Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : October 08, 2016 - October 10, 2016
In this study, a time reversal method for Lamb waves based on mode conversion is proposed for the detection and localization of a defect in a plate. To verify its validity, numerical simulation using the elastodynamic finite integration technique (EFIT) is performed for a two-dimensional model of an isotropic elastic plate which has a surface crack. For the incidence of the lowest-order symmetric (S0) mode in a low frequency range, the lowest-order antisymmetric (A0) mode is generated at the crack due to mode conversion. The waveforms of the A0 mode are obtained from the out-of-plane velocities on both surfaces of the plate. After re-emitting the time-reversed A0 mode, focusing positions on the plate surface are identified. The re-emitted A0 modes create a focusing at the position of the crack.
