Simulation Research On Drawing Forming Process Of Rail Vehicle Top End Plate

With the development of urbanization and the limit of city traffic、energy、environment and other factors, car has been unable to adapt to the increasingly growthof economic activity and the daily life of people,s growing demand.Rail transportionhave multiple advantages: land provinces、large transport capacity、operation time、no environmental pollution、low noise、high safety performance.Rail transportationcan realize the rapid transfer of personnel, suitable the characteristics of city peopleabout flow region、time、fast rhythm.so vigorously develop rail transportation as thebackbone and conventional public transit as the main body of the public transportsystem has become the domestic and foreign large-scale city development direction oftraffic planning.This paper takes a rail passenger car top end plate defective parts as the researchobject.Make analyzes of the defects and simulation of the springback situation withAUTOFORM software. According to its structure characteristics, put forword theprocess improvement scheme and the influence of the springback of adjustableparameters are analyzed. The specific work is as follows:(1) Analysis of stress state of top end plate and structural characteristics in theprocess of drawing.The top end plate with a half arc vault flat end wall and differentcurvature radius arc tangent formed.According to the forming characteristics of thetop end plate, analyze of the present stage of drawing defects.Defects include: roofwarping, end wall is winding, vault end warp, warp springback is the main defect.Thevault do not have enough plastic deformation when drawing. Different curvatureradius circular section subjected to varying degrees of stretch, and tangentialshrinkage in different degree caused internal stress distribution which is not uniform,resulting springback warping in the end of the elastic recovery forming;Theperformance and characteristics of the material of weathering steel is analyzed;Thespringback numerical simulation verified the defects on the drawing program usingAUTOFORM software.(2) According to the small crimping area and the unilateral asymmetric edgepressing the plastic deformation when drawing, the stress distribution is extremelyuneven, improve process plan and optimizate of sheet shape.Make sheet metal arcexternal expansion and increasing the pressure edge area while increasing the wingedge and the winged edge bending drawing to ease the vault arc part stressconcentration problem, increase the local plastic deformation of sheet metal, warpingrestraint springback end wall on both sides. The winged edge and extra sheet can be removed in the subsequent trimming process;(3) Simulation of the forward and reverse solutions with AUTOFORM softwareand analysis the results. The simulation results show that the bending drawing on thewing edge can effectively reduce the warpage springback end wall plane, the wingededge has better reverse drawing springback effect on direct drawing.(4) On the base of process improvement scheme,make a system analysis of thecontrol parameters of the top plate forming. Using the single factor method,get thegeneral laws of the top end plate warpage rebound with the help of AUTOFORM:a) The smaller die fillet can effectively reduce the top board warpage springback,but larger wear die will low die life and make the sheet thinning at the same time, Itneeds reasonable selection according to the actual requirements.b) The winged edge ejector plate fillet should be chosen in the range of4~8mm,the springback will be smaller; the die gap and the winged edge effect drawing gap onspringback is smaller, the gap can be selected in the range of2~2.2mm, Small gapwill cause the sheet thinning even crack;c) The greater the blank holder force,the smaller the springback, but the blankholder force lead sheet thinning and crack, so people should choose suitable blankholder force according to the actual situation. The plate warping will be smaller whenWing side blank holder force is less than300KN.The research of drawing and the influence of parameters on the top end plateprovides a theoretical reference for the actual production.