Piezoelectric shunt damping system with multiple transducers using techniques of mode adaptation and phase shift

It is known that the polarity of PZT transducer is determined by its strain state induced by the target structure under different vibration mode. In building the piezoelectric shunt damping system, multiple piezoelectric elements must be connected properly so as to obtain an integral voltage source, and then connect with the shunt circuit. For this purpose, some typical topological structures of electric network of piezoelectric shunt damping system were proposed. A critical analysis on the advantages and disadvantages of these networks in practical applications was accomplished. Based on the analysis the parallel connection was selected as the best configuration. According to the phase difference among different piezoelectric elements in this connection, a module of modal adaptation and phase shifting system was designed and built. With this module, the shunt circuit can follow the vibration modes of the structure and regulate the phases of output voltages of piezoelectric elements and make them synchronized automatically. By means of the concept of modal adaptation and phase shifting, the neutralization of induced charges on polarized surfaces of different PZT transducers can be avoided.