The main idea of this paper is to improve our knowledge on metal forming when the initial sheet is a bimaterial that is to say with two materials in the thickness. First of all, the behaviour of both materials (aluminium and steel) is studied separately to know their elastoplastic behaviour; afterwards, the behaviour of the bimaterial is studied. Then, an experiment design is done by simulating with a finite element code the forming, with a specific punch, on the bimaterial. The aim of the experimental design is to understand which proportion of each material is better according to the final geometry of the part. This study is both experimental and numerical and bring highlighting on the plastic behaviour of a bimaterial showing cross effects.

In order to earn time and raw material, engineers are developing products which are forming from strips with two different materials. In the studied example, a strip with aluminium and steel is used for the qualities of each component: aluminium for its friction properties and steel for cheap mechanical resistance.

An experimental design is achieved on a press with the same strip. The width and the height of the punch can be modified (Figure 1). The idea is then to compare this experimental design with the results given by a numerical simulation (Figure 2). All the precautions have been taken to have a predictive simulation [1].

Thanks to this work, it is possible to use the finite element as a virtual press and to find the best proportion of each material for this application. It is a track toward a better understanding of heterogeneous materials such as dual phase steels for example.