Research On The Band-gap Broadening Methods And Vibration Attenuation Properties Of The Piezoelectric Shunted Phononic Crystals

Piezoelectric shunted phononic crystals(PSPC)combine piezoelectric shunt damping technology with the band gaps theory of traditional phononic crystals.Which not only can dissipate energy and shunt damping,but also have the band gaps properties of elastic wave propagation in periodic structures.Consequently,they can be used to isolate vibration.PSPC have many advantages such as: little in added mass,convenient to adjust band gaps,etc.,but also have some disadvantages such as: low frequency locally resonant band gaps are narrow and attenuation ability are weak.To overcome these shortcomings,this paper carried out research on the band gaps broadening methods and vibration attenuation properties of the PSPC.Through physical modeling,theoretical analysis,finite element simulation and experimental tests,we made a useful exploration of band gap properties and vibration transmission properties of the broadband-enhanced PSPC.The main research content and conclusions are drawn as follows:1.Based on the long wave approximation supposition,the physical model of PSPC is set up.The band-gap properties and vibration transmission properties are calculated by the transfer matrix method.The regularity of the band gaps of PSPC beam is disclosed.2.Two new-type(negative capacitance and multimodal)piezoelectric shunting circuits phononic crystal beams band-gap properties and transmission properties are studied.And the regularity of the band gaps is also disclosed.The study shows that the negative capacitance resonant shunting circuits can significantly enhance the band gaps of phononic crystal beam.Moreover,as the magnitude of the negative capacitance is closer to the inherent capacitance of the PZT patch,the enhancement effect is better.Multimodal resonant shunting circuits can produce multiple locally resonant band gaps,which can realize broadband vibration control and enhance the capacity of vibration attenuation.3.The band gaps coupling properties of PSPC beam and elastic wave localization properties of disordered period beam are researched.When the locally resonant band gap and Bragg band gap are coupling,the band gaps of PSPC beam become broader.Circuital parameters disorder can extend the locally resonant band gaps,and the band gaps widening increases with the levels of circuit disorder,but the attenuation constant becomes smaller.Bragg band gaps are substantially unaffected with the levels of circuit disorder.4.The vibration test systems of PSPC beam is built.Experimental results show that serial negative capacitance resonant shunting circuit can increase the widths of locally resonant band gaps and the attenuation magnitudes effectively.In summary,the work in the thesis can be used to guide the design of phononic crystals with tunable band gaps,and also have guiding significance for PSPC in vibration and noise reduction of equipment.