Impact of dependent stochastic defect growth on system reliability of corroding pipelines

This paper presents a methodology to evaluate the time-dependent system reliability of corroding pipeline segment containing multiple spatially-correlated active corrosion defects. The pipeline segment is modeled as a series system considering three distinctive failure modes at a given corrosion defect. The defect depth growth is modeled using gamma distributed time-independent growth model and gamma process-based growth model; the spatial correlation between the depth growths of different defects is characterized using the copula function. Numerical examples are used to investigate the impact of the spatially dependent (or correlated) defect depth growth characteristics, the uncertainties in the initial defect sizes (i.e. depth and length) and the model error associated with the burst pressure model on the system failure probability. (C) 2012 Elsevier Ltd. All rights reserved.