基于COMSOL的声发射信号沿木材纵向传播过程的仿真

COMSOL-Based Simulation Study of Acoustic Emission Signal Propagation Process Along the Longitudinal Direction of Wood

为研究声发射信号在木材中的传播行为,分别对杨木、红锥、樟子松和杉木4种木材试件建立COMSOL三维仿真模型,通过给定位移的方法模拟弹性波点源,进而借助仿真过程的应力云图分析声发射(acoustic emission,AE)信号沿木材纵向传播的过程。针对AE源到达模型表面2个位置的时间差,利用时差定位法(time difference of arrival,TDOA)计算AE源的纵波波速。在木材试件上以相同条件进行AE试验并计算纵波波速,最终结果与仿真模型相符。研究结果表明,杨木、红锥、樟子松和杉木4种木材仿真与试验的纵波波速的相对误差分别为1.47%、1.04%、0.46%和2.33%,仿真模型能够客观反映AE信号在木材中的传播行为,为木材AE信号传播过程可视化提供一种新的途径。但AE信号幅值的相对误差较大,模型不能客观反映木材中幅值的变化规律。

In order to study the propagation behavior of acoustic emission(AE)signals in wood,COMSOL 3D simulation models were established for four kinds of wood specimens,including Populus simonii,Castanopsis hystrix,Pinus sylvestris and Cunninghamia lanceolata.The elastic wave point source was simulated using a given displacement method,and then,the longitudinal propagation of the AE signal along the wood was analyzed with the help of the stress maps of the simulation process.The longitudinal wave velocity of the AE source was calculated by the time difference of arrival(TDOA)method with respect to the time difference between the two posi⁃tions of the AE source arriving at the surface of the model.The AE tests were carried out on the wood specimen under the same condi⁃tions and the longitudinal wave velocities were calculated.The final results were consistent with the simulation model.The results showed that the relative errors between the simulated and tested longitudinal wave velocities of Populus simonii,Castanopsis hystrix,Pinus sylvestris and Cunninghamia lanceolata were 1.47%,1.04%,0.46%and 2.33%,respectively.The simulation model can ob⁃jectively reflect the propagation behavior of the AE signals in wood,which provided a new way to visualize the propagation process of the AE signals in wood.However,the relative error of AE signal amplitude was large,and the model cannot objectively respond to the change rule of amplitude in wood.