Abstract
Change of relaxation properties of bamboo in the longitudinal and radial direction were examined on the basis of results of creep measurement and the micro-structure observation in cross section using the stereoscopic microscope. Creep compliance J(t) was greater in the bottom and inner side than in the top and outer side. J(t) versus ln(t) was represented by the Nutting equation. The number of vascular bundle per mm2, that is its dispersion, increases with locating to the top and outer side of bamboo. Various values of relaxation properties, J(t), J(t)-J(0), and dJ(t)/dlnt, was characterized by just density of bamboo which was linear to the number of vascular bundle per mm2. Our results show that bamboo changes relaxation properties in the longitudinal and radial direction by controlling the dispersion of vascular bundles.
