Research On The Flexural Vibration Of The Rectangular Perforated Plate Piezoelectric Transducer

In recent years,the ultrasonic is widely applied in the air,with the development of the ultrasonic technology,such as ultrasonic dust removal,ultrasonic suspension,ultrasonic drying and ultrasonic condensation.Generally,the acoustic impedance of the transducer is much larger than that of the air.Due to the problem of the serious impedance mismatch,it is difficult to radiate the acoustic energy into the medium.To improve the radiated power and efficiency,a new transducer with a multi-layer matching plate and utilizing the bending vibration is put forward.The advantages of the piezoelectric ceramic transducers are small size,light weight,simple structure,easy to match the impedance of the air.Therefore,this transducer is used in the air.In this paper,the main contents are as follows:1.Based on the small deflection bending problem of the elastic thin plates,the equilibrium differential equations of elastic bending for the thin plates are derived.The resonance frequency equations of the rectangular thin plates under different boundary conditions are derived by the equivalent elastic method.2.A new type of a double-layer perforated piezoelectric transducer is proposed.The bending vibrational mode of the transducer is analyzed by COMSOL simulation software.The resonance frequency and the effective electromechanical coupling coefficient at different bending modes are obtained.The effect of the thickness,length and perforation ratio for the metal perforated plate on the resonance frequency and the effective electromechanical coupling coefficient is obtained.The bending vibration of the perforated plate transducer in the air is simulated,and the admittance-frequency response curve and the transmit voltage response curve are obtained.To verify the simulated results,a set of perforated plate transducers are manufactured.The full field scanning laser vibration measurement system is used to measure the surface vibration displacement.It is indicated that the simulated results are in good agreement with the experimental results.3.A new three-layered piezoelectric transducer with a metal perforated plate is proposed.The bending vibration mode of this transducer is studied with the finite element method.For the metal perforated plate,the dependence of admittance-frequency response curve on the thickness,the length,the radius and position of the hole is investigated.In addition,the admittance-frequency curve and the transmit voltage response of the bending vibration in air are obtained.The optimizing conclusions are obtained.