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In this study, we estimate the locally defined permeability of the magnetizing particles in a soft magnetic composite (SMC) material whose effective permeability, observed by macroscopic measurements, is known. This procedure is repeated for a wide range of geometries whose electrical insulation layer thicknesses between the magnetizing particles are altered. It is shown that even if the effective permeability of the material is known by some measurement, the permeabilities of the individual particles cannot be immediately determined but remain heavily dependent on the thicknesses of the insulation films. This dependence is quantified. It is shown that when using periodic geometries to imitate SMC materials, one also has to use higher local permeabilities for the magnetizing particles or thinner insulations between the particles compared with the situation where randomized structures are used in order to obtain the effective permeability determined by measurements. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to describe a new algorithmic method to imitate 3-D geometries of soft magnetic composite materials. This method allows constructing various kinds of geometries for experimenting how certain geometric features affect different electromagnetic properties of the materials. Using the geometry imitations, we demonstrate that in order to explain the nonlinear static magnetic behavior of a certain composite, it is not necessary to assume contacts between the neighboring particles in the material. The contacts may instead be replaced by thin gaps. [ABSTRACT FROM AUTHOR]

• Randomized 3-D geometries are used to imitate an SMC material. • 3-D models are compared to 2-D models, obtained by slicing the 3-D geometries. • The use of 3-D models for SMC materials is advocated. In this article, we compare 3-D finite element models of a soft magnetic composite (SMC) material to 2-D models, obtained by slicing some 2-D intersections of the 3-D geometries, in terms of magnetization curves and losses. A 3-D nonlinear static model, providing computational B - H curves, is compared to two 2-D models, one with the magnetic field parallel to the 2-D plane, and the other with the magnetic field perpendicular to the 2-D plane. We find that the 2-D models provide largely inconsistent results with the 3-D model. A 3-D time-harmonic model, providing computational effective permeabilities and losses, is compared to two 2-D models, one with the magnetic field parallel to the 2-D plane, and the other with the magnetic field perpendicular to the 2-D plane. We find that the 2-D models provide largely inconsistent results with the 3-D model, with an exception of the computational losses of the 2-D model, with the magnetic field perpendicular to the plane, almost agreeing with the computational losses provided by the 3-D model. However, the computational permeabilities do not match in these two models. This article proposes to be very critical before publishing 2-D models of SMC materials without a proper justification by symmetry. [ABSTRACT FROM AUTHOR]