Empirical study of the high velocity impact energy absorption characteristics of shear thickening fluid (STF) impregnated Kevlar fabric

Abstract

The application of shear thickening fluids (STF) allows further enhancement of ballistic resistance without hindering flexibility by the fabric impregnation process. Studies on the effect of STF impregnation on fabric ballistic performance have been limited to the impact velocity range of below 700 m/s. Considering the muzzle velocity of modern rifles with high performance cartridges, investigation of the high velocity impact energy absorption characteristics of neat and STF impregnated Kevlar fabric specimens was conducted in this study. 100 nm diameter silica nanoparticles were dispersed in a solution of polyethylene glycol (PEG) and diluted with methanol for effective impregnation to the Kevlar fabric. High velocity impact experiments with projectile velocities between 1 and 2 km/s were conducted using a 2-stage light gas gun. The experiments revealed that the STF impregnation provides substantial energy absorption enhancement in terms of volume, areal density, and fabrication material cost. Thinner shielding configurations with equivalent energy absorption performance was found to be possible through STF impregnation as the 5 layer STF impregnated Kevlar configuration showed the same energy absorption as the 8 layer neat Kevlar while the energy absorption normalized for areal density and thickness revealed that the STF impregnated Kevlar provides an approximately 70% enhanced specific energy absorption performance over neat Kevlar.