Analytical prediction of failure pressure for pipeline with long corrosion defect

Abstract

Corrosion assessment analysis and failure pressure prediction of pipelines with corrosion defects are essential in the integrity assessment of transmission pipelines. A series of semi-empirical corrosion criteria have been proposed to predict the failure pressure. However, the influence of defect width on the failure pressure is not considered in theory. In this paper, an improved model for the end-capped pipe with infinite length defect is developed based on plastic instability theory and finite strain theory, by considering the corrosion depth and width. The constitutive behavior of the pipe steel material is characterized by a power-law hardening stress-strain curve. Thus, two theoretical solutions are developed based on von Mises and Tresca criteria, by considering the strain hardening effect. Finite element analysis and sixty-one full-scale burst tests for each pipe with a single longitudinal defect are performed to validate and define the application scope of these new solutions. The results show that the proposed model based on von Mises criterion makes the best prediction and is suitable for the cases of defect length longer than 20Dt.