Forming Analysis And Springback Controlling Of Automotive Structural Part Using AHSS

Due to the forming characteristics of high strength steel, its application in the auto industry becomes very general, thus the springback problem is indispensible to be delt with. With the improvement of the finite element numerical simulation technology, the numerical simulation results can guide the optimum of forming process and the mould design, which has got the favor of enterprises. General steel sheet metal forming numerical simulation technology has already been very mature, which can get accurate results and has been widely applied in production. Due to the springback problem in the process of high strength steel, the application has been hampered, therefore, in this paper, the finite element technique and the grid strain analysis technique have been applied to research on the forming analysis and springback controlling of automobile structure using AHSS.Through the tensile test of high strength steel HC420/DP780, material mechanics performance parameters and the forming limit curve have been obtained. By comparing the V/U-shaped bending springback effect with other general steel, got a quantitative understanding of HC420/DP780 bending springback amount and realized that by changing the parameters of forming process of high strength steel materials to reduce springback can not satisfy the quality requirements, which also increases the demand for mold and stamping equipment. The springback compensation to reduce the deviation after unloading is an effective solution.Forming analysis has been carried out for the Lower-Floor-Rail-Reinf-LH/RH using HC420/DP780. The forming finite element model is established, and the software of AutoForm has been applied to simulate the Forming step and the Cutting step and optimize the stamping process.CAE softwares have been applied for the springback controlling and mold development of Lower-Floor-Rail-Reinf-LH/RH. Based on the optimization of the forming process, springback simulation has been calculated by using the AutoForm; Using the Global Shape Modeling function of Think Design as well as the Compensator function to compensate the mold surface. Finite element analysis results show that this method can control the springback within the scope of the quality requirements. According to the springback compensation mould surface, the optimized blank dimension and the optimal process parameters determined by finite element analysis, stamping process can be defined and mould structure can be designed.Verifying the springback control results based on GOM non-contact strain testing system and grid analysis technology. The strain distribution of the final forming parts and the final 3D model data have been collected; From the comparison of the FEA results with the test result, the simulation model established is rational, the springback compensation result is accurate and the finite element analysis results are correct. At the same time, according to the flow deformation of the material showed on the forming limit diagram, the optimal suggestions for stamping process have been put forward.To sum up, the formability and springback principle of HC420/DP780 are discussed in this paper, the finite element simulation analysis and optimization of the automobile part using this material have been carried on, and the springback is compensated by the software of Think Design. By applying the GOM non-contact strain testing system and the grid analysis technology, the finite element simulation analysis results is verified to be reliability and springback compensation method to be feasibility, providing the reference for the similar projects in the future.