The Research Of Repairing Errors Of STL File And Exchanging From Finite Difference Meshes To Finite Element Meshes Based On CASTSoft

Numerical simulation of mold filling of castings is the key to put an end to the backwardness of the foundry industry, to decrease the scrap of castings, and thus to improve the economic profit. Therefore, numerical simulation of mold filling of castings has been studied in the dissertation.In view of the present native researches on numerical simulation of mold filling of casting being less which has made great inconveniences to native production, the center of casting of North University of China has studied and developed the software of numerical simulation of mold filling of castings. Based on the characteristics of STL file, the author has studied errors such as gaps, overlapping facets, degenerate facets and so on. The method of checking and modifying STL file errors is given. Based on the coordinates regional block, the method which tables about points, edges and facets are established rapidly is given. This can increase the capability and efficiency of repairing.It is successful that the finite difference meshes were generated using CASTSoft software. So gaining finite difference model of the complex casting was not difficult. Finite difference method widely used in the thermal analysis is simple, operated easily, but also conducted flow analysis. However, analysis of thermal stress is difficult. Most thermal stress analysis to casting used the finite element method. In order to better thermal stress analysis, finite difference meshes will be converted into finite element meshes. Based on CASTSoft the author designed mathematical model, and developed program, and exchanged from finite difference meshes to finite element meshes.For the sake of enhancing the efficiency of finite element computation, and reducing the needed amount of storage of computation data. In the paper, an optimal method for node labels in the finite element is presented, which is an inductive and deductive method. By the analysis to the order features of the nodes when the network bandwidth is the minimum value, we can induce three regulars. Testing a large number of examples, which show that the presented scheme can reduce bandwidth for arbitrary mesh by renumbering the nodes, proves the correctness and reliability of the regulars. Thus the memory of computer is saved and the compute efficiency is improved.