Lamb wave propagation characteristics in a piezoelectric ceramic plate with spatially varying thickness

Basic studies on Lamb wave propagation in a piezoelectric ceramic plate, whose thickness varies linearly with distance, is presented. The gradient of the plate surface is taken into account in the calculation model. Phase velocities of 6 lowest-order Lamb wave modes are represented as a function of the product of frequency and plate thickness for various ratios between the thickness change and the propagation distance. The velocity dispersion curves are intermittent when the gradient is not zero. A device is fabricated using a piezoelectric ceramic plate, to experimentally demonstrate the Lamb wave propagation in the inhomogeneous plate.