Identification of electromechanical parameters in piezoelectric shunt damping and loss factor prediction

Shunted piezoelectric elements have been studied for several years as promising devices for vibration damping. Different shunting techniques have been developed to deal with the vibration energy in the appropriate way. The energy dissipated by all these techniques, expressed in terms of loss factor or damping ratio, mainly depends on two different contributions: the electromechanical coupling and the shunt design. Therefore, an accurate prediction of the damping is based on a reliable identification of the generalized coupling coefficient that completely describes the electromechanical coupling. In this study, a robust method for the measurement of this coefficient is proposed, where the influence of the inherent damping of the structure is also considered. This method is based on the analysis of the dynamic response of the structure when the piezoelectric patch is connected to a resonant shunt. The proposed method is applied to different sample structures, and the measured generalized coupling coefficients are used for predicting the values of damping attainable with different shunting techniques (such as the resonant shunt or the synchronized switching damping). Vibration tests are then carried out on the same shunted structures, and the analytical prediction of the damping is compared with the experimental results.