Lifetime assessment of a pipeline with longitudinal crack subjected to cyclic loading and local corrosion

摘要

Methods are presented for the deterministic and the probabilistic assessment of longevityrnof a pipeline with a longitudinal crack in the form of a semi-elliptical flaw on the inner surfacernof the pipe subjected to cyclic loading and local corrosion. It is an extension and generalizationrnof the methods described in (Malyukova & Timashev 1998, 1999). In this NLFM setting thernfollowing cases are considered: local corrosion is concentrated inside the crack, and is uniform orrnorthotropic (along the longitudinal x and hoop y axes). The influence of the random character of thernmost important parameters, including the velocity of internal corrosion is investigated. For this, thernmaximum entropy method in conjunction with the Monte Carlo simulation method is used. As a result,rnthe least predetermined PDF of pipeline remaining lifetime is constructed and its first fourrnmoments are calculated.