Comparisonof low-frequency piezoelectric switching shunt techniques forstructural damping

Abstract

In this paper, the performances of two novel low-frequency piezoelectric switching shunt techniques forstructural damping are compared to the traditional passive tunedresonant shunt circuit technique. The first novel technique,state switching, is a semi-active variable stiffness techniquein which bonded piezoelectric elements are switched from theshort circuit to open circuit states. This technique changesthe stiffness of the structure for two quarters of its vibrationperiod, thus dissipating energy. The second novel technique,pulse switching, is a semi-active continuous switching techniquein which a resistor/inductor shunt circuit is periodicallyconnected to the bonded piezoelectric elements. This techniqueapplies charges to the piezoelectric elements in a mannersimilar to the direct velocity feedback and bang-bang timeoptimal control techniques. A brief description of each of thedamping techniques is given. Numerical simulations of theswitching techniques are shown and compared to the resonantshunt damping technique. Finally, preliminary experimentalresults are presented for the resonant shunt, state switching, and pulseswitching techniques on a simply supported beam.