Probabilistic evaluation of EMAR signals to evaluate pipe wall thickness and its application to pipe wall thinning management

In this study an approach is proposed to probabilistically evaluate wall thickness and the probability of pipe failure when subjected to wall thinning based on the results of periodic non-destructive evaluations. Electromagnetic acoustic resonance (EMAR) has been adopted as a specific non-destructive method to evaluate pipe wall thickness. A probabilistic model correlating the true and evaluated thicknesses was proposed on the basis of the results of laboratory experiments to measure 38 artificially corroded carbon steel plates. A Bayesian approach was proposed to estimate the probability of true thickness and the probability of failure from results of multiple non-destructive evaluations at certain time intervals. The approach was applied to the analyses of several virtual periodic EMAR evaluations of pipe wall thickness that gradually became thinner, whose results demonstrate that the proposed approach is effective regardless of the variability of corrosion rates.