Study On The Algorithm Of Finite Element Mesh Generation Based On Surface

The design level of panel die is the core element to restrict the rate and quality of product development. In fact, it has become the main bottleneck to further shorten the renewal cycle and improve the quality. Nowadays, traditional methods are still in used in panel die designing and manufacturing in domestic automobile industry. Process planning and die designing depend mainly on the experience of designers, and the application of CAD technology for auto panel at home is still on the level that the alternant plotting and modeling is done on the popular CAD software system with the designer's experience, which makes CAD software become a drawing board barely, and a trial-and-error procedure is often adopted to get qualified dies. This method is inefficient, costly, time consuming, and the quality of dies can not be ensured.In recent decades, with the rapid development of computer technology, the method of CAD/CAE/CAM has achieved great success both in theory and in practice. The method of finite element analysis has been very popular as a powerful means of numerical solution and simulation for complicated problems in engineering community. Generating the meshes, which is the important process and precondition for finite element analysis, is very complicated and easily make mistakes. At the same time, the quality of a mesh directly affects both the reliability of finite element analysis result and the time that the analysis process consumes. As a result, researching how to generate high quality mesh rapidly is extremely valuable for finite element analysis.Supported by the National Outstanding Youth Foundation (No. 10125208), the Key Project of the National Natural Science Foundation of China (No. 19832020) and the Project 985-Automotive Engineering of Jilin University, How to set up"the CAE-oriented die-face design system for automobile covering parts"is a few keys technique that investigative core contents. In this thesis, some preprocessing techniques of finite element mesh generation in automobile panel are investigated for sheet metal forming is moreover perfected. it developed corresponding mesh generation function and put forward a sort of automatic generation mapping algorithm of triangular and quadrangle mesh which adapts to stamping forming finite element analysis in the blank stamping forming simulation analysis system KMAS which is developed by ourselves. Its main topics show as follows:It put forward an improved algorithm of parameter field of trimmed parametric surface, convincing with parameter field boundary, surface boundary and boundary's discretization, and reasonably refined position with larger surface curvature for getting high quality surface mesh models, so it can ensure good quality of surface mesh and surface fitting.Adopting mapping theory, it projected a surface into UV parameter plane. In another word, it transformed the surface's mesh generation method into plane's. After generating of plane mesh, it mapped nodes and elements of meshes into surface to getting actual mesh. There are two method of mesh generation in this thesis: template method and boundary's mesh generation in scanning line algorithm. The former based on the template library for mesh generation,According to the difference of discrete points of boundary, it matched the template in the template library and generate the finite element meshes. Applying knowledge base, a new template will be constructed by Transfinite Interpolation algorithm, and the new template will be put into the template library. The latter can generate triangle mesh for surface boundary with any shape to ensure whole scanning line algorithm feasible.It designed an algorithm of mesh optimization combing structure and position optimization. The former optimized being generated mesh for ensuring the shape and size of future mesh; the latter adjusted all of the inner mesh by adjusting the location of inner nodes after mesh generating. The combination of the two method greatly improved the quality of mesh.It developed mesh generation module based on geometric sculpting tools ACIS, and introduced international general OpenGL technology to develop graphic display interface so it can achieve graphic display and operation conveniently.It has done plenty of instances analysis. Not only is the better mesh quality generated by this algorithm through test, but also is the rapid computation speed.