Development of stab resistant armor for different energy levels using shear thickening fluid reinforced multi‐layered p‐aramid fabrics

Abstract

Stab‐resistant armors are important protective gear for the law enforcement officers and security forces. This research attempts to develop stab‐resistant armors for different impact energy levels using multi‐layer neat and shear thickening fluid (STF)‐ treated Kevlar® fabrics. The developed panels were tested using National Institute of Justice's (NIJ) P1 knife at wide range of stabbing energy from 6 to 36 J. The panel containing 16 layers of STF‐treated Kevlar® fabric met the requirements at normal and over‐test conditions showing penetration depth lower than 7 and 20 mm, respectively. For stabbing at high energy level (≥ 24 J), the effect of number of Kevlar® fabric layers was found to be highly beneficial in case of STF‐treated condition and not so for the neat one. STF treatment reduced the stab penetration depth by 40%–68% at 24–36 J energy level without any increase in effective weight of the panel. The fabric‐knife interaction was also studied using a novel sharpness tester and optical microscopy. It was found that the tip of knife deformes and sharpness declines at a faster rate in case of STF‐treated fabric. The study opens up possibilities to explore other materials that would damage the tip of knife during stabbing ensuring better protection.Highlights Stab resistant armor has been developed for different energy levels. Effect of number of neat fabric layers is less pronounced at higher energy levels. STF can reduce the penetration depth significantly at high energy levels. Silica particles damage the knife tip during stabbing. STF‐treated panels are lighter and efficacious than their neat counterparts.