Aluminum foam sandwich with adhesive bonding: Computational modeling

A numerical approach to simulate the delamination effect occurring in metal foam composites is being presented in this work. It is shown that in order to create reliable numerical models to simulate general components produced with aluminum metal foam sandwiches, the delamination effect of the aluminum skins from the metal foam must be considered. Delamination occurs within the polyurethane adhesive layer, causing the loss of the structural integrity of the structure. Foam is not a continuum medium, nevertheless, when simulating foam structures, foam is commonly assumed as a continuum, with homogeneous properties. This approach requires the calibration of the mechanical properties of the polyurethane adhesive layer, in order to compensate the effect of the foam's discontinuous structure. The finite element method was used to numerically simulate a three-points bending test and an unconstrained bending test. The cohesive behavior was modelled by using a traction separation law. For the damage initiation criteria, a maximum-stress-based criterion was used, whereas for the damage evolution, a displacement-based damage evolution law was adopted. The experimental data were obtained from the group's previous work, including a compression test, a tension test, a three-points bending test, and an unconstrained bending test.