High velocity impact performance of aramid fabric pre-impregnated with shear thickening fluid

This study investigate shear thickening property of fumed silica impregnated aramid fabric for high velocity impact application. 20, 30 and 40wt% fumed silica were dispersed in polyethylene glycol (Mw=200) and ethylene glycol (Mw=400) and aramid fabric (Tawron CT706 and T717) was impregnated with the solution. High velocity impact tests were carried out on the impregnated aramid fabric in velocity range of 80 to 260m/s using 8.7mm diameter harden steel projectile with a hemispherical head and length of 25mm. Rheological result indicated sever shear thickening at about 100 s-1 shear rate in the sample containing 40wt% fumed silica. High velocity impact result showed significant energy absorption in the sample which was prepared with 40wt% shear thickening fluid. Energy absorption associated with samples made with 20 and 30wt% shear thickening fluids were modest compared to neat aramid fabric. Ballistic limit velocity also showed significant enhancement as result of 40wt% STF incorporation. Energy absorption was pronounced in thicker specimens than thin section specimens.