Abstract
The expanded fundamental piezoelectric equations describing nonlinearities and losses were validated experimentally. The equations were derived in accordance with an assumption that the piezoelectric e-constant and g-constant were real and linear. In order to confirm the reasonability of the equations, the measured curves of the impedance and the displacement of d31-mode resonators of soft- and hard-PZT ceramics were fitted by the theoretical equations. Good fittings were observed in the calculations for both ceramics, describing all of the losses (dielectric loss, elastic loss and piezoelectric loss) in piezoelectric ceramics.
