Issue 35

T. Haiyan, Frattura ed Integrità Strutturale, 35 (2016) 472-480; DOI: 10.3221/IGF-ESIS.35.53 472 Damage of bamboo and wooden materials based on linear elastic fracture mechanics in garden design Tang Haiyan City College of Science and Technology.Chongqing University, Chongqing, 402167, China tanghaiyan23@sina.com A BSTRACT . Bamboo and wood are the most widely applied and the oldest natural structural materials in the world. Currently, worldwide output of wooden material is 1 billion ton, almost the same as steel. Most of them are used as structure, such as load carrying girder, scaffold, floor and support. Wooden materials and bamboo materials with clear microstructure are composite biomaterials which can be studied under multiple scales. Irregular evolution behaviors of initial defects or damage during loading determines macro mechanical behavior of wooden and bamboo materials. Taking wood and bamboo as test materials, this study explored mechanical characteristics and damage crack behavior of wood and bamboo as well as toughening mechanism. K EYWORDS . Wooden material; Bamboo material; Damage and crack; Strengthening and toughening mechanism. I NTRODUCTION ood and bamboo with special garden aesthetic features play significantly important roles in classical or modern garden landscaping. Wood and bamboo are natural structural materials which are the oldest and the most extensively applied worldwide. Long before, people have used bamboo to build bamboo house and make scaffold and bamboo ladder. Thus it is of great significance to study strength of natural structural materials and understand damage behavior for design and safety evaluation of bamboo and wooden structure. Mechanism of crack of materials and how to control occurrence of crack incidents are always being explored by material science researchers and engineering technicians [1]. He et al. [2] replaced bamboo joint with equivalent crack length Lc which stands for the length of crack produced by clear specimen bearing a stress the same as which results in initial cracking on burl specimen, but the method is only applicable for cross grain tensile loading. Shao [3] proved that crack expanded in a direction that is vertical to notch, even under parallel-to-grain stress. Moreover, Deng et al. carried out a study on type I crack on two hard woods and softwoods using acoustic emission monitoring device. Someone has also found that old wooden material is easier to produce small amplitude acoustic emission signal compared to new wooden material [5]. Ying et al. [6] once explore physical mechanical properties of bamboo, and Yong et al. [7] compared banding property between bamboo and wood. Compared to crack of W