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

Authors: Kim, Se-Yeong | Lee, Tae-Woo | Chun, Yon-Do | Hong, Do-Kwan

Article Type: Research Article

Abstract: In this study, we propose a non-contact 80 kW, 60,000 rpm coaxial magnetic gear (CMG) model for high speed and high power applications. Two models with the same power but different radial and axial sizes were optimized using response surface methodology. Both models employed a Halbach array to increase torque. Also, an edge fillet was applied to the radial magnetized permanent magnet to reduce torque ripple, and an axial gap was applied to the permanent magnet with a radial gap to reduce eddy current loss. The models were analyzed using 2-D and 3-D finite element analysis. The torque, torque ripple and eddy …current loss were compared in both models according to the materials used, including Sm2 Co17 , NdFeBs (N42SH, N48SH). Also, the structural stability of the pole piece structure was investigated by forced vibration analysis. Critical speed results from rotordynamics analysis are also presented. Show more

Keywords: Eddy current loss, forced vibration analysis, rotordynamics analysis, Halbach array, high speed and high power coaxial magnetic gear

DOI: 10.3233/JAE-209410

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 959-967, 2020

Authors: Kikuchi, Hiroaki | Sato, Yuki

Article Type: Research Article

Abstract: We investigated effects of contact gap on magnetic nondestructive evaluation technique using a magnetic single-yoke probe. Firstly, we evaluated hysteresis curves and impedance related to permeability of the material measured by a single-yoke probe, when an air gap length between the probe and specimens changes. The hysteresis curve gradually inclines to the axis of the magneto-motive force and magneto-motive force at which the magnetic flux is 0 decreases with increasing the gap length. The effective permeability also decreases with increasing the gap thickness. The incremental of gap thickness increases the reluctance inside the magnetic circuit composed of the yoke, specimen …and gap, which results in the reduction of flux applying to specimen. Show more

Keywords: Magnetic NDE, magnetic yoke probe, contact gap, coercive field, permeability, impedance, magneto-motive force

DOI: 10.3233/JAE-209411

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 969-975, 2020

Authors: Oka, Koichi | Yamamoto, Kentaro | Harada, Akinori

Article Type: Research Article

Abstract: This paper proposes a new type of noncontact magnetic suspension system using two permanent magnets driven by rotary actuators. The paper aims to explain the proposed concept, configuration of the suspension system, and basic analyses for feasibility by FEM analyses. Two bar-shaped permanent magnets are installed as they are driven by rotary actuators independently. Attractive forces of two magnets act on the iron ball which is located under the magnets. Control of the angles of two magnets can suspend the iron ball stably without mechanical contact and changes the position of the ball. FEM analyses have been carried out for …the arrangement of two permanent magnets and forces are simulated for noncontact suspension. Hence, successfully the required enough force against the gravity of the iron ball can be generated and controlled. Control of the horizontal force is also confirmed by the rotation of the permanent magnets. Show more

Keywords: Magnetic suspension system, multiple permanent magnet rotation, noncontact handling operation, FEM analysis

DOI: 10.3233/JAE-209412

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 977-983, 2020

Authors: Deri, Yi | Kawaguchi, Hideki

Article Type: Research Article

Abstract: The Pure-type HTS undulator is proposed to achieve a high-intensity magnetic field and small size undulator for a compact free-electron laser (FEL). A high precision simulation is required before making the real machine since the sizes and positions are difficult to adjust after the HTSs are magnetized in the cryostat. For this purpose, authors have been developed a numerical simulation code for the magnetization process of HTS undulator of X-FEL based on the power-law macro-model. In this paper, the previously developed simulation code can be speeded up by carefully optimizing the parameters of the power-law macro-model for the 3-HTS magnets …model and a large-scale simulation can be performed in an acceptable time by using a multipole expansion for the Biot–Savart law. In addition, for practical applications, the influence of the fluctuation of the magnets thickness and critical current for the electron trajectory are evaluated by using the speed-up simulation code. Show more

Keywords: Undulators, X-ray free-electron laser (X-FEL), power-law macro-model, multipole expansion, current vector potential method (T-method)

DOI: 10.3233/JAE-209413

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 985-991, 2020

Authors: Jiang, Jinhui | Qu, Yidan

Article Type: Research Article

Abstract: Washing machines are used very frequently in everyday life. There have been many related studies on the vibration and noise of washing machines. The suspension system is an important vibration isolation component of the washing machine. Based on the Lagrangian equation, the dynamic model of the suspension system was established. The reliability of the model was verified by finite element simulation and experimental methods. Finally, this paper used a multi-objective optimization method to obtain optimal parameters of the washing machine and further to reduce the vibration level of washing machines.

Keywords: Suspension system, dynamic modeling, the Lagrangian equation, multi-objective optimization

DOI: 10.3233/JAE-209414

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 993-1000, 2020

Authors: Guo, Xing | Sun, Jian-Hong | Liu, Ke | Zhang, Tong | Li, Ming-Qi | Ma, Fang-Yun

Article Type: Research Article

Abstract: The reliability of the emergency flotation system of helicopters is analysed by using fault tree analysis and the Monte Carlo method. We constructed a fault tree with the failure of system as the top event and obtained the minimal cut set, the ranking of the structural importance of the bottom events and the probability of the occurrence of the top event. Based on the system fault tree, a Monte Carlo simulation model of the emergency flotation system is established by using Matlab/Simulink. The results show that the Monte Carlo method is feasible and effective for the reliability analysis of the …emergency flotation systems of helicopters. Furthermore, the comparison between the criticality importance and mode importance of each subsystem suggests that the control component is the weakest part of the emergency flotation systems, thereby providing a basis for system reliability design and fault diagnosis. Show more

Keywords: Helicopter emergency flotation system, fault tree analysis, Monte Carlo simulation, reliability analysis

DOI: 10.3233/JAE-209415

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 1001-1009, 2020

Authors: Yan, Gang | Zheng, Yifei

Article Type: Research Article

Abstract: This paper proposes a new printed electrical impedance tomography (EIT) sensor for detection of damage in composite structure. The EIT sensor consists of a sensing area and related electrical circuits. It is directly printed on the surface of composite structure by a layer-by-layer screen printing process with graphene-doped carbon ink and silver ink. By injecting tiny currents into the EIT sensor and measuring the corresponding boundary voltages, damage information can be obtained by inverse analysis to reconstruct the distribution of conductivity change caused by damage. It has the potential to quantitatively identify the locations and sizes of multiple damage without …any prior knowledge. Experimental results on a glass fiber reinforced polymer (GFRP) plate with different number of simulated damage have demonstrated the effectiveness of the printed sensor itself and the related damage detection method. Show more

Keywords: Composite structure, damage detection, printed sensor, electrical impedance tomography, inverse analysis

DOI: 10.3233/JAE-209416

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 1011-1017, 2020

Authors: Lin, Hao | Geng, Haipeng | Yu, Lie | Li, Hao | Feng, Sheng | Yang, Baisong

Article Type: Research Article

Abstract: For a high-speed permanent magnet synchronous motor supported by air foil bearings, analyzing the influence of the electromagnetic torque on the strength of the combination rotor was necessary. In this study, the electromagnetic torque was obtained using the analytical calculation and the finite element simulation. The contact interface stress analytical equation affected by the electromagnetic torque was elaborated. A three-dimensional finite element model simulating the combination rotor was constructed, and the stress calculations were performed. The strength of the combination rotor met the design requirement. It properly reflected the characteristics of the electromechanical analysis in the combination rotor. The operation …experiments were realized to verify the electromagnetic performance and the strength of the combination rotor. The simulation and experimental results were significant for the electromechanical design and analysis of the combination rotor. Show more

Keywords: Permanent magnet synchronous motor, combination rotor, electromagnetic torque, strength analysis, air foil bearing

DOI: 10.3233/JAE-209417

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 1019-1027, 2020

Authors: Zhang, Chao | Zhang, Taifeng | Guo, Yu | Ji, Hongli | Qiu, Jinhao | Wang, De

Article Type: Research Article

Abstract: To guarantee the safety and reliability of aircraft structures, Lamb wave based structural health monitoring has been widely used in recent years. However, there are several factors that severely restrict its practical application, such as dispersion effect and complex boundary reflection. The overlap and deformation in wave packets make it difficult to extract the damage characteristics from the complex Lamb wave signals. To tackle this problem, a latent variable model based wave packet separation method is developed in this paper. Aimed at corrosion damage detection, several damage indices are investigated experimentally. By choosing the most sensitive damage index, the validity …and the accuracy of the proposed method in corrosion damage detection are demonstrated through the corrosion experiments. Show more

Keywords: Structural health monitoring, corrosion damage, Lamb wave, wave packet separation

DOI: 10.3233/JAE-209418

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 1029-1038, 2020

Authors: Iwamoto, Yuhiro | Nakasumi, Hayaki | Ido, Yasushi | Niu, Xiao-Dong

Article Type: Research Article

Abstract: Temperature-sensitive magnetic fluid (TSMF) is a magnetic nanoparticle suspension with strong temperature-dependent magnetization even at room temperature. TSMF is a refrigerant that enables high heat transport capability and pumpless long-distance heat transport. To enhance the heat transport capacity of the magnetically-driven heat transport device using TSMF, it is effective to use a heating body with a very large heat exchange surface such as a heat sink or a porous medium. In the present study, the thermal flow of TSMF around a single heating pipe under a magnetic field was investigated. Visualization of the temperature field by infrared thermography showed that …the application of the magnetic field dramatically developed the thermal boundary layer and improved heat transfer. It was clarified by numerical analysis that this dramatic variation in the thermal boundary layer was associated with several vortexes generated by magnetic force in the vicinity of the heating pipe. Show more

Keywords: Temperature-sensitive magnetic fluid, heat transfer, magnetic field

DOI: 10.3233/JAE-209419

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 1039-1046, 2020