Thermoelastic Excitation of Transient Lamb Wave in an Orthotropic Thin Plate

A numerical method to simulate thermoelastic excitation of transient Lamb wave propagating along arbitrary directions in orthotropic plates is presented by employing the expansion method of the Lamb wave modes. The displacement is expressed by a summation of the symmetric and antisymmetric modes in the surface stress-free orthotropic plate, and it is particularly suitable for waveform analyses of Lamb wave in orthotropic thin plates because one needs only to calculate the lowest few modes. The characteristics of dispersion and transient wave-forms are analyzed for a transversely isotropic plate. The results show that this method provides a quantitative analysis to Characterize anisotropic properties and elastic stiffness properties of the orthotropic plates by the laser-generated Lamb wave detection.