Research Of Finite Element Mesh Generation Based On ACIS

Automatic mesh generation technique of three dimensional finite element analysis for electromagnetic fields is studied in this paper. Finite element analysis is applied extensively in electromagnetic fields. Mesh generation is an important part of the pre-processing of finite element analysis. In three dimensional finite element analysis, pre-processing offer massivly original data for finite element computation. Geometric model building and automatic mesh generation are the keys of pre-processing. The kernel content is region discretization-mesh automatic generation.Visual C++ of Microsoft is adopted in object-oriented design. Three dimensional mesh automatic generation program is gained though designing the type of operand. This program includes two parts. The first part is the model input processing and the second one is mesh generation of the model. In the first part, wizard program is built to make ACIS model builder compatible with Visual C++. Data structure of SAT model is translated to the data structure related to mesh generation program which can be used in object-oriented design of Visual C++, so the input of three dimensional ACIS model is completed.In the secongd part, delaunay triangulation method is adopted to subdivide the three dimensional model. Boundary facet subdivision is adopted, which includes the building of initial tetrahedron, the building of delaunay hole, position distribute the points, iteration of segment breakdown, iteration of planar chip breakdown and maintenance data structure chain table. After mesh generation program process the convex hull model, geometric element of outlying convex hull model are deleted because it not belong to SAT, then only the mesh in constraint domain are reserved. The output files consist of the files of node coordinates and element information.The designed tetrahedron mesh program of 3D finite element can generate delaunay triangulation rapidly, which is certified by some examples. Further rearch is need to confirm size and quality of the meshes reach certain standards.