Crushing performance of multi-celled tubes fabricated by bending metal sheets

Novel folded multi-celled tubes (FMTs) fabricated by bending metal sheets were designed and introduced in this paper to achieve an effective balance between a lower initial peak force (IPF) and ease of manufacturing.The base computer model of the FMTs was corrected using physical experiment data. IPF, energy absorption (EA), mean crushing force (MCF) and specific energy absorption (SEA) served as crashworthiness indicators.Additionally, the effects of thickness, boundary conditions, welding configurations, and cross-sectional shapes on the energy absorption of FMTswere investigated, followed by a comparison of their crashworthiness with that of conventional multi-celled tubes (CMTs). The results demonstrated that FMTs outperform CMTs, achieving lower IP of up to 9.53% and offering improved manufacturability. Furthermore, FMTs featuring square-circle cross-sections demonstrated superior crashworthiness than the FMT with square-square cross-section shape. A multi-objective optimization method based on the NSGA-II algorithm was employed to further enhance crashworthiness. The optimal FMT configurations demonstrated energy absorption improvements of up to 367.05%, confirming the robustness and effectiveness of the optimization method. With their controllable collapse behavior, lower IPF, and versatile manufacturability, FMTs hold great promise for diverse engineering applications.