Three dimensional multi-step inverse analysis for the optimum blank design in sheet metal forming processes

Abstract

An inverse finite element approach is employed for more capability to design the optimum blank shape from the desired final shape. Since one-step analysis is not accurate enough to calculate the initial blank shape for complicated parts, multi-step analysis is introduced to obtain more accurate blank shapes and strain distribution. Multi-step analysis deals with the sliding surface for intermediate shapes and the coordinate transformation for appropriate Newton-Raphson iterations. The present algorithm has been applied to square cup drawing and oil-pan drawing. The numerical results confirm the validity and versatility of the algorithm with the initial blank shapes calculated and comparison to experimental results. (C) 1998 Elsevier Science S.A. All rights reserved.