Effects of electrodes and electrical connections of piezoelectric layers on dynamic characteristics of radially polarized multilayer piezoelectric cylindrical transducers

Piezoelectric cylindrical transducer is a type of excellent smart devices that can generate radial sound radiation due to its unique structural characteristics and has been widely used for ultrasonic and underwater sound applications. In the design of a piezoelectric cylindrical transducer, especially with the multilayer structure, the electrodes and electrical connections of piezoelectric layers are two key factors affecting the device performance but have not been well evaluated, which result in the inaccurate prediction of dynamic characteristics. This work establishes the exact theoretical models for radially polarized multilayer piezoelectric cylindrical transducers by taking into account the electrodes and electrical connections of piezoelectric layers. Based on the plane stress assumption, the dynamic solutions of the models are derived. Analytical expressions of electric impedances are also derived to obtain the resonance frequencies. In addition, the analytical solutions are validated using the special example in the earlier work and comparing them with the finite element analysis results. Subsequently, the effects of the electrodes and electrical connections of piezoelectric layers on the dynamic characteristics of the transducer are analyzed and discussed. The results show that the electrode thickness, the electrode type, and the parallel and series connections significantly affect the transducer's performance, thus providing useful guidelines in the design of piezoelectric cylindrical transducers. This work contributes to an overall analysis on the dynamic characteristics of the radially polarized multilayer piezoelectric cylindrical transducers, which is very helpful to improve the performance of two-dimensional emitter and receiver in underwater sound and ultrasonic applications.