Abstract: Ultrasonic guided wave-based damage detection and localization methods are widely applied in various engineering structures. However, the anisotropy of composite materials increases the complexity of guided wave propagation, often resulting in oversized imaging areas and false artifacts, which compromise localization accuracy. In this study, a novel damage localization method for delaminations in composite plates is proposed, integrating delay-and-sum (DAS) principles with the sparrow search algorithm (SSA). By designing a fitness function based on the time of flight (ToF) of scattered signals, the damage imaging problem is transformed into a scattering source search problem. The fitness function evaluates the sparrow population distribution, iteratively refining the search process to approximate the most probable scattering source locations. The damage region is ultimately represented by the areas of sparrow aggregation. Experimental results demonstrate that, compared to traditional imaging methods, the proposed approach significantly reduces the localization area and enhances accuracy.

Key words: ultrasonic guided wave, composite materials, delamination damage, scattering source search