SBIR-STTR Award

The objectives of this proposal are to develop an animal surrogate finite element (FE) model and environment that can be used as a tool to investigate injury mechanisms and mitigation of traumatic brain injury (TBI) due to blast overpressure. A rat head model with a high degree of anatomical detail will be refined for used within an FE blast environment. To avoid the use of unnecessarily costly and complex computational fluid dynamics techniques, Smoothed Particle Hydrodynamics and Arbitrary Lagrangian-Eulerian methods will be employed to simulate the blast. Verification of these methods using a brain simulant will occur before performing a feasibility study by applying the blast simulation to the rat head FE model. Existing in vivo pressure data from tests at Wayne State University will be used to establish an initial degree of validation. Because tissue properties during high-rate loading, such as blast, are largely unknown, principal component analysis will be conducted to determine the most sensitive tissue properties, and optimization techniques will be used to increase the correlation between experimentally measured and model-predicted pressures. This model will be used as a basis for further development of a research tool to study TBI in Phase II.

Keywords:
Traumatic Brain Injury, Blast, Finite Element Modeling, Rat Surrogate, Wave Propagation, Load Transmission Path, Injury Mechanism

Computational models of rat and pig heads will be developed and validated against pressure data available from previously conducted shock tube experiments by simulating complex blast interaction in a verified and validated shock tube numerical model. Finite Element and Arbitrary Lagrangian-Eulerian techniques will be utilized. Available injury data will be examined in regions of interest generated though model predictions; associated Traumatic Brain Injury mechanism and threshold will be determined for each species. A Design of Computer Experiments will be performed to elucidate a transfer function to link the dissimilar anatomy of small and large animal species for establishing a scaling law. Investigation into the applicability of the proposed transfer function and scaling law from animal to human will be performed using a previously developed human head model. Comparison with real-world blast injury cases and statistical analysis will be used to judge the efficacy of the scaling method to ensure that the results are reasonable in the absence of direct validation data. Results from the human modeling will yield recommendations on the focus of further research and guide future experimental designs to improve the scaling law so that it can be used for developing injury mitigation strategies.

Keywords:
Blast, Shock Wave, Traumatic Brain Injury, Numerical Modeling, Finite Element, Arbitrary Lagrangian-Eulerian, Computational Modeling