髓心、心材和边材的比例对应力波在活立木中传播影响数值模拟研究  

Numerical Simulation Study on the Effect of Ratio of Pith,Heartwood and Sapwood on Propagation of Stress Wave in Standing Trees

作　　者：赵扬 刘丰禄 李国梁 ZHAO Yang;LIU Fenglu;LI Guoliang(School of Mechanical and Electrical Engineering,Fujian Agriculture and Forestry University,Fuzhou,Fujian 350108,China)

机构地区：[1]福建农林大学机电工程学院,福建福州350108

出　　处：《福建农机》2022年第3期17-22,30,共7页Fujian Agricultural Machinery

基　　金：福建省教育厅中青年教师教育科研项目(JAT200098);福建农林大学科技创新专项基金项目(KFA20103A)。

摘　　要：基于固体介质中的应力波传播理论和弹性力学理论,将活立木看作是由髓心层、心材层和边材层组成的三层结构材料,假定活立木具有正交各向异性,利用COMSOL Multiphysics有限元仿真软件对应力波在活立木中的传播过程进行模拟计算与分析,研究了髓心、心材和边材的比例对应力波在活立木中传播的影响。结果表明,在髓心、心材和边材比例不同的活立木模型中,应力波的传播形式和传播规律基本相同,在开始阶段都是以倾斜曲面的形式传播,之后,随着传播距离的增大,波阵面的倾斜程度逐渐减小,且这个波阵面逐渐趋向与活立木的长度方向垂直。然而,髓心、心材和边材比例的不同对应力波在活立木中的传播速度有影响,随着活立木模型中心材比例的减少以及边材比例的增大,应力波的传播速度逐渐变大,应力波波速和髓心、心材和边材的比例之间存在显著的相关性。应力波在活立木中传播形式和传播规律受髓心、心材和边材的共同作用。Standing trees were considered to be a three layers material consisted of pith,heartwood and sapwood,and the propagation of stress wave in standing trees was simulated.The effect of ratio of pith,heartwood and sapwood on stress wave propagation in standing trees were studied by using COMSOL Multiphysics finite element analysis software based on stress wave propagation theory in the solid medium and orthotropic assumption of standing trees.It was found that ratio of pith,heartwood and sapwood had no effect on the propagation patterns and shapes of stress wave.The wave front at the starting stage was a sloping surface,bending to input point of force pulse and with the increase in distance.The inclination of the wave front decreased gradually until it was approximately vertical to the length direction.However,ratio of pith,heartwood and sapwood had an influence on stress wave speed.The velocity of stress wave in standing tree was increased with the decreased of ratio of heartwood or the increased of ratio of sapwood.There was a significant relationship between stress wave speed and ratio of pith,heartwood and sapwood.The propagation velocity of stress wave in standing trees relied on both pith,heartwood and sapwood.

关 键 词：髓心、心材和边材的比例 应力波 活立木 数值模拟 

分 类 号：S781.38[农业科学—木材科学与技术]