Mechanical Behavior of Foam-Filled Bamboo Composite Tubes under Axial Compression

In this paper, a new type of polyurethane foam-filled bamboo composite tube is proposed. Axial compression tests were carried out on unfilled and polyurethane foam-filled bamboo composite tubes. The effects of the foam filler, diameter (50 and 100 mm) and number of winding layers (10, 15 and 20 layers) on the failure mode and energy absorption capacity of the tubes were studied. The test results showed that the failure mode of the unfilled tube was buckling failure, while that of the foam-filled tube was pressure-bearing failure, and the latter was more abrupt. The foam filler enhanced the stability of the wall of the unfilled tube. The interaction between them further increased the bearing capacity of the foam-filled tube and showed a higher platform load at a later stage. In terms of the absorbed energy, specific absorbed energy and average crush load, not all foam-filled tubes were superior to unfilled tubes. However, reducing the height of the bamboo composite tube and increasing the number of winding layers of the bamboo composite tube can effectively increase the positive effect of the foam filler on energy absorption.