Tunable electrically shunted piezoceramic vibration absorber

A shunting method has been developed and experimentally verified for tuning the natural frequency and damping of a piezoceramic inertial actuator (PIA). Without power, a PIA behaves much like a passive vibration absorber (PVA). PVAs typically minimize vibration at a specific frequency often associated with a lightly damped structural mode. Large response reductions, however, may only be achieved if the PVA is accurately tuned to the frequency of concern. Thus, an important feature of a PVA is the ability to be accurately tuned to the possibly varying frequency of a target vibration mode. Tuning an absorber requires a change in either the mass or stiffness of the device. The electromechanical properties of the piezoceramic forcing element within a PIA in conjunction with an external passive electrical shunt circuit can be used to alter the natural frequency and damping of the device. An analytical model of a PIA was created to predict changes in natural frequency and damping due to passive electrical shunting. Capacitive shunting alters the natural frequency of the actuator only, while resistive shunting alters both the natural frequency and damping of the actuator. Experiments using both passive capacitive and passive resistive shunt circuits verified the ability to predictably shift the natural frequencies of the piezoceramic inertial actuator by more than 5%.