Investigation of a cascaded piezoelectric transducer with cone horn for multi-mode power ultrasound application

To meet the ultrasonic application requirement of high power intensity and large mechanical displacement, a new theoretical method is used to study the multi-mode characteristic of the cascaded piezoelectric transducer with cone horn in this paper. Based on equivalent circuit and Kirchhoff's law to obtain the frequency equation and vibration velocity expression of the transducer, then the resonance frequency and effective electromechanical coupling coefficient can be calculated, the velocity amplification ratio can be obtained in the meantime. This method is distinguish from traditional theoretical analysis, which avoids complex transformation of the multi-excitation sources in cascaded structure, and can calculate more performance parameters. The relationships between these performance parameters and the excitation position of the piezoelectric stack, the length and output end radius of the cone horn are analyzed and compared with the numerical simulation, and the optimized parameters of the transducer size are given. A transducer is manufactured for experimental test, the results show that the experimental value is in good agreement with theoretical calculation and finite element simulation. This work is expected to be used in the optimal analysis of the multi-mode transducer in high power ultrasonic field.