ANISOTROPIC PROPAGATION CHARACTERISTICS OF ACOUSTIC EMISSION SIGNALS IN WOOD

This study investigates the propagation characteristics of acoustic emission (AE) signals in Zelkova schneideriana and Pinus sylvestris var. mongolic along different directions, with a focus on amplitude and frequency variations. Sinusoidal signals ranging from 10 to 400 kHz, along with pulsed signals of 1 μs width and 1 s period, were generated using an arbitrary waveform generator to simulate the AE source. Experiments were conducted on 80 mm cubic wood specimens, with the AE source and sensors positioned at the geometric centers of each surface. AE signals were recorded at a sampling rate of 2 MHz. The results indicate that, at the same frequency, the Zelkova schneideriana exhibits higher signal amplitude and energy than the Pinus sylvestris var. mongolic. Frequency response analysis further reveals that wood enhances the propagation of signals below 75 kHz, while significantly attenuating signals above 200 kHz in the transverse direction.