Residual Leakage Field Modeling
Residual leakage fields are set up around defects in ferromagnetic materials after the active source of d. c. excitation has been removed . Defect detection and characterization then occur by using any flux density sensitive transducer such as magnetic particles, magnetic tape, a moving coil or a Hall element . Past analytical attempts at modeling these phenomena have largely been based on representing simple defect shapes by an equivalent dipole or magnetic charge distribution . In order to examine the effects of realistic defect shapes and material B/H properties, finite element analysis techniques have been used [4,5] to model both active and residual leakage field effects. This paper discusses alternative B/H representations and their impact on the numerical modeling of defect residual leakage fields.
KeywordsPermeability Resi Cote
Unable to display preview. Download preview PDF.
- 2.W. Lord and D. J. Oswald, Leakage Field Methods of Defect Detection, Int. J. NDT, 4, 249 (1972).Google Scholar
- 3.N. N. Zatsepin and V. E. Shcherbinin, Calculation of the Magnetostatic Field of Surface Defects, Defektoskopiya, 5, 50 (1966).Google Scholar
- 4.W. Lord, J. M. Bridges, W. Yen and R. Palanisamy, “Residual and Active Leakage Fields Around Defects in Ferromagnetic Material,” Mat. Eval., 36, 47 (1978).Google Scholar
- 6.Yu-shi Sun, “On the Calculating Models of Permanent Magnets,” Acta Electronica, 10, 86 (1982).Google Scholar
- 7.S. R. Satish, “Finite Element Modeling of Residual Magnetic Phenomena,” Master of Science Thesis, Dept. of Elec. Engr., Colorado State University, Fall (1980).Google Scholar
- 8.D. J. Binns, M. A. Jabbar and W. R. Barnard, “Computation of the Magnetic Field of Permanent Magnets in Iron Cores,” Proc. IEE, 122, 1377 (1975).Google Scholar