Design of a Soft Armour Consisting of Coated Aramid Fabrics

Abstract

Soft armour consisting of multi-layered high-performance woven fabrics are a popular choice for personal protection. Previous work suggests that shear thickening fluids (STFs) improve the impact resistance of woven fabrics. However, concurrent research is focused on coatings such as adhesives and polymers instead of STFs due to their superiority in performance and high stability to external factors. Recent research efforts suggest that impact resistance of woven fabrics can be significantly improved by coatings such as polymers and adhesives. However, performance of different coating materials, effects of coating amount, effects of ambient conditions and of fatigue on the impact response have not been studied to date. The present work studies the effects of coating different materials such as epoxy, polyurethane, adhesive and rubber on an aramid plain-woven fabric. The effect of the amount of coating, fatigue loading and ambient temperature on the yarn pull-out response was studied. Particularly, the effect of fatigue loading was studied for the first time. Yarn pull-out tests were conducted at low and high strain rates. Ballistic tests were carried out on selected samples using a 7.05-g (12-mm) steel ball projectile. The set-up was equipped with state-of-the-art high-speed cameras to observe the transverse deformation characteristics as well as impact and residual velocities. Moreover, ballistic impact tests using 0.357 SIG TMJ FN rounds fired at different velocities were conducted for a selected sample. The impact resistance was significantly improved by the application of the elastomeric coating. The failure mechanism was analysed using high-speed camera footage. Moreover, the coating is stable in a wide range of ambient temperatures and also performs well upon being subjected to fatigue. Our results show that the proposed method has the potential to produce a lightweight, low-thickness soft armour panel.