Artifact suppression in ultrasonic guided wave damage imaging enhanced by topologically optimized mode selective
Xiaochuan Tian1, Ailing Song1, Zhicong Cao1
1Shanghai Key Laboratory of Intelligent Sensing and Detection Technology, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China.
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In ultrasonic guided-wave inspection of plate-like structures, Lamb wave multimode interference often results imaging artifacts and reduces damage localization accuracy. To purify the ultrasonic guided-wave mode at the physical level and suppress the artifacts, this paper introduces an inverse design framework based on topology optimization and, accordingly, develops a mode selective meta-filter. Within the target frequency band near 200 kHz, the designed meta-filter effectively suppresses the A0 mode while preserving high transmission efficiency of the S0 mode. Band-structure analysis and frequency- and time-domain finite element simulations reveal the underlying mechanism of its mode-selective wave manipulation. The experimental filtering results are in excellent agreement with the numerical predictions, demonstrating both the mode purification capability and practical feasibility of the meta-filter under realistic conditions. Furthermore, by integrating the meta-filter with an improved damage imaging method, both simulation and experimental results show a pronounced enhancement in imaging focusing and a substantial reduction in background artifacts. By realizing guided-wave mode purification through physical method and avoiding complex signal post-processing, this work provides a viable solution for structural health monitoring.
