Design and vibration performance study of spherical shell high-intensity focused ultrasonic transducer in longitudinal–radial composite vibration

Abstract

This study presents the development and analysis of a high-intensity focused ultrasonic transducer featuring a spherical shell in longitudinal–radial composite vibration. The transducer consists of a longitudinal sandwich piezoelectric converter, a stepped horn, and a metal spherical shell. The longitudinal sandwich piezoelectric converter, in conjunction with the stepped horn, generates longitudinal vibration that excites radial vibration within the metal spherical shell, thereby enabling high-intensity focused ultrasound inside the metal spherical shell. The electromechanical equivalent circuits for both the metal spherical shell and the composite transducer were derived to provide a theoretical foundation for the analysis. Numerical simulations were utilized to investigate the vibration and ultrasound field features of the transducer, followed by the design and fabrication of a prototype. Experimental measurements of the impedance characteristics and radiation field were performed, with results demonstrating good agreement with both analytical predictions and numerical simulations. This validates the potential of the transducer for applications requiring high-intensity ultrasound with a larger radiating surface.