A new kind of high power ultrasonic vibration system used in liquid is investigated. The vibration system is composed of a longitudinal sandwich transducer and a large metallic cylinder which has the equivalent size.Using the apparent elastic theory, the electro-mechanical equivalent circuit and frequency equations of the cylinder in radial-axial coupled vibration are obtained. The radiation characteristics of the coupling vibration system are analyzed and simulated, then they are verified in experiment. The results show that the coupled vibration of the cylinder can be equivalent to one-dimension radial and longitudinal vibrations which interact each other with coupling coefficient.As choosing the appropriate geometry size of the cylinder, the vibration system has a strong radial-axial coupled vibration,and the vibration system can effectively radiates high power ultrasound.

coupling; electro-mechanical equivalent circuit; resonant frequency