Weft directional stick-slip force of yarn pullout in para-aramid fabric for ballistics

The aim of this study was to understand the stick-slip (Sk-Sp) properties of para-aramid woven fabrics. For this reason, pullout test was conducted on para-aramid Twaron CT (R) 716 (CT716) and Twaron CT (R) 716 (CT714) woven fabrics. The Sk-Sp region and accumulative retraction force region were defined based on the single- or multiple-yarn pullout force-displacement curve. It was found that Sk-Sp force and accumulative retraction force depend on the fabric density and the number of pulled ends in the fabric. Sk-Sp force in the multiple-yarn pullout test was higher than that of the single-yarn pullout test. Sk-Sp force in single- and multiple-yarn pullout tests in the dense CT716 fabric was higher than that of the loose CT714 fabric. In addition, long fabric samples showed high Sk-Sp force compared to that of the short fabric samples. On the other hand, the amount of Sk-Sp force was related to the number of interlacement points in the fabric, whereas the amount of accumulative retraction force was related to fabric structural response