Physics of IED blast shock tube simulations for mTBI research

Abstract

Shock tube experiments and simulations are conducted with a spherical gelatin filled skull- brain surrogate, in order to study the mechanisms leading to blast induced mild traumatic brain injury. A shock tube including sensor system is optimized to simulate realistic impro-vised explosive device blast profiles obtained from full scale field tests. The response of the skull-brain surrogate is monitored using pressure and strain measurements. Fluid- structure interaction is modeled using a combination of computational fluid dynamics (CFD) simulations for the air blast, and a finite element model for the structural response. The results help to understand the physics of wave propagation, from air blast into the skull- brain.The presence of openings on the skull and its orientation does have a strong effect on the internal pressure. A parameter study reveals that when there is an opening in the skull, the skull gives little protection and the internal pressure is fairly independent on the skull stiffness; the gelatin shear stiffness has little effect on the internal pressure. Simulations show that the presence of pressure sensors in the gelatin hardly disturbs the pressure field. © 2011 Mediavilla Varas, Philippens, Meijer, van den Berg, Sibma, van Bree and de Vries.