Fiber texture and mechanical graded structure of bamboo

Among plants, bamboo has an unique structure which resembles that of a unidirectional, fiber-reinforced composite with many nodes along its length. Furthermore, bamboo's growth rate is very fast, producing an adult tree in only one year. This paper demonstrates that bamboo has a functionally graded and hierarchical structure. Bamboo's diameter, thickness and internodal length have a macroscopically graded structure while the fiber distribution exhibits a microscopically graded architecture, which lead to smart properties of bamboo. The reinforcing fibers are oriented along the bamboo's culm (trunk), whereas in the nodes the fibers become entangled in a complicated manner to produce nodes with isotropic properties that provide additional reinforcement for the culm.