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

Authors: Pelkner, Matthias | Casperson, Ralf | Pohl, Rainer | Munzke, Dorit | Becker, Ben

Article Type: Research Article

Abstract: The application of composite pressure vessels is of great interest due to tremendous weight saving. Nevertheless, ageing of CFRP (carbon fiber reinforced plastic) composites pressure vessels underlies complex interactions between metallic liner and composite and is not fully understood yet. One main challenge is the application of appropriate testing methods for detecting the influences of pressure cycles and creep behavior on the material. This contribution presents results achieved by using conventional eddy current testing (ET) and high frequency ET. Here, we could show that also conventional ET with low frequencies are useable to investigate pressure vessels of different material combinations …like aluminum-CFRP and synthetics-CFRP. Show more

Keywords: CFRP, eddy current, ageing, composite, pressure vessel

DOI: 10.3233/JAE-171044

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-6, 2018

Authors: Lefevre, Yvan | El-Aabid, Sami | Llibre, Jean-François | Henaux, Carole | Touhami, Sarah

Article Type: Research Article

Abstract: In order to choose electric machines for transport applications, i.e. automotive, aerospace, railway and naval, a tool that can make quick tradeoffs of high specific torque electric motors has been developed. The level of the different technologies involved in an electrical machine can be quantified using the loadability concepts developed by experienced designers. After recalling these concepts, magnetic, electric and thermal balances are used to calculate the main sizes of an electric motor according to some targets. Specific power or specific torque can then be quickly assessed. The proposed approach is validated by applying the tool to some known high …torque industrial motors. Show more

Keywords: Loadability, specific power, specific torque

DOI: 10.3233/JAE-171059

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-8, 2018

Authors: Kwon, Byung-il

Article Type: Research Article

Abstract: In this paper, comparisons of the interior permanent magnet (IPM) BLDC motor characteristics considering the slot-pole combination and the magnetization direction simultaneously were done. The three directions of magnetization, radial, parallel and concentration were selected and analyzed for the same permanent magnet shape. No-load and load characteristics were compared. As a result, the motor efficiency of the combination of 6-slot and concentration directions was the best. Through analysis and comparisons, it was confirmed that the magnetization direction should also be considered as an important variable in initial design of the motor.

Keywords: Interior permanent magnet, slot-pole combination, magnetization direction, torque ripple, radial force

DOI: 10.3233/JAE-171126

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-8, 2018

Authors: Sheng, Feng | Geng, Haipeng | Zhang, Bo | Yang, Baisong | Xia, Kai | Yu, Lie | Cheng, Wenjie

Article Type: Research Article

Abstract: This paper describes a program development in testing a 100 kW Permanent Magnet Synchronous Motor (PMSM) using multi-leaf foil bearings with bump foils. The testing program includes the motor speed up to 43000 rpm, and then slow down to zero speed. The orbit of the rotor and the electrical parameters of the motor are obtained. The success in the experiments shows that the design and fabrication of the compliant gas foil bearings and motor can provide a useful guide to the development of an advanced high speed rotating machinery.

Keywords: High-speed, permanent-magnet synchronous motor, multi-leaf foil bearings

DOI: 10.3233/JAE-171069

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-9, 2018

Authors: Chady, Tomasz | Gorący, Krzysztof

Article Type: Research Article

Abstract: There are many nondestructive methods of coatings evaluation. Only a few of them can be utilized in case of coatings deposited on nonconductive elements. This paper presents application of a terahertz time domain spectroscopy for measuring thickness of thin nonconductive coatings. In order to develop a robust algorithm for thickness identification various experiments were carried out. A metal vessel filled with a small amount of oil was used as the test specimen. Such specimen allows us to easily achieve sample with a variable coating thickness.

Keywords: Non-destructive testing, coatings, terahertz

DOI: 10.3233/JAE-171063

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-8, 2018

Authors: Wang, Kaiqiang | Xie, Shejuan | Li, Shiyang | Shi, Pengpeng | Tian, Shuxia | Chen, Zhenmao

Article Type: Research Article

Abstract: Electromagnetic force due to induced eddy current during plasma disruptions is one of the key design-driving issues for the first wall (FW) in the Tokamak device. In this paper, a method to evaluate the electromagnetic force in the FW is proposed based on inversion of the measured magnetic field. An inversion scheme for reconstruction of eddy current from measured magnetic field is developed based on a newly proposed algorithm that can eliminate the effect of plasma current. To solve this inverse problem, the conjugate gradient (CG) algorithm is adopted in addition with an efficient parameterization strategy of eddy current distribution. …To demonstrate the efficiency of the method, a simplified FW plate and plasma current model is considered with the magnetic field simulated with a numerical code of the reduced magnetic vector potential (Ar) formulation. The numerical results shown that proper eddy current and electromagnetic force distribution can be predicted even for case of unknown plasma current, which reveals that the proposed method has good potential to be applied to the electromagnetic force evaluation of practical Tokamak problem. Show more

Keywords: Electromagnetic force, eddy current reconstruction, first wall, inverse analysis

DOI: 10.3233/JAE-171086

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-11, 2018

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. Pre-press, no. Pre-press, pp. 1-8, 2018

Authors: Wang, Minghui | Yu, Hongliu

Article Type: Research Article

Abstract: Fecal incontinence caused by sphincter dysfunction is a difficult medical problem which has not been fully resolved. An artificial anal sphincter (AAS) is considered an eventual choice as prosthesis to maintain anal continence. Currently, Acticon Neosphincter, the only device certified by the US Food and Drug Administration can not maintain the long-term effectiveness. The crucial problem of this study was to keeping long-term biomechanical compatibility between the AAS and the surrounding tissue. This paper presented a design of an AAS with constant force or pressure using superelastic shape memory alloy (SMA) to solve the problem. A C-shaped superelastic SMA sheet …was optimized to obtain constant force or pressure by combing finite element analysis with ANSYS and genetic algorithm in MATLAB. The result of optimization was validated by performing an experiment. The optimized model was embedding into the device to realize clamping the soft tissue with constant force, which was confirmed by experiments. Show more

Keywords: Artificial anal sphincter, constant force, superelasticity

DOI: 10.3233/JAE-171065

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-7, 2018

Authors: Fukuoka, Katsuhiro | Hasegawa, Ryo

Article Type: Research Article

Abstract: Non-uniform permeability distributions in steel materials reduce signal-to-noise (S /N ) ratios in eddy current testing (ECT). Therefore, steel materials must be magnetised to reduce magnetic noise. In this study, microcrack detection in spring steel materials using ECT was considered. An ECT system that was able to detect 40-μm-deep crack with S /N ratio of 3 or more was developed. In addition, the depth profile of microcracks using the detection signal was accurately estimated.

Keywords: Eddy current testing (ECT), microcrack, spring steel, signal-to-noise (S∕N) ratio, crack shape estimation

DOI: 10.3233/JAE-171123

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-8, 2018

Authors: Lu, Guanglin | Luo, Yajun | Xie, Shilin | Zhang, Xinong | Li, Luxian | Ma, Chicheng

Article Type: Research Article

Abstract: To overcome ill-posed problem of force identification in the Transfer Path Analysis (TPA) of a rocket engine, this paper proposes a novel TPA based on weighted Tikhonov regularization. Firstly, the upper bound of relative force identification error of the traditional TPA is derived. Secondly, weighting matrix and Bayesian theory are adopted to improve the accuracy of force identification, and then the theory of the improved TPA is built. Finally, a ground vibration testing of the rocket engine is performed to analyze its path contributions. The results show that the proposed TPA is more accurate than the traditional TPA.

Keywords: Inverse problem, force identification, transfer path analysis, weighted regularization, Bayesian theory

DOI: 10.3233/JAE-171087

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-9, 2018