Lamb waves propagating in an LiNbO3 plate under the mechanical and dielectric loadings of a fluid

This research is focused on exploring the fluid loading effects on the dispersion spectra of Lamb modes propagating in a piezoelectric (X-LiNbO(3)) plate. Theoretical calculations based on a partial wave analysis are used to characterize the shifting behaviors of dispersion spectra caused by the loading fluid with mechanical /dielectric properties. On the other hand, the fluid loading effects are experimentally investigated by measuring the dispersion spectra of an X-LiNbO(3) plate with free and immersed boundary conditions. Results of the theoretical calculations are supported by the measurement. It is also found that, for the case of water as a common immersion fluid for an X-LiNbO(3) plate, the dielectric loading effect dominates the shifting of the dispersion spectra, while the mechanical density loading effect can be neglected.