The energy-absorbing characteristics of polymer foams reinforced with bamboo tubes

This paper investigates for the first time, the energy-absorbing characteristics of a range of lightweight bamboo-reinforced foam structures. Initial attention focuses on characterizing the energy-absorbing characteristics of the individual bamboo tubes and assessing the influence of tube geometry on energy absorption. Here, it has been shown that the specific energy absorption of the bamboo tubes decreases with increasing tube length as a result of axial splitting associated with barreling of the samples under compressive loading. The influence of the tube inner diameter/thickness (D/t) ratio was also investigated using a number of tube sizes, where it was shown that there is a small increase in specific energy absorption with decreasing D/t. The tubes were then embedded in crosslinked PVC foams in order to investigate the influence of varying degree of external support applied to the reinforcement on the failure modes in the tubes as well as the measured specific energy absorption values. Finally, alternative techniques for enhancing the energy-absorbing capacity of the tubes were investigated. Here, tubes of different length were wrapped circumferentially in epoxy-impregnated kenaf fibers to enhance their resistance to axial spitting. It was shown that reinforcing the tubes in this manner can significantly enhance the ability of the tubes to absorb energy under conditions of axial quasi-static crushing.