Numerical Analysis of the Nonlinear Interactions Between Lamb Waves and Microcracks in Plate

In this paper, three-dimensional finite-element modeling is conducted to investigate the nonlinear interactions between Lamb waves and microcracks. The simulation research focuses on the influence of microcrack orientation on the propagation direction of generated sum-frequency Lamb waves. The simulation results show that the resonant conditions based on classical nonlinear theory are valid for such interactions, leading to the generation of transmitted and reflected sum-frequency S0 waves (SFSWs). Moreover, the propagation directions of these two SFSWs exhibit different trends with respect to the orientations of microcracks. The transmitted SFSW can be used to detect microcracks, whereas the reflected one can be used to measure their orientations.