Study On The Longitudinal-torsional Composite Vibration Sandwich Piezoelectric Ultrasonic Transducer With Slanting Slots

In the fields of aerospace,material processing,mechanical engineering,etc.,power ultrasonic technology has attracted attention due to its advantages of environmental friendly,high efficiency and energy saving.With the wide application of hard and brittle materials,higher requirements are placed on the efficiency and precision of ultrasonic machining.The transducers with single vibration mode have been unable to meet the more and more diverse needs,and the ultrasonic transducer with composite vibration mode has attracted more and more attention due to its higher machining accuracy and efficiency.At present,there have been a lot of theories and experiments on unidirectional composite vibration transducers,but the research on multi-dimensional composite vibration transducers is relatively lacking.In order to enable the transducer to generate longitudinal-torsional composite vibration in multiple directions at the same time,a multi-directional longitudinal-torsional composite vibration piezoelectric ultrasonic transducer with slanting slots is designed,and its equivalent circuit model is established,which provides a theoretical analysis basis for the design and processing of this type of transducer.The main research contents are as follows:(1)Based on the principle of dual excitation longitudinal vibration exciter and vibration mode conversion,a dual excitation one-dimensional oblique slot type longitudinal-torsional composite vibration piezoelectric ultrasonic transducer is proposed.The equivalent circuit model(ECM)of the transducer is established by the equivalent circuit method,and the finite element(FE)method verifies the effectiveness of the equivalent circuit model of a dual-excitation one-dimensional longitudinaltorsional composite vibration piezoelectric ultrasonic transducer with slanting slots designed in this paper,which provides a theoretical basis for the transducer.(2)A dual-excitation cross-shaped longitudinal-torsional composite transducer with slanting slots is proposed.Based on continuous boundary conditions and a twodimensional dual-excitation longitudinal piezoelectric transducer,the equivalent circuit of the dual-excitation cross-shaped longitudinal-torsional composite transducer with slanting slots is established.Comparing the results obtained by the ECM and FE verifies the accuracy of the proposed equivalent circuit,and analyzes the overall resonance frequency and torsionality of the slots parameters of the transducer through finite element simulation.(3)Based on the principles of power synthesis,vibration coupling and vibration mode conversion,a two-dimensional orthogonal longitudinal-torsional composite vibration sandwich piezoelectric ultrasonic transducer with slanting slots is proposed.Based on continuous boundary conditions,the equivalent circuit model of the twodimensional longitudinal-torsional composite vibration of the transducer is obtained.The experimental transducer samples were processed,and their impedance characteristics and the longitudinal and torsional amplitudes at the output were tested.Through the ECM,FE and experimental test,it is verified that the two-dimensional longitudinal-torsional composite vibration sandwich piezoelectric ultrasonic transducer with slanting slots can simultaneously output longitudinal-torsional composite vibration in four directions.The established equivalent circuit of the twodimensional orthogonal longitudinal-torsional composite vibration sandwich piezoelectric ultrasonic transducer with slanting slots is helpful for deriving and calculating the resonant frequency of the transducer and realizing the optimal design of the transducer.The transducer is expected to be applied in the fields of multidimensional ultrasonic motors,multi-dimensional rotary machining and robotic arms.