Crashworthy and Performance-cost Characteristics of Aluminum-CFRP Hybrid Tubes under Quasi-static Axial Loading

Metal/composite hybrid thin-walled structures combine the low cost of metallic materials and the high strength-toweight ratio of composites and thus have the potential to be utilized as cost-effective energy absorbers for vehicle applications. This study aimed to examine the crushing behaviors and performance-to-cost ratio of aluminum/carbon fiberreinforced plastic (CFRP) hybrid tubes under quasi-static axial loading. First, a single aluminum tube, a single CFRP tube and an aluminum/CFRP hybrid tube were tested to validate numerical models. The experimental results showed that the total energy absorption (EA) of the aluminum/CFRP hybrid tube was 32.46 % higher than the sum of that of the individual parts, and the special energy absorption (SEA) of the hybrid tube was improved by 105.26 % compared with that of the single aluminum tube. Then, the effects of the orientation angles ([+/- 15 degrees](n), [+/- 45 degrees](n), [+/- 75 degrees](n), [+/- 90 degrees](n), [90 degrees/0 degrees](n), n=2, 4, 6) and thicknesses of the CFRP tube wall (4-ply, 8-ply, 12-ply) on the crashworthiness of the hybrid tube were studied through validated numerical models. The numerical results showed that as the orientation angle increased, SEA, EA and the mean crushing force (F-mean) decreased first and then increased; in addition, the hybrid tubes with orientation angles of [+/- 45 degrees](n) and [90 degrees/0 degrees](n) (n=2, 4, 6) consistently exhibited the worst and best crashworthiness, respectively. Furthermore, the SEA, EA, and F-mean of the hybrid tube increased with increasing thickness of the CFRP tube wall. Finally, the performance-to-cost ratio (SEA/cost) of the hybrid tube was analyzed, and the results show that aluminum/CFRP hybrid tubes with a smaller wall thickness of the CFRP tube exhibits superior potential in terms of both cost and performance for automotive applications.