To take into account the lightweight and collision safety of the energy absorber, metal-composite hybrid thin-walled tubes have been widely studied, which combine the low-cost metal and high-strength composites. Therefore, the deformation mechanism and the characteristics of the carbon fiber reinforced plastic wound thin-walled aluminum tube (Al-CFRP) were investigated under radial compression condition. Firstly, aluminum tubes, CFRP tubes, and four winding angles of Al-CFRP hybrid tubes (27 , 45 , 74 , 90) are experimentally analyzed. The contrastive results show that the stability and energy absorption of the Al-CFRP hybrid tube are improved and the winding angle is one of the important factors that affects the radial compression performance of the hybrid tube. And then based on the hybrid model, some theoretical relations are derived to forecast the initial collapse force and energy absorption quickly. The theoretical analysis shows that the radial force on the hybrid tube during the compression is also dependent on the thickness ratio of Al-CFRP layers complicatedly except the winding angle. Therefore, the effects of the winding angle (0-90) and thickness ratio of Al-CFRP layers (0.25-3.5) on the radial compression performance are investigated. The theoretical predication results show that the hybrid with the winding angle of 90 and thickness ratio of Al-CFRP layers of 0.25 performs over six times of the initial collapse force than the Al tube. Finally, the simulated model based on ANSYS and LS-DYNA is established to explain the reason for the better radial compression performance (A5C10S90) and the deformation mechanism of the hybrid tube, through the stress analysis of inner Al tube, inner CFRP layer, and outer CFRP layer, respectively. It is found that the Al-CFRP hybrid tube (especially 90) under radial compression shows better bearing capacity which represents the higher initial collapse force, total energy absorption and specific energy absorption, due to the supporting of the inner Al tube and the protection of the outer CFRP tube.

Reasonable design of induced holes on thin-walled structure is beneficial to enhance the crashworthy performance of the structure. In order to improve the crashworthiness of Al/carbon fiber-reinforced polymer (CFRP) tube, the effect of induced holes on the Al/CFRP thin-walled structure was studied, and the Al/CFRP tube configuration with better overall crashworthiness was obtained by multi-objective optimization design method. First, the quasi-static axial compression tests were carried out on the intact Al/CFRP tube and the Al/CFRP tube with induced holes, and a numerical model validated by the experiment was established. Second, the parameters of the induced hole were studied numerically to explore the influence of the induced holes on the crashworthiness of the Al/CFRP tube. It was found that the diameter and number of the induced hole had a great influence on the crashworthiness and energy absorption (EA) capacity. Finally, the multi-objective optimization was performed to optimize the parameters of the induced holes by integrating the Kriging model technique and the nondominated sorting genetic algorithm (NSGA-II). Compared the optimal design with the intact Al/CFRP tube, the first peak load is reduced by 24.32% and the specific EA is slightly improved by 0.68%.

As a kind of lightweight structure with great economic benefits, metal/composite hybrid structure is raising rapidly among automobile safety components due to its excellent anti-collision performance. In this paper, a new design was developed by introducing an induced circular hole to improve the energy absorption performance of the AL/CFRP hybrid thin-walled tubes under different loading conditions. Quasi-static experiments and finite element simulation were carried out on the hybrid tubular sample with induced circular holes, and the crash resistance of the number and diameter of induced round holes under different loading angles (θ) of 0 ,10 , 20 , and 30 was analyzed through the verified finite element model. The results showed that the induction hole can effectively reduce the peak load and improve the energy absorption characteristics of the hybrid thin-walled tube under the axial (0) load. Under the inclined load, the energy absorption capacity of all samples decreased to different degrees with increasing loading angle, and the induced hole changed the deformation mode of the hybrid tube, especially under the 30 loading angle. The complex proportional assessment is then implemented on the optimal structures, and specific energy absorption, peak crush force, and crush force efficiency were selected as the objective functions to improve the overall impact resistance under different loading angles. Considering three design cases, the AL/CFRP hybrid thin-walled structure with three groups of induced holes are finally found as the best energy absorbing devices. The work in this paper can provide a guide for the design of advanced energy absorbing devices for arbitrary loading condition.