Ultrasonic-guided waves (GWs) have shown a high potential to be applied to the structural integrity of timber utility poles to detect and assess distinct types of defects. Yet, there are many challenges associated with this method, which may hinder its application, including the orthotropic nature of the timber, the presence of natural cracking, and the effect of environmental factors such as temperature and moisture content (MC) on the propagation of GWs. This study aims to scrutinize the effect of MCs ranging from 0 to 24%, and temperatures between − 20 and 100 °C on the propagation characteristics of GWs (longitudinal and circumferential) in cylinder timber structures excited over a range of frequencies between 10 and 20 kHz, experimentally and numerically. The numerical analysis was carried out using COMSOL Multiphysics, and Macro Fiber Composites were used to excite and sense the GWs. The anisotropic nature of timber poles was modeled using a transversely isotropic behavior. The results showed that the effect of timber’s temperature and MC on the GWs should be assessed simultaneously. Three-dimensional maps were generated to present the relationship between various wave modes, temperature, and MC. The work observed a larger critical role of MC than the temperature on the propagating GWs and timber’s material properties. The effect of temperature is more critical when timber’s MC increases above the fiber saturation point (FSP) due to high stiffness variations. This is seen as the group velocities of the longitudinal and flexural waves (as well as the bulk wave) shifted more at MCs above FSP than below FSP. When MC varies above FSP with no temperature variations the velocity difference is negligible with 1.5% due to complete timber saturation at all temperature values. The results showed that the change in the mode velocities in dry wood is not significant with varying temperatures, as the stiffness changes by 0.07%. Experimental validation, for the numerical results, showed low differences for the bulk wave, and flexural modes were within [7.1 15]% and [1.3 4.7]% for the 2nd flexural branch at 12.5 kHz, respectively. Based on the above results, the environmental conditions can highly impact the GWs characteristics in timber structures, hence this should be carefully considered in the application phase.

超声波导波 (GW) 已显示出应用于木材电线杆结构完整性检测和评估不同类型缺陷的巨大潜力。然而，这种方法存在许多挑战，可能会阻碍其应用，包括木材的正交各向异性、自然开裂的存在以及温度和含水量（MC）等环境因素对木材传播的影响。 GW。本研究旨在仔细研究 0 至 24% 的 MC 范围以及 − 20 至 100 °C 之间的温度对圆柱木结构中 GW（纵向和周向）传播特性的影响，这些结构在 10 至 20 的频率范围内激发kHz，实验和数值。使用 COMSOL Multiphysics 进行数值分析，并使用宏观纤维复合材料来激发和感测引力波。使用横向各向同性行为对木杆的各向异性性质进行建模。结果表明，应同时评估木材温度和MC对GW的影响。生成三维图来呈现各种波模、温度和 MC 之间的关系。这项工作观察到 MC 对传播的 GW 和木材材料特性的关键作用比温度更大。当木材的 MC 由于高刚度变化而增加到纤维饱和点 (FSP) 以上时，温度的影响更为关键。这被视为纵向波和弯曲波（以及体波）的群速度在高于 FSP 的 MC 处比低于 FSP 处移动得更多。当 MC 在 FSP 之上变化且没有温度变化时，由于所有温度值下木材完全饱和，速度差异可以忽略不计，为 1.5%。结果表明，随着温度的变化，干木材模态速度的变化并不显着，因为刚度变化了 0.07%。数值结果的实验​​验证表明，体波差异较小，12.5 kHz 下第二弯曲分支的弯曲模式分别在 [7.1 15]% 和 [1.3 4.7]% 范围内。根据以上结果，环境条件对木结构的GWs特性影响很大，因此在应用阶段应仔细考虑。