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Surface open corrosive wall thinning effects

: Pérez Blanco, Isabel Christina; Dobmann, Gerd

Fulltext urn:nbn:de:0011-n-2671730 (757 KByte PDF)
MD5 Fingerprint: 22c504c38a4bbf89e49443afa5ceb8e8
Created on: 29.11.2013

Akhras, George (Ed.) ; Canadian Institute for NDE -CINDE-, Hamilton; Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren -IZFP-, Saarbrücken:
International Workshop on Smart Materials, Structures & SHM 2013 : NDT in Canada 2013 Conference & NDT for the Energy Industry, October 7-10, 2013 Calgary, Alberta, CANADA
Hamilton: Canadian Institute for NDE, 2013
International Workshop on Smart Materials & Structures, SHM <2013, Calgary>
Conference Paper, Electronic Publication
Fraunhofer IZFP ()
magnetic flux leakage; defects; simulation; corrosion; pipeline

Pipelines are valuable and essential components in oil and gas industry as means of transport. However, as corrosion attack cannot be avoided there is a high risk to have accidents due to the operating conditions. Wall thinning mainly caused as a result of corrosion can provoke fatal disasters, especially for gas pipes where the corrosion effects are superimposed by high-cycle fatigue loading due to the cyclic pumping of the compressor stations. For this reason in pipeline inspection it is not enough to know where defective areas are located, the defects should be sized as accurate as possible in order to evaluate the risk for failure by fracture mechanical approaches. Magnetic Flux Leakage (MFL) is a widely used technique by intelligent pigs (Pipeline Inspection Gauges). However, the accuracy of defect sizing is still questionable and needs optimization. Furthermore, a limited knowledge about the amount of operating parameters, i.e. mainly the inner pressure and its changes, temperature variations and the use of an inaccurate analytical model for sizing influence the risk for failure and do not allow the MFL technique to be more effective. In order to reconstruct the shape and dimensions of corrosion defects from MFL signals, it is helpful to use a 2D approximation to save expensive computational costs of simulation in 3D. In the here proposed work we demonstrate that 2D simulation can be accurate enough to interpret MFL signals obtained from corrosion defects and subsequently allow the defect reconstruction. The selection of an ideal mesh resolution and the boundary conditions are two essential parameters to guarantee accurate numerical results. MFL signals are simulated in 3D- and 2D-approximations in a steel plate with three different half-spherical artificial defects. Simulation results are discussed and compared with experimental results.