1,721,469 research outputs found
ACCURATE COMPUTATION OF ELECTROMAGNETIC-FIELDS IN THE PRESENCE OF CONDUCTING AND MAGNETIC MATERIALS
No full textNumerical analysis of magnetic field diffusion in ferromagnetic laminations by minimization of constitutive error
No full textACCURATE COMPUTATION OF ELECTROMAGNETIC-FIELDS IN THE PRESENCE OF CONDUCTING AND MAGNETIC-MATERIALS
No full textIn this paper the magnetic field is computed as the superposition of two contributions: B = B-0 + Delta B. The vacuum field Bo due to the coil currents can be obtained with extreme accuracy using analytical methods. The field Delta B, due to the magnetizing currents in the iron or other perturbations like eddy currents in passive conductors, is computed numerically. The splitting yields a very high accuracy in all cases in which \Delta B\ much less than \B-0\. The method, based on a calibration of the numerical results, is shown to be similar, but less expensive than perturbation techniques and reduced potential approaches. The effect of the outer magnetic shield on the field produced by an air core magnet for magnetic resonance is studied and compared to the analytical solution available for a particular shield geometry. An example of application is also shown for a dynamic case in the presence of eddy currents
ACCURATE COMPUTATION OF ELECTROMAGNETIC-FIELDS IN THE PRESENCE OF CONDUCTING AND MAGNETIC MATERIALS
No full textIntegral boundary conditions in F.E.M approaches with the minimization of constitutive error
No full textA method based on the minimization of the constitutive error has been successfully applied to finite element formulations of Maxwell equations. Error based techniques present a number of appealing characteristics, including the possibility of providing an estimation of the error distribution and to split the equation system in two decoupled subsystems. However, except for very simple cases, a direct numerical translation of the boundary conditions can cause a number of drawbacks: on one side the lack of symmetry and positive definition of the matrix, on the other side the impossibility of splitting the unknowns. This paper is aiming to discuss the problem and to propose a technique to effectively impose a wide class of boundary conditions within the framework of error based formulations. To show the performance of the technique, some examples are proposed
Liquid-crystalline polymorphism in a new class of semiflexible polyesters containing a 2-phenylbenzoxazole group.
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Fast Solution of a 3-D Integral Model for the Analysis of ITER Superconducting Coils
No full textIn this paper, we simulate the electromagnetic behavior of cable-in-conduit conductors (CICCs) and coils using a 3-D integral formulation of magneto-quasistatic Maxwell’s equations, where the superconductors are represented by a power-law. The integral equation is numerically formulated using edge-elements and the nonlinear problem is discretized with a quasi-Newton algorithm. The solution of each iteration step is achieved with an iterative GMRES solver, which benefits from an singular value decomposition of the full matrix representing the integral operator. The model is applied to study the electromagnetic behavior of international thermonuclear experimental reactor (ITER) CICC and coils
Finite element solution of nonlinear Maxwell equations in the time domain
No full textTwo different numerical methods for the finite element solution of nonlinear Maxwell equations in the time domain are discussed: the Galerkin formulation and the constitutive error based approach. The scattering of a plane wave from a nonlinear dielectric slab is analysed. A general analytical solution for this class of problems is derived and compared with the numerical solutions
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