Optimum blank design of an automobile sub-frame

A roll-back method is proposed to predict the optimum initial blank shape i n the sheet metal forming process. The method takes the difference between the final deformed shape and the target contour shape into account. Based o n the method, a computer program composed of a blank design module, an FE-a nalysis program and a mesh generation module is developed. The roll-back me thod is applied to the drawing of a square cup with the flange of uniform s ize around its periphery, to confirm its validity. Good agreement is recogn ized between the numerical results and the published results for initial bl ank shape and thickness strain distribution. The optimum blank shapes for t wo parts of an automobile sub-frame are designed. Both the thickness distri bution and the level of punch load are improved with the designed blank. Al so, the method is applied to design the weld line in a tailor-welded blank. It is concluded that the roll-back method is an effective and convenient m ethod for an optimum blank shape design. (C) 2000 Elsevier Science S.A. All rights reserved.