Development of an inverse method for identification of materials parameters in the single point incremental sheet forming process

Summary. The purpose of this article is to develop an inverse method for adjusting the material parameters during single point incremental forming. The main idea consists in simulating tests performed on the same machine as the one used for the process itself. This reduces the costs of the equipment since no specific and costly standard test equipment is needed. Moreover, it has the advantage that the material parameters are fitted for a heterogeneous stress and strain state occurring during the real process. Before using the inverse method, the numerical results must be compared with the experimental ones. Several boundary conditions will be tested. 1. INTRODUCTION Single Point Incremental Forming (SPIF) is a new sheet metal forming process adapted to both rapid prototyping and small batch production at low cost. A clamped sheet is deformed by a smooth-ended tool following a specific tool path defining the final required shape without specific and costly dies. A wide variety of shapes can be made [1, 2]. Accuracy of the F.E.M. simulations of this process depends both on the constitutive law chosen and the identification of the material parameters. The study of the process shows that the anisotropic elastic-plastic HILL48 law is adapted for the description of the phenomenon. However it must be coupled with an isotropic and a kinematic hardening model. A simple isotropic model is not sufficient to provide an accurate force prediction [3].