A pair of interdigital electrode (IDE) piezoceramics is used to simultaneously suppress multimode vibrations of a cantilevered beam. This is achieved by connecting the IDE piezoceramics in parallel to a negative capacitive shunt circuit. The governing equations of motion of an IDE piezo/beam system and associated boundary conditions are derived using the Hamilton principle. The obtained mathematical model is validated experimentally Attenuations ranging between 5 and 20 dB are obtained for all the vibration modes over the frequency range of 0-3000 Hz. The presented theoretical and experimental techniques provide invaluable tools for designing simple and effective passive vibration dampers for structures with closely packed modes.

Piezoceramic material connected to an electronic shunt branch circuit has formed a successful vibration reduction device. One drawback of the conventional electronic shunt circuit is the large inductance required when suppressing low frequency vibration modes. Also, the large internal resistance associated with this large inductance exceeds the optimal design resistance needed for low frequency vibration suppression. To solve this problem, a modified and enhanced piezoelectric shunt circuit is designed and analyzed by using mechanical-electrical analogies to present the physical interpretation. The enhanced shunt circuit developed in this paper is proved to significantly reduce the targeted vibration mode of a cantilever beam, theoretically and experimentally.

The proper equivalent interface circuit of a piezoelectric material below ultrasonic frequency range is developed and analyzed incorporating a voltage source and a capacitor theoretically and experimentally. The emphasis is placed on the physical connection between a capacitor and a voltage source. The first model considered is of a capacitor connected in series with a voltage source. The second model consists of a capacitor connected in parallel with a voltage source. This paper presents the analyses of these two different circuit models for a piezoceramic by discussing the electric impedance and phase angle of a piezoceramic theoretically and experimentally and determines the best-fit model of a PZT to use for structural vibration applications.

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