Abstract: A novel multi-step inverse analysis method based on the principle of virtue work is proposed. Elasto-plastic material model is adopted to improve calculation accuracy. In order to fully consider the actual forming condition such as elas-tic/plastic deformation or loading/unloading, a modified consti-tutive equation for multi-step inverse analysis method is pre-sented. A new “double section curve expanding method” is proposed to get initial solutions of intermediate configurations which can take into account of plastic deformation characteris-tics. A fast and reliable local and global combined searching scheme is used to restrain the moving of corresponding nodes. Above mentioned improvements are implemented in our in-house inverse analysis software InverStamp/Multi-step mod-ule. The presented algorithms are applied to a square cup multi-stage drawing example. The numerical results compared to ls-dyna based software Dynaform confirm their validity and efficiency.

Key words: Multi-step inverse analysis, One-step inverse analysis, Sheet metal forming