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Grain-oriented electrical steels (GOES) are widely used in the manufacturing of high efficiency energy conversion systems thanks to their excellent magnetic properties along the rolling direction. Nevertheless, on the one hand, GOES exhibit strong magnetic anisotropy, resulting in distinct magnetic properties regarding the direction of the applied magnetic field to the rolling direction. On the other hand, GOES undergoes changes in their magnetic properties due to the industrial manufacturing process and mechanical constraints during operation. In general, stress, and particularly compressive stress, deteriorates magnetic properties. This paper deals with the modeling of the magnetic behavior of GOES under compressive stress. The orientation distribution function (ODF) based approach recently applied to describe the B-H first magnetization curves of a conventional GOES without stress as well as under applied uniaxial mechanical tensile stress is extended to account for the effect of compressive stress, with different considerations of modeling. The magnetic properties and the sensitivity of the ODF-based model to the magnetization direction as well as to the applied compressive stress are analyzed. Oscillation issues inherent to the ODF-based model are also discussed.

Grain-oriented electrical steels (GOES) are extensively utilized in power transformers to enhance energy efficiency and reduce their size and weight. GOES are characterized by their strong magnetic anisotropy, leading to distinct magnetic characteristics (behavior law and iron losses) according to the direction and the intensity of the applied field with respect to the rolling direction (RD). The Orientation Distribution Function (ODF) based approach is a convenient method for describing the anisotropy of the GOES behavior law owing to its ease of identification and implementation. However, it exhibits a significant oscillation issue at low magnetic fields. To address this issue, a high-order ODF-based method has been proposed in the literature. In this article, the ODF-based model, initially stress-free, is extended to include the effects of mechanical tensile stress on the first magnetization curves of a conventional GOES. An ODF-based model considering both magnetic anisotropy and mechanical tensile stress is then proposed. The results are discussed and compared with experimental data.

The interest of non-destructive testing (NDT) in steel material characterization is growing especially for quality and life cycle control. The Magnetic Barkhausen Noise (MBN) analysis shows an extreme sensitivity to different parameters: steel grade, grain size, microstructure, magnetic domains wall structure, residual stress, surface condition, etc. It is very difficult to distinguish the individual effect of each parameter on the steel MBN signature. This paper attempts to address this problematic by fixing most of these parameters and varying only one parameter of interest (either austenitizing or tempering temperature) to assess the ability of the MBN technique to dissociate the mechanical properties of different martensitic steel grades. The MBN technique presented herein has proven to be able to distinguish high-performance martensitic steel grades when applied according to the proposed experimental protocol.

Grain-Oriented Electrical Steels (GOES) are widely used in transformers to increase energy efficiency while reducing the volume and weight of such transformers. These GOES are characterized by their strong anisotropy, which leads to different magnetic properties (behavior law and iron losses) depending on the strength and the direction of the applied magnetic field to the rolling direction (RD). To describe the anisotropy of the GOES behavior law, the Orientation Distribution Function (ODF) based approach shows interesting features regarding ease of identification and implementation. However, a significant oscillation issue in this model at low magnetic field exits. It is recently reported that a high-order ODF based method can improve the accuracy of the original model. But the high-order ODF based model implies an important number of experimental data according to different directions of the applied field to RD (different magnetization angles) to build a model with sufficient accuracy. In addition, the accuracy also depends on how the input magnetization angles are selected between the RD and the transverse direction (TD). In this article, an optimal algorithm for input magnetization angle selection is proposed for the high-order ODF based method. To validate the proposed algorithm, 13 magnetization angles have been measured. A comparative study has been conducted based on the original and the high-order ODF based models built with the proposed selected magnetization angles. It is shown that the proposed algorithm can reduce the number of experimental data needed for the ODF based model while providing an acceptable global error.

Nondestructive testing (NDT) of industrial steel products is commonly used to detect defects such as cracks using among other methods, electromagnetic techniques. When properly calibrated, these NDT can be adapted to evaluate the mechanical properties of steels. It is especially of prime importance when rigorous quality control must be achieved for high performance steels. In this context, the proposed article deals with the investigation of the Magnetic Barkhausen Noise (MBN) to characterize the tensile properties of high mechanical performance martensitic steels.

The magnetic behavior of a lamination stack made of grain-oriented electrical steel (GOES) is investigated under non-conventional 3D magnetic flux excitations. An experimental demonstrator has been designed to study a normal orientation of the magnetic flux path, with regard to the lamination plane, combined with different in-plane orientations of the easy magnetization axis of the lamination stack. The results in terms of the magnetic flux distribution and the iron losses are presented and discussed.

Robustness and reliability of modern synchronous motors require an accurate design of the permanent magnets (PM) while accounting for the motor operating conditions (demagnetizing field, temperature). In this paper, the important attribute of a PM non-linear demagnetization model within a finite element method (FEM) simulation environment is clearly emphasized. To do so, starting from experimental measurement achieved on a NdFeB PM, a toolbox baptized “PM-Demag” has been developed. This toolbox manages the PM history and updates the PM B(H) characteristics depending on the temperature and the PM working point. Finally, a relatively straightforward coupling is implemented with a FEM software and applied to a simple study case. Results show local magnetization loss in the PM due to the combination of both the temperature and the demagnetizing field.

Regularly used in power transformers, grain-oriented (GO) steels are also usually chosen for the manufacturing of the stator cores of hydro and turbo-generators. These steels are renowned for their high magnetic performances in the rolling direction (high permeability and low magnetic losses). Nevertheless, in a turbo-generator where GO steels are employed to reduce the size of the stator core, the magnetic flux flows through several successive directions within the plane of the steel. So, the anisotropic behavior of the GO steel has to be considered in the design step of the related devices in order to improve their energy efficiency as well as their diagnosis based on modeling. In this paper, an anisotropic phenomenological iron loss model, quite recently developed, has been studied and successfully implemented in a finite element method (FEM) simulation environment. The implementation has been validated against experimental data achieved on an industrial conventional GO grade typically used in turbogenerators. The results show a good agreement of the computational results with the experiments for both quasi-static and dynamic regimes.

The purpose of this study is to investigate, through finite element (FE) simulations, the effect of the demagnetizing field in Epstein characterization of grain-oriented electrical steels. A 3D finite element simulation has been realized to represent the parallel and X-stacking configurations in the Epstein frame. The numerical results have been compared with experimental measures. In a parallel configuration, the measured induction is actually the one in the material, whereas the resulting magnetic field differs from the applied one (in magnitude and angle) due to the shape anisotropy (demagnetizing field). In X-stacking configuration, the resulting magnetic field is close to the applied magnetic field (and then the supposed excitation field in the Epstein frame), whereas the magnetic induction has deviated from the axis of the strips.

16MnCr5 steel parts were additively manufactured by laser powder bed fusion in order to investigate the effect of microstructure on electromagnetic properties. As process parameters have a direct impact on the obtained microstructure, different conditions were used to manufacture samples on which magnetic and electrical tests were conducted. The obtained results were presented and discussed in terms of density, microstructure and electromagnetic properties. Finally, correlations have been demonstrated between the microstructure and the electromagnetic performances. Lower magnetic and electric properties were obtained with the higher porosity rates at low volume energy density. The microstructural effects were evidenced, through a decrease in magnetic properties with grain orientation, and an improvement with stress relief annealing.

Hysteresis models allow the prediction of iron losses in materials under complex magnetic excitation, with accuracy depending on their principle and identification procedure. Commonly, to achieve high accuracy, a model may require a broad set of experimental input data, which is in some cases, not easy to obtain. We propose, in this study, a static model focusing on simplicity while still striving for accuracy. Its principle is to represent the variation of the field deviation between reversal curves and a near saturation hysteresis loop. In terms of input data, this model requires the experimental first magnetization curve and a few quasi-static centered hysteresis loops of the material. Following the principle description, the identification procedure, the model validation, as well as a sensitivity study are presented in detail.

In this research, we propose an ad hoc method for identifying adequate full permeability tensors for finite element method (FEM) simulation of grain oriented electrical steels (GOES). The tensors are obtained from dedicated measurements requiring only unidirectional excitation field. This method relies on the one hand, on the Enokizono approach which was originally established based on measurements under rotating field and on the other hand on the Fiorillo model of magnetization processes in GOES.

In this research, the magnetic behavior of a lamination stack made of grain-oriented electrical steel (GOES) is investigated under non-conventional 3D magnetic flux excitations. An experimental prototype has been designed to study different orientations of the magnetic flux path, with regard to the lamination plane, combined with different in-plane orientations of the GOES easy magnetization axis.

Electromagnetic non-destructive testing (NDT) of industrial steels is mostly employed to detect defects such as cracks or mechanical properties inhomogeneities. However, NDT can also be employed, when properly calibrated, to evaluate quantitatively these mechanical properties. It is especially of interest when rigorous quality testing must be achieved on finished steel-based products of which mechanical characteristics must be guaranteed. In that context, the proposed work deals with the evaluation of electromagnetic NDT to characterize the tensile properties of high mechanical performance steels.

This paper presents a combined experimental/numerical approach to identify the degradation profile of the magnetic characteristics regarding the distance from the cut edge of punched electrical steels. Using a dedicated magnetic measurement device and mechanical hardness measurements, the impacted cutting-edge (I.C-E) distance has been experimentally identified. In association with a magneto-plastic model, the numerical model allows to determine the I.C-E distance and its associated degradation profile by an inverse optimization method.

Magneto-optical (MO) analysis is a powerful tool to reveal the magnetization processes in magnetic materials at all relevant scales. Because the magnetization processes involve the restructuration of the magnetic domain structure (domain-wall nucleation, annihilation, and propagation, etc.), MO studies are of prime importance to link the material microstructure to its basic macroscopic properties (e.g., magnetic losses) and then improve the knowledge of these properties and their modelling. In this work, we propose a MO investigation of the magnetic domain structure evolution under rotating magnetic field.

Grain-oriented (GO) materials are widely known for their strong anisotropic behavior. Their magnetic characteristics depend on the angle between the applied magnetic field and rolling direction (RD). However, these characteristics can be further modified according to their stacking configuration and to the influence of the demagnetizing field. In this paper, a 3-D finite element analysis is performed in order to study the effect of the parallel and x-stacking configuration on the magnetic properties of the lamination stack. The results are interpreted in terms of the demagnetizing field which vectorially combined with the applied field affects the magnetization.

In this paper, a toolbox baptized “PM-Demag” taking into account the permanent magnet (PM) demagnetization phenomenon has been developed. It is based on a nonlinear demagnetization model which considers the thermal state of the PM and reproduces the knee rounded shape of the B(H) curve. Validations against experimental measurements performed on commercial NdFeB PM are presented.

This paper presents a layered multi-physical model for sizing optimization as well as solving a specific optimization problem of interior permanent-magnet (PM) synchronous machine (IPMSM) for traction application. The advantages of the model structure are the management of the calculation time and the multi-physical aspect taking into consideration the iron losses and the thermal phenomena. An analysis is conducted over an optimization problem with different nested loops and for several operating points of the IPMSM.

This article analyzes and highlights the impact of an iron loss model on temperature estimation within a multi-physical model of a radial-flux permanent-magnet (PM) synchronous machine (PMSM) for traction application. Three iron loss models have been compared in terms of computing time and accuracy within the machine torque-speed plane. This study underlines the iron loss calculation impact on the temperature estimation in the PMSM in relation with the required performances.