International Journal of Applied Electromagnetics and Mechanics - Volume 59, issue 1

Authors: Li, Yilun | Zheng, Taiying | Yang, Shiyou | Ren, Zhuoxiang

Article Type: Research Article

Abstract: Compared to a density based procedure, the level set method can acquire a clear boundary without any intermediate density elements, and has become a topical issue in topology optimization studies. In this method, the material properties of the discretized elements are usually defined as the design variables, giving rise to the so called discrete or sawtooth topologies. In this paper, a topology optimization methodology based on level-set method (LSM) and radial basis function (RBF) is proposed. To enhance the performance of the LSM, an improved material interpolation model is proposed. The RBF based post-processor is proposed to smooth the preliminary …optimized topology. The proposed method is applied to the topology design of a piezoelectric energy harvester. The effect of different penalization factors is compared and analyzed. The numerical results validate the feasibility and effectiveness of the proposed method. Show more

Keywords: Coupled problems, level set method, topology optimization

DOI: 10.3233/JAE-171098

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 79-85, 2019

Authors: Sasaki, Hidenori | Igarashi, Hajime

Article Type: Research Article

Abstract: This paper presents a new topology optimization of interior permanent magnet (IPM) motors using the genetic algorithm with aid of the deep leaning. The data composed of the rotor shape of an IPM motor and its performance, obtained by a prior topology optimization process, is input to a convolutional neural network (CNN). After the learning process, CNN is shown to provide fairly accurate estimate of the motor performance. During the posterior topology optimization, the finite element analysis (FEA) is carried out only for the limited number of individuals; probability that FEA is performed increases with the motor performance evaluated by …CNN. It is shown that the computing time is reduced to about 1/10 without deterioration of the optimization performance with aid of the deep learning. Show more

Keywords: Topology shape optimization, deep learning, finite element method, IPM motor

DOI: 10.3233/JAE-171164

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 87-96, 2019

Authors: Stolzke, Tobias | Dirnecker, Tobias | Schwarz, Julian | Frey, Lothar

Article Type: Research Article

Abstract: This paper presents a new type of a polymer bonded soft magnetic material (PBSMM) which can be used to create complex magnetic core geometries. The PBSMM consists of two separate materials, manganese zinc ferrite powder and polydimethylsiloxane (PDMS) as matrix material. The magnetic core losses of the PBSMM where analyzed at 10 kHz and 1 MHz with self-fabricated toroidal core samples by using a custom-made measurement setup in accordance with the IEC-62044-3 norm. The complex permeability was determined by evaluating impedance analyzer measurements between 10 kHz and 1 MHz. It is pointed out that the investigated material can be used for power electronic filter …applications and opens the opportunity to create geometrical complex inductive components. Show more

Keywords: Soft magnetic-polymer, manganese–zinc–ferrite, high frequency

DOI: 10.3233/JAE-171244

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 97-104, 2019

Authors: Nakai, Tomoo

Article Type: Research Article

Abstract: A thin-film magneto-impedance (MI) sensor has the unique property of step-like magneto-impedance change, in the case where the sensor has an in-plane uniaxial inclined easy axis. A domain observation shows that the step-like change is due to a magnetization transition within three states, such as longitudinal single domain with parallel state, the one with anti-parallel state and the inclined Landau-Lifshitz domain (ILLD). In a condition where the sensor has an easy axis of 70 degrees relative to the short side axis of the rectangular element, the transition is limited between the parallel and anti-parallel in spite of existing of stable …ILLD. This paper reports a trial of control the magnetization transition from the single domain state to the ILLD state by controlling a normal field with canted angle distribution along the element position, which is aiming for realizing a low energy consumption sensor with inextinguishable memory function using a phenomenon of a magnetic domain transition for the use of sensor network. Show more

Keywords: Magnetic domain, magneto-impedance, normal field, stepped GMI, thin film

DOI: 10.3233/JAE-171005

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 105-114, 2019

Authors: Alimohammadi, Sahar | Meydan, Turgut | Williams, Paul

Article Type: Research Article

Abstract: Previous investigations of the Matteucci effect in amorphous microwires have yielded a basic understanding of the underlying physical mechanism. However, a complete quantitative model is still elusive particularly in explaining the role of magnetoelastic interactions. This is important because the Matteucci effect is an under-utilized phenomenon with promising potential for exploitation in stress sensing applications. In this work, we have studied the influence of tensile stress on the Matteucci effect in two types of amorphous wires (Fe77.5 Si7.5 B15 and Co68.15 Fe4.3 5Si12.5 B15 ). This paper shows how the axial stress significantly affects the Matteucci voltage and that …this behaviour is dependent upon the sign of the magnetostriction constant. Measuring the Matteucci voltage as a function of stress in magnetostrictive wire produced an equivalent gauge factor over two orders of magnitude greater than that obtained in a conventional resistive strain gauge. This offers the potential for the development of a new type of wire-based strain sensor. Show more

Keywords: Matteucci effect, strain sensor, amorphous wire

DOI: 10.3233/JAE-171225

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 115-121, 2019

Authors: Kikuchi, Hiroaki | Nakamura, Hikaru | Sumida, Chihiro

Article Type: Research Article

Abstract: We investigated the effects of DC bias current applied directly to the elements on the inclined easy axis thin-film magnetoimpedance element indicating a discontinuous impedance jump. We clarified that the DC bias current contributes to changes in the configuration of domain structure, which induces modification of impedance profiles on the 20 μm-wide element. On the other hand, 40 and 80 μm-wide elements did not show the apparent changes on the magnetoimpedance profiles. The influence of DC bias current on jumping point is not so much, which is attributed to the small bias magnetic field generated by the current; the limited bias level …is not high due to Joules heating by the current. Show more

Keywords: Magnetoimpedance, discontinuous jump, DC bias, inclined easy axis, thin-film

DOI: 10.3233/JAE-171095

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 123-128, 2019

Authors: Makeeva, Galina | Golovanov, Oleg | Rinkevich, Anatoly

Article Type: Research Article

Abstract: Rigorous mathematical models of nonlinear terahertz (THz) graphene-based devices are developed by solving nonlinear Maxwell’s equations with boundary conditions simultaneously with a model of graphene surface conductivity as a nonlinear function on the time-varying electric field. The numerical approach is based on the projection method. Nonlinear phenomena, related to the parametric instability due excitations by the incident pumping TEM -wave in the multilayer graphene-dielectric nanostructures, are investigated numerically at THz frequencies.

Keywords: Nonlinear, parametric, graphene-based devices, nanostructure, bias electric field, numerical approach, projection method

DOI: 10.3233/JAE-171074

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 129-136, 2019

Authors: Pakhomov, Yaroslav | Kuznetsova, Eugene | Perov, Dmitry | Rinkevich, Anatoly | Samoylovich, Michael

Article Type: Research Article

Abstract: A study of the structure, phase composition and dielectric permittivity is performed of the nanocomposites with the particles of the titanates of rare earth metals of R2 Ti2 O7 type. As the rare earth metals ytterbium, erbium, samarium, praseodymium, terbium and gadolinium are used. Frequency dispersion of dielectric permittivity of the nanocomposites in the considered frequency range from 26 to 38 GHz is found to be small, which enables to describe approximately the nanocomposite with a single value of the dielectric constant across the whole frequency range. At frequencies less 108 –109 Hz the dielectric permittivity of nanocomposites …increases substantially. Show more

Keywords: Nanocomposites, rare-earth titanates, dielectric permittivity

DOI: 10.3233/JAE-171073

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 137-144, 2019

Authors: Chrobak, Artur | Ziółkowski, Grzegorz | Granek, Krzysztof | Chrobak, Dariusz

Article Type: Research Article

Abstract: The paper refers to determination of magnetic coupling between Dy2 Fe14 B hard and Fe soft magnetic phases by first-principle calculations. The supercell used in our simulations was composed of Dy2 Fe14 B unit cell and thin layer of body-centered Fe-bcc structure, separated by distance of 1–5 Å. It was shown that the magnetic order depends on the interface direction and the distance which is presented and discussed in the paper.

Keywords: Hard magnetic composites, DFT calculations, spring-exchange magnets

DOI: 10.3233/JAE-171204

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 145-150, 2019

Authors: Chrobak, Dariusz | Chrobak, Artur | Ziółkowski, Grzegorz | Granek, Krzysztof

Article Type: Research Article

Abstract: This paper concerns the elastic properties of Dy2 Fe14 B crystal investigated by ab-initio calculations. We determined the elastic constants of the considered crystal: C 11 = 297, C 12 = 92, C 13 = 99, C 33 = 287, C 44 = 82, C 66 = 80 GPa. Moreover, estimated from elastic constants physical properties (acoustic wave velocities, elastic moduli, Debye and melting temperature) are consistent with the reference data obtained for other (RE)2 Fe14 B crystals.

Keywords: Permanent magnet, atomistic modelling, elastic properties

DOI: 10.3233/JAE-171202

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 1, pp. 151-156, 2019