Experimental and theoretical study on an innovative energy absorption structure comprised of composite materials with necked-down section subject to axial compressive load

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.