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鹅掌楸天然林木材物理力学及垂直变异特性研究

A Study of Wood Physical and Mechanical Properties and Vertical Variation Characteristics of Natural Liriodendron chinense Forest

  • 摘要: 对鹅掌楸天然林木材物理力学与垂直变异进行了测定分析,结果表明:鹅掌楸天然林木材的基本密度、全干密度和气干密度分别为0.352 g·cm-3、0.396 g·cm-3和0.558 g·cm-3,基本密度、全干密度和气干密度性状在垂直方向均为上部 > 中部 > 下部,各部位的差异极显著。木材气干状态时体积干缩率为7.21%,全干状态时干缩率为2.54%;从全干到气干时,木材体积湿胀率为4.54%;从气干到吸水饱和时,木材体积湿胀率为12.41%;在垂直方向上,木材的体积干缩率为上部 > 下部 > 中部,而体积湿胀率为上部 > 中部 > 下部,且不同部位出体积干缩湿胀性在垂直方向上存在差异性显著。木材的顺纹抗压强度和抗弯强度分别为34.7 MPa和53.22 MPa;横面、弦面和径面的硬度分别为3.49 kN、2.55 kN和2.45 kN;在垂直方向上,木材的顺纹抗压强度、抗弯强度、横面硬度和径面硬度表现出上部 > 中部 > 下部的规律。由此可知,鹅掌楸天然林木材密度属轻中等水平,顺纹抗压、抗弯性能及硬度属一般水平,是适合加工利用的树种。

     

    Abstract: Studies were made of the physical and mechanical properties and its vertical variation of Liriodendron chinense wood from natural forest.The results showed the wood basic density(BD),over-dry density(DD)and air-dry density(AD)were respectively 0.352 g·cm-3,0.396 g·cm-3 and 0.558 g·cm-3.The characteristics of BD,DD and AD displayed the upper > middle > lower parts in the vertical direction,and the difference was very significant.The wood volume shrinkage ratio of natural L.chinense forest under air-drying condition were 7.21%,while under oven-dry condition,it was 2.54%.The wet expansion rate of wood volume was 4.54% from oven-dry to air-dry,while the volume wet expansion rate of wood was 12.41% from air-dry to water absorption.The wood shrinkage was the upper > the lower > the middle part in the vertical direction,while the volume wetting rate was the the upper part > the middle part > the lower part.The volume dry shrinkage dampness was different in the vertical direction.The compressive strength and flexural strength of the wood were 34.7 MPa and 53.22 MPa,respectively.The hardness of the transverse,chord and diameter surfaces were 3.49 kN,2.55 kN and 2.45 kN,respectively.In the vertical direction,the CIS compressive strength,bending strength,transverse hardness and the hardness of the diameter surface of wood showed the rule of the upper part > the middle part > the lower part.It was proved that wood density of natural forest of L. chinense was a light medium level,and its CIS compression,bending resistance and hardness were general level.The wood of L. chinense was suitable for processing and utilization.

     

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