Transient lamb wave analysis of the interaction S0 mode with a circular blind hole in isotropic plate

The paper studies the interaction of fundamental S0 Lamb wave mode generated by a point source with asymmetrical circular blind hole in an isotropic plate. A theoretical analysis is carried out in an effort to understand the properties of transient Lamb wave propagating in an isotropic plate with a circular blind hole. The case of the incident S0 Lamb wave being generated by a point source is considered. Due to mode conversion in presence of asymmetrical damage, the scatterings of the extensional S0 as well as flexural A0 waves must be solved. In this research, Poisson and Mindlin plate theories for depicting extensional and flexural wave motions are utilized. The wave function expansion technique and boundary conditions at the hole boundary are employed to derive the scattered wave fields of the two modes. The transient scattering Lamb waveforms of interaction of S0 wave with the hole are analyzed numerically. The strong scattering and mode conversion behavior can be observed in transient waveforms. The work also provides a quantitative analysis for nondestructive detection of blind hole diameter.