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Modelling Magnetic Flux Leakage Signals From Dents
2008 7th International Pipeline Conference, Volume 2, 2008The Magnetic Flux Leakage (MFL) technique is sensitive both to pipe wall geometry and pipe wall strain, therefore MFL inspection tools have the potential to locate and characterize mechanical damage in pipelines. However, the combined influence of strain and geometry makes MFL signals from dents and gouges difficult to interpret for a number of reasons:
Lynann Clapham +4 more
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The Effects of Magnetizer Velocity on Magnetic Flux Leakage Signals
1993In many magnetic flux leakage applications, the nondestructive inspection constraints suggest the use of high inspection velocities. However, high inspection velocities can compromise the ability to detect and characterize defects. In general, velocity effects can be detected at speeds exceeding a few miles per hour [1].
Nestleroth, J. Bruce, Davis, Richard
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Understanding Magnetic Flux Leakage Signals From Gouges
2010 8th International Pipeline Conference, Volume 1, 2010The Magnetic Flux Leakage (MFL) technique is sensitive both to pipe wall geometry and pipe wall strain, therefore MFL inspection tools have the potential to locate and characterize mechanical damage in pipelines. The present work is the first stage of a study focused on developing an understanding of how MFL signals arise from pipeline gouges. A defect
Lynann Clapham +3 more
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A lift-off revision method for magnetic flux leakage measurement signal
2018 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2018Magnetic flux leakage (MFL) measurement technique is commonly used in oil and gas pipeline integrity detection and defect estimation. Subject to the measurement condition, the lift-off effect is unavoidable which will affect the strength and trend of MFL signal seriously.
Lisha Peng +3 more
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Understanding Magnetic Flux Leakage Signals From Dents
Volume 2: Integrity Management; Poster Session; Student Paper Competition, 2006The Magnetic Flux Leakage (MFL) technique is sensitive both to pipe wall geometry and pipe wall stresses, therefore MFL inspection tools have the potential to locate and characterize mechanical damage in pipelines. However, the combined influence of stress and geometry make MFL signal interpretation difficult for a number of reasons: 1) the MFL signal ...
Lynann Clapham +2 more
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A Practical Signal Progressing Method for Magnetic Flux Leakage Testing
Applied Mechanics and Materials, 2014The magnetic flux leakage (MFL) testing, as a modern nondestructive testing technology, requires fast and accurate signal progressing methods. A practical signal progressing method for MFL testing was presented, especially for tank floor MFL testing. According to the FFT result of the original signal, a difference amplifier and a low-pass filter were ...
Zhang Wei Ling +3 more
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Inverse mapping of magnetic flux leakage signal for defect characterization
NDT & E International, 2013Abstract Estimation of shape and size of metal loss defects in ferromagnetic plates/pipes from magnetic flux leakage (MFL) signals calls for the development of an inverse mapping system, which is very often non-linear and ill-posed. Identification of such systems needs regularization and modeling in multi-resolution framework.
Debmalya Mukherjee +2 more
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Finite element calculation of magnetic flux leakage detector signals
NDT International, 1987Abstract Two-dimensional finite element calculations are presented for anomalous leakage fluxes generated by nearside and farside grooves in pipes inspected by magnetic flux leakage anomaly detectors. Flux density ( B ) is shown to be a nonlinear function of penetration, increasing rapidly for deep grooves.
D.L. Atherton, M.G. Daly
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Calculations of the effects of anisotropy on magnetic flux leakage detector signals
IEEE Transactions on Magnetics, 1996Oil and gas pipelines are inspected for corrosion using magnetic flux leakage (MFL) inspection tools. It has been found that varying line pressure, bending or residual stresses cause changes in the MFL signals. Changes in the amplitude are thought to be due to stress-induced changes in the bulk magnetic anisotropy or preferred easy axis of the steel ...
S. Leonard, D.L. Atherton
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Numerical Prediction of Signal for Magnetic Flux Leakage Benchmark Task
AIP Conference Proceedings, 2003Numerical results predicted by the finite element method based code are presented. The nonlinear magnetic time‐dependent benchmark problem proposed by the World Federation of Nondestructive Evaluation Centers, involves numerical prediction of normal (radial) component of the leaked field in the vicinity of two practically rectangular notches machined ...
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