Identification of Optimized Cranial Bone Constitutive Model Parameters at High Strain Rate Using Polymeric Split Hopkinson Pressure Bar Test Results

Abstract

AbstractThe aim of this study is to use the conventional inverse problem to identify the parameters of a nonlinear constitutive model of cranial bone under compression loading, which then can be used in numerical simulations such as those involving impact, ballistic and blast events. The dynamic compression of the material was obtained according to the procedure of Polymeric Split Hopkinson Pressure Bar (PSHPB) tests, for high strain rates of approximately 1500 s−1. Five cylindrical specimens of embalmed human cranial bone were tested under dynamic loading. The corresponding 3-D mesh models of these samples were obtained using a micro-Computed tomography (µCT) images. Based on these experiments, corresponding finite element simulations were undertaken using commercial LS-DYNA software. A monolayer elastic-plastic constitutive material model was assigned to the cranial bone which exhibit a foam-type behavior for all compression tests explored in this study. The optimization problems were solved using a commercial optimization code, LS-OPT, based on the Successive Response Surface Methodology (SRSM). The aim was to obtain optimal solutions of the design variables by minimizing the differences in dynamic test responses between simulation and experimental results.KeywordsCranial boneCharacterizationDynamicSHPBFinite element analysisInverse method