按照中国国家标准研究杉木和I-214杨树木材的抗弯弹性模量、抗弯强度、顺纹抗压强度和密度,同时按照日本国家标准研究2个树种的顺纹抗剪强度.结果表明:杉木的抗弯强度、顺纹抗压强度和密度由胸高直径处向上呈波浪形增加,抗弯弹性模量则稳定降低,但不同高度间杉木的物理力学性质没有显著差异;近树皮处木材的物理力学性质高于近髓心处木材,并有极显著差异.对于I-214杨树,只有抗弯弹性模量从髓心到树皮逐渐增加,其他的物理力学性质,最小值在从髓心到树皮的过渡区,最大值在近树皮处,从髓心到树皮,杨树的物理力学性质有极显著的差异.杉木和杨树的径面顺纹抗剪强度从髓心到树皮有极显著差异,并且近树皮的高于近髓心的木材,而弦面顺纹抗剪强度从髓心到树皮没有显著差异.木材密度与力学性质有很好的线性相关关系,木材密度是一个很好的力学强度的预测手段.%Chinese Fir and poplar are very popular plantation species in China. Better understanding of the variability of mechanical properties within a tree will result in economic and effective utilization of these two species. The MOR( modulus of rupture), MOE(modulus of elasticity), compression strength parallel to grain, shear strength parallel to grain and wood density were studied. The results showed: The MOR, compression strength parallel to grain and wood density of Chinese Fir increased wavelike from butt to top while MOE decreased contrarily. They had no statistically significant difference (at 5 % level) between heights. Outer wood had higher properties than core wood, and all physic-mechanical properties had a statistically significant (at 1% level) different between core wood and outer wood. Only the MOE of I-214 poplar wood increased steadily from pith to bark,and the MOR in north direction had the same trend. As to other physic-mechanical properties, the lowest value appeared in the transition section while the highest value appeared near the bark. All the physic-mechanical properties had a statistically significant (at 1% level) different between position from pith to bark. Shear strength of core wood was lower than outer wood in radial section, and there was a statistically significant (at 1% level) difference between core wood and outer wood, not only Chinese Fir but also I-214 poplar. On the other hand, the shear strength of core wood was a little higher than outer wood in tangential section, but they had no statistically significant difference. Wood density had positive linear relationship with other mechanical properties, so wood density proved to be a good predictor for wood quality.
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