An Experimental Investigation on Dynamic Behaviors of Shear Thickening Fluid Impregnated Aramid Fabrics for Different Number of Layers

Shear thickening fluid (STF) is a solution performs an increase in its viscosity under shear stress. This study investigates rheological behavior of STF, then its effectiveness against dynamic loadings for the case it is applied on aramid fabric. Polyethylene glycol 200 and 400 g/mol, and Aerosil 200, 300, 380 were used for preparation of STF. Rheological analysis was performed to determine thickening behavior and parameters for the solutions having 5, 10 and 20% silica concentrations by weight. The solution having optimum shear thickening performance for dynamic impact loading was selected and it was impregnated aramid fabric to prepare low velocity impact and ballistic test samples. Low velocity impact experiments were executed for different number of layers from 1 to 8 at different energy levels to obtain absorbed energy and maximum contact force values. A curve fitting equation was derived for absorbed energy and number of layers of aramid fabric. Finally, Level IIA ballistic test was done to test whether the curve fitting equation is effectively working or not. Additionally, STF impregnated aramid fabric with its neat counterpart against ballistic impact was compared. A detailed ballistic test characterization was performed including the last shape of ammo. It is determined that impregnation of STF has important effects on ballistic behavior of aramid fabric.