Passive piezoelectric damping tuned by using measured electrical impedance

摘要

In this paper, multi-mode piezoelectric shunt damping and the damping performance comparison according to different piezoelectric materials are studied. Multi-mode damping is tried by using a newly proposed tuning method. This method is based on electrical impedance model and maximizing the dissipated energy at the shunt circuit. By measuring the electrical impedance at the piezoelectric patch bonded on a structure, an equivalent electrical model is constructed near the system resonance frequency. After shunting elements are connected to the equivalent circuit, the shunt parameters are optimally searched based on the criterion of maximizing the dissipated energy at the shunt circuit. This is for a single mode and it is expanded to multi-mode damping. Cantilever beam is taken as examples. Piezoceramics are bonded near root of the beam and electrical impedance is measured using HP 4192 impedance analyzer. Small electronic shunt circuits are made according to the found optimal shunt parameters. The first and second vibration modes are damped out independently. However, it was found that the presence of the shunt circuit tuned for the second resonance deteriorates the electrical impedance near the first resonance. Discussion on this fact is provide. The piezoelectric damping performance is compared according to different piezoelectric materials. Three piezoelectric materials are selected: PZT-5, PZN-PT single crystal and QuickPack IDE actuator. When resonant shunt circuit is considered, the use of PZN-PT single crystal exhibited the best piezoelectric damping performance. When IDE actuator is used with resistive shunt, although the tip displacement reduction is not so large, the first and second resonance modes can be damped out by a simple passive electronics- a resistor.