Abstract
This work deals with the electromechanical power conversion in piezoelectric materials. In this study we will use the reverse piezoelectric effect to determine the tensorial properties of piezoelectric ceramics. The eigen vibration modes of a piezoelectric cube are modelled and characterized using resonant ultrasound spectroscopy. This method, which examines the vibration modes of a piezoelectric cube, relates mechanical resonances that can be measured by Laser interferometry to electromechanical properties. The direct problem is first solved; the resonance modes of a piezoelectric cube are modelled and mechanical displacements are calculated as functions of frequency and boundary conditions. Because the geometry of the sample is fixed, the vibrations depend only on the material properties and the electrical excitation. The displacement response of a PMN-34.5PT piezoelectric ceramic cube is investigated using a coherent optical detection. According to properties determined by electrical impedance measurements, the cube presents a first resonance around 125 kHz. Results on the amplitude of the detected velocities versus the frequency of the input excitation voltage are reported and compared to theoretical predictions. This validates the electrical modelling of the cube vibrations.