Simulation And Structural Optimization Of Radial Composite Piezoelectric Ceramic Ultrasonic Transducer

Ultrasonic transducer is one of the most important parts of ultrasonic technology.Piezoelectric transducer has become the most widely used transducer because of its high efficiency,low cost and easy forming.In recent years,piezoelectric ceramic composite ultrasonic transducer is the research hotspot of experts and scholars at home and abroad.Its vibration mode is radial vibration mode.The working frequency of piezoelectric ceramic transducer is its natural frequency,so it is very important to study its radial vibration characteristics.In this paper,the radial vibration characteristics and optimal design of the converter are studied.The work and achievements of this paper are as follows:(1)The mechanical model of the interference fit composite thick wall tube composed of piezoelectric ceramic tube and metal prestressed tube is established.The mathematical model of the radial vibration of the transducer composed of the radial coupling vibration wave equation of piezoelectric ceramic tube and metal prestressed tube,the continuity condition and boundary condition of the radial vibration of the composite thick wall tube is derived.The characteristic equation and the vibration mode of the transducer radial vibration are derived Function.Based on the analytical method and the difference method,the numerical simulation model of the radial vibration of the transducer is established.Through MATLAB programming,it is found that the natural frequency value of the characteristic equation is in good agreement with the existing experimental value,and the resonance frequency and displacement response of the analytical method and the difference method are the same.(2)The mechanical and mathematical model of interference effect on radial vibration of transducer is established.The calculation model of dynamic interference force between piezoelectric ceramic circular pipe and metal prestressed pipe is established.Based on the difference method,the numerical simulation model of interference effect on the radial vibration of transducer is established.Through MATLAB programming,it is found thatthe interference has a significant impact on the radial vibration characteristics of the transducer,which will make the radial vibration amplitude larger.(3)The mechanical and mathematical model of radial vibration of transducer under the combined influence of interference and end effect is established,and the numerical simulation model is established based on the difference method.Through MATLAB programming calculation,it is found that the natural frequency of the transducer is closer to the existing experimental value when the end effect is considered;the natural frequency is larger and the amplitude is smaller when the end is fixed than when the end is free;the axial displacement distribution under the influence of the end effect presents the symmetrical distribution characteristic of "small at both ends and large in the middle".(4)Sensitivity analysis and structure optimization of the converter are carried out.When the wall thickness of the metal prestressed pipe and the piezoelectric ceramic pipe is fixed,the natural frequency of the radial vibration of the transducer decreases with the increase of the inner diameter of the piezoelectric ceramic pipe;when the total thickness of the transducer is fixed,the natural frequency of the radial vibration of the transducer decreases with the increase of the wall thickness ratio of the piezoelectric ceramic pipe and the metal prestressed pipe.The objective function and constraint conditions of the optimal design of the transducer are established,and an example of the transducer design under a specific working condition is calculated.In general,this paper makes a deep research on the radial vibration characteristics of the transducer,and provides a new idea for the optimal design of the transducer,which has a certain guiding significance for the design and development of the transducer and the components with the same structure.