Human surrogate head response to dynamic overpressure loading in protected and unprotected conditions

Abstract

The ballistic performance of helmets has contributed to increased soldier survivability through the prevention of penetrating injuries. However, the efficacy of helmets in mitigating primary blast-induced traumatic brain injury (bTBI) is unclear. The objective of this effort was to utilize the Human Surrogate Head Model (HSHM) to investigate brain response to shock tube overpressure loading conditions, both with and without personal protective equipment (PPE). The HSHM is a physical surrogate which includes a brain, skull, facial structure and skin, all fabricated using biosimulant materials. The system was mounted to a Hybrid III Anthropomorphic Test Device neck to allow head motion during overpressure exposure. Pressure sensors were embedded along the sagittal plane in the anterior and posterior regions of the biosimulant brain. A series of shock tube tests using driver pressures at four levels (ranging from 420 to 1150 kPa) were conducted to simulate blast loading conditions. Internal pressure response was highly correlated to driver pressure, thus demonstrating the surrogate models sensitivity to load conditions. Characteristic features observed in the archetypical pressure waveform were used to evaluate differences between test parameters, including the effects of a helmet system on response. Results suggest that the helmet does not alter the initial peak pressure response. However, certain subsequent pressure peaks were found to undergo statistically significant reductions when a helmet was placed on the HSHM. The results of this test series demonstrate the use of a surrogate head system in characterizing the brain response to overpressure loading. Future studies will further evaluate the efficacy of PPE and contribute to the understanding of blast-induced injury mechanisms. © 2010 Springer-Verlag.