In recent years modeling and simulation have emerged as effective means to investigate blast loading to the head and identify intracranial regions of elevated stress. To that end, to gain further insights into the wave mechanics, we developed a computational tetrahedron meshed model of a human head form filled with representative brain simulant material placed in an Eulerian air domain and subjected to simulated blast waves. We have previously validated our models against experiments employing RDX explosive charge used to generate primary blast. Both qualitative and quantitative comparisons produced good agreement based on high-speed imaging techniques and strategically placed embedded pressure probes.
The current research seeks to expand our previously validated work to investigate early time intracranial wave mechanics in the surrogate head model based on directed primary blast impact from the anterior, lateral, and posterior directions. We are investigating the influence of wave physics variables (pressure, shear stress, impulse) on intracranial brain regions. In particular, the shear stress distribution based on internal wave mechanics has the potential to produce shear damage in different areas of the brain. This study’s preliminary results show the most dominant shear response occurred in the anterior region from the frontal blast impact. The results show small early time oscillations in the anterior area out to time 0.55 msec. The surrogate’s posterior region shows no initial oscillation, and the shear stress levels were minimal (below 0.01546 kPa for times less than 0.496 msec). A steep rise in shear response occurred after 0.496 msec, with stress levels peaking upwards to 0.106 kPa to complete the simulated time. Due to the brain simulant’s viscoelastic nature, the shear responses were delayed up to 0.5 sec after the frontal blast impact. Further findings from this work will be shared with this community at the upcoming meeting at the 2021 Mach conference.
2022-04-06 08:00:00
