Study on electromechanical coupling model of piezoelectric ultrasonic transducer

In this paper, an electromechanical coupling model of piezoelectric ultrasonic transducer is proposed. The structure of piezoelectric ultrasonic transducer is designed to be a sandwich type piezoelectric-metal composite beam with an exponential variable cross section working at second-order bending vibration mode. Then, the bending vibration model is solved by way of the Timoshenko beam theory. According to vibration model and electromechanical equivalent diagram, the effective electromechanical coupling factor of piezoelectric ultrasonic transducer is obtained. When overall size of the transducer remains unchanged, the influence of piezoelectric ceramics to effective electromechanical coupling factor is studied by changing the position of piezoelectric ceramics. The most reasonable transducer structure is got by optimizing the structure of transducer. By using FEA, the proposed analytical model is analysed and validated.