Implementation of backward tracing scheme of the FEM to blank design in sheet metal forming

Blank design is a critical part for net-shape sheet forming. This study app lies the backward tracing scheme of the rigid-plastic finite element method to the three-dimensional blank design of sheet metal forming. Originally, the backward tracing scheme was developed for preform design in bulk formin g, and applied to several firming processes successfully. Its key concept i s to trace backward and from the final desirable configuration to an interm ediate preform or initial blank. A program for initial blank design in shee t forming which contains the capabilities of forward loading simulation and backward tracing simulation has been developed and proven in effectiveness by applying it to a square cup stamping process. In the blank design of sq uare cup stamping, the backward tracing program can produce an appropriate blank configuration which forms a sound net-shape cup product without requi ring machining after forming. The blank design has been confirmed by a seri es of experiments, since the application of the backward tracing scheme was the first trial in the blank design of sheet metal forming. (C) 2001 Elsev ier Science B.V. All rights reserved.