Passive And Semi-active Vibration And Noise Control Of Piezoelectric Laminates

In recent years, the emergence of passive vibration control of piezoelectric shunt damping system has provided a new powerful method for control of vibration and noise in flexible structures. In this thesis, the principle and implementation of the passive vibration control systems were discussed in detail. The several shunt damping circuits were studied experimentally on both single mode and multimode passive vibration and noise control of a flat structure. Then, a novel semi-active vibration control systems was developed based on the passive vibration control systems. This approach not only can achieve better vibration and noise damping effect, but also has several advantages, such as good environmental adaptability, low circuit mutual interference , simple circuit structure and so on. In detail, the research work of this thesis mainly consists of the following three parts:First, based on piezoelectric equation, the relation between the mechanical impedance and the electric impedance of the shunt circuit was analyzed. The displacement transmissibility of the whole system and the method for the shunt circuits'parameters optimization were obtained.Second, series RL shunt damping circuit, series–CR shunt damping circuit, analog synthetic impedance shunt damping circuit and DSP synthetic impedance shut damping circuit were selected for single mode vibration and noise control. In addition, the optimal inductance value of the RL shunt circuit was reduced by paralleling a capacitor to the piezoelectric laminate, and the multimode vibration control was implemented by using the"blocking circuit".Third, by combining the adaptive filter and the DSP synthetic impedance, a new semi-active vibration control system that is based on the adaptive synthetic impedance was presented, and the corresponding experiment of multimode vibration and noise control is done.In short, passive vibration control system has good vibration damping effect and simple circuit structure, is easy to realize and do not require high-power energy source, so it is mainly used in the occasion that require the control system small and light. The new semi-active vibration control system that is based on the adaptive synthetic impedance inherits the advantages of passive vibration control system and also has the active vibration control system's characteristics, so it is a new good promising approach.