Study On The Dynamic Characteristics Of Giant Magnetostrictive Transducer Considering The Joint Surface

As the core component of the ultrasonic vibration system,the transducer directly determines the application of ultrasonic technology.The joint surface has been widely existed in transducer,which is one of the most important factors that affect the dynamic characteristics of the transducer.Base on this,this study investigates the influence of the nominal contact area,prestress and roughness of the joint surface on the dynamic characteristics of the transducer through designing giant magnetostrictive ultrasonic transducer.The dynamic characteristics of giant magnetostrictive transducers are studied considering the influence of the joint surface in this study,and the research results have important value for designing the transducer.Firstly,according to the principle of quarter wavelength,a composite horn with tool head and a double giant magnetostrictive rod ultrasonic transducer are designed.According to the difference of the nominal contact area of the joint surface,the transducers are designed in different sizes,and the size of the horn is optimized through finite element simulation.According to the magnetic field requirements,the bias magnetic field and driving magnetic field of the transducer are designed.In addition,a cooling system is designed for cooling to reduce the heat generated during the operation of the transducer.And then,the transducer is analyzed from the two aspects of the prestress and area of the joint surface.In the finite element analysis,Prets179 No.preload force unit is selected to apply the same set of different preload force to the two preload bolts of transducers of different sizes.The change of the transducer’s mode and amplitude is analyzed,and the transducer prototype is made for experimental verification.It can be concluded that the natural frequency of the transducer increases with the bolt preload,and the increment decreases with it;the resonance amplitude increases first and then decreases with the increase of the bolt preload,and has the maximum amplitude when the preload is 300-500N;when the nominal contact area of the interface is small,the transducer has a large output amplitude.The two-dimensional magnetic field analysis of transducer with different contact area shows that the giant magnetostrictive transducer has a large magnetic field strength and magnetic induction strength when the nominal contact area of the joint is small.Finally,the effects of different roughness combination surfaces on the dynamic characteristics of transducer are studied.According to the theory of joint surface,the joint surface with different roughness is transformed into Combin14 element with certain stiffness and damping for finite element simulation.The dynamic characteristics of the giant magnetostrictive transducer are studied when the stiffness,damping,stiffness and damping of the joint are changed simultaneously,considering only the joint surface between the horn and the front magnetic disc,the joint surface between the back cover plate and the rear magnetic sheet,and the two joint surfaces are comprehensively considered.A prototype of the transducer was fabricated to verify the dynamic characteristics of the transducer according to the roughness research plan,which can be concluded that under the same conditions,as the stiffness of the joint increases,the natural frequency of the transducer increases,and the amplitude of the transducer increases too.As the damping of the joint surface increases,the natural frequency of the transducer does not change,while amplitude increases.As the stiffness and damping of the joint surface increase simultaneously,the natural frequency of the transducer is equal to the natural frequency of the transducer at the same stiffness,and the resonance amplitude of the transducer increases.That is,as the joint surface roughness decreases,the transducer amplitude increases.When the roughness of the two joint surfaces are the same,the amplitude of the transducer is smaller than that of the transducer when only the roughness of the joint surface between the back cover plate and the rear magnetic sheet is changed.