Research on the excitation modes of PZT element in bending cylindrical transducers

The PZT element acts as a core component which transforms the input electric energy to output mechanical energy in ultrasonic transducer. So the excitation modes of PZT element have an important influence on the characteristics of transducer. The force factor formulas of cylindrical transducers based on the bending vibration mode are deduced in theory and the excitation modes of PZT elements in bending cylindrical transducers were investigated. In detail, the influence of distributing positions and dimensions of PZT plates on the output performance of transducer were discussed and simulated by FEM. It indicated that disposing the PZT plates on the peak of strain curve for the bending vibration mode is the optimal method to excite the transducer. The total length of PZT element should not exceed the distance of two vibration nodes. For the bending cylindrical transducer bonded with PZT plates, increasing the thickness of each PZT plate is propitious to enhance the output characteristics of this type transducer. Whereas, the thickness of each PZT plate should be decreased to achieve an excellent performance for the transducer with a sandwich structure.