Micro-Structures And Impact Resistance Of Skull Cellular Bones

Skull is a typical lightweight porous structure, as the external protective layer of the brain, skull fracture is one of the most common type of traumatic brain injury. The purpose of this paper is to carry out the research work of the destruction and energy absorption ability of the skull under impact load.Using non-destructive 3D micro computer tomography(Micro-CT) to scan real human skull structure, reconstruct the finite element model by it, which is used to get the microstructure characterization of human skull, study the impact resistance ability and deformation failure mechanism of the skull structure. Use reverse engineering software RAPIDFORM to get the 2D skull sections, from which we can get parameters of the skull microstructure features. Import the skull section s into HYPERMESH to divide high quality finite elements. When reconstruct 3D beam model and 3D cube model, first, we manage and optimize the scan data based on RAPIDFORM and medical imaging software MIMICS. Then, import the preliminary finite element model to HYPERMESH to optimize the mesh again. Finally, make impact resistance analysis on both 2D and 3D finite element model by ANSYS LS-DYNA module.Make impact resistance analysis on 2D skull section to study the impact performance of the 2D skull structure in detaile, the 2D computational cost is low. The boundary conditions are doubly clamped and the impactor which is rigid body flies to the middle part of human skull bones section. Change the impact velocity, impact angle, shape and density of the impactor to investigate the influence of these different parameters on the failure mechanism and energy absorption of the structure. Conclude and contrast the energy apsorption ability of the structure under different parameters of impact, including energy absorption, energy absorption ratio and the failure mode of the structure eventually.Make impact resistance analysis on 3D beam model. Reconstruct 3D beam model by two methods, one is through extruding the two-dimensional model and one is by reconstructing the real skull, the former is easier to get but is a simplified model, the latter is real but more complicated and time-consuming. Also use both ends clamped as the boundary conditions and the cylindrical impactor flies to the middle of the model. Change impact velocity of the compactor, compare the deformation, failure modes and energy apsorption abilities of this two kinds of model. Summarize the influence of structure characteristics on the impact resistance, and compared with the results of 2D calculaions.Make impact resistance analysis on the reconstructed 3D cube model, clamped around, with spherical impact, study the structure’s failure modes and energy absorption characteristics. Design skull alternative structure whose quality should be similar with the real skull structure, and it’s shock resistance ability should superior to the real structure. Using the same load and boundary conditions as the 3D cube model to study the alternative structure’s mechanism of deformation and energy absorption. Compare the result with the real skull cube model.