Influence of crush mechanisms on energy absorption of PMC square tubes

An experimental investigation was carried out to correlate the crushing res ponse of square unidirectional polymeric composite tubes with the associate d major failure modes in the crushing process. The failure modes of interes t included axial splitting, transverse cracking, and delamination. The effe ct of using external constraints on the crushing performance and energy abs orption capability of square tubes was also analyzed. The tubes used in the tests were unidirectional fiber-glass/polyester and fiber-glass/vinyl este r tubes. Tests were performed for flat crushing and using initiators with a 12-mm radius. The results showed that the external constraint can signific antly affect the major failure modes in the crushing process, leading to co nsiderable improvement in the specific energy absorption (SEA) of the tubes .