Structural Design And Acoustic Characteristics Analysis Of Sandwich Longitudinal Piezoelectric Transducer

Application of power ultrasonic has been considerably progressed during the last decade and sandwich longitudinal ultrasonic transducer has had a common use as the heart of power ultrasonic.So the applications of power ultrasonic will be more broad if the efficiency and performance get improved.This paper studies the performance and corrosion resistance of sandwich longitudinal piezoelectric transducers.On the one hand,from the perspective of improving the electromechanical coupling coefficient and the velocity ratio of the front and rear radiating surfaces,the sandwich longitudinal piezoelectric transducer is optimized by numerical method The optimization process takes into account the material optimization and geometric dimension optimization of the t ransducer.The material optimization mainly considers the influence of the acoustic impedance of the material on the velocity ratio of the transducer and the requests of impedance matching,and selects the material with the highest vibration velocity under the premise of satisfying the impedance matching.The geometric size optimization mainly considers the influence of the size of the piezoelectric ceramic and the size of the front and rear cover on the electromechanical coupling coefficient and the vibration velocity ratio.Under the condition of satisfying the frequency equation,the size with high electromechanical coupling coefficient and the vibration velocity ratio can be selected at the same time.Then,the finite element software was used to analyze the modal analysis,prestress analysis and harmonic response analysis.The resonant frequency,antiresonance frequency and admittance curve parameters of the transducer are obtained by modal analysis of modal analysis.The electromechanical coupling coefficient and mechanical quality factor of the transducer were obtained by admittance curve,and the results were compared with the theoretical calculated values.The prestressing force analysis of the piezoelectric ceramics inside the transducer is studied,and the influence of the prestress on the resonant frequency is studied.On the other hand,on the basis of sandwich longitudinal piezoelectric transducers,a new type of piezoelectric transducer was designed to compensate for some of the defects of the transducer and to deal with the corrosive environment.The modal analysis and harmonic response analysis of the transducer are carried out by finite element software to determine the performance of the transducer.