Ultrasonic Casting Transducer Analysis And Design Study Of The Detuning Phenomenon

Nowadays, casting treated by ultrasonic is a new developing direction of technology of aluminum alloy casting .But the mechanism of structure treated by ultrasonic in casting process was not very clear .Therefore it needs urgently to carry out a deep-going investigation in the region. The first problem is developing the power ultrasonic transducer system using in the metallurgical industry. The major content of this article is as follows:1. Measured the longitudinal oscillation frequency, the amplitude and vibration speed of output end, the actual working frequency and so on, using the Laser Doppler Velometer and impedance analyzer. It established the foundation of subsequent researches. This article analyzed the phenomena that the ultrasonic transducer system can not work in the simulation experiments and field experiments, water simulation experiments, temperature of piezoelectric ceramic experiments and temperature of ultrasonic horn simulation experiments analysis were completed, by these researches we get one of the main influencing factor: the temperature of ultrasonic horn is too high, and the material parameter is changed, that causes the resonance breaking of the system.2. The new transducer system with new material parameter that fits the high temperature environment is designed in this article, for solving the resonance breaking of the original transducer system, the harmonic frequency of new system is set to 20KHz too. At the first the longitudinal oscillation equation of a ultrasonic horn with random variable cross-section was discussed. The physical and mathematical model was analyzed, and the design formula was established. Based on these the new transducer, front and back end caps, ultrasonic horn and tool were designed. In this article the equivalent circuit of the crystal stack of piezoelectric ceramic was deduced, and some detail, for instance the optimal circular arc of stepped ultrasonic horn was considered.3. The dynamics simulation analysis of the designed structure is completed, by ANSYS—finite element software. First of all, the finite element model was established, and the natural frequency and mode of the original transducer system with normal and high temperature and the designed system were calculated. The dynamics characters and distribution of amplitude were calculated by mode analysis. These results indicate that the material parameter will influence the resonance of the system. Through harmonic response analysis, the displacement response under the motivation of high frequency electric signal of the original and new systems was calculated in this article, from the results, the change of displacement of the structure with the different frequency signal can be deduced. Through comparing with the measuring results and designing results, the designing process and the finite element model is correct and reasonable, and optimal dynamics design of the structure can be carry out in the future according to the results.