Modelling of the electrical admittance of a piezoceramic cube using Ultrasonic Resonance Spectroscopy
Résumé
Ultrasonic Resonance Spectroscopy allows the characterization of piezoelectric materials thanks to the study of their mechanical and electrical resonances. In order to simplify the method, the present work deals with the modelling of electrical admittance of rectangular shaped piezoelectric materials. First, the natural mechanical and electrical resonant frequencies of a piezoelectric cube are calculated from the stationary points of the Lagrangian of the system. Then the electrical resonances are identified taking into account the short-circuit electrical boundary conditions and the electrical admittance is determined as a function of the frequency from calculations of the charge quantity on both electrodes of the cube. Experimental measurements are carried out on a PMN-34.5PT ceramic cube. According to properties determined by mechanical velocity measurements, the cube presents a first resonance around 125 KHz. Experimental admittance measurements confirm the electrical modelling of the cube vibrations. To show the valitdity of the method for Non Destructive Evaluation applications, it is then applied to a piezoelectric material with unknown properties in order to determine its properties.
Domaines
Acoustique [physics.class-ph]
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