Energy absorption properties of composite tubes with hexagonal and re-entrant honeycomb fillers

•A novel composite tube with auxetic honeycomb filler is proposed.•The mechanical properties, deformation characteristics, and fracture modes of three specimens are investigated under three-point bending.•The auxetic honeycomb-filled composite tube exhibits better ductility and a lower degree of load drop after the occurrence of fracture.•The energy absorption performance of the composite tube is optimized by the method of multi-objective optimization. Compared to traditional materials, auxetic materials possess superior bending resistance and energy absorption properties due to their special deformation mechanism. To take advantage of these desirable properties, a novel composite tube with auxetic honeycomb filler was proposed in this work. The honeycomb filler of the composite tube was manufactured by 3D printing technology. The bending properties of two kinds of tubes were studied, namely aluminum tube with re-entrant honeycomb filler and aluminum tube with hexagonal honeycomb filler, respectively. The mechanical responses, deformational characteristics, and failure mechanism of the composite tube under three-point bending were studied by experimental and numerical methods. The study showed that the experiment and numerical results match well with each other. In addition, parametric analysis was carried out to examine the effects of filler and aluminum alloy tubes on the bending properties of the composite tube. Finally, kriging model and the non-dominated sorting genetic algorithm (NSGA-Ⅱ) are used to optimize the design of composite tubes, and the parameter solution with better energy absorption capacity is obtained.