Propagation Characteristics of Lamb Waves in Periodically Stiffened Structures

Periodically stiffened structures are widely used in large-scale equipment due to their excellent strength-to-weight ratio. However, their complex geometry presents significant challenges for structural health monitoring (SHM). This paper investigates the propagation characteristics of Lamb waves in periodically stiffened structures from the perspective of stress monitoring, focusing on their dispersion properties, mode conversion, and transmission bandgap effects. Experimental results demonstrate that by selecting the low-frequency S0 mode as the excitation signal, it is possible to maintain high signal quality under complex mode conversion conditions while accurately reflecting stress variations in the structure. This study provides both theoretical support and experimental evidence for Lamb wave-based stress inversion, enhancing the stress monitoring capability of periodically stiffened structures and providing critical data for structural maintenance and safety evaluation.