Energy Absorption of Aluminium Extrusions Filled with Cellular Materials Under Axial Crushing: Study of the Interaction Effect

This investigation focuses on the interaction effect during the quasi-static axial crushing of circular and square thin-walled aluminium extrusions filled with polymeric foam or cork. The increment in the absorbed energy due to interactions between materials was assessed using a validated numerical model calibrated with experimental material data. Simulations were run with variable cross-section dimensions, thickness, and foam density. The results were used to adjust the parameters of design formulas to predict the average crush forces of foam- and cork-filled thin-walled tubes. The analysis of the energy dissipation per unit volume revealed that the highest increments due to the interaction between materials appeared in the foam-filled square extrusions. Energy dissipation increased with higher density foams for both cross-sections due to a stronger constraint of the aluminium walls, and thus a reduction of the folding length. Thinner tube walls also delivered a higher improvement in the energy dissipation per unit volume than those with thicker walls. The contribution of friction was also quantified and investigated.