The Implementation Of Coupling Of FEM And BEM Of 3D Elastomer With OOP

The structure analysis has great importance in the engineering application and investigation. With the quick development of computer, the technique of structure analysis is improved greatly. However, the program of structure analysis is involved with various calculated content. The classical structured programming for structure analysis needs plenty of man-hour, and it's extensibility and reusability are restricted. The emergence of the object-oriented technology made the program design refrain from those disadvantages. The boundary integral in BEM(Boundary Element Method) effects the precision and the speed of the method. The nonsingular integrals are popularly calculated by the Gauss numerical integral, and they are low in precision when the source points approach the element, and the singular integrals are complex. It is significant for structure analysis to implement object-oriented programming of BEM and improve singular integrals. In this thesis, it is introduced the object-oriented method, and used VC++6.0 as development tool. The main research and conclusion in this thesis are as follows: 1. Establishment of the object-oriented BEM program frame based on a FEM(Finite Element Method) program frame. Definition of abstract element class and material class, which provide a open interface for add relative object to the program frame. The object-oriented BEM program has good extensibility and reusability. It's convenient for the obtainment and input of data. 2. This paper presents an alternative way to transform the double integral in elasticity problem on 3-d into the linear integrals on the boundary of each subdomain, so that all the singular integrals and nonsingular integrals are calculated by analytical method. The method takes a new way for singular integrals in BEM. The exact integrals has no distinguish for the singular integrals and nonsingular integrals, which is convenient for the program design. The examples indicate that the precision and the speed of BEM is improved. 3. Implementation of coupling of FEM/BEM used object-oriented method. In this thesis, the program of coupling of FEM/BEM obtain satisfactory result, which indicate that the FEM and BEM have complementarity for each other and display their predominance respectively in the structure analysis.