Optimal designing of soft body armour materials using shear thickening fluid

This paper deals with the optimal design of soft body armour materials by treating Kevlar (para-aramid) fabrics with silica nano-particle based shear thickening fluid (STF). Box and Behnken design of experiment (DOE) plan in conjunction with contour analysis has been used to study the effect of silica concentration, padding pressure and diluent: STF ratio (solvent ratio) on STF add-on% and impact energy absorption. Silica concentration, solvent ratio and square of solvent ratio were found to be statistically significant terms influencing the STF add-on% on Kevlar fabrics. On the other hand, silica concentration, padding pressure and the square of solvent ratio were the statistically significant terms influencing the impact energy absorption. Higher padding pressure enhances the impact energy absorption by the STF treated Kevlar fabrics although it does not influence the STF add-on% significantly. Higher STF add-on% is a necessary but not the sufficient condition for improving the impact resistance performance of Kevlar fabrics.