An experimental study on the effect of failure trigger mechanisms on the energy absorption capability of CFRP tubes under axial compression

The energy absorption characteristics of graphite/epoxy tubes of circular cross sections, subjected to quasi-static axial compression, were experimentally investigated. Tubes with chamfered-ends, inward-folding or outward-splaying crush-caps, or combined (chamfered-end and crush-cap) failure trigger mechanisms, were investigated to identify the optimal configuration that would result in the lowest initial peak load while providing the highest possible specific energy absorption (SEA). The chamfer failure trigger proved to be the most effective at lowering the initial peak load while yielding a high SEA. The inward-folding crush-caps were more effective than the outward-splaying crush-caps in terms of decreasing the initial peak load and increasing the SEA. These results were significantly affected by the corner radii of the crush-caps: the smaller the radius the higher the initial peak load and the SEA. It was determined that combining a chamfered tube with an inward-folding crush-cap yielded the lowest initial peak load and the highest SEA.