FINITE ELEMENT (FE) EVALUATION OF DYNAMIC COMBAT HELMET TRANSIENT DEFORMATION CONTACT AREA ON A HEADFORM

Abstract

Current ballistic helmets are designed to protect the head from penetrating threats. The compliance of composite helmet materials allows for ballistic transient deformation (BTD) of helmets that defeat a threat. These BTDs can result in a unique set of injuries known as behind-helmet blunt trauma (BHBT). Quantifying the loading behind the helmet to help understand the risk for BHBT has been challenging because the BTD occurs at high velocities with high loads that is obscured by the helmet itself. For this study, finite element (FE) simulations of a combat helmet, with and without a suspension system (i.e., pads), impacted by a ballistic threat were performed to evaluate contact area and regional force concentrations of BTD on a headform surrogate. Overall, the results indicate that the helmet pads significantly influence the contact area and magnitudes of the loading from BTD. The loading behavior differed between the front and side helmet impacts, most likely from differences in the position of the pads relative to the center of impact. Understanding the spatial and temporal evolution of loading on the head, and the components of the protection system that influence the loading is important to identify potential vulnerabilities or design strategies for combat helmets.