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1 – 10 of over 6000Takashi Todaka, Kenji Nakanoue and Masato Enokizono
The purpose of this paper is to reduce computation time of magnetic characteristic analysis considering 2D vector magnetic properties.
Abstract
Purpose
The purpose of this paper is to reduce computation time of magnetic characteristic analysis considering 2D vector magnetic properties.
Design/methodology/approach
The paper proposes a complex E&S modelling with assumption that both flux density and field strength waveforms are sinusoidal. The computation time of the complex E&S modeling becomes 1/10 in comparison with one of the conventional E&S modeling. This modeling is applicable up to 1.4 T of the local magnetic flux density condition in the case of non‐oriented magnetic materials.
Findings
In the results of the magnetic field analyses of a linear‐induction motor model core by means of the finite element method taking account of the complex E&S modeling, the distributions of the flux density and the field strength were able to be approximately analyzed and their phase differences in space were represented. The results of the magnetic characteristic analysis of the linear‐induction motor showed that the teeth‐end shape had large influences on the thrust and cogging.
Practical implications
This technique helps to know approximately local vector magnetic properties in core materials. This modeling is very useful for magnetic core design taking account of the simplified 2D vector magnetic properties.
Originality/value
The method presented in this paper enables expression of the simplified 2D vector magnetic properties in magnetic field analyses. The computation time can be considerably reduced in comparison with the conventional method.
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Keywords
Naoya Watanabe, Yasuhito Takahashi and Koji Fujiwara
This paper aims to propose an effective modeling method of dynamic hysteresis properties for soft magnetic composite (SMC) core using an equivalent circuit representation. Because…
Abstract
Purpose
This paper aims to propose an effective modeling method of dynamic hysteresis properties for soft magnetic composite (SMC) core using an equivalent circuit representation. Because the eddy currents flowing inside iron powder particles should be considered, it is well known that an accurate magnetic field analysis of the SMC core in a wide range of excitation frequency is not easy. To overcome this difficulty, a dynamic hysteresis modeling based on the standard Cauer circuit is investigated.
Design/methodology/approach
In the proposed method, the first inductance represents the static magnetic property of the SMC, and the latter part represents the dynamic effect because of the eddy currents. The values of the circuit elements were determined by an optimization method based on symmetric loops measured at several frequencies. To verify the validity of the proposed modeling method, finite-element analyses of a ring core inductor and an alternating current reactor were performed.
Findings
By comparing the simulated and measured magnetic properties, the necessity to consider magnetic hysteresis in the equivalent circuit model is clarified. Furthermore, the frequency-dependent inductances of practical reactors can be obtained from the finite-element analysis combined with the proposed method.
Originality/value
This paper demonstrates the significance of determining the circuit parameters in the equivalent circuit for dynamic hysteresis modeling based on the measured magnetic properties. The effectiveness of the proposed method is verified by comparing frequency-dependent inductances of two kinds of reactors between the simulation and measurement.
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Keywords
Tuomas Riipinen, Sini Metsä-Kortelainen, Tomi Lindroos, Janne Sami Keränen, Aino Manninen and Jenni Pippuri-Mäkeläinen
The purpose of this paper is to report on the developments in manufacturing soft magnetic materials using laser powder bed fusion (L-PBF).
Abstract
Purpose
The purpose of this paper is to report on the developments in manufacturing soft magnetic materials using laser powder bed fusion (L-PBF).
Design/methodology/approach
Ternary soft magnetic Fe-49Co-2V powder was produced by gas atomization and used in an L-PBF machine to produce samples for material characterization. The L-PBF process parameters were optimized for the material, using a design of experiments approach. The printed samples were exposed to different heat treatment cycles to improve the magnetic properties. The magnetic properties were measured with quasi-static direct current and alternating current measurements at different frequencies and magnetic flux densities. The mechanical properties were characterized with tensile tests. Electrical resistivity of the material was measured.
Findings
The optimized L-PBF process parameters resulted in very low porosity. The magnetic properties improved greatly after the heat treatments because of changes in microstructure. Based on the quasi-static DC measurement results, one of the heat treatment cycles led to magnetic saturation, permeability and coercivity values comparable to a commercial Fe-Co-V alloy. The other heat treatments resulted in abnormal grain growth and poor magnetic performance. The AC measurement results showed that the magnetic losses were relatively high in the samples owing to formation of eddy currents.
Research limitations/implications
The influence of L-PBF process parameters on the microstructure was not investigated; hence, understanding the relationship between process parameters, heat treatments and magnetic properties would require more research.
Originality/value
The relationship between microstructure, chemical composition, heat treatments, resistivity and magnetic/mechanical properties of L-PBF processed Fe-Co-V alloy has not been reported previously.
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Mykola Riabchykov, Liudmyla Nazarchuk, Oksana Tkachuk and Victoria Stytsyuk
This paper aims to prove the expediency and effectiveness of magnetic textiles use obtained by adding nanopowder synthesized on the basis of oxides of divalent and trivalent iron…
Abstract
Purpose
This paper aims to prove the expediency and effectiveness of magnetic textiles use obtained by adding nanopowder synthesized on the basis of oxides of divalent and trivalent iron oxides, taking into account bacteriostatic, magnetotherapeutic and compressive properties.
Design/methodology/approach
The research includes methods of synthesis of nanoelements of bivalent and trivalent iron, methods of the theory of elasticity for determining the pressure between compression clothing and a limb, methods of creating an annular magnetic field with determination of its voltage, methods of determining the growth dynamics of mold bacteria and methods of approximation of experimental data.
Findings
On the base of the determination of the forces arising from the interaction of magnetic nanotextiles with a magnetic field, the expediency of using these materials in the creation of compression clothing has been proven. An additional medical value of magnetic textiles is the bacteriostatic effect. The content of magnetic nanoelements in the textile composition of 0.2% almost completely suppresses mold infections
Research limitations/implications
Cotton samples with the addition of nanocomponents based on ferric and ferric oxides were studied.
Practical implications
Magnetotextile materials can be used in magnetotherapy, compression clothing, in textile products that provide bacteriostatic properties.
Originality/value
The use of magnetic textile materials is a perspective direction for the creation of medical textile products with complex properties.
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Keywords
Kevin McMeekin, Frédéric Sirois, Maxime Tousignant and Philippe Bocher
Surface heat treatment by induction heating (10-100 kHz) requires precise prediction and control of the depth of the induced phase transformation. This paper aims at identifying…
Abstract
Purpose
Surface heat treatment by induction heating (10-100 kHz) requires precise prediction and control of the depth of the induced phase transformation. This paper aims at identifying common issues with the measurement and modeling of magnetic properties used in induction heating simulations, and it proposes ways to improve the situation.
Design/methodology/approach
In particular, it is demonstrated how intrinsic magnetic properties (i.e. the B-H curve) of a sample can change during the magnetic characterization process itself, due to involuntary annealing of the sample. Then, for a B-H curve that is supposed perfectly known, a comparison is performed between multiple models, each one representing the magnetic properties of steel in time-harmonic (TH) finite element method simulations. Finally, a new model called “power-equivalent model” is proposed. This model provides the best possible accuracy for a known nonlinear and hysteretic B-H curve used in TH simulations.
Findings
By carefully following the guidelines identified in this paper, reduction of errors in the range of 5-10 per cent can be achieved, both at the experimental and modeling levels. The new “power-equivalent model” proposed is also expected to be more generic than existing models.
Originality/value
This paper highlights common pitfalls in the measurement and modeling of magnetic properties, and suggests ways to improve the situation.
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Keywords
Jan Karthaus, Silas Elfgen and Kay Hameyer
Magnetic properties of electrical steel are affected by mechanical stress. In electrical machines, influences because of manufacturing and assembling and because of operation…
Abstract
Purpose
Magnetic properties of electrical steel are affected by mechanical stress. In electrical machines, influences because of manufacturing and assembling and because of operation cause a mechanical stress distribution inside the steel lamination. The purpose of this study is to analyse the local mechanical stress distribution and its consequences for the magnetic properties which must be considered when designing electrical machines.
Design/methodology/approach
In this paper, an approach for modelling stress-dependent magnetic material properties such as magnetic flux density using a continuous local material model is presented.
Findings
The presented model shows a good approximation to measurement results for mechanical tensile stress up to 100 MPa for the studied material.
Originality/value
The presented model allows a simple determination of model parameters by using stress-dependent magnetic material measurements. The model can also be used to determine a scalar mechanical stress distribution by using a known magnetic flux density distribution.
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Keywords
The paper deals with methods of tailoring magnetic properties of soft and hard magnetic composites. Comparison of magnetic properties of injection moulding and compression…
Abstract
The paper deals with methods of tailoring magnetic properties of soft and hard magnetic composites. Comparison of magnetic properties of injection moulding and compression moulding Nd-Fe-B magnets are presented. Magnetic properties of Nd-Fe-B bonded magnets were tailored by different ways such as: amount of resin, addition of barium ferrite, Al or Fe powders. Influence of technological parameters such as compression pressure, time and temperature of curing on magnetic parameters of Nd-Fe-B bonded magnets are presented in the paper. Magnetic properties of soft magnetic composites made of Fe, Ni, Co are presented in the paper. Influence of technological parameters such as compression pressure, time and temperature of curing on magnetic parameters of iron soft magnetic composites are presented also in the paper.
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Ryoko Minehisa, Yasuhito Takahashi, Koji Fujiwara, Norio Takahashi, Masafumi Fujita, Kazuma Tsujikawa and Ken Nagakura
This paper aims to propose a homogenization method considering magnetic anisotropy for a magnetic field analysis of a turbine generator. To verify the validity of the proposed…
Abstract
Purpose
This paper aims to propose a homogenization method considering magnetic anisotropy for a magnetic field analysis of a turbine generator. To verify the validity of the proposed method, the effects of magnetic anisotropy and a space factor on a no-load saturation curve and no-load iron loss of the turbine generator are discussed.
Design/methodology/approach
The proposed method was derived from the combination of the homogenization of microscopic fields in a laminated iron core with the modelling of two-dimensional magnetic properties based on free energy. To verify the validity, the proposed method was applied to a finite-element analysis of a simple ring core model. Finally, a no-load saturation curve and iron loss of the turbine generator was investigated by using the proposed method.
Findings
The computational accuracy of the homogenization method considering magnetic anisotropy is almost the same as that of the detailed modelling of the laminated structure in the magnetic field analysis of the laminated iron core. Furthermore, it is clarified that magnetic anisotropy does not have a large influence on the no-load saturation curve of the turbine generator because of the large air gap. On the other hand, the space factor affects the shape of the no-load saturation curve.
Originality/value
This paper verifies the validity of the homogenization method considering magnetic anisotropy method and elucidates the effects of magnetic anisotropy and a space factor on no-load characteristics of the turbine generator.
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Keywords
Ville Akujärvi, Tord Cedell, Kenneth Frogner and Mats Andersson
The purpose of this paper is to investigate the added value of using temperature-dependent electric and magnetic properties in high-temperature electromagnetic simulations.
Abstract
Purpose
The purpose of this paper is to investigate the added value of using temperature-dependent electric and magnetic properties in high-temperature electromagnetic simulations.
Design/methodology/approach
In this work, the electromagnetic properties of Domex 420, SSAB, have been characterized as a function of the temperature, from room temperature to 900°C. The measurement of the electric and magnetic properties was performed inside a vacuum furnace at a number of discrete temperature steps, with particularly small intervals around the Curie temperature. A simple transient multi-physics model was used to investigate the impact of the measured properties in three different representations.
Findings
In certain intervals, a simplified approximation of the properties produces accurate results, while fully parametric representation is beneficial when heating above the Curie temperature.
Originality/value
Temperature-dependent electromagnetic properties are rarely found, especially in an easy-to-use form. Using parameterized temperature-dependent approximation of key properties shows noteworthy differences in the outcome of high-temperature electromagnetic modeling.
Details
Keywords
Jiabao Pan, Rui Li and Ao Wang
The adverse effects of temperature on the lubricating properties of nano magnetorheological grease are reduced by applying of a magnetic field.
Abstract
Purpose
The adverse effects of temperature on the lubricating properties of nano magnetorheological grease are reduced by applying of a magnetic field.
Design/methodology/approach
Nano magnetorheological grease was prepared via a thermal water bath with stirring. The lubricating properties of the grease were investigated at different temperatures. Then the lubricity of the prepared nano magnetorheological grease was investigated under the effect of thermomagnetic coupling.
Findings
As the temperature rises, the coefficient of friction of grease lubrication gradually increases, surface wear gradually increases and lubrication performance gradually decreases. Compared with grease, magnetorheological grease has a decreased coefficient of friction and enhanced lubrication effect under the action of a magnetic field at different temperatures.
Originality/value
A lubrication method using a magnetic field to reduce the effect of temperature is established, thereby providing new ideas for lubrication design under a wide range of temperature conditions.
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