Abstract:
This study combines high-speed experimental testing and advanced hydrocode simulations to characterize the biomechanical response of a KEVLAR® PASGT helmet under ballistic impact. In controlled experiments, 11.9 g steel spheres fired at 205 m/s struck the helmet, with high-speed imaging capturing transient deformation and post-test inspection revealing a ≈12 mm impression and sub-millimeter penetration depth. Parallel simulations using AUTODYN-3Ds—employing an orthotropic equation of state, anisotropic strength degradation, failure criteria, and erosion logic—accurately replicated these outcomes, confirming the model’s fidelity. The framework was then extended to predict V₅₀ limits against fragment-simulating projectiles (FSP) and 9 mm full-metal-jacket rounds per MIL-H-44099A and NIJ-STD-0106.01 Type II standards. Simulated V₅₀ values of 680 m/s (helmet vs. FSP) and full defeat of 9 mm FMJ at 358 m/s align with empirical data and analytical estimates, highlighting the critical role of helmet curvature, material anisotropy, and strain-rate–dependent failure in governing protective performance. These biomechanics-centered insights demonstrate how stress-wave propagation, energy absorption, and load-transmission mechanisms underpin helmet design and validation for effective head protection.
