Automotive Body Panel Forming Analysis And Numerical Simulation

Automotive industry plays an important role in China. Automotive body panel forming and mould design is the key technology to develop our mould industry, especially automobile. The numerical simulation of automotive body panel forming is the research area of interdiscipline including metal plastic forming theory and process, computational mechanics, CAD technology, computer graphics, etc. It is a very difficult project because sheet metal forming includes three kinds of nonlinearity such as material, geometry and boundary condition. Nowadays, developed countries have put FEA in practice during production design and manufacture, but in our industry it is just at the beginning. Therefor, this dissertation focuses on the forming analysis and numerical simulation of automotive body panels which come from フレス corporation of Japan and First Automobile Works of China. When using Pro/E and UGII software as modeling tools, DYNAFORM just imports the surface data in an IGES format. The numerical simulations are consistent with actual conditions. The author learned and summed up the latest achievement domestic and abroad, discussing and deepening the practical application of sheet metal forming numerical simulation. This dissertation research content includes:Theory and key technology of sheet metal forming numerical simulation are systematically summarized, including material model, geometry model, contact and friction, mould system and process parameters, as well as springback. Discussing and comparing the essential characteristic and applicable scope of dynamic explicit algorithm with those of static implicit algorithm, the author considers that the dynamic explicit algorithm is more suitable for the numerical simulation of sheet metal forming at the present time. General steps of the numerical simulation of sheet metal forming are summed up. The noticeable problems such as geometry model and meshing are brought forward, which are relating to panel.On commission of フレス corporation of Japan, the author uses DYNAFORM software to simulate the forming of the PANEL FRONT RAIL of Toyota common car. The binder force, corner radii of tools, drawbeads and blank shape are optimized, so the fractures and wrinkling of panel front rail are eliminated. The problems in the numerical simulation are mentioned and their solutions are given. The BACK COLUMN OUTER PANEL of car is a big and complex automotive body panel, which is easy to be fracturing or wrinkling during forming. The author has fixed on the process makeup and die round by detailed analysis, building up reasonable FEA model. With the comparing of deformation theory and increment theory, the author considers that one step simulation can be used to evaluate the formability of sheet metal forming parts and feasibility of the process as the early design stage, and gives a numerical simulation to validate this method. The blank outline was optimized by several numerical simulations. Furthermore, theory and implement tools are given to update the process makeup.The basic theory and application of equivalent drawbead model are discussed, and the problems which are still unsolved are analyzed. By setting real drawbead and equivalent drawbead respective on BACK COLUMN OUTER PANEL and comparing their difference, the author gets a result from numerical simulation that equivalent drawbead model is reliable and timesaving. For multi-step forming, the succession of the information of deformation such as stress and strain should be concerned. The precision of numerical simulation at a working procedure is not only correlative with the previous one, but also has own peculiarity. The numerical simulation of trimming can be predigested as a geometric process. Generally, the motion structure of flanging mould is complex. so as to reduce the time of modeling and contact searching, the mould surfaces which never contact with part can be ignored.The numerical simulation of Unconstrained Cylindrical Bending and Forming of Front Fender are the benchmarks of NUMISHEET2...