A fast crack profile reconstitution model in nondestructive testing is developed using an arrayed eddy current sensor. The inverse problem is based on an iterative solving of the direct problem using genetic algorithms. In the direct problem, assuming a current excitation, the incident field produced by all the coils of the arrayed sensor is obtained by the translation and superposition of the 2D axisymmetric finite element results obtained for one coil; the impedance variation of each coil, due to the crack, is obtained by the reciprocity principle involving the dyadic Green’s function. For the inverse problem, the surface of the crack is subdivided into rectangular cells, and the objective function is expressed only in terms of the depth of each cell. The evaluation of the dyadic Green’s function matrix is made independently of the iterative procedure, making the inversion very fast.

This paper deals with the design and optimization of a 2.1 MW rim-driven electric thruster for ship propulsion. For this purpose, a double stator ironless rotor axial flux permanent magnet (AFPM) motor is considered as the propulsion motor. The analytical model of the selected AFPM motor is presented. The magnetic field in the AFPM machine is calculated using the 3D magnetic charge concept in combination with image theory and permeance functions to take into account the stator slotting effects, and a simple thermal model is used to evaluate the heat dissipation capabilities of the machine and the thermal dependence of the main electromagnetic losses. To optimally design the AFPM, an optimization process based on genetic algorithms is applied to minimize the cost of the active motor materials. An appropriate objective function has been constructed, and different constraints related to the main electrical, geometrical, and mechanical parameters have been taken into account. The achieved results are compared with the performance of a podded radial flux permanent magnet (RFPM) motor, which is considered a reference propulsion motor. The obtained results show a fairly satisfactory improvement in the cost and masses of the active motor materials. Finally, the accuracy of the obtained optimum solution is validated by performing 3D finite element analysis (3D-FEA) simulations.

High temperature superconducting (HTS) flux pumps have emerged as a promising contactless method for magnetizing closed HTS magnets. These systems rely on HTS switches, which operate through the principle of dynamic resistance, which is a phenomenon where a voltage is induced along a type II HTS tape carrying a direct current (DC) when exposed to a changing magnetic field. While this effect is well known, conventional methods using alternating current (AC) sinusoidal magnetic fields often require demanding conditions, such as high amplitudes and frequencies of applied field to attain high values of dynamic resistance. In this work, we explore a novel approach to generating dynamic voltage in HTS tapes carrying DC transport current by employing pulsed magnetic fields (PMF). To investigate this approach, an experimental bench was designed and implemented to measure the dynamic voltage under these conditions. Additionally, a two-dimensional (2D) electromagnetic thermal coupled model, based on the finite element method, was used to check out the measured quantities.

The Lorentz force is a new technique used recently for nondestructive testing (NDT) of conducting materials. Several scientific works have focused on the use of Lorentz force generated by translation motion. In our study, we propose an analysis of defects using Lorentz force in the case of rotation motion. Our method is based on a rotational relative motion between an aluminum sheet and a permanent magnet. The tested object is subject to a torque due to Lorentz force. The presence of a defect disturbs the measured torque. We suggest a calculus of this torque using a voluminal discretization of the specimen using current distribution adjacent to the defect. The result will be compared to a finite element simulation using the COMSOL software.