns. Wide and long fabric samples showed high fabric displacement compared to that of the narrow and short fabric samples. Fabric displacement resulting from the multiple yarn pull-out test was also higher than that of the single yarn pull-out test. Future research will concentrate on the development of the analytical relations between pull-out and yarn-fabric structural parameters which could result in a ballistically better fabric structure for use in soft ballistic applications.