Investigation on dielectric, mechanical and piezoelectric non-linearities in piezoceramics through a new equivalent circuit

A lot of non-linear effects have been observed in piezoceramics driven at high power. Such non-linear behaviors occur either at low frequency or at the series resonance frequency of a fundamental mode. The purpose of this work is to establish a link between these nonlinearities : A resistance and a reactance, proportional to the current density over the square frequency, are introduced in series at the input of the conventional equivalent circuit model. The good agreement between the experimental results and the analytical model confirms that all types of non-linearities mainly originate in non 180/spl deg/ domain walls motion.