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 4, 2025
JINGGUI WANG, MING LI, SAIYIN FANG, TINGTING DENG, JIAXIN GUO, ERZHUANG ZHAI, and WENTAO XU

THE STUDY ON THE DAMAGE CHARACTERISTICS OF PINUS SYLVESTRIS VAR. MONGOLICA UNDER DIFFERENT MOISTURE CONTENTS

This study investigated the effects of moisture content (0%, 12%, 20%, 30%, 40%, 50%) on the mechanical behaviour and damage evolution of Pinus sylvestris var. mongolica three-point bending tests. A Weibull distribution model quantified damage progression, extracting scale (λ) and shape (k) parameters. Results revealed moisture regulated failure mechanisms, Low moisture (≤20%) induced brittle fracture (high k, low λ) with tensile crack dominance and stress concentration. High moisture (≥30%) promoted ductility (low k, high λ) via enhanced λ, driven by shear cracks. Mixed cracks persisted across all stages. Moisture altered cell wall plasticization, inter-fibre friction, and interfacial bonding, modulating damage evolution. Weibull modelling effectively captured stage dependent damage variable trends. Increased moisture facilitated fibre slippage and interlayer shear through lubrication and cell wall softening.This work establishes quantitative links between moisture content, mechanical response, and micromechanical damage mechanisms in wood, providing insights for moisture dependent structural applications of engineered timber.

WOOD RESEARCH Volume 70, Number 1, 2025
JINGGUI WANG, MING LI, SAIYIN FANG, TINGTING DENG, ERZHUANG ZHAI, CHUMIN CHEN, and KEFEI CHEN

RESEARCH ON WOOD DAMAGE FRACTURE CHARACTERISTICS BASED ON ACOUSTIC EMISSION RA-AF VALUE AND ENERGY CONCENTRATION

To study the acoustic emission (AE) characteristics and fracture properties of wood at different stress stages, three-point bending tests and real-time AE monitoring were carried out on Zelkova schneideriana and Pinus sylvestris var. in this paper. Different stress stages were classified according to AE ringing counts-cumulative AE ringing counts-load curves, damage modes of wood at different stages were identified based on distribution characteristics of RA-AF data, and fracture behavior of wood was predicted by energy concentration k. Results show that distribution characteristics of AE RA-AF data can characterize the types of cracks generated in each stress stage of wood. The crack modes generated by both specimens during three-point bending loading are tension shear composite cracks, and the proportion of tensile cracks is significantly higher than that of shear cracks, but during the elastic-plastic stage, Zelkova schneideriana specimens will produce a large number of shear cracks, whereas Pinus sylvestris var. specimens have predominantly tensile cracks, with only a small number of shear cracks produced before and after fracture. The sudden change in the energy concentration k curve between elastic-plastic deformation stage and fracture stage can be used as a precursor of damage for both specimens under three-point bending test conditions