针叶树木材细胞力学及纵向弹性模量的计算--试件纵向弹性模量的预测

依据针叶树木材管胞和射线细胞的结构模型。使用计算机抽样模拟解剖结构参数。以及使用针叶树木材纵向弹性模量计算公式和方法,计算人工林杉木,马尾松幼龄材和成熟材试件纵向弹性模量,计算结果与常温条件下气干试件测定结果十分符合。在试件晚材率和管胞解剖结构参数改变的条件下。计算预测了人工林杉木,马尾松幼龄材和成熟材纵向弹性模量的变化。结果表明：试件纵向弹性模量随晚材率,管胞长度,管胞壁厚度的增加而增加,而试件纵向弹性模量随管胞直径增加而减小。本文提出的纵向弹性模量计算的预测方法,对于运用现代生物技术控制和改变针叶树木材的材质,材性有实际意义。

MECHANICS OF WOOD CELL AND ESTIMATION OF LONGITUDINAL ELASTIC MODULUS OF SOFTWOOD --ESTIMATION OF LONGITUDINAL ELASTIC MODULUS OF SPECIMEN

Based on the models of tracheid and ray cell, and by means of computer sampling simulation, the longitudinal elastic moduli were evaluated with corresponding equations and calculating methods for juvenile and mature wood from plantation Chinese Fir(Cunninghamia lanceolata) and Masson Pine (Pinus massoniana).There was a great agreement between estimated values and measured values for the elastic moduli of two species. This research report presented a practical way to study on the longitudinal elastic modulus of wood from above two species and ones with similar structure, and it was useful to develop the theory on the mechanical behaviors of softwoods.Variations of the longitudinal elastic modulus were estimated for specimens from Chinese Fir and Masson Pine when latewood percentage and structural parameters of tracheid were changed in the specimens. Results showed that the longitudinal elastic moduli increased with increasing of latewood percentage, tracheid length,and thickness of cell wall, and it decreased with increasing of radial and tangential diameter of tracheid. Finding and conclusion in this paper can be used in the practice to improve the wood properties of softwood through using the modern biological technology.