Experimental and numerical investigation into the crashworthiness of metal-foam-composite hybrid structures

To meet the growing demands for structural lightweight and safety, metal-foam-composite hybrid tubular sandwich structures, which combine low-cost metallic materials and high-strength composites with low-density cellular materials, have been recently introduced to be a class of energy absorber configurations for automotive engineering. This study proposed four different hybrid sandwich tubes and investigated their crashworthiness and performance to cost ratio under quasi-static axial condition. For a comparative purpose, individual carbon fiber reinforced plastic (CFRP) tube, aluminum tubes and aluminum foam were also tested here. From the energy absorption perspective, it is found that all the hybrid specimens exceeded the sum of the individual components. Of different configurations, specimen C-F-C (i.e. outer CFRP tube + aluminum foam + inner CFRP tube) had the highest energy absorption capacity (in energy absorption): 6.70 kJ, specific energy absorption (SEA): 37.32 kJ/ kg, improvement of energy absorption: 39.1%, and material cost 6.877 pound, respectively. The specimen C-F-A (i.e. outer CFRP tube + aluminum foam + inner aluminum tube) exhibited the highest crushing force efficiency (0.87) and value-added performance of energy absorption (0.325 kJ/) pound. The specimen A-F-A (i.e. outer aluminum tube + aluminum foam + inner aluminum tube) exhibited the lowest peak crushing force (63.56 kN) and lowest material cost (2.227 ) pound. Further, the finite element (FE) model was established to analyze the crashworthiness characteristics of hybrid sandwich tubes through validating the simulation results with the experimental data, which provided a basis for further parametric analysis and structural optimization.