| With the continuous expansion of the application field of ultrasonic technology,due to the limitations of its own structure and design theory,the traditional one-dimensional longitudinal ultrasonic transducer has gradually emerged in the aspects of ultrasonic power capacity,ultrasonic output direction and ultrasonic radiation area.This paper proposes the Y-type longitudinal composite converter and piezoelectric transducer,which consist of three longitudinal vibrators forming an angle of 120 degrees with each other in two-dimensional space and a central regular triangular prism made of steel.Through the cooperative work of multiple longitudinal vibrators,the purpose of high-power ultrasonic output and multi-directional ultrasonic radiation is achieved.The main research contents are as follows:(1)Based on the basic principle of the apparent elasticity method,the mechanical coupling coefficient and the longitudinal force conversion coefficient are introduced,establishing the relationship b etween three longitudinal vibrations combined with the infin itesimal method.The equivalent circuit and its frequency equation of the three-way resonance of the Y-type longitudinal composite converter are deduced.The finite element software COMSOL is used to simulate the model,and the harmonic response curves and resonance frequencies corresponding to different size parameters are obtained.The sample of the directional converter is processed,and its resonance frequency is measured by the experimental me thod.The obtained results are basically consistent with those obtained by the equivalent circuit method and finite element simulation.The correctness of the equivalent circuit method is proved,and the design theory is provided for this kind of ultrasonic vibration system.(2)Based on the Y-type longitudinal composite converter,a single-excitation Y-type longitudinal composite piezoelectric transducer is designed,and its electromechanical equivalent circuit and resonance frequency equation are deduced.The correctness of the established equivalent circuit is verified by the finite element method,and the vibration characteristics of the transducer are studied experimentally.The results show that the transducer can realize one end input and multi-directional output,which effectively expands the ultrasonic radiation area of the transducer.(3)Based on the principle of power synthesis,a two-excited Y-type longitudinal composite piezoelectric transducer is designed,and its electromechanical equivalent circuit and resonance frequency equation are obtained by using the equivalent circuit method.Through finite element simulation,it is concluded that the transducer can achieve higher intensity vibration output at the forced end.The transducer samples were processed,and the correctness of the finite element method and the equivalent circuit method were verified by experiments.The transducer can realize power input at both ends and output at one end,it is suitable for some ultrasonic applications requiring high intensity and high power,such as ultrasonic metal welding and ultrasonic plastic welding(4)A three-excited Y-type longitudinal composite piezoelectric transducer is designed,and its electromechanical equivalent circuit and resonance frequency equation are derived.The resonant frequency of the transducer is calculated by the equivalent circuit method,the finite element method and the experimental method respectively,and the results of the three are in good agreement.The proposed transducer has the advantage of generating specific angle two-dimensional three-dimensional ultrasonic radiation in longitudinal resonance mode,which can be applied in some ultrasonic environments that require specific angle and multi-dimensional acoustic radiation,such as phacoemulsification,ultrasonic defoaming,ultrasonic dust removal and ultrasonic sonochemistry,etc. |
