Numerical Simulation Of Sheet Metal Forming Of Automobile Panel

The panels change most frequently and their market cycle are short. The stamping quality of the panel is one of main factors which determine the vehicles'success in the market. The designing level of mould is the key of stamping quality of the panel. So the design of mould is a bottle-neck problem in auto development.Designing sheet metal forming dies is still an art requiring people with special skills and knowledge. It is trial-and-error process based upon past experience. It would increase the cost and stamping quality of the panel is difficult to be guaranteed.With the development of the CAD/CAE/CAM, in order to overcome this inefficiency, a scientific approach should be taken to design sheet metal forming dies. The application of numerical simulation is a new development in sheet metal forming. The distribution of stress and strain and the predicate of defects in metal forming can be investigated by numerical simulation. On the one hand, numerical simulation can provide theoretical prediction of the form feasibility before the mould is manufactured. So it is relatively secure, economical, and time-saving comparing with the traditional design of mould. On the other hand, it can give the optimization parameters for the design of the mould. It provides general guidance for the design and analysis of mould technics. The main work is as followings:1. Finite element theory, the know-how technology in the sheet metal forming and the basic processing from CAD to CAE are introduced briefly. The method of a finite element modeling was discussed in detail. Belytschko-Tsay shell element theory and contact handing algorithm are also researched.2. Some parameters such as draw bead friction coefficient, material and blank thickness were analyzed. Then, a numerical simulation of the forming process of deck lid inner panel was carried out with the software DYNAFORM. The results show that the method is feasible. The obtained results were used to optimize parameters and to guide the mould design.3. The springback theory, the spingback factors and the methods to control the springback are described in the paper. Then four main spingback factors, which are die gap, binder force, blank thickness and friction coefficient, were researched by the orthogonal experimental design method. From the results of test with range analysis method, we obtained the different effects degrees on the forming, and got a satisfactory conclusion.