Simulation And Experimental Study Of Varibale Thickness Blanks Stamping Forming

As a useful method to improve automotive gas mileage and reduceemission, light weighting strategies have been put into automobileindustry to achieve this target. Variable-thickness rolled blanks (short forVRB), based on new material processing technology, become one of themost important methods to reduce car weights and increase performanceof components. Flexible rolled technology, core technology of VRB,request timely control of roller gap by computer to achieve blanks that themetal thickness is change continuously. Inhomogeneous characteristics ofgeometry and material lead to a problem which is how to simulate VRBforming in finite element software accurately. In order to expand usage ofVRB in automotive lightweight design, in this paper, based on variousexperiments and simulations, system study have been put on VRB’sstamping simulation.First, tensile test results of equal-thickness zone of VRB show thatmaterial mechanical parameters of equal-thickness zone differ from eachother. Also results of Digital Image Correlation tensile test of VRB leadto the same conclusion that in thickness transition zone differentthickness means different material mechanical parameters. So, as tomaterial model of VRB, overall methods and segmentation methods havebeen put forward. There are three ways, which is Interpolation,Discretization and Average among Segmentation methods to deal withTransition Zone of VRB. All these methods are applied to VRB’snumerical simulation, force-displacement curve acquired from real testand simulation have been compared, the results show thatSegmentation-Discretization method should be adopted to describeVRB’s material model. As for how to display VRB’s thickness change in finite elementsoftware, two software is selected for comparison. In ABAQUS, solidelement and shell element have been discussed from the aspect ofcalculation efficiency when used for simulating VRB. Results show thatreduced integral shell element owns the highest calculation efficiency. InDYNAFORM, way of changing element node thickness to make theelement thickness change continuously have been proved impossible, sodiscretization method is put forward. Since discretization method is usedboth in material model and thickness dealing, it is necessary to establishprecision for discretization method based on comparison of simulationresults and experiment results.In this paper, another important job is to study forming limit curveof VRB. Two method have been put forward to deal with this problembased on analysis of theory, Keeler’s experience formula and forminglimit diagram experiment. One of this two methods is discretizationmethod based on Keeler’s experience formula, the other is curve fittingmethod based on experiment. Comparison between VRB deep drawingsimulation and experiment show that this two methods both areadaptable.As last, apply VRB simulation methods established in this paper infront rail numerical simulation to judge forming ability of VRB.