Within-stem variations in mechanical properties of Melia azedarach planted in northern Vietnam
Within-stem variations in mechanical properties of Melia azedarach planted in northern Vietnam
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越南北部种植的苦楝机械特性的茎内变化
DOI：
10.1007/s10086-018-1725-9
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发表时间：
2018
影响因子：
2.9
通讯作者：
J. Matsumura
中科院分区：
文献类型：
--
作者：
Doan Van Duong;J. Matsumura
采用破坏性和非破坏性方法研究了越南北方两个地点17-19年生苦楝（Melia azedaracha）的茎内力学性质的变化。木材样品收集从10，50，和90%的径向长度从髓两侧（北和南）在0.3，1.3，3.3，5.3，和7.3米的高度以上的地面。木材密度（WD）、抗折模量（莫尔）、弹性模量（莫伊）和动态弹性模量（艾德）在12%含水率下的全木平均值分别为0.51 g/cm ~ 3、78.58 MPa、9.26 GPa和10.93 GPa。在股骨柄内，径向位置是机械性能变化的高度（p< 0.001）显著来源。莫尔、莫伊和弹性模量从髓心到树皮呈递增趋势。WD与莫尔（r= 0.85，p < 0.001）和莫伊（r= 0.73，p < 0.001）均呈显著正相关。这表明通过控制WD来改善机械性能是潜在可能的。莫尔与ED也有较强的线性关系（r= 0.84，p < 0.001）。这表明，在已知被测元素密度的情况下，Ed是预测木材强度的一个很好的指标。此外，本研究所采用的应力波法为确定越南北方苦楝的刚度提供了较为准确的信息。
Within-stem variations in the mechanical properties of 17–19-year-oldMelia azedarachplanted in two sites in northern Vietnam were examined by destructive and nondestructive methods. Wood samples were collected from 10, 50, and 90% of the radial length from pith on both sides (North and South) at 0.3, 1.3, 3.3, 5.3, and 7.3 m heights above the ground. The mean values in whole trees of wood density (WD), modulus of rupture (MOR), modulus of elasticity (MOE), and dynamic modulus of elasticity (Ed) at 12% moisture content were 0.51 g/cm3, 78.58 MPa, 9.26 GPa, and 10.93 GPa, respectively. Within the stem, the radial position was a highly (p< 0.001) significant source of variation in mechanical properties. MOR, MOE, andEdincreased from pith to bark. WD had a strong positive linear relationship with both MOR (r= 0.85,p< 0.001) and MOE (r= 0.73,p< 0.001). This suggests that it is potentially possible to improve mechanical properties through controlling WD. MOR had also a strong linear relationship withEd(r= 0.84,p< 0.001). This indicates thatEdis a good indicator to predicting the strength of wood if the density of measured element is known. Besides, the stress wave method used in this study provides relatively accurate information for determining the stiffness ofMelia azedarachplanted in northern Vietnam.