Influence and mechanism of radial prestress on the electro-acoustic performance of spherical transducers

A radial prestressed spherical piezoelectric transducer is proposed to meet the demand for high-power applications. The feasibility and validity of radial prestress in improving the electro-acoustic performance of spherical transducers are comprehensively evaluated. The calculated stress distribution suggested that the prestressed spherical shell is compressed, and its equivalent tensile strength limit is improved. An advanced electromechanical equivalent circuit model was first proposed on basis of the traditional lumped model, and the resonance frequency can be accurately predicted within an error of 1.5%. The feasibility of radial prestress on power capacity and electro-acoustic performance was experimentally verified by power limit test and acoustic radiation tests. Compared with the unprestressed shell and transducer, the mechanical power capacity of the 3.4 MPa prestressed shell increased by 75.3%, and the maximum transmitting voltage response level of the transducer increased by 2.2 dB. Thereby, this work provided theoretical and experimental means for the design and evaluation of prestressed spherical transducers.