Modelling on electromechanical coupling process of a bending type piezoelectric ultrasonic transducer

We present an analytical model of electromechanical coupling process of a bending type piezoelectric ultrasonic transducer. The piezoelectric transducer consists of two groups of PZT elements sandwiched between four thin electrodes. The ceramics are thickness polarized, and the two groups of ceramics are polarized in opposite directions. All the PZT elements are clamped by a screwed connection between fore beam and back beam. The modeling process is consisted of two stages. In the first stage, bending vibration model of the piezoelectric transducer is built. Resonance frequency and vibration parameters are obtained. In the second stage, analytical model of effective electromechanical coupling coefficient which represents energy conversion efficiency of the transducer is built. To validate the analytical model, a prototype transducer is fabricated and tested. A comparison between analytical model and experimental model is carried out. The comparison result show that the analytical model is in good agreement with the experimental model.