Non-probabilistic time-dependent reliability analysis for suspended pipeline with corrosion defects based on interval model

When a suspended pipeline has corrosion defects, its failure is due to the combination of being suspended and corrosion. Compared with the probability reliability method, the non-probabilistic interval model that considers the factors to be independent only needs a small amount of data to obtain the variation bounds, and it is more economical for reliability analysis. Given that time-dependent reliability analysis based on a random process requires a large amount of data, an interval model for the suspended pipeline with corrosion defects based on the convex model method is proposed. First, based on the extreme suspended length's formula of pipeline through numerical simulation, this paper proposes a model that combines the time-accumulation effects of resistance and corrosion growth with time. Second, the time-dependent limit state equation is established considering the corrosion-defective suspended pipeline for the assessment of practical pipeline engineering. Finally, the non-probabilistic time-dependent reliability model is put forward for the decay characteristics of the resistance under the influence of multi-factors, which can be used as the effective complement of time-dependent reliability analysis based on random process theory. By combining numerical examples, the effectiveness of the present method is demonstrated. Thus, this paper provides a theoretical basis for the maintenance of buried oil and gas pipelines as well as the integrity management of pipelines. More importantly, an assessment standard for a suspended pipeline with corrosion defects is established that can work with poor information. It is of considerable significance for the safe operation of pipelines. (C) 2019 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.