Numerical Analysis of Pipeline Dent Damage Based on Uncoupled Fracture Model

Abstract Throughout the service life of oil and gas pipelines, the occurrence of dents represents a significant threat to their safe operation. To accurately evaluate the extent of damage induced by dents, finite element analysis (FEA) was employed to systematically investigate the affected regions of the pipeline and the associated numerical variations. A numerical simulation model for pipeline denting was developed, and damage was quantified using an uncoupled fracture model implemented through the ABAQUS/VUMAT subroutine. A mesh sensitivity analysis was also conducted to ensure the accuracy of the FEA. The results demonstrate that the developed FEA model effectively captures the variation in damage indicator (D) relative to dent depth under internal pressure. The optimal mesh size for the damage analysis is found to be 2 mm. As dent depth increases, the location of maximum damage shifts from the central area of the inner pipe surface toward the periphery. Larger internal pressures and smaller dent radii result in more severe damage. When the dent depth is either less than 5% or greater than 10% of the outer diameter (OD), the rate of D growth increases significantly. This is particularly pronounced when the dent depth exceeds 10%OD. The damage growth rate increases with the rise in internal pressure and the reduction in dent radius. This paper provides critical data and a theoretical foundation for evaluating dent-induced damage in pipelines.