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Magnetostrictive materials have excellent magneto-mechanical properties and are widely used in the field of energy conversion. Temperature has an important influence on the magnetic properties of them. Accurately studying the temperature dependence of magnetostrictive materials is a necessary prerequisite for the design of precision actuators. In this paper, we constructed a high-frequency magnetic property measurement system that can control the temperature. The magnetic characteristics of Terfenol-D, Fe-Ga and Fe-Co were measured at temperatures ranging from 10 °C to 80 °C, the frequencies from 1 kHz to 20 kHz and magnetic induction amplitudes from 0.01 T to 0.07 T. The temperature dependence of the three materials under different exciting conditions was comprehensively compared. The variation trends and temperature sensitivities of the coercivity, permeability, equivalent inductance, equivalent resistance and the magnetic energy losses are analyzed respectively. The results of this paper are oriented to practical engineering applications and can be used for high-frequency loss prediction and temperature control system design. [ABSTRACT FROM AUTHOR]

The dynamic magnetic characteristic curves of TbDyFe alloy (TbxDy1−xFe1.9–2.0, $0.27 \leq x \leq 0.3$) under varying temperatures at different high-frequency excitation conditions were measured. The results show that when the excitation amplitude and frequency keep constants, the dynamic hysteresis loop, the permeability, and the magnetic energy loss all vary with the increase in temperature (from 10 °C to 80 °C). Their trends of temperature dependence are analyzed in detail. Based on the Bertotti loss separation method and experimental data, a magnetic energy loss calculation model for TbDyFe alloy under variable temperature conditions is proposed. The model considers the influence of high-frequency hysteresis characteristics and skin effect. It introduces temperature-related terms to modify the loss coefficients. The calculation results are compared with the experimental ones at different temperatures. It shows that this calculation method can accurately calculate the magnetic energy losses under variable temperature at higher frequencies (1–20 kHz). This research can provide an experimental and theoretical support for high-frequency engineering application of magnetostrictive materials. [ABSTRACT FROM AUTHOR]

According to the actual operation conditions, a kind of high-frequency losses testing system of magnetostrictive materials under dc bias is built. The dynamic hysteresis loops for Terfenol-D samples at different ac driving frequencies and magnetic densities are studied experimentally under variable dc bias excitation. The magnetic energy losses are obtained from these dynamic hysteresis loops. The three-variable magnetic energy loss matrix is established by these measured data. On the basis of Bertotti loss separation theory, the high-frequency losses calculating model of magnetostrictive materials considering variable dc bias excitation is proposed by using the algorithm of Levenberg–Marquardt and the method of matrix transformation. In this model, according to the multivariate parametric regression, the loss coefficients are modified by introducing dc bias-related terms. The loss comparison at different operating conditions shows that the computed results in this proposed model are in good agreement with the experimental ones. [ABSTRACT FROM AUTHOR]

The effect of variable compressive stress on hysteresis, eddy-current, and anomalous losses in magnetostrictive materials is investigated by the built magnetic characteristic testing system. Based on experimental results of Terfenol-D and loss separation theory, the trends of loss coefficients of three variables, magnetic frequency f, peak flux magnetic density Bm, and compressive stress σ, are analyzed. The reasons for the change in losses are explained from the point of view of micro-magnetism and physical mechanism. A variable coefficient magnetic energy loss calculating model considering compressive stress is derived using the algorithm of Levenberg–Marquardt and the method of multivariate parametric regression. The experimental and computed results of magnetic energy losses are compared and analyzed under different operating conditions. The analysis results show that the proposed model could well predict the losses under compressive stress at high-frequencies (5–20 kHz). The average error of the computed and experimental results is 5.5%. This research has improving significance in giving theoretical guidance for magneto-mechanical design in the high-frequency operated conditions of magnetostrictive devices. [ABSTRACT FROM AUTHOR]

Accurate calculation of magnetic energy losses for magnetostrictive material is a necessary step in designing high-power magnetostrictive transducer. In this article, based on the losses separation formula and measured data of Terfenol-D, the changing trends of the losses coefficients are investigated. An improved magnetic energy losses calculation method with variable coefficients is established. The measured and calculated values of magnetic energy losses at different frequencies and flux densities of driving magnetic field are compared and analyzed. The results show that the calculation method can accurately calculate the magnetic energy losses at higher frequencies (1–20 kHz). The average error between the calculated and the measured values is 4.32%. This research can provide theoretical and experimental guidance for the higher frequency applications of magnetostrictive materials. [ABSTRACT FROM AUTHOR]

The accurate calculation of magnetic energy losses for electromagnetic materials directly affects the global optimization design and operating efficiency of electromagnetic devices, especially under high frequency excitation. This study gropes for measurement methods of hysteresis, loss, and temperature rise characteristics for magnetostrictive Tb-Dy-Fe alloys materials under comprehensive operation conditions of high-frequency excitation, compressive stresses, temperature, and DC bias. Based on the measured data, a multiple variables loss matrix that can describe the characteristics of multiple energy fields (electromagnetic-, thermal- and mechanical fields) is established. Using loss matrix transformation method, the variation of hysteresis loss coefficients and generalized eddy current loss coefficients with different energy field characteristic variables are obtained. By establishing a dual statistical framework of sensitivity and deviation degree, the main influence variables which have the greatest impact on loss coefficients are extracted from these variables. Then a loss model for magnetostrictive material considering comprehensive operation conditions is presented which can describe the output characteristics of electromagnetic devices with strong non-linearity and multi-coupling effects among different energy fields. Furthermore, this method allows for the expansion of dimensions of linear or nonlinear variables and considers more energy fields, enabling a comprehensive analysis of interplay between multiple fields and facilitating engineering calculations. • A measurement method for high-frequency magnetic energy losses of magnetostrictive Tb-Dy-Fe alloys under different energy fields is constructed. • A new magnetic loss calculation model is proposed and the loss and hysteresis properties are analysis for magnetostrictive Tb-Dy-Fe alloy under multivariable comprehensive operation conditions. • A new method is proposed to expand the dimensions of linear or nonlinear variables, and to consider more energy fields related to Tb-Dy-Fe alloys. [ABSTRACT FROM AUTHOR]

• Building a test platform for high frequency magnetic properties of magnetostrictive materials. • Measuring and analyzing high frequency magnetic properties of rod gallium iron alloy were under different exciting conditions. • Developing a high-frequency dynamic model for rod gallium iron alloy taking into account compressive stress. • Predicting the change of high frequency magnetic loss of materials under variable compressive stress conditions. Magnetostrictive rods have stress-sensitive properties. They are the core component of high-frequency high-power magnetostrictive sensor and actuator devices. In practical high frequency applications, a certain compressive stress needs to be applied to improve the magnetostrictive coefficient of the material. However, unsuitable operating conditions can lead to increased magnetic energy losses and deterioration of device performance. Therefore, the loss modelling as well as other physical behaviour of the material need to be investigated before designing magnetostrictive devices. This paper builds a test platform for high frequency magnetic properties of magnetostrictive materials. The high frequency magnetic properties of rod gallium iron alloy were measured and analyzed under different exciting conditions (different compressive stress σ , magnetic field frequency f , and magnetic field strength H). Then, based on the experimental data and the classical static J-A model, a high-frequency dynamic model for rod gallium iron alloy taking into account compressive stress was developed. The novelty of the model is that the variation pattern of the J-A model parameters with frequency and compressive stress is obtained by importing the experimental data into a parameter identification program written based on a hybrid particle swarm algorithm. The trend is fitted as a polynomial function of frequency and compressive stress to account for its effect on the magnetic properties of the material. The model can effectively predict the change of high frequency magnetic loss of materials under variable compressive stress conditions. Comparing the calculated values of magnetic energy loss with the measured ones show that the maximum error is 4.37% and the average error is 2.57%, which verifies the accuracy and feasibility of the model. [ABSTRACT FROM AUTHOR]