Research On Output Stability Of Giant Magnetostrictive Transducer

The ultrasonic vibration processing system composed of giant magnetostrictive transducers has large eddy current loss during long-term operation,which affects the working efficiency of the transducer and the stability of output vibration;at the same time,the output of the giant magneto strictive transducer may become unstable or even stop vibration under the condition of a strong load,which severely limits the application of the giant magnetostrictive transducer in industry.Therefore,it is necessary to explore the influence law of giant magnetostrictive material eddy current loss and force load on the output stability of giant magnetostrictive transducer,and solve the key problems restricting its application,in order to meet the urgent needs of giant magnetostrictive ultrasonic vibration processing in the fields of aerospace,national defense and military industry.In this thesis,a giant magnetostrictive transducer and a longitudinal-bending coupling horn for ultrasonic spinning are designed.The finite element method was used to explore the influence of the thickness,major diameter,minor diameter and fillet radius of the horn on the longitudinal and bending coupling natural frequency and rim amplitude of the horn.Through continuous correction of the geometric size parameters of the rotary wheel,the amplitude was finally determined.The structural parameters of the device and the vibration test were carried out.The results show that the major diameter,minor diameter,thickness and fillet radius of the rotary wheel have different effects on the natural frequency of the horn longitudinal and bending vibration mode and the rim amplitude.The thickness of the rotary wheel affects the natural frequency of the longitudinal and bending coupling mode of the horn.And the rim amplitude has the greatest influence.In addition,the rotating wheel has a pitch circle when longitudinal and bending coupled vibration occurs,and its structure itself also has a certain amplification characteristic.The overall structural dynamics analysis of the transducer verifies the rationality of the transducer structure design.Through the joint simulation of electromagnetic field and temperature field,the eddy current loss of giant magnetostrictive rods of different structures and the temperature rise characteristics of the transducer are explored.In order to further reduce the heat effect of eddy current loss,a comparative analysis of air-cooled,oil-cooled and water-cooled conditions is carried out.The temperature field distribution of the energy device.The results show that after the structure treatment of the giant magnetostrictive material,the eddy current effect of the giant magnetostrictive material is effectively suppressed,the internal temperature of the giant magnetostrictive rod is reduced,the thermal deformation of the giant magnetostrictive rod is reduced,and the exchange rate is improved.The stability of the energy device;The effect of each structure on the suppression of eddy current loss:slicing treatment>cutting treatment>cutting treatment>untreated>internal and external slitting treatment;Under oil-cooled and water-cooled conditions,the temperature of the transducer is significantly reduced and the cooling effect is good.The maximum temperature of the transducer is about 60℃,which belongs to the normal working temperature range.Under this condition,the transducer can work stably.The static force loading test of the transducer was carried out with the space three-way force loading test device,and the influence law of the force load on the electrical parameters of the transducer was explored.The resonance of the static load on the horn was analyzed by the method of combining simulation and test.The influence of frequency and rim amplitude.The results show that:as the force load increases,the dynamic inductance and dynamic capacitance of the transducer change,causing its resonance frequency to drift;the dynamic resistance of the transducer increases with the increase of the force load,which causes the reactive power of the vibration system to increase and the output amplitude to decrease.When the axial force is greater than 750N or the radial force is greater than 550N,the force load has an obvious inhibitory effect on the output amplitude,and the transducer almost stops vibration.Compared with the axial force,the resonant frequency of the transducer is more sensitive to the radial force,and the radial force load has a more significant influence on the output stability of the transducer.The research results provide an effective way to improve the output stability of giant magnetostrictive transducers.