International Journal of Applied Electromagnetics and Mechanics - Volume 49, issue 2

Authors: Li, Jian-Gang | Tan, Qing-Chang | Pei, Yong-Chen

Article Type: Research Article

Abstract: Using interaction forces between two magnetic sleeves, the contactless magnetic driver changes the rotating motion of a motor into reciprocating motion by a link mechanism. In an ideal state, the two sleeves of the driver are coaxial, but due to manufacturing and/or assembly errors, the real working state is non-coaxial. The air gap and consequently the magnetic field and interaction forces are altered. Therefore, it is very important to predict the changing of interaction force for some application. Assuming that the magnetizations are rigid and uniform, a mathematical model of the interaction force between two axial magnetized sleeves is developed …based on the theory of equivalent magnetic charges. The model considers two magnetic sleeves at any relative position and attitude, and is verified experimentally for the two sleeves being coaxial. A numerical solution is implemented to compare interaction forces at the coaxial and non-coaxial states. Through numerical prediction, eccentricity between the sleeves of 0.5 mm generates a radial force approximately 70 N. The modeling method is also applicable to cuboidal magnets. Show more

Keywords: Magnetic driver, interaction force, non-coaxial, magnetic sleeve, magnetic charges

DOI: 10.3233/JAE-150021

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 169-177, 2015

Authors: Wang, Huijun | Xue, Bingkun | Tang, Shaofei

Article Type: Research Article

Abstract: In this paper, a new type of E-Core permanent magnet biased radial magnetic bearing with low coupling and high utilization of the stator space is proposed. In the structure, eight permanent magnets are used to provide the bias magnetic field. Two pairs of coils are used to provide control flux. The stator pole of one direction consists of one main pole and two secondary poles, which is called E-Core magnetic poles. Firstly, basic structure and operation principle of the novel magnetic bearing are introduced. Moreover, based on simplified equivalent magnetic circuits, the mathematic magnetic circuit models, which are for biased …flux from permanent magnet and control flux from control coils, are established. In the meanwhile, the basic characteristics such as force with respect to the eccentric displacement and current, coupling between X- and Y-channel are deeply analyzed. Finally, according to the analysis results it can be shown that proposed E-Core magnetic bearing has some advantages such as high stiffness and low coupling between two channels, which is good for realizing the high precision control. Show more

Keywords: Magnetic bearing, permanent magnet, coupling

DOI: 10.3233/JAE-140177

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 179-193, 2015

Authors: Karimi-nemch, H. | Sedighi, M. | Khandaei, M.

Article Type: Research Article

Abstract: Electromagnetic metal forming (EMF) is a high velocity forming process which uses electromagnetic body force to deform metal work piece. The challenging aspect of simulation of this process is complexity of magnetic pressure distribution and high speed deformation. Furthermore, coupling these two aspects is so important in order to analyze EMF. In this study, a simple approach has been proposed for simulation of EMF using two strong finite element commercial codes separately for modeling of electromagnetic and mechanical phenomena of this process. Another challenging aspect of this process is determination of the current pulse which is discharged into the electromagnetic …actuator. So, the effect of mutual inductance on discharged current and deformation were also investigated by experiments. Validation of this numerical approach was done by comparing the measured and simulated final deflection and strain distribution. Show more

Keywords: Inductance, electromagnetic, forming, strain, simulation

DOI: 10.3233/JAE-140186

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 195-205, 2015

Authors: Bouaziz, Amel | Bouaziz, Slim | Hentati, Taissir | Cholley, Jean Yves | Haddar, Mohamed

Article Type: Research Article

Abstract: The use of Active Magnetic Bearings (AMBs) in the High Speed Machining (HSM) field is increasing. In fact, they have important advantages such us: high speed which can reach 150000 rpm, high stiffness and absence of lubrication. Indeed, these bearings operate through magnetic interaction generated between the stator and the rotor. The spindle, principal component in the HSM, supported by AMBs, is considered as a source of vibration in machine tool spindles when it is affected by some defects during their functioning. These defects can affect either the rotor of the spindle like the unbalance defect, or the AMBs such …us misalignment of bearings, failure of actuators, sensors, amplifier and also the eccentricity defect. This paper studies the influence of spindle or AMBs defects on the dynamic behavior of a spindle supported by two AMBs. The system modeling is based on the finite element method. Four degrees of freedom is used and the coupling between elastic and rigid displacements is taken into account. Show more

Keywords: Spindle, defects, eccentricity, unbalance, windings, misalignments

DOI: 10.3233/JAE-140190

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 207-221, 2015

Authors: Chen, Junjie | Huang, Songling | Zhao, Wei

Article Type: Research Article

Abstract: This paper explores the property of three-axial magnetic flux leakage (MFL) signals in pipeline inspection. Then, metaheuristic optimization methods, including genetic algorithm (GA) and tabu search (TS) algorithm, are utilized to reconstruct defect profiles from three-axial MFL signals. Performances of the two methods are testified and compared, and a series of improving methods are proposed to minimize the time consumption while maintaining the accuracy of defect reconstruction. Experiments of defect reconstruction demonstrate that the proposed inversion methods have high performance in terms of both accuracy and robustness.

Keywords: Magnetic flux leakage, defect reconstruction, genetic algorithm, tabu search

DOI: 10.3233/JAE-140195

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 223-237, 2015

Authors: Shi, Wenze | Wu, Yunxin | Gong, Hai | Zhao, Zhiran | Fan, Jizhi | Tan, Liangchen

Article Type: Research Article

Abstract: Three differential equations based on different definitions of current density are compared. Formulation I is based on an incomplete equation for total current density (TCD). Formulations II and III are based on incomplete and complete equations for source current density (SCD), respectively. Using the weak form of Finite Element Method (FEM), the three formulations were applied in a meander coil Electromagnetic Acoustic Transducer (EMAT) example to solve magnetic vector potential (MVP). The FEM results from frequency domain and time domain models are in excellent agreement with previously published works. Results show that the errors for Formulations I and II vary …with coil dimensions, coil spacing, lift-off distance and external excitation frequency, for the existence of eddy-current and skin and proximity effects. And the current distribution across the coil conductors also follows the same trend. It is better to choose Formulation I instead of Formulation III to solve MVP when the coil height or width are less than twice the skin depth, due to the low cost and high efficiency of Formulation I. Show more

Keywords: Electromagnetic acoustic transducer, eddy current, finite element method, skin and proximity effects

DOI: 10.3233/JAE-150005

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 239-249, 2015

Authors: Ahsan, M.R. | Islam, M.T. | Habib Ullah, M. | Aldhaheri, R.W. | Sheikh, M.M.

Article Type: Research Article

Abstract: A new defected ground plane planar antenna feed by microstrip line is proposed for triple-band wireless communications. The proposed design of the antenna contains a radiating patch embedded with pair of open square-loop slot and pair of arc slot, and full length ground plane with defect on it. The final optimized design of the antenna is printed on ceramic filled polytetrafluoroethylene based dielectric substrate with size of 50 mm × 55 mm and 1.905 mm thick. The measured data reveal that the antenna offers bandwidths of 630, 600 and 690 MHz at 2.49, 3.54 and 5.6 center resonant frequency respectively …which can cover the bandwidth requirements for WLAN/WiMAX standards. The antenna offers good radiation pattern and reflection coefficient characteristics in the frequency band of interest. Moreover, the experimental results well agreed with the simulated results of the proposed antenna and it can be a good candidate for multiband operations in wireless applications. Show more

Keywords: Microstrip-fed antenna, patch antenna, triple-band applications, ceramic-PTFE, wireless communication, defected ground

DOI: 10.3233/JAE-150007

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 251-262, 2015

Authors: Kim, Jeong | Noh, Hak-Gon | Song, Woo-Jin | Kang, Beom-Soo

Article Type: Research Article

Abstract: A sequential coupled field analysis of an electromagnetic free bulging process was performed using the FEM. A 2D axisymmetric electromagnetic model based on the magnetic vector potential is proposed for the calculation of the magnetic field and Lorentz forces, and then, the Newmark integration method is used to calculate the transient dynamic plastic deformation of a sheet during the free bulging process. In the finite element model, the effect of sheet deformation on the electromagnetic field analysis is taken into account. In order to confirm the sequential electromagnetic-structural coupling analysis, an experiment with an electromagnetic forming apparatus was carried out. …This showed that the final bulge height of the sheet predicted using the method proposed in this paper was in good agreement with the experimental one. Show more

Keywords: Electromagnetic forming, sequential coupling simulation, electromagnetic-structural coupling, ANSYS/Multiphysics, high speed forming

DOI: 10.3233/JAE-150011

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 263-278, 2015

Authors: Di Barba, Paolo | Dughiero, Fabrizio | Forzan, Michele | Sieni, Elisabetta

Article Type: Research Article

Abstract: In the paper, a new solution to a benchmark problem of inverse induction heating is presented. The problem refers to an industrial device for the controlled heating of a graphite disk. In particular, the solution of a bi-objective optimization problem characterized by a multi-physics field analysis is investigated. The solution strategy of the bi-objective optimization problem is based on a modified multi-objective genetic algorithm in the class of Non-dominated Sorting Genetic Algorithm. The expected goal of the optimization process is to improve temperature uniformity in the disk as well as electrical efficiency of the induction device. The proposed algorithm exploits …the migration concept to vary the population genetic characteristics during optimization process, with the final aim of improving the approximation of the Pareto front. Show more

Keywords: Induction heating, multi-objective optimization, Pareto front, magnetic and thermal problem, multi-physics benchmark

DOI: 10.3233/JAE-150023

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 279-288, 2015

Authors: Ali, A. | Farooq, M.U. | Naz, M.Y. | Qayyum, A. | Khan, Y. | Ghaffar, A. | Shukrullah, S.

Article Type: Research Article

Abstract: In this research work, time resolved measurements of floating potential, electron temperature and number density were performed in air discharge plasma. A symmetric tungsten triple probe diagnostic and circuitry were developed to diagnose DC discharge at different operating conditions. Motivation behind the direct access of electrical probe diagnostic to the plasma chamber was stemmed from the need to characterize the plasma for time resolved measurements of the discharge parameters with high accuracy. The error analysis showed that overall inaccuracy in the measurements for electron temperature and number density remained in the range of 8.2-11.6% and 7.65-13.9%, respectively. Traditionally, the error …in electrostatic probe measurements is typically 20% for electron temperature and 50% for electron number density. Although these values are sufficiently large, the given analysis on consecutive measurements under same operating conditions yielded the data with high accuracy. The time resolved spectra of floating potential, investigated at all applied voltages, showed negligible variations in potential wave shape over time. However, the pressure dependent spectra predicted that the floating potential changed into sinusoidal waves of growing amplitude at higher air pressures. Overall floating potential was appreciably decreased with rise in air pressure. Show more

Keywords: Tungsten wire, triple probe, plasma parameters, DC biasing

DOI: 10.3233/JAE-150030

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 2, pp. 289-298, 2015