Research On Micro-Strcutures And Bending Properties Of Skull Cellular Bones

As a medium which can resist impact to the brain from the outer space, the skull plays an important role in the protection of human life. However, data shows evidence that the skull is susceptible to injuries. Therefore, the study on the deformation and failure mechanism of the skull become a focus which attracted more and more scholars. The research on the biomechanical behavior of the skull has important meanings in many fields, such as the prevention of the head injuries, the development of alternative materials and new structure, the design of safety protection equipment and medicolegal expertise. Since the experimental methodology has many defects and limitations, the finite element method was used to study the bending properties and failure mechanism of the skull under quasi-static load.Firstly, computed tomography scan was performed on the skull sample and we obtained the 2D images of the sample. Based on the reverse engineering technology, a 3D reconstruction model with high similarity to the real skull was obtained and the 2D cross section of the skull was reconstructed. Several section stretch models and a multi section combined model were built based on the 2D images of the skull.Secondly, two constitutive models were adopted to simulate the three point bending test of the skull and the results showed that the ultimate load and the bending strength of the two kinds of constitutive models were all in the range of other scholars’ experimental results, which demonstrated that the constitutive models were reliable. The skull was investigated under different load conditions, such as three point bending test, distributed load and external compression. The effect of age on the mechanical properties of the skull was studied. Several 2D images were chosen and the differences between the mechanical properties of the different section stretch models were compared.Then, finite element simulation was carried out on the three-point bending of the multi section combined model. The characteristics of the load-displacement curve and the stress distribution were analyzed, and the difference of the carrying capacity between the multi section combined model and the section stretch model was compared. The deformation and failure of the multi section combined model under distributed load were simulated, and the relationship between the bearing capacity of the skull and the range of the distributed load was investigated.Finally, the mechanical properties and failure mechanisms of the two 3D reconstruction models in the direction of X and Y axis were simulated respectively. The stress distribution state and failure process of the elastic stage were analyzed and the differences of the mechanical properties between the two mutually perpendicular models were compared, which proved the anisotropy of the skull. The carrying capacity, fracture process and calculation cost of the three kinds of finite element models were compared and analyzed.