Research On The Dynamic Characteristics Of A Periodic Piezoelectric Smart Structure With Vibration Suppression Ability

The harmful environmentalvibration tends to be complicated. Therefore thevibration damping systems have to be adjustable and effective for wide-banded and multi-directional vibration sources. In this thesis, piezoelectric material is utilized to the designation of aparticular periodic structure, where the mechanic-electrical coupling effectof piezoelectric materials and the wave-filtering merit of periodic structuresare combined. Thus the proposed vibration reduction device has both advantages of active vibration control functionality and passive vibration isolation gap. The main completed research work is as follows:1.The distributions of electric field and electric displacement in a three-layer beam-like piezoelectric harvester are revisited from the accurate piezoelectricity theory. The electric displacement D3 is obtained from the Gauss theorem in electrostatics and found to be uniformly distributed along the thickness direction. The electric field is observed linearly dependent on x3. The efficiency is calculated finally and found to be always less than one, which eliminates a paradox that may appear for piezoelectric harvesters with large electromechanical coupling coefficients when calculated from the assumption of uniform electric field.2. Tuned vibration reduction mechanism of piezoelectric shunt circuit is discussed. The SDF(single degree of freedom) piezoelectric systemand piezoelectric cantilever bimorph are respectively analyzed, the frequency response characteristics of which are effectively adjustable by the shunt circuit. The equivalent circuit modelsare presented, based on which a circuit optimization tactic isrecommended, which is proved to be effective through numerical calculation.3. The motion equation of the proposed periodic piezoelectric structure is established based on transfer matrix method. The frequency response characteristics under both horizontal and verticalharmonic excitationare calculated, where the attenuation band is sensitive to the inertia effect of top mass and partition plate.4.The frequency response characteristicsof the proposed periodic piezoelectric structure under relatively low-frequency excitationare calculated with different circuit conditions. The circuit optimization tactic is utilized to the designation of piezoelectric shunt circuit.It is found that the voltage aroused by the optimized resonant circuit can intensely suppress the amplitude of structural vibration.