The vibrational properties of the high power ultrasonic focused radiator with rodlike and tubular structures in a composite vibration

• A high power ultrasonic focused radiator is investigated.
• The electro-mechanical equivalent circuit of the focused radiator is derived.
• The resonance frequency equation is obtained.
• The results validate that the radiator can produce high-intensity focused ultrasound.

In this paper, a high power ultrasonic (HPU) focused radiator composed of a sandwich longitudinal transducer, a metal rod with barbell structure and a long metal tube is investigated. The physical mechanism of the HPU focused radiator is due to intensive radial vibration of the long metal tube excited by the longitudinal vibration of the sandwich transducer and the metal rod. The electro-mechanical equivalent circuit for the composite vibration of the HPU focused radiator is derived, and the resonance frequency equations are obtained. The composite vibrational modes of the radiator are analyzed and the structure dimensions for the intense composite vibration of the radiator are optimized. The resonance frequency and the harmonic response curves as well as the vibrational displacement distribution are numerically simulated and experimentally measured. It has been shown that the analytical and numerical results are in good agreement with experimental data. The present radiator may be used in HPU applications, such as ultrasonic cleaning, ultrasonic extraction and ultrasonic sonochemistry.