US Army Research Laboratory Aberdeen Proving Ground United States
Behind-armor blunt trauma BABT is a current research topic because of increased interest in lightweight armor. A finite element analysis was performed to improve the biofidelity of the US Army Research Laboratory ARL human torso model in preparation for simulating blunt chest impacts and BABT. The overly stiff linear elastic material models for the torso were replaced with material characterizations drawn from current literature. Biofidelity of the ARL torso was determined by comparing peak force, force-displacement, peak compression, and energy absorption data with cadaver responses to a 23.5-kg pendulum impacting the chest center at 6.7 ms. Nonlinear foam, viscous foam, soft rubbers, fibrous hyperelastic rubbers, and low moduli elastic material were considered as material models for the flesh, organs, and bones. Simulations modifying one tissue type revealed that the flesh characterization was most crucial for predicting compression and force, followed closely by the organs characterizations. Combining multiple tissue modifications allowed the ARL torso to mimic the cadaveric torsos by reducing peak force and increasing chest compression and energy absorption. Limitations imposed by the Lagrangian finite element approach were discussed with potential workarounds described. Proposed future work was split between considering additional impact scenarios accounting for position and biomaterial variability.