International Journal of Applied Electromagnetics and Mechanics - Volume Pre-press, issue Pre-press

Authors: Su, Sanqing | Wei, Luxi | Wang, Wei | Yang, Yiyi | Ma, Xiaoping | Zuo, Fuliang

Article Type: Research Article

Abstract: Metal magnetic memory testing (MMMT) is a nondestructive testing technique that can detect early damage of component. In order to distinguish the effect of normal stress and shear stress on magnetic field, the flexural loading testing of inclined steel box girder with corrugated web is carried out by four-point bending pattern, and the normal component of the magnetic field at different position of the beam under different load level are collected. It is found that the law of normal component of the magnetic field changing with load is similar under different stress states, but the amplitude is quite different. The …stress in Jiles–Atherton model can be replaced by equivalent stress when calculating the magnetic field under shear stress. Show more

Keywords: Metal magnetic memory testing (MMMT), bridge steel Q345qC, four-point bending, shear stress, equivalent stress

DOI: 10.3233/JAE-190075

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-16, 2019

Authors: Yao, Xing-Yan | Pecht, Michael

Article Type: Research Article

Abstract: Magnetorheological (MR) damper is a smart device which the damping force can be adjusted according to the working operations in a short time. Metal foam MR damper is a new type of MR dampers in which uses the metal foam to store and release the MR fluids. The dynamic response time of the metal foam MR damper is quite different due to the added metal foam especially for the dynamic response time model. This paper proposed a dynamic response time model for the metal foam MR damper based on the demonstration of the working mechanisms and the factors about the …response behaviors. Show more

Keywords: Magnetorheological (MR) fluid, MR damper, metal foam, dynamic response time model

DOI: 10.3233/JAE-190063

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-10, 2019

Authors: He, Yunfeng | Zhan, Jiawen | Lu, Qinfen

Article Type: Research Article

Abstract: In order to fast calculate the thrust force and normal force of linear induction motor (LIM) for low-speed maglev train under overall conditions including traction and braking, this paper proposes an improved equivalent circuit (EC) method. Firstly, the improved equivalent circuit model is proposed based on the traditional one by adopting a precision correction factor, which can accurately consider the transverse edge effect of cap-shape secondary conducting sheet. Moreover, the permeability of back-iron and magnetic inductance are amended considering the saturation effect. The corresponding calculation procedure is given out. Then, the precise correction factor is investigated based on 2D finite …element (FE) model. By comparison with the traditional Russell and Norsworthy correction factor (RNF), the precision correction factor is proved to be more suitable to LIM with wide-range slip frequency. Finally, the thrust force and normal force of LIM with different slip frequency are predicted under braking and traction conditions by improved EC method. The predicted results and the proposed method are validated by 3D FE method and experiment results. Show more

Keywords: Braking condition, equivalent circuit (EC) method, linear induction motor (LIM), low-speed Maglev train, normal force, slip frequency, transverse edge effect

DOI: 10.3233/JAE-190053

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-13, 2019

Authors: Hao, Yang | Heng, Liu | Fan, Yang | Zhenwei, Ji | Bing, Gao | Min, Gong | Boda, Zhou | Chenzhi, Zhu

Article Type: Research Article

Abstract: The special working condition of shore power cable is more likely to form a crack air gap in insulating medium, which will cause gap discharge. The continuous gap discharge will cause local temperature rising and stress concentrating, which will lead to cable insulation deterioration. The electro-thermal-stress coupling method, in this paper, is used to establish the finite element model of the shore power cable. The electric, temperature and stress field distribution for the shore power cable with a crack air gap in the insulating medium is also studied, and the correctness of temperature and stress field distribution is verified by …experiments. In addition, this paper investigated the variation law of the ampacity for shore power cable under different discharge energy. The results show that the maximum electric field is equal to the electric field intensity (36.1 kV/cm) at the inner edge of the insulating medium when the gap length d = 2 mm and that the temperature and stress of the cable are quadratic with load current, linear with the gap discharge energy. The research results of this paper have an engineering significance for monitoring shore power cables. Show more

Keywords: Shore power cable, multi-physics field, discharge energy, ampacity

DOI: 10.3233/JAE-190088

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-15, 2019

Authors: Wu, Jiamin | He, Yucheng | Shen, Sheng | Guo, Pan | Huang, Xin | Xu, Zheng

Article Type: Research Article

Abstract: Traditional nuclear magnetic instruments are not convenient for measurement in situ due to the closed magnet structure and heavy weight. It is crucial to improve tree planting by exactly detecting moisture parameters of living trees. To investigate this problem, an open and portable magnetic resonance sensor was proposed. In this work, we introduced unilateral magnetic resonance sensor which can achieve onsite nondestructive measurement of large-volume samples due to its open structure. To fit the shape of living trees, the region of interest was set in an arc region. A magnet structure was optimized by ANSYS software. Because the magnet has …a constant natural gradient along radial direction, we need gradient fields in the other two directions (Z and Y). Z/Y gradient coils for unilateral magnetic resonance sensor are studied based on the Fourier series method. Current density in gradient coils is assumed as Fourier series composed of trigonometric functions. We introduced stream function to establish relationship between the current density and the winding structure, then constructed an optimization model by combining power dissipation with the deviation between calculated field and target field. The coils are manufactured using a flexible printed circuit board and measured by gauss meter. The measurement and simulation results are consistent. Measurement results of the gradient coils showed that the magnetic fields have good linearity which is helpful to realize 3D measurement in the upcoming work. Show more

Keywords: Unilateral magnetic resonance, Fourier series method, gradient coil design

DOI: 10.3233/JAE-190076

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-13, 2019

Authors: Liu, Bingcheng | Liu, Ning | Wang, Shaoyi | Jia, Wenguang

Article Type: Research Article

Abstract: Magnetic induction intensity and current are crucial factors to determine the effect of electromagnetic anti-fouling technology (EAFT). For getting the current value in the coil which was tightly wrapped around the PVC pipe, the inductance and equivalent resistance of the coil was measured by LCR meter, and the current in the circuit of the anti-fouling system was obtained by Ohm’s law. The magnetic induction intensity in the solenoid centre can be calculated by Faraday’s law. The purpose of the experiment was to find the optimal output parameters of EAFT and explored the anti-fouling effect. Therefore, we established an experimental platform …to optimize the output parameters and explore the effect of different output frequency on solution conductivity and particle diameter. Through experiments, it’s found that current in the coil was reduced with increasing frequency, the number of turns and the diameter. As the frequency and diameter increase, the magnetic induction intensity reduced, and the turns basically no impact on the magnetic induction intensity. The hardness solution of 10 mol ⋅ m−3 (as CaCO3 ) is treated by four different frequencies electromagnetic field shows that the lower the frequency, the greater decrease in conductivity and the greater increase in particle size, that phenomenon verifying that the higher current and stronger magnetic field intensity has a better anti-fouling effect. Show more

Keywords: Electromagnetic anti-fouling technology, current, magnetic induction, conductivity, particle diameter

DOI: 10.3233/JAE-190055

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-13, 2019