Damage detection in circular tubes using nonlinear ultrasonic guided waves with metasurface

• Metasurface assisted second harmonic generation for circular tubes is proposed. • Numerical results indicate the selective filtering property of the metasurface. • Effectiveness of reducing undesired second harmonics is verified by experiment. • Sensitivity of the second harmonics to damage are enhanced with metasurface. This paper investigates the use of metamaterials to enhance the sensitivity of nonlinear guided waves in detecting incipient local damage in circular tubes. Firstly, a metasurface configuration based on the local resonance metamaterial is proposed to filter outside the undesired or irrelevant second harmonics when employing the second harmonic generation technique for circular tubes. The dispersion calculation method is presented to determine the bandgap properties of the metasurface. Then, frequency domain analysis provides insights into the wave attenuation capabilities of the metasurface with finite dimensions, allowing wave components outside the bandgap to pass through while effectively blocking those within it. Next, the three-dimensional (3D) finite element (FE) models are developed to evaluate the performance of the metasurface. The numerical results show that the metasurface can significantly reduce the second harmonic transmission. The experimental results further verify the numerical findings. Finally, a comparative study on detecting local corrosion damage demonstrates the potential applications. With metasurface to suppress the undesired second harmonics, the nonlinear guided waves become sensitive to progressive corrosion damage. Incorporating metasurface with nonlinear guided wave technique enhances the robustness and accuracy of early damage detection for practical structural health monitoring (SHM) applications.