Dynamic Model And Experimental Study Of Fe-Ga Transducer

The giant magnetostrictive material is a kind of intelligent material with magnetostrictive effect.Fe-Ga alloy is a new kind of giant magnetostrictive material,which is developed by the United States Naval Surface weapon research laboratory after Terfenol-D.Fe-Ga alloy has the advantages of large strain,small hysteresis and short response time.It is a new material for the optimization of the new actuator,sensor,vibration generator,etc..In this paper,the dynamic model of the Fe-Ga alloy transducer has a positive guiding significance for the design and control of the Fe-Ga alloy transducer.Firstly,introducing the hysteresis nonlinearity of Fe-Ga.Two important parameters,the skin depth and the cutoff frequency,are introduced for the alternating excitation magnetic field.Through the Maxwell equation,the mathematical model of the eddy current field distribution in the Fe-Ga alloy was derived.Based on the mathematical model of eddy current field distribution,the relevant parameters are set up and the distribution of the magnetic field of Fe-Ga rod at different frequencies is studied.The results show that the eddy current effect is more obvious with the increase of frequency and when the frequency is 1000 Hz,the central location of the Fe-Ga rod is not magnetized.Secondly,on the basis of Fe-Ga alloy local free energy,considering the ferromagnetic material under magnetic field excitation eddy current loss and additional loss in exchange,energy equations of Fe-Ga alloy dynamic magnetization process is established and the Fe-Ga dynamic magnetization is deduced.The strain of Fe-Ga alloy under the action of dynamic magnetic field is calculated by calculating the ratio of the volume ratio.The relationship between the strain and magnetic field under different prestress of Fe-Ga and the strain under the action of dynamic magnetic field are tested.Comparison of dynamic strain testing under magnetic field values and the calculated values,The results show that the dynamic model can accurately simulate the dynamic strain output when the magnetic field frequency is below 200 Hz.The results of the model and the experimental results are in error when the frequency is increased.Finally,based on the structure and principle of the Fe-Ga alloy transducer,the electromagnetic theory model and the solid mechanics model of the Fe-Ga alloy transducer are studied.Based on the simplified COMSOL Fe-Ga alloy transducer,a geometric model of Fe-Ga alloy transducer,parameters related to the definition of the conditions set,electromagnetic field and solid mechanics field related to the grid,set up Fe-Ga alloy transducer excitation current drive under dynamic state and the relationship between different current frequency and Fe-Ga alloy rod transducer output displacement output.The results show that the resonance frequency of the Fe-Ga alloy transducer is 700 Hz,the maximum output displacement is 6?m.