Reflection and transmission of fundamental Lamb wave modes obliquely incident on a crack in a plate

Lamb waves are increasingly being used for structural health monitoring of plate-like structures. In order to take advantage of Lamb waves, it is important to have a good understanding of how they interact with defects such as cracks. In this study, the scattering of the fundamental S0 Lamb mode by a part-through transverse symmetric crack in an isotropic plate is examined. The modal decomposition technique coupled with the method of collocation is used to determine the energy reflection coefficients of reflected and transmitted waves. These coefficients are shown to depend on the crack depth and the incident frequency. Experiments were conducted to verify the analytical results. Two different crack depths and frequencies were used. The experimental results follow the trends seen in the analytical results.