Ultrasound-guided wave dispersion curve reconstruction based on generalized dispersive mode decomposition

In non-destructive testing, the received signal may be a multi-mode overlapped guided wave. To extract effective properties of the waveguide, appropriate signal processing methods must be used to separate the individual modes. In this paper, a semi-analytical finite element method is first used to establish a theoretical model for the propagation of Lamb waves in a plate, and the theoretical dispersion curve is calculated based on this model. Then, the Generalized dispersive mode decomposition method is used to separate Lamb wave signals with multiple modes overlapped, and separate $\boldsymbol{A}_{\mathbf{0}}$ and $\boldsymbol{S}_{\mathbf{0}}$ modes can be obtained. Subsequently, the reconstructed dispersion curves corresponding to the separated $\boldsymbol{A}_{\mathbf{0}}$ and $\boldsymbol{S}_{\mathbf{0}}$ modes can be obtained by executing the zero-crossing technique. Finally, by comparing the reconstructed results with the theoretical dispersion curve, the effectiveness of the Generalized dispersive mode decomposition method in Lamb wave mode separation is demonstrated.