Vibration control with state-switched piezoelectric materials

In this paper, a semi-active control law is used to switch the electrical shunt circuit of a piezoelectric actuator for energy dissipation in a simple mechanical system. Switching is carried out between open-circuit (high stiffness) and short- or resistive-circuit (low stiffness) states. The actuator is held in its high stiffness state when the system is moving such that energy can be stored in the actuator. When the system's motion would cause it to receive energy back from the actuator, the actuator is switched to a low stiffness state, dissipating the energy. In this paper, the concept is developed starting with the governing piezoelectric equations. Numerical simulation results are presented which show that the technique provides energy dissipation that is comparable to other piezoelectric shunt mechanisms, using optimal shunt resistance in each case. Finally, a brief analysis is presented in which the piezoelectric element is used in a flexible beam element to illustrate the effects of a parallel structural stiffness on such a switching method.