Research on the influence of the winding angle on the compression properties of bamboo tubular sections

Characterized with thin and hollow walls, bamboo has very few connective tissues in the transverse direction, and can be easily divided into thin bamboo strips. It is convenient to weave bamboo strips and wind them into loaded components since bamboo possesses good elasticity, flexibility and flexural ductility,. In this paper, the tensile properties of bamboo strips in parallel to the fiber directions were tested, and the relationship between their properties and the number of layers was analyzed. Circular tubes were manufactured using bamboo veneers by varying the winding angle (the angle between the longitudinal axis and the winding direction) to be tested under compression. Seven groups of tubular specimens were manufactured by varying the winding angle between 0 and 90 degrees with 4 identical specimens in each group. The load-displacement and stress-strain responses of each winding angle were investigated and the relationship between the key mechanical properties of tubular sections and the winding angle was analyzed. Obtained results indicate that with increase in the winding angle, the elastic modulus decreases and the ultimate displacement increases. The ultimate stress reached its maximum at a winding angle of 15 degrees.