Automatic finite element mesh generation of proximal femur and prosthesis

Finite element method is currently the most appropriate method to understand the femoral stress distribution before and after implantation of a hip prosthesis. From the finite element analysis results, prosthesis design engineers can evaluate and modify the implant designs and hopefully to increase the success rate for the implantation. Due to the highly irregular geometry and material properties of the femur, it is rather difficult and time consuming to build finite element models for the femur and the prosthesis. In this study, a procedure for automatically generating surface models and finite element meshes of a proximal femur and implant is described. CT scan images were used to obtain the inner and outer contours of the cortical bone and cancellous bone on each section of the femur and the prosthetic contours were obtained from a CAD program. The contours were then input to a computer program-NUAGES which based on the Delaunay triangulation algorithm for generating triangular surface models and four-node tetrahedral finite element meshes. Finite element analyses for these meshes were performed using a commercial finite element analysis package-ANSYS and the convergence of the meshes were tested. By using the mesh generation procedure described in this study, the mesh generation time can be greatly reduced when performing finite element analyses for the femur and implant systems.