Microstructure-Based Model of the Deformation and Failure Response of the Human Skull under Uniaxial Compression
Technical Report,01 Oct 2018,30 Sep 2019
Army Combat Capabilities Development Command Army Research Laboratory Aberdeen Proving Ground United States
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Numerical studies for head injury from applied loading can be made more biofidelic by incorporating mechanism-based, microstructurally inspired material models representing the mechanical response and fracture of the human skull. A hybrid experimental modeling computational HEMC concept was used to develop a mesoscale finite-element FE model of the heterogeneous microstructure of a human skull coupon. Elements were mapped to corresponding regions from micro-computed tomography images, and the bone volume fraction BVF of each element was identified. Then, element-specific moduli were calculated from a BVF modulus power relationship previously derived from experiments with critical assumptions. The simulation was able to match within 5 of the measured global modulus, thus validating the use of assumptions in the derivation of initial linear response. The subsequent nonlinear response, up to the point of instability from pore collapse, was represented by failure of elements either by compression or tension. Evolution of measured nonuniform full-strain fields on coupon surfaces, showing localized regions of failure, was compared between experiment and simulation and was qualitatively similar, thus validating the HEMC procedure with failure concepts. The methodology enabled identification of failure locations within the skull coupon, thereby providing a tool to predict localized failure initiation in FE simulations at larger length scales.
- Anatomy and Physiology