Design Of The Two-dimensional Two-dimensional Vibration Sandwich Piezoelectric Transducer

With the development of high power ultrasonic technology,and the continuous expansion of application fields,the traditional one-dimensional(1-D)longitudinal sandwich piezoelectric transducer have been not able to meet some new specific ultrasonic applications,because of their single direction of acoustic radiation,limited power capacity and the small radiation area,and so on.In some applications of ultrasonic technology,such as in large power ultrasonic cleaning,ultrasonic welding,sonochemistry and ultrasonic motor,etc.,novel ultrasonic vibration systems with large ultrasonic power,large radiating surface,omni-directional or multi-directional acoustic radiation,should be developed urgently.To improve the vibration performance and the power capacity,improve the radiation direction,increase the radiation area of traditional ultrasonic transducers,the two-dimensional longitudinal vibration sandwich piezoelectric transducer is proposed,which is composed of a central coupling mental block,a piezoelectric ceramic stack and four outer metal cylinders.The mainly contents of this paper are as follows:(1)Basing on elastic vibration theory and the electromechanical analogy principle,we derived the electro-mechanical equivalent circuit and the resonance frequency equation of the L-L vibration direction converter,computed its frequency of in-phase-mode and anti-phase-modes.The results of the equivalent circuit method are compared with those results calculated by the wave equation group,which indicates that the results calculated by the equivalent circuit method have higher accuracy.Meanwhile,we simulated L-L vibration direction converter vibrating in anti-phase and in-phase mode by the FE methods.Lastly,we produced the corresponding experimental samples,and tested its vibrational characteristics,which shown the correctness of the equivalent circuit of L-L type converter proposed in this paper.(2)Using two-dimensional longitudinal coupling vibration mechanism,the dual-excited L-L type sandwich piezoelectric transducer was proposed,and its equivalent circuit and resonance frequency equation were deduced.Vibrational characteristics of transducer was studied by Numerical methods simultaneously.The resonance frequencies calculated by two methods,are good agreement,which proved that analytical method is right.(3)To further improve the power capacity and ultrasonic radiation intensity of the dual-excited transducer,basing on the power synthesis technology and two dimensional coupled vibrations of the metal elastomer,we proposed a four-excited two-dimensional longitudinal sandwich piezoelectric transducer.The electromechanical equivalent circuit and the resonant frequency equation of the transducer are deduced.The effect of the size parameter and the material parameters on the vibration performance is investigated.The theoretical results are verified by using FEM software.This study is extremely useful in design and application of such transducer,and provides theoretical design guidance.Those transducers,we introduced,producing large ultrasonic power,high-intensity and multidimensional sound radiation,can be used as an excitation source and as an ultrasonic motor,can also be used for ultrasonic degassing technology.This study greatly improves the vibration performance of ultrasonic transducer and extends considerably its application range.