International Journal of Applied Electromagnetics and Mechanics - Volume 46, issue 3

Authors: Tian, Wen-Yan | Wu, Ying-Chun | Li, Ze-Min | Dong, Zeng-Shou | Guo, Yi-Na | Luo, Ming

Article Type: Research Article

Abstract: A hybrid S-matrix is proposed based on artificial neural network (ANN) and Baum-Liu-Tesche (BLT) equations to analyze the electromagnetic interference (EMI) effects on PCB with active and passive circuit components. Transmission line equations and Finite difference time domain (FDTD) method are employed to compute the excited fields and extract the port parameters for passive printed circuits. ANN method is used to predict the S-parameters for some active components. Then, the trained ANN …model is combined with other S-parameters to compose a hybrid S-matrix for the characterization of the PCB. The resulting hybrid S-matrix and excited fields are subsequently exported to BLT equations to evaluate the responses. Examples are studied and the numerical results are compared with those obtained by experiment. The agreement is generally good that validates this method. Show more

Keywords: Hybrid S-matrix, artificial neural network (ANN), Baum-Liu-Tesche (BLT) equations

DOI: 10.3233/JAE-141938

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 537-545, 2014

Authors: Angiulli, G. | Cacciola, M. | Calcagno, S. | De Carlo, D. | Morabito, C.F. | Sgró, A. | Versaci, M.

Article Type: Research Article

Abstract: To efficiently solve the large, dense and non-Hermitian matrix system provided by the E-field Integral Equation (EFIE) modelization of the electromagnetic scattering by arbitrarily shaped perfect conducting bodies, the Generalized Minimal Residual method (GMRES) with preconditioning is usually employed. Nonetheless, even if optimal in a broad sense, the GMRES suffers of the drawback that its memory space demand grows linearly with the number of iterations. To avoid possible out-of-memory errors, a Krylov subspace method …involving a fixed amount of memory per iteration has to be used. This is the case of the Bi-Conjugate Stabilized (BiCGStab) method. Although this method has been exploited with success to handle dense matrix system arising from EFIE discretization, its flexible version, the Flexible-BiCGstab, at the best of the authors knowledge, has not received any attention within this context. In this work, a study on the performances of the Flexible BiCGStab to solve the discretized EFIE is presented. Numerical results demonstrate that the Flexible BiCGStab is, at least in the examined cases, a workable alternative to the the standard BiCGStab with ILUT preconditioning. Show more

Keywords: Electromagnetic scattering, integral equations, krylov subspace methods, method of moments

DOI: 10.3233/JAE-141939

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 547-553, 2014

Authors: Bahiraei, Mehdi | Hangi, Morteza

Article Type: Research Article

Abstract: This study has used the two-phase Euler-Lagrange method to evaluate the hydrothermal characteristics for a laminar flow of water-Mn_{0.6} Zn_{0.4}<FORMULA>Fe<FORMULA>_{2} O_{4} magnetic nanofluid in a circular pipe under the effect of magnetic field with both positive and negative gradients. Brownian and thermophoretic forces were considered in the simulation. Concentration distribution was found to be non-uniform at the cross section of the pipe, the value of which is greater in center of the …pipe than near wall. Non-uniformity in the concentration distribution will change the velocity profile under the application of magnetic field. Applying magnetic field with negative gradient increases the convective heat transfer coefficient, while decreases it in the case of positive gradient. Increasing the magnitude of magnetic field gradient causes a more considerable change in the convective heat transfer coefficient. In the presence of the magnetic field, the convective heat transfer coefficient also increases with increasing Reynolds number, concentration and particle size which the effects of magnetic field on heat transfer is less significant at higher Reynolds numbers. Moreover, the pressure drop increases in the case of applying magnetic field with negative gradient while applying the positive one would act as a pump and sucks the fluid from upstream. Show more

Keywords: Heat transfer, nanofluid, Mn-Zn ferrite, Euler-Lagrange, magnetic field

DOI: 10.3233/JAE-141955

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 555-567, 2014

Authors: Jung, Kwang Suk

Article Type: Research Article

Abstract: When a spiral-shaped, radial electrodynamic wheel with an axial pitch is rotated around a conductive rod, the magnetic field produced by the wheel can travel in the axial direction as well as in the circumferential direction of the wheel. Therefore, the rotating spiral wheel produces three-axial magnetic forces: a torque in the circumferential direction, a thrust force in the axial direction, and a repulsive force in the radial direction of the rod. These forces can be …used effectively in the contact-free conveyance of the conductive rod. In this paper, the magnetic forces produced by the spiral wheel are modeled theoretically, and the model is verified by FEM and experiment. And, desirable design specifications of the wheel are proposed by analyzing the influences of the pitch angle and the number of permanent magnets that govern the characteristics of the spiral wheel. However, the only parameter that influences the forces generated by the wheel is the rotation speed of the wheel. So, a control algorithm that varies only the rotating speed of the wheel to convey the conductive rod is proposed, and its feasibility is verified by application to a constructed set-up. Show more

Keywords: Contactless conveyance, radial electrodynamic wheel, independent control, spiral-shaped wheel

DOI: 10.3233/JAE-141956

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 569-582, 2014

Authors: Pal'a, Jozef | Bydžovský, Jan

Article Type: Research Article

Abstract: A simple method of measuring the Barkhausen noise in two stages was developed. The purpose of the proposed method was to remove the magnetizing frequency component from the induced electromotive force signal without using complex analog or digital filters, which also suppress the Barkhausen noise. In the first stage, an instance of the electromotive force signal was temporarily recorded, and in the second stage another instance of the electromotive force signal subtracted from the previously recorded …instance of the electromotive force signal was measured. Using this method we will obtain only the stochastic component of the electromotive force signal – the Barkhausen noise. The method is illustrated on measuring the Barkhausen noise in an electrical steel sample. The experiments proved that with this method we are able to remove the dominant continuous component from the induced electromotive force signal and we can simplify the measurement. The general problems associated with the method are discussed. Show more

Keywords: Barkhausen noise, electromotive force signals subtraction, two-stage measuring method

DOI: 10.3233/JAE-141957

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 583-591, 2014

Authors: Zhao, Yong | Li, Hao | Lv, Ri-Qing | Hu, Hai-Feng

Article Type: Research Article

Abstract: Magnetic fluid was a novel functional material with many unique properties, especially in the case that the magnetic field was applied. It was found that the special properties of magnetic fluid were determined by its unique microstructure. Then, the special properties could be understood fundamentally by researching the extraordinary nature of the microstructure of the magnetic fluid. At the same time, it was a good theoretic guidance for the experimental research on the properties of magnetic …fluid to make clear about the microstructure model theoretically. Therefore, it was particularly important to study the simulation methods to obtain the microstructure of magnetic fluid. The development of the microstructure simulation methods of magnetic fluid were introduced in this article, and the basic principles of various simulation methods were expounded in detail. The features of each microstructure simulation methods of magnetic fluid were summarized and compared with each other. Finally, the key problems and research direction of the numerical simulation method in the future were described. Show more

Keywords: Magnetic fluid, magnetic field, microstructure, simulation methods

DOI: 10.3233/JAE-141958

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 593-610, 2014

Authors: Ashraf, Muhammad A. | Rizvi, Azhar A.

Article Type: Research Article

Abstract: Total scattering cross section (σ_T ) of a PEC cylindrical scatterer is a function of it's scattering amplitude and is closely related to scatterer's cross section. It is difficult to determine σ_T analytically for arbitrary cross sections of scatterer, especially for random cross sections. Defining some bounds on the value of σ_T is therefore very helpful in its estimation. In this paper, σ_T of canonical shaped …objects is used to define bounds on σ_T of random cylinder. The geometrical parameters of canonical scatterers are obtained from the geometric parameters of the random cylinder. A formulation is also developed to approximate the value of σ_T from its bounding values. This work therefore, helps to predict the σ_T of a random cylinder from its geometrical parameters, without solving an electromagnetic boundary value problem. Show more

Keywords: Random cylinder, total scattering cross section, equivalent area, equivalent perimeter

DOI: 10.3233/JAE-141959

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 611-618, 2014

Authors: Torkaman, Hossein

Article Type: Research Article

Abstract: The performance of the Switched Reluctance Motors (SRMs) in different applications has widely been investigated by various studies. The research areas are oriented toward fault effects on electromagnetics behavior and its diagnosis for operation improvement. One of the most observed faults is the stator winding short circuit which may lead to produce the unbalanced distribution of magnetic field. In this paper, it is attempted to firstly introduce the conventional SRM and new structure of double stator …SRM (DSSRM). Secondly, by means of three dimensional finite element method (3D FEM) the effects of short-circuit faults (SCF) on motor profiles are investigated, in which static and dynamic behaviors of the motor in healthy and several SCF conditions are evaluated. A new method namely as maximum current point tracking (MCPT) is introduced to evaluate the SCF in SRM, so an index is proposed to detect the numbers of shorted turns in faulty phase. The overall outcomes highlight the advantages of using this method and index which is general enough to be applied to any type of SRM. Show more

Keywords: Switched reluctance motor, electromagnetics analysis, fault analysis, short circuit fault, maximum current point tracking

DOI: 10.3233/JAE-141960

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 619-628, 2014

Authors: El Dhaba, A.R. | Ghaleb, A.F. | El-Seadawy, J. | Abou-Dina, M.S.

Article Type: Research Article

Abstract: The static, uncoupled problem of thermomagnetoelasticity for long cylinders carrying a steady, axial current is investigated in stresses within a numerical approach by a boundary integral method in terms of real harmonic functions.This is the numerical realization of the field equations, boundary conditions and other relations presented in [1]. The method is complemented by the use of boundary collocation method to evaluate some path-independent line integrals needed in the representation of the mechanical displacement field. …The material of the cylinder is assumed homogeneous and isotropic, and linear dependence of the magnetic permeability on strain is taken in consideration through two material constants. Formulae are obtained for the boundary values of functions of practical interest like stress and mechanical displacement. Evaluation in the bulk may then be carried out by quadrature on the basis of well-known formulae of the theory of potential. The special case of an elliptic boundary is treated and the results are compared to the analytical solution established in [11]. It is concluded that the proposed numerical scheme performs efficiently in this case, and may thus be used for other forms of the boundary, subject only to smoothness condition. Show more

Keywords: Plane problem, thermo-magnetoelasticity, electric current, magnetic field, thermomagnetic stresses, Maxwell stress, boundary method, boundary integrals, numerical methods

DOI: 10.3233/JAE-141961

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 629-648, 2014

Authors: Yang, J.S. | Tiersten, H.F.

Article Type: Research Article

Abstract: The equation for transversely varying thickness modes in doubly-rotated quartz resonators is applied in the analysis of the vibrations of contoured resonators with beveled cylindrical edges. The treatment in this work differs from that of earlier work in that the dominant condition at the edge of the resonator is satisfied and the approximation made earlier in the beveled annulus is not made here where the solution is exact. A procedure for the analytical determination of the …required diameter for a good resonator is identified and calculated results are compared with those of the earlier work. Show more

Keywords: Piezoelectric, resonator, vibration

DOI: 10.3233/JAE-141962

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 3, pp. 649-661, 2014