Implementation And Characteristics Research Of Longitudinal-torsional Composite Vibration Of Ultrasonic Transducer Under Mode Conversion

With the development of science and technology,especially in aerospace high technology,there are some higher requirements on materials.Conventional machining methods can be used to machining ordinary materials,but some special materials are hard to process,such as brittle materials.Ultrasonic machining technology not only has a good processing effect on the common mechanical processing materials,but also has a good effect on the special materials,especially the brittle materials.At present,the one-dimensional ultrasonic machining is used widely in practical applications,and the technology is relatively mature.But with the machining quality improved,one-dimensional ultrasonic machining has been unable to meet the needs of production,two-dimensional ultrasonic machining is paid high attention,with the characteristics of high processing efficiency,high processing quality.Longitudinal-torsional ultrasonic machining is one of the important processing methods in 2D machining,and the domestic and foreign scholars have done research on this kind of composite processing.Ultrasonic transducer is an important part in ultrasonic machining system,it can output the amplitude directly,but the output of the vibration is generally one dimension.In this paper,it mainly studies the ultrasonic transducer which can produce two dimensional longitudinal-torsional vibration.The principle of sandwich ultrasonic transducer is discussed,and then the working mechanism of longitudinal-torsional vibration is analyzed.The feasibility of longitudinal-torsional composite vibration is studied.The geometric dimensions of spiral groove,which influence the performance of ultrasound transducer,are obtained,such as groove depth,groove width,pitch.The simulation results show that: the effect of groove depth on the resonance frequency of ultrasonic transducer has certain regularity.Whereas,the effect of groove width on the resonance frequency has not strict regularity.The resonance frequency increases with pitch increased.The effect of pretension force on the performance of the longitudinal-torsional ultrasonic transducer is analyzed through experiment research.The reasonable range of the pretension force is calculated,and then the vibration characteristics of longitudinal-torsional composite piezoelectric ultrasonic transducer are researched.The effect rules of pretension force on transducer frequency,dynamic resistance,quality factor,longitudinal-torsional amplitudes are obtained.The transducer resonance frequency is closer to the theoretical frequency,and relative ideal longitudinal-torsional amplitudes are acquired under the reasonable pretension force.Meanwhile,the rationality of theoretical design is proved.The longitudinal-torsional ultrasonic transducer laboratory sample is detected,and the results show that experimental values of the transducer are in good agreement with the theory and simulation results.