Research On Mesh Generation Method Of Hip Joint And Program Implementation

Mesh generation is an important step in finite element analysis, and theelement quality severely affects the accuracy of solution. In this thesis, researchachivements, which come from domestic and foreign, are analyzed and accordingto its structure feature, the Delaunay triangle method is adopted and applied to ahip joint model.Firstly, according to the Delaunay criterion, a point is inserted. Read theSTL file and merge the duplicate node and edge. Then an adjacent relationship isbuilt. Depend on this relationship, the initial element is found out quickly fromwhich the search is started. Along the direction from the circumcenter of initialelement to the inserted point, the BASE element can be located easily. In theprocedure of forming the core, two mistakes are studied and solutions on eachsituation are put forward in order to avoid failure in performing the program.Secondly, an operation to recover the missing boundary is performed andthe quality of the mesh is improved. In this section, all the situations ofintersection between boundaries and tetrahedrons are analyzed and classified. Adivision method is adopted in order to improve the quality of the element. Thefemur has two boundaries, inner boundary and outer boundary, which areindependently and they must be guaranteed in the recovery process. In this thesis,the inner boundary is separated from the outer boundary based on theirindependences and the normal of boundary face follows the right-hand rule. If anelement volume is negative, it will be deleted, and then the missing boundariesare recovered. Take the aspect ratio as inspection standard and adoptdecomposition method to eliminate the siliver element.Finally, an experiment is conducted to test whether the mesh model canmeet the needs of visual surgery system. The mesh model of femur is applied to finite element analysis and the deformation data are obtained under differentloads. The deformation data with the experimental data are compared and theresult proves that the program is efficient and the mesh model is able to meet thepractical application.