Title: Radial vibration of a slit-type annular ultrasonic concentrator 

Author: LIU Shiqing； GUI Fengli； WANG Jiatao； YANG Xianli； LI Luhua； 

Affiliation: Applied Acoustics Institute, Zhejiang Normal University；   

Abstract: The radial vibration characteristic of an annular ultrasonic concentrator with multislits is studied. Based on the electro-mechanical analogy and by introducing an area ratio coefficient, the radial vibrational equivalent circuit and the frequency equation of the concentrator are derived. The radial displacement amplitude magnification factor of it is obtained. By numerical calculating, the relationship between the radial displacement amplitude magnification factor, the resonance frequency of the concentrator at the first and second resonance and its radius ratio are investigated. Also, the relationship between the radial displacement amplitude magnification factor, the resonance frequency of the concentrator and the length, the angle and the number of the silts are analyzed. It is illustrated that a maximum of displacement amplitude magnification factor of the concentrator appears with the increase of the radius ratio, and the amplitude magnification factor increase as the length, the angle and the number of the silts increase, while the radial resonance frequency of the concentrator decreases as the length, the angle and the number of the silts increase. The theoretical resonance frequencies are in good agreement with that of the FEM simulations and measurement.