Failure analysis and multi-objective optimization of crashworthiness of variable thickness Al-CFRP hybrid tubes under multiple loading conditions

Different structural parameters and interlaminar damage will have significant effects on the crushing performance of metal-composite hybrid structures. A hybrid gradient structure is proposed in this paper. By varying the external CFRP thickness of the hybrid tube, realize the gradient of the crushing performance of AI-CFRP hybrid tube. Considering the above effects, under the different loading angles, it has realized that the optimization design of comprehensive crushing performance of Al-CFRP hybrid gradient structure. The results indicated that compared with pure Al tube and hybrid structure, hybrid gradient structure has obvious performance advantages; during the compression process, the damage initiation point is at the tip of the crushing end of the tube. The matrix damage evolution shows strong directionality, and the matrix tensile stress of CFRP is the main cause of interlaminar damage. Compared with the specific energy absorption, the variation pattern of the delamination rate of the hybrid gradient tube shows similar regulation. Compared with the gradient hybrid tube under the structural parameters of the specimen, the peak crushing force under the optimal structural parameters (in Case 1) is reduced by 36.07%, and the specific energy absorption (in Case 3) is increased by 23.24%.