抄録
Bamboo is a natural unidirectional fiber-reinforced material and so it is mechanically anisotropic. In this study, the relationship between the Young's modulus in the tangential direction of cylindrical wall within internode and the volume fraction of bundle sheathes Vf or the specific gravity ρ was investigated on two samples of Mousou bamboo. The experimental results obtained are as follows:
(1) The Young's modulus in the tangential direction ET increased parabolically from the inner bark toward the outer bark in the cylindrical wall for both of the samples, and had a tendency of relative increase with height.
(2) ET could be approximated by the next equation.
ET=(1-C)Ef·Em/Ef(1-Vf)+Em·Vf+C{Ef·Vf+Em(1-Vf)}
where, Ef and Em are Young's moduli of bundle sheathes and parenchyma, respectively. C is the ratio (0≤C≤1) of a parallel model.
(3) The variation of specific gravity ρ among samples became large with increasing Vf when compared at the same Vf level. This is because the cell diameter of parenchyma differs with samples and the specific gravity increased with decreasing cell diameter of parenchyma.
(4) An approximate equation was established between ET and Vf. Consequently, ET could be evaluated by the measurement of ρ by means of the linear relationship between Vf and ρ.
