Localized impact stress concentrations in soft armors due to microscale projectile edge geometries

Although extensive focus has been placed on the ballistic performance of projectiles with certain macroscale geometries and dimensions, the microscale geometries are not as rigorously standardized. The localized stress concentrations arising from microscale geometries introduce multiaxial and locally concentrated stress states within the constituent material of the soft-armor target, which can result in premature failure that is not predicted with existing models. In this study, the microscale edge/corner geometries of right circular cylinder (RCC) projectiles are varied, and their respective ballistic performance was determined via experiments to examine the effects of the localized stress concentrations. Target panels were examined post-mortem and the effects of these localized stress concentrations on the failure modes were quantified. Experiments results indicate that stress concentrations drastically reduce the ballistic performance of the soft armor targets, and the fabric targets appear to fail without significant strain energy absorption.