Acoustic source localization using three L-shaped sensor clusters for highly anisotropic plates by linear and...

Anisotropic materials are of significant interest for major structural applications, where fast and accurate acoustic source localization (ASL) of damages is crucial for structural assessment and maintenance. Existing ASL methods for highly anisotropic plates often require assumptions of straight‑line wave propagation, solution of nonlinear equations, prior knowledge of wave velocity, or acoustic event duration. To address these limitations, this paper proposed an ASL method using three L-shaped sensor clusters (TLSSC), combining the advantages of linear and nonlinear Lamb waves with the LSSC, for highly anisotropic plates having rhombus-shaped wavefronts. Feasibility of this approach was verified through localization experiments on a [0/90]_2s composite plate using linear ultrasonics for passive acoustic emission detection at various acoustic source locations. Additionally, Lamb wave propagation in an anisotropic silicon wafer was simulated for active microcrack detection via nonlinear ultrasonics, considering different material orientations, microcrack locations, and cluster arrangements. Both experimental and simulated results confirm the effectiveness of the proposed method: compared to the LSSC-based ASL, localization accuracy is significantly improved, with absolute errors below 6 mm for a plate of dimension 500 mm × 500 mm and a wafer of 8 in. considered in this study and relative error under 5 % in nearly all cases. This method is not only effective for acoustic emission detection, but can also be extended to active detection of microcrack through appropriate mode pair selection and the pulse inversion technique.