Interlaminar Fracture Properties of Bamboo

Abstract

In this chapter, Mode I, II, III interlaminar fracture properties of bamboo and the fracture mechanism are studied by double cantilever beam (DCB) method, end-notched flexure beam (ENF) method, modified split cantilever beam (MSCB), and split cantilever beam (SCB) method respectively. The results show that: (1) the Mode I, Mode II, and Mode III interlaminar fracture toughness (G_IC, G_IIC, and G_IIIC) of bamboo are the basic attributes of bamboo that represent the capacity of bamboo to resist the propagation of cracks; (2) On the Mode I fracture surfaces of bamboo, smooth fibers, and plane ground tissue are found, which indicate that the longitudinal interface strength was weak among bamboo cells. The Mode II fracture surfaces is rougher, and ground tissue is characterized by hackle shearing deformation, which indicates that a large amount of fracture energy would be absorbed by the shear deformation of ground tissue, and G_IIC ≈ 2.5 G_IC; From the Mode III fracture surface of bamboo, it can be seen that the resistance that hindered the propagation of interlaminar crack is contributed by the transverse shear strength of ground tissue cell wall and interface strength, and G_IIIC ≈ 4.0 G_IC; (3) The study on the toughness contribution of bamboo node to the interlaminar fracture toughness of bamboo and the mechanism show that $G_{\text{IC}}^{\text{Node}}$ ≈ 2.9 $G_{\text{IC}}^{\text{Internode}}$, $G_{\text{IIC}}^{\text{Node}}$ ≈ 1.3 $G_{\text{IIC}}^{\text{Internode}}$, and $G_{\text{IIIC}}^{\text{Node}}$ ≈ 2.7 $G_{\text{IIIC}}^{\text{Internode}}$, thus bamboo node can contribute a lot to hinder the interlaminar fracture of bamboo.