The Study Of Two Dimensional Electromagnetic Fields Finite Element Pre-processing System Based On Object Oriented Technology

With electromagnetic field FEM extensively applied to the electromagnetic analysis and optimized design of all kinds of electromagnetic devices, users are putting forward higher requirement for electromagnetic field FEM analysis. It is known that the FEM pre-processing is bottleneck for the development of FEM analysis, so that the efficient high-qualified electromagnetic field FEM pre-processing has become an important research topic.Firstly, in the development design of FEM pre-processing system, the paper has designed the foundation class of pre-processing system and developed relevant object-class-centered software with popular method. The software development platform is Microsoft VISUAL C++, which has integral object-oriented software development function and provides rich foundation class library. Therefore FEM pre-processing software is successfully programmed with such development tools.Secondly the part of electromagnetic field FEM pre-processing is combined with plotting software in this paper. Such integration development makes it easy to transfer FEM information such as geometric information, physical information, and boundary conditions into FEM pre-processing part. The finished 2D small-sized plotting software has good plotting function, which could plot not only basic pictures of line and arc, but also all kinds of curves. Both mouse and keyboard are used for interface development. In picture function manipulation, there are many options such as moving, rotating, mirroring, copying, deleting and etc., which are convenient for users to build FEM geometric model.Advanced front method is used to automatically create triangle mesh. At the same time, this paper finishes such works as improving the arithmetic, optimizing and checking meshes. Aiming at multiply connected regionsproblems, the paper analyses the previous method of inducting aided line of syncopation and points out its shortcoming, then proposes a new method of transformation between multiply connected regions and single connected regions by study of AFM arithmetic characteristic. The concepts of static advanced front and dynamic advanced front are defined. When nodes and elements are created, it should be judged whether static advanced front is included into dynamic advanced front. If the inclusion is needed, when new elements are created, static advanced front and dynamic advanced front are integrated into new dynamic advanced front, thus the problem of multiply connected regions can be turned into the problem of single connected regions.Finally, the paper applies the latest engineering database technology and relevant object-oriented data modeling method to the electromagnetic field FEM pre-processing system, which makes data stream of pre-processing easily organized.The results of numerical experiments prove that the finished FEM pre-processing software can successfully create high-qualified meshes with a satisfactory speed.