The Study On Forming Process Of Automotive Front Rails

Automotive front rails is a typical U-shaped pieces. Its change of section height is rapidly which has a high surface quality requirements and a complex shape. In addition, it exists local shaping feature. Front rails is commonly manufactured by metal forming. It can be automated production, owing to its height production efficiency and the production with a rather stable quality. This paper mainly researches the stamping forming of automotive front rails.In order to ensure part quality and dimensional accuracy, the forming of automotive front rails is usually used by ways of left and right two symmetrical arrangement, and forming in the same time. As a result, it saves the cost of mold manufacturing, improves production efficiency, as well as availing the flow of material during forming. In the actual production process, the accomplishment of front rails requires multi-steps stamping process which contains blanking, drawing forming, trimming punching, punching cutting, flanging and so on.As more complex panel shape, the larger size, the stamping technology of covering parts is a complicated task. In the actual production, high strength steel panels forming rise to plenty of problems, such as fracture, wrinkling, springback and so on.The theory of automobile panel stamping forming with finite element method is elaborated and researched, which include:nonlinear materials of elastic-plastic constitutive relationship, dynamic explicit algorithm, yield criterion, flow rule, shell element types, material model, contact treatment and friction characteristics and so on. Also briefly the main program of stamping process design, key considered problems of stamping process design and its main content. Through the process analysis, determine the front rails stamping process plan.In this thesis, taking high-strength steel front rails as an example, establishing front rails cad model, using large non-linear dynamic explicit FEA software DYNAFORM for stamping simulation analysis. It can simulate the forming process of front rails and analyze the finite element simulation model. Through predicting the defects such as wrinkle and cracks of automobile behind outdoor stamping simulation, we adjusted drawbead and die structure. Also, we discuss a possible improvement program according to the theory FLD. Followed through simulation, the author propose a more reasonable parameters, to improve the results of its shape, which has a reference for the actual production.