Phased Array System for Damage Detection in Plate-Like Structures Based on Single Lamb Wave Mode Extraction

Large-scale plate-like structural components have been widely used in engineering fields. The occurrence and accumulation of structural damage will threaten the integrity of plate-like structures. Guided wave-based structural health monitoring (SHM) technology has been demonstrated as an effective tool to detect small-scale damage at a high sensitivity. Due to the advantages of baseline-free, concentrated sensor arrays and rapid inspection of the full area, Lamb wave-phased array SHM systems have been extensively investigated in recent years. However, the inherent multi-mode characteristic of Lamb waves is well-known to have a significant influence on wave propagation and further development of phased array method. In this study, a single Lamb wave mode extraction method combined with phased array SHM system is proposed based on a concentric piezoelectric active transducer (CPAT). First, a brief review of a Lamb wave-phased array system is presented, including working principle, sensor array, and Lamb wave excitation and sensing. Then, the single mode wave extraction method is performed based on the CPAT. The effectiveness of the single mode wave extraction-based phased array SHM system is first examined numerically. Finally, the proposed phased array system is used to monitor large plate-like structures and the availability and validity of the proposed SHM system is confirmed by an experimental study. This work provides an effective and practical tool to detect damage in large-scale plate-like structures.