Research On Vibration Intensity Distribution Of Ultrasonic Tool Sliding Interface

An ultrasonic tool based on the ultrasonic principle,the core component is an ultrasonic transducer that can convert electrical energy into mechanical energy,and each component is mechanically connected,and there is a contact interface.This paper aims to improve the energy transfer efficiency of the contact interface of ultrasonic tools,takes the sandwich piezoelectric ultrasonic transducer as the research object,and analyzes the contact surface formed between its various components.In the connection structure,there is micro-slip between the contact surfaces,which affects the energy transfer of the transducer.The energy transfer efficiency of the sandwich piezoelectric ultrasonic transducer can be characterized by the vibration intensity at its output.The main research contents of this paper:Firstly,the reasons for the micro-slip of the contact interface of the sandwich piezoelectric ultrasonic transducer in the ultrasonic tool are studied.The sandwich-type piezoelectric ultrasonic transducer consists of a front cover,a rear cover and a piezoelectric ceramic crystal stack,which are fixed by pre-tightening bolts.Through the analysis of the bolted connection structure,the axial vibration model of the bolted connection is established.Due to the tangential friction on the contact surface,microslip will occur,and energy dissipation will occur.The lost energy is related to the amplitude and natural frequency of the axial vibration.is proportional to the square of.Based on the asperity theory,a rough interface model considering slip is established,the rough contact interface is equivalent to a thin layer medium,and the equivalent normal stiffness and tangential stiffness are solved.Second,the ultrasonic vibration generated by the ultrasonic tool is mainly converted from electrical energy into mechanical energy by the ultrasonic transducer.Therefore,it is of great significance to study the design principle of the ultrasonic transducer to improve the energy transfer efficiency of the ultrasonic tool.Ultrasonic transducer design adopts traditional analytical method and equivalent network method to design and process longitudinal sandwich piezoelectric ultrasonic transducer with resonant frequency of 23 k Hz.The piezoelectric ceramics,front cover,rear cover and horn are designed,and the design dimensions of each component are obtained.Thirdly,on the basis of the theoretical size design,Solid Works is used to model the components of the ultrasonic transducer in 3D;in order to simplify the solution process of the finite element analysis,the transducer model is simplified and then the finite element analysis is carried out through Ansys.: First,perform modal analysis on the transducer to obtain its resonance frequency of each order and the corresponding mode shape.The designed transducer produces longitudinal vibration at 23109 Hz;then analyze its harmonic response to check the stress and strain of its output end face.,frequency response,acceleration response curve,etc.It is found that the designed transducer has a maximum stress and strain around 23109 Hz.The transducer is processed and assembled according to the design size,and its resonant frequency is22290 Hz measured by an impedance analyzer.Comparing the theoretically calculated result with the Ansys simulation value,it is in good agreement with the actual resonant frequency.Fourthly,the vibration intensity distribution of the designed ultrasonic tool is measured to verify the rationality of its design.Second,the influence of micro-slip on the ultrasonic transducer is verified by changing the contact conditions.The above research content has a positive effect on analyzing the vibration characteristics of ultrasonic transducers and improving the understanding of the contact interface of ultrasonic transducers,and also has certain reference significance for the design of other ultrasonic transducer systems.