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Vertical axis on the graph is an axial load quantity. 53 per cent more energy is absorbed by crushing the tube via a semi-circular “trigger” at the top of the tube.
FROM:
Yan Tong and Yuanming Xu (School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China),
“Improvement of crash energy absorption of 2D braided composite tubes through an innovative chamfer external triggers”, International Journal of Impact Engineering, Vol. 111, pp 11-20, January 2018, https://doi.org/10.1016/j.ijimpeng.2017.08.002
ABSTRACT: Braided composites tubes have been reported to have a great potential in crash energy absorption applications. In this study, an innovative chamfer external trigger was introduced which is different from the traditional chamfer-flat crush-cap to guide the 2D braided tube. To make the material fully destroyed in the impact process, the innovative trigger restricts the space of tube under compression by a semi-circle cavity. A 3D-FE model for impacting processes of thin-walled braided tubes was built to study the effects of geometrical parameters on external trigger guiding tubes. Simulation and analysis of the influence laws of geometrical parameters on the cavity were then carried out. The results show that braided tubes worked with cavity effect can increase the energy absorption efficiency by 53% than traditional crush-cap, and the result and failure mechanism is significantly affected by the ratio of cavity radius of tube thickness(R/t). It is found that as the R/t ratio increases, the amount specimen energy absorption increases sharply then decreases and tend to be stable, while the ratio of peak load to mean load decreases and then increases. These two trends are very instructive for designing effective energy absorption structures using braided tubes with this innovative external trigger.
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