New method for finding initial guess of original blank in inverse finite element of sheet metal forming

Abstract

Traditionally, sheet metal forming processes are modelled using incremental Finite Element Modelling (FEM) methods. Although this is accurate, incremental FEM is very expensive in computation. Recently, the so‐called one‐step FEM, also called inverse FEM, has been developed. With acceptable accuracy, the one‐step FEM method can find the strain distribution and the initial blank shape in minutes instead of hours. However, the current versions of one‐step FEM suffer from a number of limitations, one of which is the ability to handle complex parts, such as those having multiple peaks and cavities. To solve this problem, the key is to find the initial blank profile. This study presents a new method, referred to as the modified arch‐length method. This new method is capable of finding the initial blank profile for any parts, including those having multiple peaks and cavities. The present study contains the technical details and two demonstration examples.

Keywords:

• Modified arch‐length method
• Sheet metal forming
• One‐step FEM

The project is partially supported by the Foundation of the State Key Lab of Materials Processing and Die and Mold Technology, HUST, also by SRF for ROCS, SEM and by a research grant (UIM/94) from Mansfield Manufacturing Co. Ltd. and Hong Kong Innovation and Technology Commission.