落叶松生材12个弹性常数的试验研究

以含水率为95%的落叶松生材为研究对象，将纵向、弦向和径向定义为3个弹性对称主轴，将材料看作是正交各向异性体，分别采用电测法单向压缩试验和三点弯试验得到了材料的12个弹性常数。按美国试验与材料协会制定的试验标准（ASTM标准）进行加工制备，由压缩试验得到了材料3个主轴方向的弹性模量和RT面内的剪切模量，测定得到的弹性模量与泊松比基本满足Maxwell定理，说明通过电测法测定得到的数据可靠有效。通过三点弯试验得到了LT和LR面内的剪切模量，对试验数据线性回归分析知，高跨比的平方与抗弯弹性模量的倒数到的相关系数分别为0.99和0.94，说明数据的测定与计算合理有效。为应力波在落叶松活立木中传播的数值模拟研究提供模型参数。

Twelve Elastic Constant Values of Larch Forest

Taking green larch (Larix principis-rupprechtii Mayr) with a moisture content of 95% as the study object, the longitudinal (L), tangential (T) and radial (R) orientation were defined as three elastic symmetric axes, and the materials were considered as a orthotropic bodies, twelve elastic constants of the material were obtained by uniaxial compression of electrical testing method and three-point bending experiments. The timber specimens were prepared by American Society for Testing and Materials (ASTM) standard. The elastic modulus of the material in three main axis directions and the shear modulus in RT-plane were obtained by compression experiments, by which the modulus were basically within Poisson’s ratio and Maxwell theorem, indicating its reliability. The shear moduli of LT-plane and LR-plane were obtained by three-point bending experiments. Through the linear regression analysis on experimental data, it was known that the correlation coefficients of the square of span-depth ratio and the recip of flexural modulus of elasticity were 0.99 and 0.94, respectively, indicating that the measured and calculated data were reasonable and effective. The results would provide the model parameters for numerical simulation of stress wave propagation in larch forest.