Energy absorption properties of braided glass/epoxy tubes subjected to quasi-static axial crushing

Quasi-static axial compression tests were performed to study the failure mechanisms and energy absorption capabilities of braided composite circular tubes. The effect of braiding parameters and chamfer initiators on energy absorption was investigated. The braided preforms consisted of various triaxial architectures using S-glass. It was found that tubes with external chamfers were crushed progressively, but unchamfered tubes failed catastrophically. The crushing response of glass/epoxy braided tubes can be categorised into four basic modes: splaying, fragmental fracture, progressive folding and catastrophic failure. The levels of the mean crush load and specific energy absorption are determined by the energy absorption mechanisms, which are related to the dominant failure modes of the tubes. The specific energy absorption of the braided tubes with these four different failure modes follows the sequence of splaying, fragmentation, progressive folding and catastrophic failure.