A simplified finite element method called the Inverse Approach has been developed to estimate the large elastoplastic strains in thin metallic panels. The Inverse Approach mainly exploits the knowledge of the 3D shape of the final workpiece. A non linear iterative scheme is used to find the original position of each material point in the initial flat blank and then it is possible to estimate the strains and stresses in the final workpiece. Important assumptions are adopted regarding the constitutive equations (the deformation theory of plasticity) and the action of the tools (the punch, die and blank holders). The I.A. implies only two degree of freedom per node even if bending effects are considered. In this paper, we present several recent developments: 1) The bending effects are taken into account using a simple triangular shell element without increasing the number of the dof per node. 2) Some analytical formulas are introduced to consider the restraining forces due to the drawbeads. 3) Some improvements of resolution algorithms such as the introduction of a relaxation coefficient, a damping factor and a good initial solution are realized. The results are compared with other numerical and experimental results for some academic and industrial problems.

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