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This paper describes iterative methods for the high frequency electromagnetic analysis using the finite element method of Maxwell equations including displacement current. The conjugate orthogonal conjugate gradient method has been widely used to solve a complex symmetric system. However, the conventional method suffers from oscillating convergence histories in large-scale analysis. In this paper, to solve large-scale complex symmetric systems arising from the formulation of the E method, an iterative substructuring method like the minimal residual method is presented, and the performance of the convergence of the method is evaluated by numerical results. As the result, the proposed method shows a stable convergence behavior and a fast convergence rate compared to other iterative methods. [ABSTRACT FROM AUTHOR]

The nonconformal domain decomposition methods (DDMs) of the hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) are presented for computing large electromagnetic scattering/radiation problems. The numerical performance of different transmission conditions between finite element method (FEM) subdomains, and FEM and BI domains is studied in this paper. The Dirichlet transmission condition (DTC) employed at the interface between FEM and BI domains has faster convergence than the Robin-type transmission condition, and this finding is different from the conclusions for the FEM DDMs published in the literature. Furthermore, the cement-element (CE)-based dual-primal finite element tearing and interconnecting (FETI-DP) DDM has faster convergence than the Lagrange-multiplier-based FETI-DP method under the FE-BI system, and is also different from that under the system of the FEM with the absorbing boundary condition (FEM-ABC). It shows that the DDMs of FE-BI-MLFMA have some essential differences from those of FEM-ABC. The analysis of these numerical phenomena is presented in this paper. Further comparison between the DDMs of FE-BI-MLFMA and FEM-ABC demonstrates that the DDMs of FE-BI-MLMFA have essential advantages over those of FEM-ABC. Various numerical experiments confirm the accuracy, efficiency, and flexibility of the nonconformal DDM of FE-BI-MLFMA, which is the CE-based FETI-DP DDM with DTC connecting FEM and BI. [ABSTRACT FROM AUTHOR]

In this paper, the characteristics of the electromagnetic noise radiated by an external rotor in-wheel motor (IWM) are investigated with the Doppler effect taken into consideration. First, Maxwell stress tensor method is employed to derive electromagnetic forces on the magnet surface. The effect of common current harmonics is also analyzed. Then, a structural model of the rotor is built and modal test is conducted to validate the model. Nodal forces, which are calculated by finite element method, are transferred from the electromagnetic mesh to the structural model for further vibration prediction. Finally, boundary element method is used to calculate the noise radiated by the rotor. In particular, the Doppler effect is considered. The calculated results are validated by the noise test. It is found that the end cap contributes more to the overall noise than the shell, and obvious sound directivity appears in the noise of the IWM. The noise measured perpendicular to the outer end cap is larger than that measured in other directions. In addition, the Doppler effect would induce additional side-frequency components around high-frequency peaks in the external rotor motor. [ABSTRACT FROM PUBLISHER]

SUMMARY To realize fast electromagnetic field analysis, the parallelization technique has been often introduced into the preconditioned Krylov subspace method. When the multicolor ordering is applied to parallelization of forward and backward substitution, the elapsed time of matrix calculation might increase owning to the increment of bandwidth. Therefore, the block-multicolor ordering based on the level structure arising in reverse Cuthill-McKee ordering has been developed. The validity of developed method was demonstrated on the parallelized incomplete-Cholesky-preconditioned conjugate gradient method. In this paper, the parallelization performance of preconditioned minimized residual method based on the three-term recurrence formula of the CG-type (MRTR) method supported by developed ordering is investigated. Furthermore, the affinity of developed ordering or cache-cache elements technique for parallelized forward and backward substitution in Eisenstat's technique is particularly examined. [ABSTRACT FROM AUTHOR]

This paper deals with some aspects of formulation and implementation of a broadband algorithm with build-in analysis of some dispersive media. The construction of the finite element method (FEM) based on direct integration of Maxwell's equations and solution of some additional convolution integrals is presented. The broadband, fractional model of permittivity is approximated by a set of some relaxation sub-models. The properties of the 3D time-dependent formulation of the FEM algorithm are determined using a benchmark problem with the Cole-Cole and the Davidson-Cole models. Several issues associated with the implementation and some constraints of the broadband finite element algorithm are presented. [ABSTRACT FROM AUTHOR]

The aim of this paper is to highlight the capabilities of a new hybrid analytical modeling (HAM) approach for the analysis and design of various electromagnetic structures. After an introduction, where the aim of the development of this modeling approach is presented, the modeling approach is described. The new HAM is based on a strong coupling of the magnetic equivalent circuits method and analytical models (AMs). The AM, based on the formal solution of Maxwell’s equations, is established thanks to the separation of variables method. The HAM is applied to different permanent magnet electric machine structures, and the results are validated extensively by comparison with the finite-element analyses. [ABSTRACT FROM AUTHOR]

Most studies presented to date in the use of the marine controlled source electromagnetic (CSEM) method to detect hydrocarbons analyze the homogeneous reservoir models of isotropic or anisotropic resistivity. In the present paper, we use 3D vector finite element modeling to calculate the electromagnetic response from various inhomogeneous reservoir models of a complex structure. Also, we study the electromagnetic field propagation inside the homogeneous and inhomogeneous 3D reservoirs, as well as the problem of equivalence of inhomogeneous and homogeneous reservoirs. [ABSTRACT FROM AUTHOR]

In this paper we present a finite element model in frequency domain which computes the Lorentz force that drives an electromagnetic forming (EMF) process. The only input data required are the electrical parameters of the capacitor bank, the coil and the work piece. The main advantage of this approach is that it provides an explicit relation between the parameters of the EMF process and the frequency of the discharge, which is a key parameter in the design of an optimum EMF system. The method is computationally efficient because it only requires to solve time-harmonic Maxwell's equations for a few frequencies and it can be very useful for coil design and for testing modeling conditions on complex three-dimensional geometries. [ABSTRACT FROM AUTHOR]