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Description
Many materials and machines that may pose a real risk of catastrophe due to fatigue wear, exceeding stress limits or the appearance of plastic deformation are magnetic. In addition, there is a constant trend indicating the need to develop methods towards the technology of detecting early stages of damage, which is possible thanks to the use of magnetic methods [1]. However, due to the variety and complexity of the magnetomechanical effects, it is difficult to identify quantitative measures that can precisely define diagnostic thresholds for specific magnetic signals.
Both quantitative and qualitative changes of the object magnetization status are coupled with thermal, electrical and mechanical effects in the structure. Complex, multiparametric non-linear relations between chemical composition, physical structure, stresses and magnetization of the material can be observed under test. Required for analysis and interpretation of such multiple interrelations and non-linear actions, are suitable models which would highlight the most effective reactions (phenomena). Therefore, the publication analyzed near yield area in construction steel on the behavior of magnetomechanical phenomena. For this purpose, the test stand was built, that is able to analyze the magnetic characteristics of samples that are simultaneously subjected to tensile stresses. The specimens were stretched with full control on strain in the material. In the experiment a customized measurement device (MagMouse) which consisted of a matrix of three-axis magnetoresistive sensors was used.
Fig. 1 Diagram of the test stand for the experiment.
The obtained results indicate new possibilities of describing and modeling phenomena that better describe the observed reality. Along with the new description of physical interactions, new methods of measuring and analyzing the magnetic signal were presented, both in terms of elastic and plastic loads. In both cases, changes in the mechanical properties of the material, taking into account near yield area of the steel, result in changes in the magnetic properties, mainly magnetization and magnetic permeability of the material. The results of the research indicates tips on how to conduct the experiment, considering rolling direction of steel, to find diagnostic information.
References
[1] A. Daem, P. Sergeant, L. Dupré, S. Chaudhuri, V. Bliznuk, and L. Kestens, “Magnetic Properties of Silicon Steel after Plastic Deformation,” Materials, vol. 13, no. 19. MDPI AG, p. 4361, Sep. 30, 2020. doi: 10.3390/ma13194361.
