Shape of specimen impact on interaction between earth and eigenmagnetic fields during the tension test
Many materials that could cause real threat of the catastrophe caused by fatigue wear, exceeding stress limits or emerging of plastic deformation have magnetic properties that could affect the local magnetic field. As far as quite well known and applicable are active magnetic methods for condition monitoring, passive techniques which bases only on the existence of natural magnetic field of Earth still need researches and improvement. It is obvious that every physical object, which enclose in magnetosphere interacts for Earth magnetic field, follows to special physics lows. Such objects could focus or deflect the magnetic lines around its matter. Own magnetic field of object: H = -∇(w) where ‘w’-magnetic potential, is a function of magnetization gradient: w = w (div M). So, the measure magnetic field of object depends on object magnetization and distribution of this volume in medium (space). Considering magnetoelastic effects (Villary Effect, magnetostriction), the additional stress causes transformation to magnetic state of material which reflect to magnetization of object. This magnetization depends from many factors. In this paper shape of specimen impact on interaction between earth and eigenmagnetic fields during the tension test is considered. Due to simply model analysis, the laboratory experiment was proposed and performed. Controlling plastic and elastic range of specimen deformation, there was proved that exist relation between stress and magnetization degree which is strict connected with the deformation and effort state. Magnetic anomalies which are generated due to magneto-mechanic effect were collected by the three axial fluxgate magnetometer what allows exhibition of the own magnetic field component, which is least sensitive for the disturbances which are present in the real world. In the paper, it was proved that exist dependence between the stress and magnetization degree but it is very complex because additionally it depends on magnetization, history of magnetization, deformation and the shape of object. Also, the place of measurement relative to the shape of object has the influence on results. Further directions and comments about development of the techniques for technical state objects evaluation which could make use with the presented effects, were included.
KeywordsMagnetic Anomaly Tension Test Magnetic Field Component Elastic Range Magnetic Method
Unable to display preview. Download preview PDF.
- 2.R.L. Hu, A.K. Soh, G.P. Zheng, Y. Ni (2005) Micromagnetic modeling studies on the effects of stress on magnetization reversal and dynamic hysteresis, J. Magn. Magn. MaterGoogle Scholar
- 3.Janusz ŁUKASZEWICZ, Zbigniew ŁAPIŃSKI, (2001) Określanie parametrow akustycznych materiałow konstrukcyjnych; KBN, WITU ZielonkaGoogle Scholar
- 4.Sprawozdanie z pracy nt. „Przeprowadzenie badań zjawiska emisji akustycznej towarzyszącej rozciąganiu probek stalowych”; IPPT 2001.Google Scholar
- 5.Sprawozdanie z pracy nt. (2001) Badanie zjawiska emisji akustycznej w trakcie prob rozciągania przygotowanych probek ze stali 30HGS”; PW Wydział InŜynierii MateriałowejGoogle Scholar
- 6.Dubov A.A. (2002) Diagnostyka wytrzymałości oprzyrządowania i konstrukcji z wykorzystaniem Magnetycznej Pamięci Metalu; Dozor Techniczny 2, 2002, 14 – 18 i Dozor Techniczny 1, 37-40Google Scholar
- 7.Gontarz S., Radkowski S. (2007) Own magnetic field as a source of diagnostic information. VI International Technical Systems Degradation Seminar 2009, Liptowski MikulaszGoogle Scholar
- 8.Gontarz Sz., Radkowski S. (2008) Use of passive magnetic method for condition monitoring. Proceedings of the 3rd World Congress on Engineering Asset Management and Intelligent Maintenance Systems Conference (WCEAM-IMS 2008), 27÷30 October, 2008, Beijing, China, str. 543÷552 (CD-ROM)Google Scholar