Long-termpitting corrosion depth, once initiated, is of interest for predicting remaining offshore pipeline and containment infrastructure service life. Failure could lead to substantial economic and environmental consequences. The present paper outlines a statistical extreme value analysis based on long term pitting measurements, including the effect of propagation of ‘maximum’ observed depth, based on previously reported field trials using coupons, providing variability of pit depth and its changing behaviour with time. Probabilistic failure assessment includes parameters related to corrosion, pipeline dimension and liquid flow, treated as random variables. Influence of weld heat affected zone is considered critical in the analysis. For typical case example, effect of random variable variabilitywas assessed by means of sensitivity study. Results showlong-term reliability estimate, including high influence of pit diameter followed by corrosion parameters on the probability of failure.
From Materials to Structures: Advancement through Innovation. 22nd Australasian Conference on the Mechanics of Structures and Materials (ACMSM2012) (Sydney, NSW 11-14 December, 2012) p. 947-952