Probabilistic analysis of corroded pipeline under localizedcorrosion defects based on the intelligent inspection tool

Type : Publication
Auteur(s) :  Zelmati Djamel, BOULEDROUA Omar, HAFSI Zahreddine, Milos B. Djukic
Année :  2020
Domaine : Génie mécanique
Revue : Engineering Failure Analysis
Résumé en PDF :  (résumé en pdf)
Fulltext en PDF :  (.pdf)
Mots clés :  Reliability, corrosion, Inspection, FEM

Résumé : 

A methodology is developed in this paper to estimate the time-dependent reliability of a pipeline in Algeria, which is in exploitation from 1981 and with internal and external localized corrosiondefects detected in 2009. A probabilistic approach was applied to a pipeline made of API 5L X60steel for the long-distance transportation of natural gas (55 km), which crossing several geographical reliefs in different country areas. The analysis was carried out by taking into consideration the potential stochastic variables altering drastically the reliability of the pipeline, i.e.,dimensions of the localized corrosion defects, their locations, and distribution, and the corrosionrate. The correlations between the pipeline spatial corrosion defects distribution and their dimensions, obtained by using an intelligent inspection tool are used to analyze the actual inservice corrosion attack rate and for enhancement of the accuracy of the reliability assessment.The failure scenario was considered as the moment when the pipeline operating pressure exceedsthe failure pressure defined analytically in accordance with different commonly used standards.The assessment of the reliability index of the corroded pipeline subjected to internal pressure andthe failure probability was done. The detailed reliability analysis is carried out by using thesecond order reliability method (SORM) for the basic random variables with different probabilistic density within a nonlinear limit state function. The latter is based on the limit analysis ofthe failure pressure model for different standards and the numerical analysis using the finiteelement method and ANSYS software.