Longitudinal And Bending Vibration Of Complex Frequency Of The Vibration Characteristics Of The Transducer And The Sound Field Radiated

High power ultrasound has been extensively used for ultrasonic soldering, ultrasonic testing, ultrasonic cleaning and other fields. Ultrasonic cleaning is the most widely and mature technique of all the applications. The effect of ultrasonic cleaning is determined by the frequency of the ultrasonic wave. When something to be washed is dirty and large, the low-frequency is ready for your right choose. A number of factors might account for the effect, one of the most common causes is ultrasonic cavitations; when you cleaned small objects with complicated structures, the high-frequency is right the only option. It has only one resonance frequency because the geometric dimension of the traditional transducer has been designed. When it is working on the designed frequency, a standing wave is formed, and it caused different effects of ultrasonic cleaning because of the positions of the cleaned things. In order to enhance the quality of ultrasonic cleaning, multi-frequency ultrasonic cleaning was devised. In the field of chemical ultrasound, extensive research shows that the performance of the chemical ultrasound acted by multi-frequency is superior to which acted by one frequency. However, some multi-frequency transducers were constituted by several transducers, which caused the high price. It is necessary to produce a transducer with different frequencies. In this paper, a kind of multi-frequency ultrasonic transducer, which is based on coupled vibration, was designed and analyzed through finite element.The detailed content and work of this paper are as follows:1.Both thick and thin rectangular plates with flexural vibration are analyzed, the rate equation and vibration equation were given when the rectangular plate was in flexural vibration. The result shows that whether a thin plate or a thick plate has plenty of resonant frequencies. Due to the complexity of the bending vibration, Some frequencies of the rectangular plate are designed and simulated by finite element method, With the increasing thickness of the plate, the influence on frequency was analyzed. Through discrete Rayleigh's integral formula, a new method for calculating rectangular plate directivity pattern is proposed by the finite element method.2. The frequency equation of sandwich transducer in longitudinal vibration was deduced. Longitudinal vibration transducer was constituted from a cross-section bar and a rectangular plate. Due to the coupling interaction between flexural vibration of the rectangular and longitudinal vibration of the sandwiched ultrasonic transducer, it can be proved that this kind of ultrasonic transducer has several resonance frequencies by FEM. In addition, using finite element method can also finish harmonic response analysis and modal analysis. Acoustic directivity under each modal was calculated.3. The multi-frequency ultrasonic transducer consists of a rectangular radiator and two sandwich ultrasonic transducers, no matter how much of the thickness of the plate, the multi-frequency ultrasonic transducer can own several resonance frequencies due to the coupling between bending vibration of the rectangular plate and longitudinal vibration of the sandwich transducers. According to this phenomenon, I used the finite element method not only to design and simulate some multi-frequency ultrasonic transducers but also to complete the harmonic response analysis and modal analysis. The effect of the location of two sandwich transducers and the geometry of the multi-frequency transducer is analyzed. Acoustic directivity under each modal was calculated.