Improvement of crash energy absorption of 2D braided composite tubes through an innovative chamfer external triggers

- Circular cavity external triggers for composite tube are proposed.
- Improved external trigger enhance energy absorption capacity over 50%.
- The finite element model of braided tubes with trigger is established and verified.
- The effect of this structure under different geometrical parameters is obtained.

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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