Structural Vibration Reduction by Switch Shunting of Piezoelectric Elements: Modeling and Optimization

This work deals with the reduction of structural vibrations by means of synchronized switch damping techniques on piezoelectric elements. Piezoelectric patches are attached to the vibrating structure and connected to an electrical circuit that includes a switch. The latter allows to continuously switch the piezoelectric elements from an open-circuit state to a specific electric impedance, synchronously with the mechanical oscillations. The present study focuses on two goals: (i) the quantification of the added damping, (ii) the optimization of the electric circuit parameters, carried out on a one degree of freedom model. The free and forced responses of one mode of the mechanical structure are studied in detail. The precise time response of the system is obtained with semi-analytical models for the two cases where the electrical impedance is a simple resistance (synchronized switch damping on short circuit) or a resistance in series with an inductance (synchronized switch damping on inductor). The damping added by the device is estimated. In all cases, the main result of the study is that the piezoelectric coupling factor is the only parameter to optimize and has to be maximized in order to maximize the added damping. An optimal value of the electric circuit quality factor is obtained when using an inductance, for free and forced response.