Simulation Research On The Stamp Forming Of Side Column Of Rail Vehicles Car-body By Pam-stamp

Sheet stamp forming,which is called sheet forming in foreign country,is involved in alot of industrial fields.Its process is achieved by the stamping molds.The sheet stampforming is an advanced,efficient,low elementary and inexpensive manufacturetechnology.At the same time,it is a complicated elastic-plastic deformation process whichinvolves geometrical nonlinearity,material nonlinearity and nonlinearity of boundaryconditions etc.It will lead to the lack of systemic and accurate tricks for theoretical analysisin traditional sheet forming process and design of molds.There will be a lot of defectduring process of production,such as rupture,wrinkling and springback etc.With the rapidgrowth of computer technology and information technology,engineers start trying to designmoulds refer to numerical simulation.Finite element method is a reliable way to analyzethe process of sheet stamp forming,which is proved by much practices,with the rational useof finite element numerical simulation technology,it will be efficacious in improving thequality of moulds and shortening the period of moulds’ designing.Combining with the production practice,this paper selected a side column for asubway car using the material of09CuPCrNi-B as the research subject.Side column,whichis longer than2300mm,94mm high and70mm wide,is welded with side beams of the bodyto form the skeleton structure of side wall of the car-body,it is under pressure andprocessed on stamping dies with accurate sheet at one time.Because of its highrequirements for precision of sheet,it left little space for adjusting,so its forming accuracymust be in a high level.However,the workpiece proned to some defect,such as largecross-section ‘s opening,sidewall’s bending and wing edges’ uneven etc,in these defect,thecross-section’s opening is the most difficult problem to solve and the factors which influence the opening accuracy is the most complex.In order to solve this problem andprovide instruction for actual production,this paper discussed the formability andspringback of the side column based on Pam-stamp.The research activities are presented asthe following points:1.Expounded the finite element theory related to numerical simulation analysis ofstamp forming,then discussed the constitutive models of elastic-plastic material,elementarytechniques,contact arithmetic and numerical simulation techniques of springback;2.Researched the deformation of side column in the respects of stress,strain,thicknessand FLD based on Pam-stamp,the research showed that the forming quality of theworkpiece was very good,it made a foundation for following studies;3.Conducted the springback numerical simulation of side column,then discussed thathow BHF,mould gap and mould round-corner affect the springback,then took theemulation of die compensation,the numerical simulation results showed:increasedBHF,reduced the bottom fillet of punch and the top fillet of die and reduced the gapbetween punch and die could be effective in controlling springback;verse bending andpunch with introversion by side wall did well in controlling the springback,but they shouldbe moderately used in actual production;4.Took the improvements in mold based on optimized process parameters and thechoice of die compensation,led to a best program on forming technology of sidecolumn,then took an experiment which was combined numerical simulation with actualproduction to verify its feasibility,the results showed that the program could control thevalue of springback below1mm,it could be used in actual production.