Effect of shear thickening fluid impregnation on the high velocity impact energy absorption characteristics of Kevlar fabric

With the development of firearms and protective body armor, materials to enhance the ballistic resistance have been the subject of various studies. The development of high performance fabrics like Kevlar have advanced body armor technology and improved the ballistic performance while allowing flexibility and mobility to personnel. The utilization of the shear thickening phenomenon exhibited by Shear Thickening Fluid (STF) has allowed further enhancement without hindering flexibility of the fabric through an impregnation process. The effect of STF impregnation on the ballistic performance of Kevlar fabric is very much limited to impact velocities approximately below 700 m/s. Studies of the energy absorption characteristics of STF-impregnated Kevlar fabric for high velocity impacts, which would provide a transition to significantly higher velocity ranges allowing applications in the development of hypervelocity impact shielding against micrometeoroids and space debris in orbital conditions, are not publicly available and rare to come across. This study aims to investigate the effect of STF impregnation on the high velocity impact energy absorption characteristics of Kevlar fabric by effectively dispersing silica nanoparticles in a suspension, impregnating Kevlar fabrics, and performing high velocity impact experiments with projectile velocities above 1 km/s to compare the energy absorption characteristics with neat Kevlar calculating the kinetic energy difference of before and after impact. The silica nanoparticles of 100 nm diameter were dispersed using a homogenizer and sonicator in a solution of polyethylene glycol (PEG) and diluted with methanol for effective impregnation to Kevlar fabric and the methanol was evaporated in a heat oven. The nanoparticles on the surface of the fabric after impregnation were observed through SEM imaging, where the nanoparticles were relatively well dispersed on the fiber strands. High velocity impact of STF-impregnated Kevlar fabric revealed difference in the post-impact formation compared to neat Kevlar.