Optimization of a FEM Model for the Simulation of Metal Foams Deformation

This work deals with the formability of Aluminum Foam Sandwich (AFS) panels and it is focused on the FEM simulation of a compression processes. An experimental campaign, based on upsetting tests between flat parallel dies, analyses of density and foam cells distribution, was carried out to investigate the mechanical behaviour and the physical properties of commercial AFS. The panels were composed by a foam core with closed cells of AIMg3Si6 and coversheets of AA6082. Square specimens were extracted from panels having different thickness and a metallurgical bonding between cover-sheets and foam core. The results of this investigation were used to optimize a FEM model for the simulation, using the Deform 2D code, of metal foams deformation. The AFS panels were simulated by combining a rigid-plastic model for the coversheets and a porous material model for the metal foam. Moreover, an external routine tried to reproduce the non-homogeneous dimension of the foam cells into the sandwich panel; after the definition of the average value and the variation of the density, the routine creates a mesh having a random distribution of density. An inverse characterization method was applied to evaluate the optimal material law and to optimize the model. The model was finally validated by simulating a three point bending process.