Crashworthiness design of self-similar graded honeycomb-filled composite circular structures

Lightweight cellular materials can effectively improve the crashworthiness of thin-walled structure. To further investigate the potential of honeycomb-filled composite structures, an innovative self-similar graded honeycomb-filled thin-walled structure is proposed in this paper. First, the numerical model of the self-similar graded honeycomb-filled circular tube (SGHCT) is established in ABAQUS and then is validated via the existing experiment. To systematically study the bending behavior of this novel structure, eight kinds of SGHCT with different graded patterns are designed and compared with uniform honeycomb-filled circular tube (UHCT). Through parametric study, we find that the novel structure exhibits better energy absorption characteristics than the corresponding UHCT. In addition, various parameters like thickness, mass ratio and yield stress of column wall have a considerable effect on the crashworthiness performance of this innovative structure. Furthermore, the bending behaviors of effective SGHCT are also investigated to increase the weight efficiency. Finally, the SGHT and UHCT are optimized by adopting the non-dominated sorting genetic algorithm II (NSGA-II) and Kriging modeling technique. The optimization results show that the SGHCTs show superior Pareto solutions to the uniform honeycomb-filled tubes, also better crashworthiness than foam-filled tubes under high PCF conditions in the previous researches. Especially, the specific energy absorption of ascending single-direction self-similar tube increases from 1.17 kJ/kg to 1.74 kJ/kg by 48.9%. The findings of this study offer a new route of designing novel crashworthiness structure with high energy absorption capacity. (C) 2019 Elsevier Ltd. All rights reserved.