| Autor: |
Heida, Ciska, Regtien, Paul |
| Jazyk: |
angličtina |
| Rok vydání: |
2004 |
| Zdroj: |
STARTPAGE=321;ENDPAGE=326;TITLE=10th International IMEKO TC7 Symposium |
| Popis: |
Non-destructive testing techniques are gen-erally used for the evaluation of material properties and the detection of defects in pipelines. Especially, the measure-ment 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 mate-rial 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 perme-ability of the pipeline material in the MFL set up proved that flux leakage signals could be predicted accurately for sev-eral defects by model simulation. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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