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Litz wires consist of many individual, isolated conductor strands. Certain litz wires are fabricated by simply twisting the bundle of strands, hence a wire pitch is realized. In this paper, the ac resistance of coils made of such twisted litz wire are calculated by combining two-dimensional finite element simulation and circuit laws. In so doing, the inherently three-dimensional problem can be solved at much lower computational cost. Results are presented for the current distribution, and for the alternating current resistance of coils, validated against measured data. [ABSTRACT FROM AUTHOR]

In this work, a parametric study is carried out on carbon fiber-reinforced plastic (CFRP) materials to investigate how the spatially varying fiber distribution influences the measured signal in an eddy current testing (ECT) configuration. The measurement setup was modeled using finite element method, while the fiber distribution is taken into account by an inhomogeneous anisotropic conductivity tensor. The study revealed a trade-off relation between the size of the ECT coil and the maximal dynamic range of the ECT signal, which contributes to the understanding of the connection between the fiber arrangement and the ECT signal and provides an opportunity for optimal ECT coil design. [ABSTRACT FROM AUTHOR]

A nonlocal generalization of the IBC (impedance boundary condition) concept is introduced in this work for modeling the coil wires in resonant WPT (wireless power transfer) links. Such NLIBCs (nonlocal IBCs) can accurately account for the skin and proximity effects in the wires for all frequencies relevant to resonant WPT systems and can be utilized in both finite-element and surface-integral-equation numerical frameworks. The NLIBCs have run-time performance close to that of the IBC because the NLIBCs take advantage of the quasi-2D nature of the electromagnetic field inside the wires. The results for a typical WPT configuration illustrate the performance. [ABSTRACT FROM AUTHOR]

Scattering from propellers is investigated using the 3D Finite Element Method (FEM), alongside a simpler integral equation (IE) method using 1D discretization. It is shown that under certain conditions and near the propellers' resonant frequency, results using the two methods are in agreement, justifying the use of the IE method; this is advantageous because of smaller computation times, and for providing a physical insight to the scattering phenomena at hand. Anechoic chamber measurements are performed to validate the numerical results. [ABSTRACT FROM AUTHOR]

Magnetic flux simulations were utilized in a novel magnetic measurement method performed for the detection of local thinning of ferromagnetic plates. It was shown by numerical simulation, how parameters affect detectability of the defects. Linear relationship was found between the evaluated parameters and size of the artificial slot. Good correlation was found between theoretical and experimental results. [ABSTRACT FROM AUTHOR]