A Numerical Investigation of Cup-Forming by the Stretch-Drawing Process-Single and Double Operations

Abstract

In stretch- and deep-drawing processes, each material element of the sheet changes its moving direction by a right angle once or twice when it passes over the die profile and, in the second stage of double operations, over the blank-holder profile. Thus it was considered very difficult to simulate it by a dynamic code. Therefore, the effectiveness of the dynamic explicit bite element code DYNA-3D for simulation of cup forming by the quasi-static processes of deep- and stretch-drawing both in single and double stages is tested. The numerical results show that the prediction of the cup depth is fairly accurate for almost all cases investigated except for a few cases. The limiting drawing ratio predicted numerically, however, considerably exceeds the corresponding experimental value for all cases tested. Stretch- and deep-drawing accompanied by ironing of a thick sheet is also well simulated with regard to the cup depth, at least in a practical sense. Improvement of simulation will be carried out by elaboration of the constitutive equation.