Simulation Of Stamping Forming Based On Autoform

Along with the competition becomes white-hot in the automotive market,appearance design has become an important link, the consumers also raise new claimsconcerning about color, hand feel, precision, shape and other aspects.People in thefield generally accept that large, sophisticated， rational design cold stamping die willget the welcome of the market. In all types of vehicles, an average of a new car modelneed about2000sets of stamping dies, in which there are300sets of large andmedium-sized automobile panel dies. According to the statistics,60%-80%of theparts on the car are produced by the stamping process.In auto-body development, diedevelopment course usually takes about8to12months, accounting for nearly70%ofall theworkload. It affects not only the time of the whole development course but alsothe development cost control. Therefore, in order to improve the marketcompetitiveness, research about enhancing abilities of the die development to reducecost has been taken into agenda by every automobile enterprises.The traditional automobile panel die development is based on the long-termaccumulated experience and take measures to test mold over and over again after thedie design has finished. In this course, workers can find out the problems and proposetheir amendments. But this method can lift the input costs, can also increase thedifficulties in the phase of both manufacture and adjustment. An error in the designprocess is not only a waste of manpower and material resources, it can even result inthe mold scrapped. At present, the sheet forming simulation based on the finite element technologyis widely used in the automotive field for the reason that it can provide a positive andeffective way in mold and process design courses. According to conservativeestimates, using this system can make the whole die design and manufacturing cycleshortens about2/5, the whole mold production costs lowered about1/3, the wholevehicle cost also get greatly reduced, meanwhile the market competitiveness of thistype of vehicle can be highly improved.The sheet finite element simulation process is to decompose the continuumstructure into limited amount of unit bodies, which are interconnected by nodes. Theapplied load and constraint conditions are imposed on these nodes, then we can usedisplacement mode or stress mode to establish balance equations for each node on theunit body, finally we can figure out the displacement or stress distribution of thisstructure through adding the boundary conditions.In the automobile panel stamping simulation process involves the question aboutchoosing the reasonable element, the results of choosing the shell element is moreaccurate than that choosing the membrane element because the shell element canreflect the thickness change more accurately. Meanwhile, the advantage in time stepof static implicit method makes me finally choose the software Autoform to completethe paper.Accompanied by the simulation results, we need to deal with these results. Thesimplest and most direct way we usually adopt is to use the material forming limitdiagram. Autoform devices the forming limit diagram into7areas based on thematerial properties and strain state of the sheet, the crack area, the risk of crack area,the excessive thinning area, the safe area, the insufficient stretching area, the wrinkletendency and the wrinkle area. Then illustrate the color of each region and its regionalcriteria.We take use of Autoform software to complete the B/S Inner LH or B/S InnerRH’s example analysis. Determine the processes at first, then decide about the shapeof the blank, after that the drawing modeling should be determined. A reasonable drawing modeling can influence the forming result, for which we must make the bestfiguration on these factors to control the flow resistance. We give the figurationprocess a detailed explanation, include factors about the determination of the binderforce, the shape of the binder, the set of drawbead and the frictional resistance. Weultimately determine the various parameters of the simulation, and most of the pointson the forming limit diagram of the blank finally fall on the green zone, the resultscomply with the requirements.At last, we give explanation to several key factors in the simulation process. First,the initial blank-holder force, if the initial blank-holder force is insufficient to makethe deformation of the sheet fully done in the drawbead, then the drawbead cannotplay the role of blank flow obstacle. Second, shape of the blank, the resistanceprovided by the optimized blank is larger than that provided by the blank beforeoptimization. Third, the drawbead, we usually use virtual drawbead instead of actualdrawbead in the simulation process.