WOOD RESEARCH Volume 71, Number 3, 2026
Xingyu Shao, MING LI, SAIYIN FANG, TINGTING DENG, KUN DU, JINGGUI WANG, WENTAO XU, and HAO SHI

The Study on the Frequency Response Characteristics of Wood Orthotropy Based on Stress Wave Propagation Direction and Distance

This study investigates the frequency response of Zelkova schneideriana and Pinus sylvestris var. mongholica Litv. along longitudinal, radial, and tangential directions at different propagation distances. Sinusoidal signals from 20 to 200 kHz with 2 kHz intervals were applied using a piezoelectric device, and the responses were recorded by an acoustic emission sensor. Frequency response curves were obtained from the amplitude ratios of response to excitation signals. The results showed that attenuation in the radial direction was lower than that in the longitudinal and tangential directions between 20 and 100 kHz. Both species exhibited stable characteristic response bands around 35, 154, and 188 kHz, which showed good agreement with one-dimensional elastic wave theory, with a minimum relative error of 0.48%. Zelkova schneideriana also exhibited a characteristic frequency near 79 kHz and more stable high-frequency responses.

WOOD RESEARCH Volume 70, Number 2, 2025
YONGCHUAN WU, SAIYIN FANG, MING LI, TINGTING DENG, CHUMIN CHEN, and ZHIYING TIAN

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