Dorota Jackiewicz

Reliability and Efficiency of Differential Evolution Based Method of Determination of Jiles-Atherton Model Parameters for X30CR13 Corrosion Resisting Martensitic Steel

Paper presents new possibilities of Jiles-Atherton model of magnetic hysteresis parameters determination. The main problem connected with this model is the fact that its parameters have to be determined during the optimization process. However, due to the local minima on the target function, the gradient optimization methods are not effective, whereas evolutionary strategies, such as (μ+λ) strategy, are very time consuming. Results of calculation presented in the paper indicate that differential strategies create possibility of reliable and fast determination of Jiles-Atherton model parameters. Paper also presents guidelines for practical determination of model’s parameters, which is very important from practical point of view.

Preparation, Processing and Selected Properties of Modern Melt-Quenched Alloys

Rapidly quenched amorphous and nanocrystalline alloys in form of thin ribbons are for several decades already among traditional materials used in construction, biomedical, catalytic and mainly electromagnetic applications. These alloys exhibit excellent properties tunable by a wide range of tools – compositional optimization, pre-preparation and post-preparation processing. The contribution focuses on recent technologies of preparation of metallic glasses with enhanced thickness and consisting of different alloy layers. Specific processing aspects to optimize the desired properties are presented. Attention is given also to possibilities of using these materials for power electronics, sensors, actuators and mechanical construction elements.

Magnetoelastic Characteristics of Constructional Steel Materials

Paper presents the methodology and results of magnetoelastic characteristics investigation of three types of constructional steels. Investigated steels were formed into frame-shaped samples with both magnetizing and sensing windings coiled on their columns. Magnetic characteristics of materials were measured by computer controlled hysteresisgraph. In order to apply tensile stresses in material of the sample, special force reversing system was used. The tested samples and the procedure of their investigation were described. Obtained results were processed and presented in the paper as charts, which were analyzed and discussed. On the basis of the results, the conclusions were formulated, which are also included in the paper.

New Methodology of Testing the Stress Dependence of Magnetic Hysteresis loop of the L17HMF Heat Resistant Steel Casting

This paper presents the results of investigation on the tensile stresses dependence of magnetic characteristics of the L17HMF steel casting. To ensure uniform stress distribution in the sample for this investigation and the closed magnetic circuit, the frame-shaped samples were used. This is very important because it provides results independent of the shape and dimensions of the sample. On the columns of the sample both sensing and magnetizing windings were made. It is highly recommended to wound magnetizing and sensing windings on both columns. Due to the specialized force reversing system, compressive force generates the uniform tensile stresses in the sample. Magnetic characteristics are measured under these stresses by digitally controlled hysteresis graph. On the base of results of measurements the magnetoelastic characteristics of L17HMF steel casting were determined. Determined this characteristic is necessary to developed nondestructive testing method for monitoring of industrial and energetic constructions with elements made by L17HMF steel casting.

MAGNETOELASTIC PROPERTIES OF SELECTED AMORPHOUS SYSTEMS TAILORED BY THERMOMAGNETIC TREATMENT

Abstract Magnetoelastic properties of Fe6iCoigSÍ5Bi5 alloy after thermomagnetic treatment were tested for both compressive and tensile stresses, what is significant novelty. Results of presented investigation opens new ways of modelling the magnetoelastic effects in amorphous systems tailored by thermomagnetic treatment.

Investigation of the Magnetoelastic Villari Effect in Steel Truss

The following paper presents results of investigation of the magnetoelastic Villari effect in steel truss. Construction of the specially developed steel truss allowed to investigate three identical steel elements at the same time, where one element was subjected to the tensile stress and two elements were influenced by the compressive stress. For all three elements the magnetic characteristics for different values of applied mechanical stress were measured. Purpose of the performed investigation was experimental validation of the theory of magnetoelastic Villari effect for steel. For tensile stress initial increase of the magnetic flux density was observed up to the Villari reversal point and then values of magnetic flux density started to decrease. For compressive stress only decrease of the magnetic flux density was observed. Obtained experimental results confirmed theoretical description of the Villari magnetoelastic effect.

Investigation Method for the Magnetoelastic Characteristics of Construction Steels in Nondestructive Testing

Paper presents new, reliable method of testing the magnetoelastic properties of construction steels. In this method frame-shaped samples are used. Moreover, due to special, force reversing mechanism, tensile stresses may be generated in the sample with use of compressive force produced by the oil hydraulic press. Paper presents also the result of analyze of flux density and stress distribution in frame-shaped sample during the tests. Moreover, developed method was validated during the investigation of magnetoelastic properties of C45 construction steel. As a result it was confirmed, that presented method may be applied for magnetoelastic characterization of construction steels for nondestructive testing.

Possibilities of Application of Amorphous Fe77Cr2B16Si5 Alloys in Different States of Thermal Relaxation as Magnetic Tensile Force Sensors

Paper discusses the possible of application of iron-based amorphous Fe77Cr2B16Si5 alloys for tensile force sensors. In proposed sensor uniform stresses were generated in direction of the ribbon ring core axis. As a result stresses were perpendicular to the magnetizing field direction, what increases sensor sensitivity as well as simplified analyses. The results show high magnetoelastic sensitivity of Fe77Cr2B16Si5 amorphous alloy. Moreover, this magnetoelastic sensitivity increases during the annealing process, which is connected with thermal relaxation of amorphous alloy.

Stress assessment in steel truss structures on the basis of magnetoelastic effects

In this paper, magnetoelastic evaluation method of stress assessment in constructional steel samples is presented. For the investigation special test stand was designed and built, along witch the truss structure, which allowed for installation of sample members. Measurements of the hysteresis loops of the sample members were performed under varying mechanical load, resulting in magnetoelastic Bm(σ)Hm characteristics. The experimentally obtained characteristics were consistent with the magnetoelastic effect theory, and allow for the on-line monitoring of the structure state. Presented results confirm the feasibility of the magnetoelastic effect based NDT stress assessment in the steel truss constructions.

The Application of the Extended Jiles-Atherton Model for Simulating the Magnetic Characteristics of X30CR13 Steel

The application of magnetic-property oriented methods for non-destructive testing is very promising due to its low cost and robustness. This paper presents the methodology of simulating the magnetic properties of martensitic X30Cr13 steel applying the extended Jiles-Atherton model. On the basis of experimental measurements, the parameters of the Jiles-Atherton model were determined by an evolutionary strategy together with gradient optimisation. A very good agreement between experimental hysteresis loops and the model was confirmed by a high value of determination coefficient. The presented results open new possibilities of developing methods for non-destructive testing of energetic turbines made of X30Cr13 stainless steel. Moreover, quantitative simulation gives a possibility of a better understanding of magnetisation processes.