International Journal of Applied Electromagnetics and Mechanics - Volume 66, issue 1

Authors: Guo, Huan | Su, Sanqing | Wang, Wei | Ma, Xiaoping | Yi, Shuchun | Zhao, Xuran

Article Type: Research Article

Abstract: Metal magnetic memory (MMM) testing is a nondestructive approach for evaluating the stress concentration and early damage of ferromagnetic components. However, research on the MMM testing of large steel structures has been limited. Thus, this study investigates the suitability of MMM technology for monitoring the damage in steel structures exposed to complex stresses. The normal components of magnetic signals H p (y ) on the beams and columns of a portal frame are obtained through pseudo-static testing. The signal increment ΔH p (y ) and its absolute value |ΔH p (y )| under different loads are …analyzed. The relationship between the equivalent stress and magnetic signal is investigated through numerical simulation. The results show that the ΔH p (y ) curves are similar during the elastic stage but change abruptly during the plastic phase. Moreover, the differences in the magnetic signal directions caused by the varying detection directions cannot be ignored. In the elastic stage, with the increase in the load, |ΔH p (y )| curves initially increase and then decrease. The formation of the ΔH p (y ) curve is similar to the distribution of the equivalent stress. The mutation of ΔH p (y ) can determine whether a specimen is entering the plastic phase, and can warn against structural failure. The magnetic signal distribution qualitatively reflects the stress distribution. Show more

Keywords: Metal magnetic memory testing, monitoring damage, normal magnetic signals, pseudo-static test, portal frame, equivalent stress

DOI: 10.3233/JAE-190135

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 1-19, 2021

Authors: Ma, Yuanyuan | Feng, Wenjie | Yan, Zhen

Article Type: Research Article

Abstract: The buckling analyses of type-II superconducting strip under applied perpendicular magnetic field and/or distributed uniform mechanical load are investigated in this paper. Based on the Bean critical state model, the electromagnetic body force is firstly given. Then, based on the classical plate theory and two-point initial value method, the critical buckling states of the superconducting strip with different boundary conditions are analyzed. Numerical results show the effects of both the thickness and boundary conditions of superconducting strip on the corresponding critical buckling loads. The present work should be helpful to the research and application of superconducting thin strips.

Keywords: Superconducting thin strip, electromagnetic body force, buckling, critical buckling load

DOI: 10.3233/JAE-190115

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 21-33, 2021

Authors: Nick, Arash S. | Vynnycky, Michael | Jönsson, Pär G.

Article Type: Research Article

Abstract: A recent three-dimensional (3D) model that revisited earlier theoretical work for longitudinal electromagnetic stirring in the continuous casting of steel blooms is analyzed further to explore how the bloom width interacts with the pole pitch of the stirrer to affect the magnetic flux density. Whereas the first work indicated the presence of a boundary layer in the steel near the interface with the stirrer, with all three components of the magnetic flux density vector being coupled to each other, in the analysis presented here we find that the component along the direction of the travelling wave decouples from those in …the other two directions and can even be determined analytically in the form of a series solution. Moreover, it is found that the remaining two components can be found via a two-dimensional computation, but that it is not possible in general to determine these components without taking into account the surrounding air. The validity of the asymptotically reduced model solution is confirmed by comparing it with the results of 3D numerical computations. Moreover, the asymptotic approach provides a way to compute the time-averaged Lorentz force components that requires two orders of magnitude less computational time than the fully 3D approach. Show more

Keywords: Asymptotic analysis, continuous casting, electromagnetic stirring

DOI: 10.3233/JAE-200010

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 35-61, 2021

Authors: Lin, James | Oka, Koichi | Harada, Akinori

Article Type: Research Article

Abstract: This papers discusses a method of magnetic levitation which allows a levitated platform to remain both level and zero-power under arbitrary eccentric loading conditions. A hardware system is proposed and developed which laterally displaces hybrid electromagnets (HEMs) to counteract the moments caused by eccentric loads. In this system, the displaced HEMs are the same HEMs which are used for the levitation of the platform. A mathematical formulation is provided to explain the control methodology, and data from successful experimental trials of the developed hardware is discussed.

Keywords: Zero-power levitation, magnetic levitation, tip-tilt control

DOI: 10.3233/JAE-200011

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 63-74, 2021

Authors: Liu, Qing | Wang, Li | Zhang, Shiping | Li, Yuanyuan | Lei, Gang

Article Type: Research Article

Abstract: Active magnetic bearings (AMBs) bring extraordinary benefits such as free of contact, elimination of lubrication, active control of rotor position, and a built-in monitoring system. In the design of AMBs, the bearing structure is of significance since it has an important impact on bearing performances. However, the effect of winding configurations of AMBs is still obscure. In this paper, the system-level implications of two radial AMB winding configurations termed the Ortho and the Cross types are investigated, including the bearing characteristics, power consumptions and rotor dynamic behaviors. The simulation results demonstrate that the Cross type contributes to larger load capacity …in the direction of gravity. In condition of a heavier gravity load (−200 N), the Cross-type winding configuration saves power consumption with a percentage of 17.2% at steady state (20,000 rpm) and 12.7% considering unbalance mass during the run-up process. However, the rotor vibrations of the Cross type in case of external loads and unbalance mass are larger than the Ortho type. The proposed results of this paper provide some useful information for the AMB winding configuration design. Show more

Keywords: Active magnetic bearing, winding configuration, power consumption, rotor dynamics

DOI: 10.3233/JAE-201502

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 75-89, 2021

Authors: Li, Jiahao | Yang, Guolai | Fan, Yumeng

Article Type: Research Article

Abstract: This paper provides an analytical method for calculating the electromagnetic field of the tubular linear permanent magnet eddy current brake. The method of separating variables based on Fourier series is used to solve the boundary value problem, and the analytical solution of electromagnetic field is obtained. The braking force is obtained by calculating the Lorentz force. Then the accuracy of the analytical method is verified by comparing the analytical solutions with the solutions obtained by finite element method (FEM). In order to improve braking performance in a limited space, the parameter analysis is carried out to investigate the influence of …various structural parameters on the braking characteristics. According to the results of parameter analysis, the range of design parameters is determined. Finally, a multi-objective optimization is applied to find the optimal design parameters of the eddy current brake. The braking force increases by 27% and the volume of permanent magnet decreases by 7.7% after optimization. Show more

Keywords: Eddy current brake, braking force, finite element method, genetic algorithm, Halbach array

DOI: 10.3233/JAE-201523

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 91-113, 2021

Authors: Qiao, Yukai | Wang, Yinshun | Yuan, Xi | Zhang, Guangyi | Pi, Wei

Article Type: Review Article

Abstract: High temperature superconducting (HTS) magnets have widespread applications in a strong and steady magnetic field at low temperature. However, they can not be operated in persistent current mode (PCM) due to their immature joint technique without resistance. In order to realize the PCM, an HTS magnet stacked by double-hole rectangular HTS plates was proposed and fabricated. The trapped field of the HTS magnet was measured and simulated under four kinds of magnetization methods, field cooling (FC), zero field cooling (ZFC) and inner magnetization (a solenoid is placed at right/left hole of double-hole rectangular HTS magnet to magnetize HTS magnet) as …well as combination of both methods. Meanwhile, the H-formulation is applied to the 3D model to analyze the electromagnetic behaviour. It was found that the trapped field of double-hole rectangular HTS magnet magnetized by FC with inner magnetization or ZFC with inner magnetization is higher than pure FC or ZFC magnetization. In inner magnetization, the trapped field of one hole in HTS magnet has no effect on the other one. In addition, the experiment results are in good agreement with numerical analysis, which can provide significant references for the magnetization method. Show more

Keywords: Double-hole, FC, rectangular HTS magnet, trapped field, ZFC

DOI: 10.3233/JAE-201530

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 115-125, 2021

Authors: Shahid, Anwar | Ali Abbas, Munawwar | Huang, Hu Lin | Mishra, Satyaranjan | Bhatti, Muhammad Mubashir

Article Type: Research Article

Abstract: The present study analyses the dissipative influence into an unsteady electrically conducting fluid flow embedded in a pervious medium over a shrinkable sheet. The behavior of thermal radiation and chemical reactions are also contemplated. The governing partial differential equations are reformed to ordinary differential equations by operating similarity transformations. The numerical outcomes for the arising non-linear boundary value problem are determined by implementing the Successive linearization method (SLM) via Matlab software. The velocity, temperature, and concentration magnitudes for distant values of the governing parametric quantities are conferred, and their conduct is debated via graphical curves. The surface drag coefficient increases, …whereas the local Nusselt number and Sherwood number decreases for enhancing unsteadiness parameter across suction parameter. Moreover, the magnetic and suction parameters accelerate velocity magnitudes while by raising porosity parameter, velocity decelerates. Larger numeric of thermal radiation parameter and Eckert number accelerates the temperature profile while by enhancing Prandtl number it decelerates. Schmidt number and chemical reaction parameters slowdowns the concentration distribution, and the chemical reaction parameter influences on the point of chemical reaction that benefits the interface mass transfer. It is expected that the current achieved results will furnish fruitful knowledge in industrious utilities. Show more

Keywords: Electrically conducting fluid, Darcy flow, radiation, shrinking sheet, permeable medium

DOI: 10.3233/JAE-201540

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 127-140, 2021

Authors: Liang, Yongli | Xu, Lizhong

Article Type: Research Article

Abstract: In this paper, the structure and operating principle of the electromagnetic harmonic movable tooth drive system is introduced. Equations of the magnetic density and the electromagnetic force are given. The force model on the flexible wheel under magnetic force is presented. The equivalent concentrated force applied to the flexible wheel is determined. Based on it, the displacement equations of the flexible wheel are deduced. Using these equations, the displacement distribution of the flexible wheel and its changes along with the main parameters are investigated. Relationship between coil current and the maximum radial displacement is determined. The limit current corresponding to …the limit radial displacement is obtained and its changes along with the main parameters are analyzed. The results show that the displacements of flexible wheel increase with the radius of flexible wheel and the coil current, and decrease with the initial air gap and the thickness of flexible wheel. A limit current under which the flexible ring will be buckled occurs under electromagnetic force. The limit current corresponding to the limit displacement increases with the thickness of flexible wheel, the pole pair number and the air gap, and decreases with the radius of flexible wheel. The results can be used to design and analyze the drive system. Show more

Keywords: Electromagnetic drive, harmonic drive, displacement, force model, limit current

DOI: 10.3233/JAE-201546

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 141-157, 2021

Authors: Alharbi, Khalid Hamed | Moniruzzaman, Md | Aldhaheri, Rabah Wasel | Aljohani, Abdulah Jeza | Singh, Simranjit | Samsuzzaman, Md | Islam, Mohammad Tariqul

Article Type: Research Article

Abstract: In this paper, a monopole antenna with Ultra-wideband (UWB) characteristics is presented for applications in 5G and short-distance wireless communications. It consists of a rectangular shaped patch having truncated corners and central notch with an extended stub at top edge. Two layers of slots are engraved in the middle of the patch within which the outer layer contains four L shaped slots and the inner layer contains two face to face vertically placed U-shaped slots. A partial ground is structured with staircase slots to attain ultra-wideband response with sufficient gain and efficiency. The proposed antenna provides 124% of impedance bandwidth …(2.8 GHz–12 GHz) implemented on a low-cost FR4 substrate having the electrical dimension of 0.3𝜆 × 0.19𝜆 at the low cutoff frequency. The effect of the inclusion of slots within the patch is clearly observable as it increases gain and efficiency. The proposed antenna exhibits better response with a maximum measured gain of 6.5 dBi and efficiency of 85% within the bandwidth. Near constant time delay around 1 nS and good fidelity factor of 0.8316 represents that this slotted antenna can be used for undistorted reliable signal transfer. This antenna also provides symmetrical radiation patterns with less cross-polarization effects. Therefore, this monopole antenna can be an appropriate candidate for short-range communication applications like 5G, wireless local area networks, transfer data from biomedical sensors and imaging. Show more

Keywords: Ultra-wideband, defected ground structure, monopole, slotted patch, 5G wireless communication

DOI: 10.3233/JAE-201553

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 66, no. 1, pp. 159-180, 2021