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【目的】探究应力波在落叶松活立木中的传播形式和传播规律,为人工林材质预测评估提供理论基础。【方法】依据固体介质中的应力波传播理论和弹性力学理论,基于活立木的正交各向异性假定,利用COMSOL Multiphysics多物理场仿真软件对应力波在活立木中传播的波阵面进行了模拟计算,并通过试验验证数值模拟方法的合理性。【结果】应力波传播波阵面在开始阶段为倾斜曲线(二维)或倾斜曲面(三维),且曲线和曲面都弯向脉冲力输入点,随着距离的增大,波阵面倾斜度逐渐减小,直至最后与活立木的长度方向近似垂直,即应力波在活立木中由三维膨胀波传播形式逐渐转向准平面波传播形式;波阵面倾斜度的减小速度随着活立木直径的减小而加快;传播距离对波速没有影响,波速总体上随着直径的增大而增加。最后,通过试验验证,证明了这种数值模拟研究应力波在活立木中传播规律的方法是可行的。【结论】通过数值模拟手段研究应力波在活立木中的传播规律以及直径和传播距离对波速的影响是合理可行的,直径和传播距离都会对应力波在活立木中的传播形式及规律造成影响,但二者对波速的影响不同。
【Objective】 The purpose of this study is to investigate the propagation and propagation of stress wave in live larch wood and to provide a theoretical basis for the prediction of plantation material. 【Method】 Based on the theory of stress wave propagation and elastic mechanics in solid media, based on the assumption of orthogonal anisotropy of living wood, the wave front of stress waves propagating in standing wood was carried out using COMSOL Multiphysics multiphysics software Simulation calculation, and through experiments to verify the numerical simulation method is reasonable. 【Result】 The results show that the wavefront of stress wave propagates obliquely (two-dimensional) or obliquely curved (three-dimensional) in the initial stage, and both the curve and the surface bend to the input point of impulsive force. As the distance increases, the wavefront inclination Gradually decreases until it is approximately perpendicular to the length of the standing wood, that is, the stress wave is gradually shifted from quasi-plane wave propagation in the live wood by the three-dimensional expansion wave propagation mode. The wave velocity decreases with the diameter of the standing wood Reduce and accelerate; propagation distance has no effect on the wave velocity, the wave velocity generally increases with the increase of diameter. Finally, through the experimental verification, it is proved that this numerical simulation is feasible to study the propagation law of stress wave in standing wood. 【Conclusion】 It is reasonable and feasible to study the propagation of stress wave in standing wood and the influence of diameter and propagation distance on the wave velocity by means of numerical simulation. The diameter and propagation distance will affect the propagation form and law of stress wave in standing wood , But the impact of the two on the wave speed is different.