Experimental and numerical analysis of metal foams for the application as crash-energy-absorbing safety elements

Due to their excellent energy absorption capacity, closed-cell metal foams are candidate materials to be integrated in cars, trucks or railway systems as crash-absorbing safety elements. In order to exploit this potential to increase the passenger safety in transport vehicles, finite element simulations have been carried out to analyze the potential benefit of metal foam applications, e.g., in car seat elements. In a first step, simulations of the behavior of aluminum foams as stiffening elements for tubes and profiles in the case of a rear crash were made. The aluminum foam shall contribute to avoid buckling of the lower tube or profile. Further aluminum foam components were tested in a simulation as light-weight reinforcement between comfort polymer foam and metal structure. Here, the foam shall be used as an energy dissipater in order to reduce moments in the front seat recliners. In addition to the numerical simulation, monotonic and cyclic loading tests as well as metallographical studies were performed using various commercially available metal foams and foam-sheet sandwiches, e.g., Alulight foam, Foamtech foam, Pohltech-AFS sandwich with aluminum foam core and aluminum sheets and IWU-sandwich with foam core and steel sheets, which are promising candidates for the above-mentioned applications. The results are used in a LS-Dyna material model for finite element calculations.