The Research And Development Of 3D Motion Simulation And Numerical Simulation Environment Based On STEP

Motion simulation and numerical simulation are key technologies of computer simulation and computer aided engineering, which are used to check the rationality of the design, in order to aid designers to optimize product designs or processing parameter during product design and development. The application of those technologies will shorten product design cycle, reduce products cost and improve the competitive capacity of enterprise.In this thesis, present domestic and overseas research situation of motion simulation and numerical simulation environment is investigated roundly and their deficiencies are analyzed. According to this situation, the research and development of 3D motion simulation and numerical simulation environment based on the data model of STEP is proposed.The standard for the exchange of product model data (STEP) is analyzed and the structure and geometrical entity description method of the neuter documents based on AP203(application protocol 203) is studied. Entities described in EXPRESS are mapped into corresponding classes in C++. Geometrical information from STEP documents is extracted and stored in C++ memory. Then the geometrical information is reconstructed for OpenGL drawing. The reconstruction method of advanced B_rep model from STEP documents is studied. A triangulation algorithm for curved surface usually used in engineering is proposed and an algorithm for triangulation of cylindrical surface is designed in details. The meshed triangular model is drawn by OpenGL functions in 3D environment. In this thesis, implementation method of motion function for geometrical model is discussed. Discrete multi-layer collision detection algorithm for triangular model is improved and detailed processing flow and implementation method of this algorithm are proposed. By object oriented method, the classes and their functions, which are needed in numerical simulation program, are analyzed. Relationships among the classes are discussed and the properties and methods of them are studied. Key algorithms and processing flow used in finite element analysis are studied. Numerical simulation program of finite element is developed by object oriented language.