Efficient use of lamb waves to characterize multilayered anisotropic plates

In this paper the use of Lamb waves to characterize multilayered anisotropic plates is investigated. Individual layers in the multilayered specimen are elastic, homogeneous and anisotropic. The incident angle and frequency of an ultrasonic signal for the Lamb wave generation in a multilayered composite plate are first obtained. Displacement and stress fields inside the plate associated with different Lamb wave modes are computed for a number of orientations of a two layered fiber reinforced composite plate. It shows that for detecting and imaging defects in a specific layer certain Lamb wave modes are more effective than others. Preliminary results also indicate that Lamb waves are more efficient for characterizing composite plates made of anisotropic layers rather than isotropic layers.