Stress effects and magnetic flux leakage induced by defects in pipelines

Clapham, L.; Atherton, D. L.
May 2000
AIP Conference Proceedings;2000, Vol. 509 Issue 1, p1581
Academic Journal
The operating pressure in oil and gas pipelines can produce hoop stress as high as 70% of yield stress. Superimposed on this are bending stresses and residual stresses from pipe forming operations. Furthermore defects cause local changes in both the magnitude and direction of pipe wall flux density and stress. The combined stresses affect magnetic properties, such as anisotropy, and hence alter magnetic flux leakage signals from magnetic flux leakage (MFL) inspection tools used to detect and size defects. These factors need to be mitigated and taken into consideration when interpreting MFL signals to size defects. This paper describes research undertaken to elucidate the effects of these complex interactions. Results from magnetic Barkhausen noise, neutron diffraction and flux leakage monitoring of local, bulk surface and “at depth” stresses are presented. Tensor measurements of magnetic properties and stress-induced variations are described and discussed. © 2000 American Institute of Physics.


Related Articles

  • Effect of order of stress and field application on the measured flux density in 1% Mn pipeline steel. Atherton, David L.; Sudersena Rao, T. // Journal of Applied Physics;10/1/1987, Vol. 62 Issue 7, p2914 

    Presents a study that examined the effects of the order of stress and field application on the measured flux density in pipeline steel. Background on the interaction between stress and magnetization; Investigation of the effect of tension on the magnetization of a material with positive...

  • Impact of viscous flux flow on the stress in long rectangular slab superconductors. Yang, Yong; Xiao, Li-Ye; Li, Xiao-Hang // Journal of Applied Physics;Jan2010, Vol. 107 Issue 2, p023910 

    We have attempted to resolve the influence of the rate (dBa/dt), at which an external magnetic field Ba is swept down, on the tensile stress in bulk type-II superconductors. The effect of viscous flux velocity (Ï…0) on the stress is discussed for two magnetization processes: the decreasing...

  • Voltage from mechanical stress in type-II superconductors: Depinning of the magnetic flux by moving dislocations. Albert, Jaroslav; Chudnovsky, E. M. // Applied Physics Letters;7/28/2008, Vol. 93 Issue 4, p042503 

    Mechanical stress causes motion of defects in solids. We show that in a type-II superconductor, a moving dislocation generates a pattern of current that exerts a depinning force on the surrounding vortex lattice. The concentration of dislocations and the mechanical stress needed to produce...

  • Transfer matrix solutions to axisymmetric and non-axisymmetric consolidation of multilayered soils. Ai, Zhi; Wang, Quan; Han, Jie // Acta Mechanica;Apr2010, Vol. 211 Issue 1/2, p155 

    Transfer matrix solutions are presented in this paper to study the axisymmetric and non-axisymmetric consolidation of a multilayered soil system under an arbitrary loading. Starting with the governing equations for consolidation problems of saturated soils, the relationship of displacements,...

  • Magnetic and Thermal Properties of HTS Bulk Magnet in the Pulsed-Field Magnetizing Process. Oka, T.; Ishiduka, D.; Ogawa, J.; Fukui, S.; Sato, T.; Yokoyama, K.; Murakami, A. // Journal of Superconductivity & Novel Magnetism;Apr2013, Vol. 26 Issue 4, p1301 

    In order to enhance the field-trapping ability of high T superconducting melt-textured bulk materials which act as quasi-permanent magnets when they capture the external magnetic fields, it is important to enhance the mechanical toughness of the materials to stand the stress induced by the...

  • INFLUENCE OF STRESS-STRAIN STATE OF SHELL STRUCTURE ON MAGNETIC CHARACTERISTICS. Khajbullina, L. V.; Vasilev, V. V. // Oil & Gas Business;2013, Issue 5, p376 

    In this paper, the influence of stress - strain state of the shell structure of steel 20 on the strength of the constant magnetic field by the metal magnetic memory method (MMM). The MMM method - a method of non-destructive testing, based on recording and analyzing the distribution of intrinsic...

  • The Multidisciplinary Design of Rotor Geometry in a Permanent Magnet Traction Motor. Lindh, P.; Heikkinen, J.; Kurvinen, E.; Pyrhönen, J.; Naumanen, V. // International Review of Electrical Engineering;Sep/Oct2013, Vol. 8 Issue 5, p1437 

    The paper addresses the embedding parameters of permanent magnets and their effects on the performance of an interior permanent magnet radial-flux machine. Special attention is paid to the embedding depth of the permanent magnets and the design of the magnet pockets in the rotor laminations to...

  • Evaluation of Stress Loaded Steel Samples Using Selected Electromagnetic Methods. Chady, T. // AIP Conference Proceedings;2004, Vol. 700 Issue 1, p1296 

    In this paper the magnetic leakage flux and eddy current method were used to evaluate changes of materials’ properties caused by stress. Seven samples made of ferromagnetic material with different level of applied stress were prepared. First, the leakage magnetic fields were measured by...

  • Measurement of Local Strain Distribution of Austenitic Stainless Steels by Using Magnetic Sensors. Tsuchida, Y.; Oka, M.; Yakushiji, T.; Enokizono, M. // AIP Conference Proceedings;2006, Vol. 820 Issue 1, p1261 

    Austenitic stainless steel is classified as a nonmagnetic material. However application of stress transforms the plastic part of it into a martensitic crystal structure and it takes on magnetization. Strain evaluation can be performed by measuring the leakage magnetic flux from the remanent...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics