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Energy absorption structure with necked‐down section possesses great application prospect owing to superior energy absorption ability. However, rare studies on this innovation structures were conducted. Therefore, an innovative energy absorption structure which consists of a composite tube and a trigger structure was proposed. In the trigger structure, necked‐down section is included. To investigate effect of thickness of composite tube, diameter variation and angle variation of the necked‐down section on energy absorption performance, 56 kinds of parameter configuration were generated, each of which was repeatedly tested three times. From the results of comprehensive experimental study, it can be concluded there were five different energy dissipation patterns for the proposed energy absorption structure. Different energy dissipation patterns were related to different failure modes. Brittle failure was featured by energy dissipation pattern I and II at stable energy dissipation stage while energy dissipation pattern III and IV played important role in progressive failure. Compared to the brittle failure mode, the SEA and force fluctuation ratio of the progressive failure mode increased and decreased by 48% and 52%, respectively. Energy absorption ability can be described by average compressive load capacity at stable energy dissipation stage, for which the theoretical model was developed. Effectiveness of proposed theoretical model was validated by comparing predicted average compressive load capacity with that obtained from experiment. [ABSTRACT FROM AUTHOR]

This paper proposed a novel periodic cellular structure by introducing re-entrant hexagon-shaped honeycombs and Miura origami geometry. The large-scale multi-layer metallic specimens were manufactured by a selective laser melting (SLM) system and tested for the first time. The compression deformation and energy absorption characteristics under quasi-static load were investigated thoroughly, considering three loading directions and various geometric parameters. The results show that this novel structure has balanced mechanical properties in the three loading directions. Among them, the z-direction is the best bearing direction. Moreover, this structure exhibits an obvious three-dimensional negative Poisson's ratio effect during the compression process. Besides the experimental study, the numerical investigation base on ANSYS/LS-DYNA was carried out to provide an accurate and effective simulation method. Predictive formulas for the critical energy absorption indexes were derived by theoretical analysis based on the rigid folding assumption, validated to be well-matched with the experimental results. [ABSTRACT FROM AUTHOR]