Damage Identification Using Meta-Lens and Dual-Enhanced Backscattered Waves: Numerical and Experimental Design

This paper introduces a Meta-lens designed for the detection of minute damage in Structural Health Monitoring (SHM) by amplifying backscattered waves originating from anomalous areas. Our approach starts with the development of an easily installed Meta-lens, optimizing wave focusing on an aluminium plate through strategic planning of the A0 wave trajectory, resembling a hyperbolic secant. Subsequently, we detail the configuration of the actuator, lens, and sensor in both healthy and damaged scenarios, the latter involving a through-hole defect in the plate. A comparative analysis of signals, accounting for damage size and location variations, is conducted against a baseline. The results demonstrate that the Meta-lens induces a unique wave behaviour, resulting in double intensification of backscattered signals, significantly increasing sensitivity to damage features compared to systems without the lens. The focusing effect of the Meta-lens is further validated experimentally, which shows good agreement with the simulation results. The findings underscore the significant potential of employing the Meta-lens for damage detection, thereby eliminating the reliance on intricate sensor networks and complex signal post-processing.