Finite Element Simulation Research On Reverse Bending Of Automobile Frame Steel Plate Stamping Based On Stress Evolution History

Improving the strength of automobile body panels is an important method to realize automobile energy and emission reduction.High-strength steel needs to be cooled quickly in the production process to obtain good overall performance.However,high cooling speed will cause uneven residual stress in the plate,which will have a great impact on the accurate control of the subsequent stamping and forming process of the steel plate.At present,the research on the residual stress of high-strength steel plate is mostly limited to the experimental characterization,and the relationship between the generation and release and elimination of the residual stress is not considered.This paper takes coiled plate as the research object,starting from the steel plate heat treatment,deeply researches the generation,release and improvement process of residual stress.The constructed model and residual stress analysis result have high guiding significance for the production of high-strength steel plate.The main research contents of the paper include: 1)Based on the ABAQUS finite element software,the heat dissipation model of the inner plate of the steel coil is established,and the rationality of the finite element model is verified through the plate heat dissipation experiment,and the built model is used to study the heat dissipation of the plate under different heat dissipation parameters.After the residual stress distribution;2)Three different stamping models,and use the heat-dissipated sheet as the stamped blank for stamping analysis were established;3)A sheet straightening model to simulate the process of straightening to eliminate residual stress was built.The research results show that the residual stress generated by the heat dissipation process of the plate increases with the increase of the initial heat dissipation temperature and heat dissipation speed,and decreases with the increase of the plate width.In the stamping process of the sheet,the residual stress distribution of the sheet is the same,the greater the residual stress,the greater the amount of back bending;under the same initial residual stress,the U-shaped flat-bottom punching has the largest amount of back bending,and the V-shaped punching takes the second time.However,the U-shaped round bottom stamping has the smallest back bending.During the straightening process,the residual stress decreases with the increase of the reduction,and the middle roller has the greatest effect on the reduction of the residual stress;in the straightening process,when the plastic deformation of the cross section of the sheet reaches 70%,the residual stress can be reduced to 30 %,and the straightening process can effectively reduce the residual stress in the S33 direction.