ESTIMATION OF PERMEABILITY FOR MAGNETIC FLUX LEAKAGE MODELLING |
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| Ciska Heida, Paul L. Regtien |
- Abstract:
- Non-destructive testing techniques are generally used for the evaluation of material properties and the detection of defects in pipelines. Especially, the measurement of magnetic flux leakage (MFL) is one of the most used methods for in-service monitoring of corrosion in buried oil and gas pipelines. However, for the geometrical reconstruction of defects in a pipeline from measured signals (the inverse problem), the magnetic properties of the material need to be known accurately. Due to the pipe geometry and wall thickness measurement of the bulk properties is complicated. In particular, the permeability of ferromagnetic steels shows a non-linear and hysteretic behaviour. Current research is focussed on the measurement and simulation of the permeability of pipeline material. The magnetic properties of a small ferromagnetic test sample is first investigated using a transformer set up in order to find a correct fitting equation for the non-linear permeability as a function of the magnetic flux density. This equation is then used for model simulations of a MFL test set up. Refitting the parameters of the permeability equation to the permeability of the pipeline material in the MFL set up proved that flux leakage signals could be predicted accurately for several defects by model simulation.
- Keywords:
- permeability, magnetic flux leakage (MFL), finite element modelling
- Download:
- IMEKO-TC7-2004-105.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC7
- Event name:
- TC7 Symposium 2004
- Title:
10th Symposium on Advances of Measurement Science
- Place:
- St. Petersburg, RUSSIA
- Time:
- 30 June 2004 - 02 July 2004