In order to study the influence of wood viscoelasticity characteristics on the propagation behavior of acoustic emission(AE)signals,a finite element simulation model of wood specimens was established by setting the viscosity coefficients of wood in COMSOL software.The effectiveness of the simulation model was verified by combining the results of wood AE experiments.Firstly,a Hanning window modulated sine pulse signal was generated by a signal generator at a distance of 100 mm from the left end face on the sur-face of the fir specimen.Two AE sensors were placed at a distance of 200 mm from the left end face at a distance of 300 mm on the surface of the specimen to collect the AE signals.Then,a filter was used to de-noise the AE signals collected by the sensors.Secondly,finite element simulations were conducted on the fir specimen to obtain the displacement cloud map of elastic wave propagation in the specimen and the prop-agation law in viscoelastic materials.Finally,the time difference of arrival(TDOA)method was used to compare the transverse and longitudinal wave velocities and time-domain waveforms obtained from the simu-lations and experimental measurements.The results showed that the simulated transverse and longitudinal wave velocities were 1 118 m/s and 5 245 m/s,and the experimental transverse and longitudinal wave ve-locities were 1 290 m/s and 5 209 m/s,respectively.The amplitude attenuation and the time-domain waveforms were in good agreement when comparing the simulated and measured waveforms with the experi-mental waveforms.Therefore,the effects of viscoelasticity on Chinese fir specimens and the validity of the simulation model were confirmed.
关键词
木材/声发射/有限元分析/传播速度/黏弹性
Key words
wood/acoustic emission/finite element analysis/propagation speed/viscoelasticity
维普
万方数据