The Design And Application Of Automatic Mesh System In Two-dimensional Grid

The automatic generation of an unstructured mesh is an important procedure for the finite element analysis. There are three types of methods to generate the mesh:advancing front methods, quadtree and octree methods, and Delaunay methods. The Delaunay methods are based on the concept of the Delaunay partition of a points set. The Delaunay methods have the property of empty circum sphere for three dimensional cases and empty circumcircle for two dimensional cases. In the two dimensional cases, the Delaunay triangulation is the one with the maximum minimum angle, and has the best ensured quality for the elements.Using object-oriented method, TMG, a two dimensional automatic unstructured mesh generation system, has been designed and implemented. TMG can do the constrained Delaunay triangulation to an input plane domain. The input domain can be one edited in the graphic user interface, randomly automatic generated, or read in from a graphic file with GDSII or DXF format.TMG supports special pre-processing algorithms and removes the input condition of planar straight line graph for the constrained Delaunay triangulation. TMG supports the input of polygon lists and can remove the small features of the input domain to improve the quality of the triangulation.A plane thermal stress finite element analysis system has also been developed based on the mesh generation system.