FE simulation of rectangular box forming using material characteristics from the multi-dome forming test

摘要

The finite element (FE) simulation of superplastic rectangular box forming process was conducted to examine the validity of the material characteristics, stress-strain rate relationship, strain rate sensitivity, m, and strength coefficient, K, which have been obtained by utilising a multi-dome test. The simulation results were then compared with those obtained with material characteristics from the tensile jump test. The material characteristics m and K were included as variable parameters and a function of the strain rate in a special subroutine. The subroutine was linked to the FE simulation in order to investigate the correctness of the superplastic material characteristics. The influence of die shape factor (length-to-width-to-depth ratio) and die friction on the deformation behaviour and on the final thickness distribution was also demonstrated. The results of rectangular box forming simulation revealed that the multi-dome test can be used not only in simple processes (such as free bulge-forming) but also in more complex situations such as rectangular box forming process and with consideration of the friction between the sheet metal and the die surface.