Fibers of Bamboo and Hem Palm Tree
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Fibers of Bamboo and Hem Palm Tree Shigeyasu Amada (Gunma University, Japan) Abstract Bamboo is a typical composite material which is axially reinforced by very strong fibers. So that, the fibers play an important role for the bamboo structure. The elastic properties of the bamboo culm have been measured only by tensile test so far, which needs a large specimen. Recently ultra-sonic technique, which has a simple procedure and uses a small specimen, has been applied to woods as well as metals. This report reviews about the elastic properties of bamboo and Hemp palm fibers. The Young’s modulus and Poisson’s ratio of the bamboo fibers are measured by ultra-sonic method with a transmitting wave. On the other hand, the strength of the bamboo and Hemp palm fibers are measured by the tensile tests. Using the volume fraction of fibers in the specimen and mixture principle, the Young’s modulus and strength of the fibers and parenchyma were obtained. The fiber has a high strength up to 1GPa and an strong anisotropic property because its axial Young’s modulus has 7 times higher than the one in the transverse direction.
1.Introduction Bamboo is a typical composite material which is axially reinforced by very strong fibers. Furthermore the fiber distribution constructs a functionally grade structure which leads to a marvelous property for bamboo and other tress. Hence the fibers play an important role for the bamboo structure and other woods. The elastic properties of the bamboo culm have been measured only by tensile test so far, which needs a large specimen. Recently ultra-sonic technique, which has a simple procedure and uses a small specimen, has been applied to woods as well as metals. This report reviews about the elastic properties of bamboo and Hemp palm fibers. The Young’s modulus and Poisson’s ratio of the bamboo fibers are measured by ultra-sonic method with a transmitting wave. On the other hand, the strength of the bamboo and Hemp palm fibers are measured by the tensile tests. Using the volume fraction of
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fibers in the specimen and mixture principle, the Young’s modulus and strength of the fibers and parenchyma can be separated. Finally, a fiber structure is discussed based on the functionally graded materials. 2. Specimens and measurements The two types of specimens are provided for the measurements. One is the composite of the fiber and matrix called parenchyma. The other is a separated fiber from the matrix dissoluted by NaOH. The fiber strength is measured by tensile tests and Young’s modulus by tensile tests and ultra-sound approaches. 3. Fiber Properties (1) The bamboo fiber has a high strength, 0.5~1.0 GPa. On the other hand, the Hemp palm fiber has a lower one, ~0.38GPa. (2) Their elastic modulus gives about 46GPa for the bamboo and 0.7GPa for Hemp palm fiber. (3) The specific strength of the bamboo fiber shows 5.36X104m which is a little lower than the carbon fiber of 8.3X104m. (4) The fiber has also a micro-structure corresponding to a multi-layered cylinder which is made of a helical winding st
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