Analysis And Experimental Studies Of High Frequency Loss Characteristics Of Giant Magnetostrictive Materials

As a new type of functional material,giant magnetostrictive material generates telescopic deformation under the driving of magnetic field.Tb Dy Fe alloy is a kind of giant magnetostrictive material,which has the characteristics of fast response speed,high energy density,large magnetostriction.The application field involves cleaning,desulfurization,metal flaw detection,seabed detection,etc.This provides a technical guarantee for the application of giant magnetostrictive materials in high-frequency and even ultrasonic frequency devices.Therefore,the research on giant magnetostrictive materials and related devices has not only academic value but also great engineering practice significance.Due to the small resistivity of the giant magnetostrictive material Tb Dy Fe alloy and the remarkable skin effect of eddy current at high frequency,the internal magnetic field distribution of the material is uneven,and eddy current loss and abnormal loss are produced at the same time,resulting in overheating,low output power and unstable performance of the device.Therefore,it is necessary to carry out theoretical analysis and experimental research on the high-frequency loss characteristics of Tb Dy Fe alloys.First,based on the Jiles-Atherton model,the law of conservation of energy,and using the Maxwell's equation and Bessel function,a high-frequency dynamic hysteresis model of a giant magnetostrictive material considering the non-uniformity of the internal magnetic field distribution is established.The numerical method was used to calculate the established model.The influences of frequency and temperature on the hysteresis and loss of materials are studied.The accuracy of the model was verified through experiments.It gives a theoretical guidance for the design and application of Tb Dy Fe alloy devices at high frequencies.Secondly,using the AMH-1M-S magnetic characteristic test system to measure the dynamic hysteresis loops of Tb Dy Fe alloy samples with different slice thicknesses at different frequencies and different magnetic density amplitudes,and to extract coercive force,remanence,amplitude permeability and loss characteristic parameters,explore the change law of the material characteristic of each sample under different high-frequency magnetic field conditions,study the influence of slice thickness on the high-frequency loss characteristics and hysteresis characteristics of Tb Dy Fe alloy,and then give data support for structural optimum design of Tb Dy Fe alloy devices in different high frequency bands.Then,the dynamic hysteresis loops of Tb Dy Fe alloys with different structures at different frequencies and different magnetic density amplitudes were measured.The dynamic magnetic characteristic parameters such as complex permeability and amplitude permeability are obtained from it,the loss factor variation rule is obtained,and the high frequency dynamic magnetic characteristics and loss characteristics of monolithic and laminated Tb Dy Fe alloys with different structures of the same volume are compared and analyzed.Finally,based on the high frequency loss measured data of the Tb Dy Fe alloy,the change trend of the loss coefficient was studied.An improved calculation method of variable coefficient magnetic energy loss was established,which is more suitable for magnetostrictive materials under high frequency excitation conditions.The measured and calculated values of different magnetic flux density amplitudes and frequencies are compared and analyzed.The results show the accurracy of the method.Based on the improved variable coefficient loss calculation formula,the loss mechanism in the high frequency range of Tb Dy Fe alloy was studied.