Lamb wave propagation in a metallic semi-infinite medium covered with piezoelectric layer

The Lamb wave propagation in a metallic semi-infinite medium covered with a piezoelectric layer is studied in this paper. The numerical solution of the dispersion curve is simplified by segmenting the phase velocity spectrum into different ranges based on the longitudinal and transverse wave velocities of both materials, and using different forms of wave equations. The results show that the dispersion curves are asymptotic to the transverse velocity of the piezoelectric layer as the wave number increases. The first two mode shapes of the electric potential correspond to a half-cosine distribution at low wave number and a full-sinusoidal distribution at relatively higher wave number.