木材横纹压缩大变形过程测定与分析

Measurement and Analysis of Large Compressive Deformation of Wood in the Transverse Direction

以采自我国东北林区１１个树种的木材为试材，设置水分饱和２０、１００℃和气干２０℃三种测试条件，对不同树种的试材，分别进行径向和弦向的大变形压缩试验。以力学试验机、绘图仪、Ａ／Ｄ转换器、电子计算机构成数字化采集系统，连续采集压缩过程中的变形及载荷数据，转换为应力—应变数据文件。经数学推导和统计分析，得出能够揭示木材横纹压缩大变形全过程，较完善地定量描述常用树种的各种压缩条件下应力—应变关系的数学表达式。比较分析了不同构造类型（针叶树材、阔叶树材、散孔材、半散孔材和环孔材）的木材横纹压缩力学指标参数在径向和弦向上的差异。

The samples of 11 species used in this study came from the Northeast forestry region. The tests of the large compressive deformatoin in the radial and tangential directions have been carried out under three conditions, the wet condition at 20℃, wet condition at 100℃ and the air-dried condition at 20℃. The digital collecting system is composed of the mechanical testing machine, mapper, A/D converter and computer. The data of deformation obtained in the tests of continuous compression were translated into the stress-strain data file. By statistical analysis the formulas of the large compressive defomation of wood in the transverse direction were obtained, which could quantitatively describe the stree-strain relationships under the various compressive conditions. The adaptability of the formulas were valid for various species used in this study under the most of conditions. The correlation codfficients were large than 0.99. The caculated values fit the experiment well. This study also compared the difference of the large compression deformation between the radial and tangential directions among the different kinds of structures (hard wood, soft wood, ring-pored wood, semi-diffuse-porous wood and diffuse-porous wood), and analyzed the effects of wood on the difference.