International Journal of Applied Electromagnetics and Mechanics - Volume 64, issue 1-4

Authors: Ling, Xiao | Xiwu, He | Wenjie, Cheng

Article Type: Research Article

Abstract: Based on the working condition of the magnetic thrust bearing (MTB), the single-objective optimization model (SOOM) is built. The optimum design of structure parameters for two types of magnetic bearings including traditional carbon bearing and soft magnetic composite (SMCs) bearing has been carried out using genetic algorithm. The analysis of eddy current field for two types of bearings are obtained by FEM. It is found that the maximum eddy current field of SMCs bearing is less than that of carbon steel one, and the air gap magnetic density is larger than that of carbon steel bearing at the same frequency. …SMCs obtained by the compression of insulated soft magnetic powders have low eddy current. Thus, under the same magnetic force conditions, the input current of SMCs bearings is lower than that of carbon steel ones. The analysis shows that SMCs can replace carbon steel and has superiority in bearing application. Show more

Keywords: Magnetic thrust bearing, soft magnetic composites, single-objective optimization model, eddy current field

DOI: 10.3233/JAE-209330

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 263-270, 2020

Authors: Yan, Fayi

Article Type: Research Article

Abstract: Alpha Magnetic Spectrometer (AMS-02) is a particle-physics detector from a module attached to the outside of the International Space Station (ISS). The temperature of the components in AMS-02 must be kept within their different operational ranges but also must be stable over both time and volume. Thermal modeling and simulations for the radiator and the electronic crates of AMS-02 were carried out by applying the Crank–Nicholson implicit solution. Based on reducing the temperature gradient of the radiator and the mass of the thermal control system, the layout of the heat pipes in the radiator was optimized to solve the overheating …issue of the electronic crates. The non-operational and operational temperature dissipation for the thermal control system was calculated. The analysis results for the radiator and the electronic crates can meet the running requirements of AMS-02 on the ISS. Show more

Keywords: Thermal analysis, optimization, spacecraft, AMS-02, electronic crates, radiator

DOI: 10.3233/JAE-209331

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 271-279, 2020

Authors: Tohara, Makoto | Gotoh, Yuji

Article Type: Research Article

Abstract: The ferromagnetic steel tubes are used as heat exchangers in power plants or oil plants. When the usual eddy current testing (ECT) of inner type is used for the defect inspection of these steel tubes, it is difficult to detect defects on the opposite side due to the influence of skin effects. In this research, the non-destructive inspection method using rectangular wave excitation current with DC bias is proposed for detecting of the opposite side defect. It is shown that the detecting of the opposite side defect in the steel tube is possible, and the detection sensitivity using the alternating …magnetic field of rectangular wave is higher than that with sine wave. The detailed phenomenon of the inspection method is examined using the 3-D nonlinear FEM (finite element method) taking account of minor loop magnetizing properties using the play model method. Show more

Keywords: Non-destructive inspection, ferromagnetic steel tube, defects on the opposite side, play model, 3-D nonlinear FEM

DOI: 10.3233/JAE-209332

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 281-288, 2020

Authors: Li, Li | Zhang, Dianhai | Wang, Zhi | Zhang, Yanli | Fan, Xiaopeng | Zhou, Yongyan

Article Type: Research Article

Abstract: The vibration and noise are serious problems for large oil-immersed power transformers, which directly affect the performance and stability of transformers. The no-load current, as the excitation source, is very important for accurate calculation of vibration and noise. This paper provides a novel approach based on the new field-circuit coupling model to calculate no-load current of large power transformers. For one 110 kV large oil-immersed power transformer, the multi-physics coupling problem including magnetic field, structural force field and acoustic field under alternating magnetic field is analyzed. Following the multi-physics coupling calculation, distributions of vibration and noise are obtained. To validate feasibility …and applicability of the proposed method, the actual vibration and noise of transformer are measured experimentally. Finally, the simulation results are compared with experimental ones, which show better goodness of fit. Show more

Keywords: Transformer, new field-circuit coupling model, multi-physics field, vibration and noise

DOI: 10.3233/JAE-209333

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 289-298, 2020

Authors: Zhang, Xiaodong | Uchimoto, Tetsuya | Wu, Bin | Takagi, Toshiyuki | Ducharne, Benjamin | Liu, Xiucheng | He, Cunfu

Article Type: Research Article

Abstract: The Dynamic Magnetostriction (DM) measurement method as a nondestructive testing method of ferromagnetic materials, measures the DM curve using electromagnetic acoustic transducer (EMAT) to characterize material and predict the mechanical properties. Lorentz forces and magnetostriction forces contribute mainly to the ultrasonic generation. Only the range of low field, in which the magnetostriction force mechanism is predominant can be used to measure the DM curve, but the boundaries of this range are uncertain. The improved DM measurement method based on shear wave Magnetostriction EMAT (M-EMAT) is proposed and the theory of generation of shear waves is derived. For the M-EMAT, only …magnetostriction force mechanism contributed to the generation of shear waves. A theoretical model for the optimization of the transducer is developed, the model is in good agreement with the experimental results. The microstructure changes caused by residual strain will affect the magnetostriction coefficient and the DM curve. Therefore, the DM curves of low carbon steel specimens with different levels of residual strains are measured by the optimized transducer to characterize the residual strain. The normalized results demonstrate that the slope of the DM curve obviously changes with the residual strain. This leads to the conclusion that the DM measurement method can be used to characterize the residual strain of the low carbon steels. Show more

Keywords: Dynamic Magnetostriction, EMAT, shear wave, optimization, residual strain

DOI: 10.3233/JAE-209334

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 299-306, 2020

Authors: Ma, Chicheng | Jing, Dong | Shao, Mingyu | Yu, Hui | Guo, Zonghe

Article Type: Research Article

Abstract: Manipulators are widely used in industrial fields as automation equipment and robotic structures. Besides moving objects, manipulators often work with variable payloads, and the residual vibration significantly affects the position accuracy of manipulators. This paper mainly investigates the dynamic characteristics of flexible manipulators with time varying mass payloads and active control of the residual vibration is carried out. Finite element method is utilized to construct the dynamical model, and responses of the system are calculated by Bathe’s method. The influence of the time varying mass is analyzed in details, including an increasing mass case and a decreasing mass case. Then …active control of the residual vibration is given based on a PID controller. To improve the control effect, genetic algorithm (GA) is applied to tune the parameters of the PID controller. Simulations demonstrate that the time varying mass affects the residual vibration of the system remarkably. For a decreasing mass system, a nonstructural negative damping is induced and the residual vibration may be strengthened, while for an increasing mass system, a nonstructural positive damping is caused and the residual vibration may be attenuated. The comparison of the control methods demonstrates that the GA-PID controller results in a significant improvement in the vibration reduction. Show more

Keywords: Rotatory manipulator, active vibration control, time varying payload, GA-PID controller, non-structural damping

DOI: 10.3233/JAE-209335

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 307-314, 2020

Authors: Dong, Guangxu | Ma, Chicheng | Zhang, Feng | Luo, Yajun | Bi, Chuanxing

Article Type: Research Article

Abstract: To suppress the low frequency vibrations of airborne photoelectric system and improve measurement accuracy, a novel passive airborne photoelectric quasi-zero stiffness platform (APQZSP), which is composed of upper/bottom planes, anti-shaking structure and six quasi-zero stiffness (QZS) legs, is designed. The QZS leg is constructed by connecting the folded beam spring with magnetic negative stiffness spring (MNSS) in parallel. According to current model, the magnetic force and negative stiffness of MNSS are derived. As the friction damping is introduced with anti-shaking structure, the isolation performance of the platform under friction damping is investigated based on harmonic balance method. Then the effect …of damping and excitation on the isolation performance is analyzed. The results indicate that with the QZS technology, the resonant frequency of the platform is reduced and the low frequency vibrations can be effectively isolated with APQZSP. Moreover, the friction damping can maintain the displacement transmissibility at unity as long as the excitation frequency is lower than the break-loose frequency, and then the resonance can be avoided. Show more

Keywords: Vibration isolation, magnetic negative stiffness, friction damping, non-resonant response

DOI: 10.3233/JAE-209336

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 315-324, 2020

Authors: Gong, Yunyi | Otomo, Yoshitsugu | Igarashi, Hajime

Article Type: Research Article

Abstract: In this paper, the multi-objective topology optimizations of wireless power transfer (WPT) devices with two different coil geometries are proposed for obtaining the designs with good balance between transfer efficiency and safety. For this purpose, the proposed method adopts the normalized Gaussian network (NGnet) and Non-dominated Sorting Genetic Algorithm II (NSGA-II). In addition, the optimization under the different constraint on ferrite volume is carried out to verify its influence on optimization results. It has been shown that the proposed method successfully provides the Pareto solution to the design problem of the WPT device.

Keywords: Wireless power transfer, topology optimization, Pareto solution, electric vehicles

DOI: 10.3233/JAE-209337

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 325-333, 2020

Authors: Sun, Yun | Xu, Jiang | Hu, Chaoyue | Chen, Guang | Li, Yunfei

Article Type: Research Article

Abstract: The flexural mode guided waves of pipes which are sensitive the axial crack and suitable for wave focused gain more attention recently. In this paper, a non-contact flexural mode guided wave transducer based on magnetostrictive effect is provided for pipes. Based on the magnetostrictive transduction principle and the wave structure of the flexural mode guided wave, the sensing method for generating and receiving the flexural mode guided waves based on magnetostrictive effect is obtained. According to the theoretical analysis, a non-contact magnetostrictive transducer for F (3, m) mode guided waves is given. Six permanent magnets which are evenly distributed in …the circumferential direction of the pipe and arranged in opposite polarities are employed to provide the bias magnetic field in the circumferential direction. A solenoid coil is employed to induce the axial alternating magnetic field. The bias magnetic field distribution of the flexural mode guided wave in the pipeline is analyzed by the finite element simulation. The mode of the transduction guided wave in the pipe is verified by experiments based on the dispersion curves. Show more

Keywords: Flexural mode, guided wave, transducer, magnetostrictive effect, pipe

DOI: 10.3233/JAE-209338

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 335-342, 2020

Authors: Sasaki, Takahiro | Igarashi, Hajime

Article Type: Research Article

Abstract: This paper presents a three-dimensional optimization method of a meander inductor for high-frequency circuits. The proposed method determines the structure of the meander line using the micro-genetic algorithm in which the eddy current loss and inductance are evaluated by finite element method. It is shown that the total loss composed of the eddy current loss in the magnetic core and Joule loss in the meander line is successfully minimized keeping the inductance to the specified value by this optimization.

Keywords: Meander inductor, parameter optimization, micro genetic algorithm

DOI: 10.3233/JAE-209339

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 343-350, 2020