Guided stress waves are considered one of the most efficient and reliable techniques that provide sufficient quantitative and qualitative assessment. In this study, we focused on scrutinizing the propagation behavior of guided waves in western white pine timber poles, experimentally, and numerically using COMSOL Multiphysics. Macro fiber composites (MFCs), due to their flexibility and convenience to install on curved profiles, were used to actuate and sense guided waves along the tested specimens. Various solutions for wave mode tuning and characterization have been tested for traction free and embedded boundary conditions. The behavior of propagating wave modes was analyzed and compared in the two boundary conditions tested. Also, the excitation frequency, based on the dispersion curves generated for transversely isotropic timber, was selected to ensure the presence of favorable propagating (for instance longitudinal modes) modes with minimal dispersion. Undesirable wave modes—such as flexural modes (non-axisymmetric)—were eliminated by a ring design composed of multiple MFC actuators coupled around the pole’s circumference. The remaining propagating longitudinal modes and their reflections, such as modes L(0,1) and L(0,2) propagating at nearly 1000 m/s and 800 m/s respectively, were significantly enhanced by the actuation of the ring which could be effectively used for the assessment process. The results demonstrated the complexity of the propagating modes in circular timber structures and the importance of the ring design in the excitation of the selected modes of interest and damping unwanted ones.

引导应力波被认为是提供足够的定量和定性评估的最有效和可靠的技术之一。在这项研究中，我们重点研究了实验性和使用COMSOL Multiphysics数值模拟的导波在西部白松木杆中的传播行为。宏纤维复合材料（MFCs）由于其灵活性和安装在弯曲型材上的便利性，被用来激励和感应沿着被测样品的导波。已经针对无牵引力和嵌入边界条件测试了用于波动模式调整和表征的各种解决方案。在两个测试边界条件下，分析并比较了传播波模式的行为。同样，基于为横向各向同性木材生成的色散曲线，激发频率 选择α以确保存在具有最小分散度的有利传播（例如纵向模式）模式。环形设计消除了不良的波动模式，例如弯曲模式（非轴对称），该环形设计由多个围绕极的圆周耦合的MFC执行器组成。剩余的传播纵向模式及其反射（例如分别以近1000 m / s和800 m / s传播的模式L（0,1）和L（0,2））通过激活环而显着增强。有效地用于评估过程。结果证明了圆形木结构中传播模式的复杂性，以及环设计在激发选定的感兴趣模式和抑制有害模式方面的重要性。