The Imaging and Localizing Method of Crack Damage in Stiffened Plates Based on Lamb Waves

Stiffened plates are widely employed in the aerospace and weaponry equipment domains because of their outstanding characteristics like high rigidity, high strength and lightweight. Nevertheless, during the process of long-term service, crack damage is inevitable. In response to this problem, this article presents a crack damage imaging and localization method based on Lamb waves. This method, by analyzing the propagation characteristics of Lamb waves before and after damage, proposes a novel damage indicator—the crack damage factor (CDF)—for the visual visualization characterization of cracks. The research approach was validated through experiments. Initially, a sensor array was configured to form a relatively dense detection network, and then the guided wave signals of the stiffened plate both before and after damage were acquired, the CDF was computed. Subsequently, the initial imaging of the damaged area was accomplished by the reconstruction algorithm for probabilistic inspection of damage (RAPID). On this foundation, to rectify the CDF of the crack parallel path, a method of grouping refinement was put forward. Finally, the corrected CDF and the CDF values of other paths were utilized in RAPID to realize the imaging and localization of the crack damage. The experimental outcomes demonstrate that this approach visualizes and localizes the cracks in stiffened plates accurately and efficiently, validating its feasibility and efficacy in practical applications. It offers a novel solution for damage detection and crack imaging of stiffened plate structures.