Electromechanical equivalent circuit of the radially polarized cylindrical piezoelectric transducer in coupled vibration.

Electromechanical equivalent circuit of the radially polarized cylindrical piezoelectric transducer in coupled vibration is obtained. The equivalent elasticity method is used to analyze the coupled vibration. It is an approximate analytical method, ignoring the shear and torsion stresses and strains, dividing the coupled vibration into the extensional radial and longitudinal vibrations. A mechanical coupling coefficient is introduced to connect these two equivalent vibrations. According to the electromechanical equivalent circuit, the resonance frequency equations as functions of the frequency and the mechanical coupling coefficient are acquired. The sound pressure level and far field sound pressure distribution for the transducer in water are simulated. It is demonstrated that the radiation range of the cylindrical transducer is larger than that of the ring-type transducer. Several prototypes of the transducer are fabricated; the radial and longitudinal resonance frequencies are measured. The experimental resonance frequencies are in good agreement with the analytical results. The acquisition of the electromechanical equivalent circuit contributes to analyzing the electromechanical characteristics of the radial polarized cylindrical transducer.