Ballistic performance of p-aramid fabrics impregnated with shear thickening fluid; Part II - Effect of fabric count and shot location

The objective of this research was to characterize the ballistic performance of p-aramid fabrics impregnated with shear thickening fluid (STF) focusing on the fabric count and shot location. Panels made of fabrics with different fabric counts were tested against 9 mm bullets at 436 m/s for body armor application. Panels with higher fabric count dissipated a higher fraction of the given impact energy through tensile dissipation and this led to a lower backface signature. The decrease in backface signature value by the hybridization of neat and STF impregnated fabrics was smaller for panels of densely woven fabric due to the larger difference in the warp and weft crimp ratios. Shot location affected the ballistic limit value (V-50), as well as the BFS value of the panels, where both values increased as the shot location approached the edge. The energy transferred to the backing material upon an impact was calculated based on the weight dropping test results, where the dent volume was proportional to the impact velocity.