Stamping Forming Simulation Of The Autobody Panel

As an important part of the auto-body, automotive panel, decides the quality of the automotive appearance, therefore enjoys high demands for its quality. However, due to the large-size of its structure and irregular and complicated shape, some shortcomings such as tension fracture and crinkle always emerge in the process of molding. Traditional methods for that such as seeking the optimum molding parameter of mould with existing experience before Repeating pre-stamping or mold trial can neither ensure the quality of the product nor shorten the cycle for research and development or decrease the production cost, and therefore hinders the development of new automotive model.The rapid development of computer technology makes the sheet forming technique go to a new high, CAE software for sheet forming can perform not only the prediction of various defects which may appear in the process of sheet forming and the analysis for the causes of defects, but optimization of the stamping processes parameter and mold construction with the help of experimental result to improve the quality of pressing, cutting down of the development cycle and lowering of the production cost.The main contents of this paper are as follows:1. This paper systematically discusses finite element analysis theory of press forming dynamic explicit nonlinear analysis, analyzes some basic theories and the foundation for dynamic explicit Arithmetic such as balance equation, constitutive relations of the flexibility and plasticity, yielding laws, theories on elements and so on, and then gives the method to cope with the problems caused by friction and contact.2. Some key issues about simulation modeling of automotive panel press forming are studied, that includes material model, die clearance, treatment of brake bead, die addendum surface, friction coefficient, treatment of blank holder and calculation of blank holder force.3. And then it demonstrates the process of how to model the finite element for the fender of the auto body, by analyzing the craft it used, setting the direction for stamping, designing the additional crafts, optimizing the shape, the finite element model is established and the parameters for material and model are also set finally. Based on the computing process over and over again to select the proper parameters for crafts, the result conforms to the requirements can be gained.4. Then this paper discusses the fundamental principle and practical application of the equivalent brake bead. By analyzing problems exist in the equivalent brake bead and performing simulation with three different working conditions , the action of brake bead and its effect to forming quality can be showed. By determining the subsection brake bead, filling resistance can be ameliorated effectively and drawing deficiency and part crinkle and rip can also be facilitated obviously.5. This paper finally summarizes basic features of techniques for spring-back value simulation and its principal factors that affect spring-back simulation accuracy.