Study On Some Non-linear Characteristics Of Giant Magnetostrictive Transducer

As the representative of the rare-earth magnetostrictive materials, Terfenol-D is a new type of highly efficient magnetic (electricity)-machinery (sound) conversion materials and its performance is far superior to piezoelectric ceramic and other materials. This kind of material which has a large strain, high-power density and high-precision, rapid response and high-reliability and other advantages, is widely used in super-magnetostrictive transducer. But in the practical application super-magnetostrictive transducer is related to nonlinear vibration, magnetic flexible dynamics, precision machining and many other cross disciplines; And the material'internal magnetic hysteresis, swirl and any other nonlinear problem are that which constrain super-magnetostrictive transducer' theoretical study and practical application.Based on the above reasons, the paper carried on the study on the nonlinear properties inside the giant magentostrictive material and the magneto-elastic coupling of the giant magnetostrictive transducer, which provided theoretical foundation to the areas of machining application to the giant magnetostrictive transducer and had great theoretical and application value. The paper' major researches are as follows:(1) There is a significant hysteresis between the giant magnetostrictive transducer' output and the external magnetic field. That the material's nonlinear constitutive relation is the main reason that leads to hysteresis. Based on the first class of nonlinear magnetic pressure equations and through researching GMM rod' vertical vibration, to study the material itself hysteresis. So all of these laid a theoretical foundation to analyze and control transducer' hysteresis.(2) The third chapter studied on the pre-spring' square and cubic nonlinearity and at the sane time took into account material's hysteresis nonlinearity. Considering the above two non-linearity, we establish the mathematical model of the super-magnetostrictive transducer and use approximative analytical method and numerical simulation to analyze the dynamics model' nonlinearity.(3) On the condition of turning process we established dynamic models under different treatment of magnetostrictiveλ, considering the spring' non-linearity geometry and the material'hysteresis nonlinearity. And then discussed the impact on the output of response under various parameters using numerical methods and made a comparison between different dynamic models. So we can better control the output of transducer according to the parameters'impact on the output.(4). Because of material itself hysteresis is so complex that we use three times of rate and displacement hysteresis model to replace it and set up double degrees dynamic hysteresis model of transducer; Then use analytical and numerical methods to solve the transducer' response and discuss the parameters on the impact of frequency response curve. At the same time the paper does some comparison of the output response between the single and double freedom model.