Damage assessment in fatigue-prone connection of orthotropic steel deck based on Lamb-wave characteristic

Orthotropic steel deck is extensively utilized in infrastructure owing to its superior structural performance; however, it is susceptible to fatigue failure induced by stress concentration. Lamb-wave technique offers advantages for fatigue damage assessment, including broad coverage and high sensitivity to damage, while the propagation characteristics of Lamb-wave in fatigue-prone connection of orthotropic steel deck remain poorly revealed. This study investigates the damage assessment in fatigue-prone connection of orthotropic steel deck based on Lamb-wave characteristic. Theoretical deduction was primarily performed to derive the frequency dispersion curves of Lamb-wave in fatigue-prone connections, and numerical simulation was then conducted to examine the influence of fatigue damage on Lamb-wave propagation characteristics. Modal experiment was finally carried out to verified above wave characteristics. The results demonstrate that the dispersion characteristic of Lamb-wave in special-shaped sections from fatigue-prone connections lead to both frequency bandwidth amplification and multi-modal vibration responses. Meanwhile, the effect of damage on Lamb-wave propagation exhibits phase hysteresis behavior as damage length increases, while the wave characteristic reveals distinct dependence patterns with damage length. Furthermore, the proposed damage evaluation model incorporates both damage severity parameters and Lamb-wave propagation characteristics, demonstrating potential for quantitative damage severity assessment based on Lamb-wave signals. The research contributes both fundamental insights into wave-damage interaction and practical methodology for structural health monitoring application.