| Stamping process is widely used in mass production of multiple parts in auto body due to its advantage of higher production efficiency and dimension accuracy.In car frame many key stamping parts present a U-shaped section,such as crossbeam and collision box.Compared with the automobile body panels,because of larger stamping depth and higher strength of the sheet material,this kind of U-shaped parts can easily lead to larger springback deformation,higher thinning rate and residual stress value in the forming process owing to its incomplete plastic deformation during stamping process.Along with the development of car lightening,high strength steel sheet and aluminum alloy sheet are more and more applied to automobiles manufaction.However,due to its extremely high yielding limit of high strength steel,the springback problem becomes more prominent,thus the subsequent assembly precision is influenced.This article takes the U-shaped simple part and trailing arm as the research object,then the residual stress and deformation are analyzed by PAMSTAMP 2G.The main work as follows:Firstly,taking the U shaped sample as the research object,a finite element model is constructed.Response surface method is used to design the experimental scheme,and to analyze the influence of the combination of different process parameters on the simulation analysis results of the U-shaped parts.It is mainly discussed when blank holder force,the mould filet radius and the friction coefficient change,how deformation and residual stress of U-shaped sample are influenced,which lays the foundation of further research on the distribution rule of residual stress and deformation of longitudinal arm.Secondly,a finite element model of SPCEN longitudinal arm is established based on actual production process,taking the longitudinal arm as the research object.Then the deformation,thickness variations and residual stress are analyzed by simulation,and the dangerous position are found.By comparing the simulation with the actual production,the reliability of the simulation analysis for the prediction of dangerous position is verified,and the feasibility of the simulation analysis of the residual stress and deformation of the longitudinal arm stamping is also illustrated.Finally,SPCEN steel is replaced by DP600 steel with lower thickness and higher strength due to consideration of car lightening.In the meantime,the finite element model is established to analyze the residual stress and,thickness and spaingback deformation of DP600 longitudinal arm.Aiming at the springback and taking the influence law of technological parameters on deforming results,they are optimized.And the stamping process of DP600 longitudinal arm with optimized parameters is further conducted to the simulation analysis.The results show that the maximum positive deformation of the longitudinal arm decreases from 2.492 mm to 0.837 mm,and the inhibitory effect on springback is evident.This atrial is intended to analyze the stamping forming results of U-shaped section parts,mainly discuss the residual stress,thinning and springback deformation of the forming result,which also has a certain theoretical value and guiding significance for the optimization of the process parameters of the longitudinal arm in the actual production. |
