Theoretical prediction model and failure mechanism map of human skull porous structures with quasi-static bending performance

Abstract

A theoretical model has been developed to predict the bending properties and failure mechanism of the human skull. The structure of the skull bone, which is naturally a porous material, was obtained via non-destructive 3D micro-computed tomography. By considering the combined influence of curvature and porosity of the skull, the mid-span deflection of the skull bone loaded in three-point bending was calculated using theoretical prediction. The cranial bending peak load corresponding to several possible failure modes was also analyzed, and the relevant failure mechanism map was generated. The models also showed that the curvature is a critical consideration for accurate precisions to be achieved. To verify the reliability of the theoretical results, as well as to gain a good understanding of the intrinsic connections between internal geometric features and mechanical properties of the cranium, 3D finite element (FE) models, based on posteriorly reconstructed by 2D cranial scanning images, were developed. The bending properties of various reconstructed sections were studied in detail using the FE simulation models, leading to an understanding of the bending failure mechanism and crack propagation path. The numerical results of deflection and peak loads agree well with the theoretical results. In addition, the failure modes of the numerical models have been verified using published experimental results. This work has overall demonstrated that the theoretical and numerical models would provide a reliable basis for predicting cranial bending performance.