Measurements and Modeling of the Effects of External Stimuli on the Magnetic and Magnetostrictive Properties of High-Strength Steels
Open AccessThe effect of mechanical stresses, bias fields, and general deformations on the magnetic and magnetostrictive properties of ferromagnetic materials has been a subject of research for more than a century. No quantitative agreement has been reached that canlead to a unique model or theory to expound such effects. The results typically show various patterns which differ depending on the specimen under study. The complexity of how magnetization, magnetostriction and external stimuli are vastly interdependent isclearly manifested in polycrystalline specimens, like high-strength steels. Kinks, jumps, reversals, sign changes, and any other experimental observation of a measurement that incorporates magnetization, magnetostriction and external stimuli are very difficult to be generalized. These features are not necessarily a characteristic of their respective materials; they result as a consequence of a unique heterogeneous arrangement of crystals and distinctive localized strains.High-strength steels have a specific structural role due to their ability to withstand very high mechanical stresses. Effective operation of such materials in actuator applications, non-destructive testing, and construction requires precise understanding of how external stimuli induce hysteretic changes in their magnetic and magnetostrictiveproperties.The objective of this dissertation is to characterize the properties of high-strength steel through developing hysteresis models to gain better understanding of the magnetostrictive, magnetic, and magnetoelastic changes, and through presenting vector magnetization measurements.Preisach modeling, conventionally used to characterize the magnetization of magnetic materials, is the basis of the models developed. The dissertation will present (i) a magnetostriction model for ferromagnetic materials exhibiting the Villari reversalphenomenon, (ii) a stress-dependent magnetization model manifesting two unique features which were rarely addressed in the literature, namely, the stress crossover and the bulge in the magnetization curves, (iii) a coupled-hysteron vector magnetizationmodel for sequential application of orthogonal fields, and (iv) rotational and angular-dependent magnetization measurements. The models aim at characterizing the microstructure of the samples used based on physical principles. The usage of the modelswill permit the description of the contribution of different domains and magnetization mechanisms to the magnetic and magentostrictive properties of high-strength steels.In addition to advancing the field of ferromagnetic hysteresis modeling, direct practical application to these efforts include (1) developing magnetic devices and sensors, (2) nondestructively evaluating stresses and fatigues, and (3) predicting the magneticsignature of steel ships subjected to navigation stresses and to the earth's magnetic field.
- All rights reserved
Notice to Authors
If you are the author of this work and you have any questions about the information on this page, please use the Contact form to get in touch with us.
| Thumbnail | Title | Date Uploaded | Visibility | Actions |
|---|---|---|---|---|
|
|
ElBidweihy_gwu_0075A_12131.pdf | 2018-01-16 | Open Access |
|