Federal regulatory standards require repair of dents with depths exceeding 6% of the pipeline diameter and for dents exhibiting signs of mechanical damage interacting with secondary features. However, leaks have been known to occur at dents with depths less than 3% of the pipe diameter and dents interacting with secondary features have been known to survive in service for extended periods of time.
With the improvement in ILI technologies, there is an increase in detection of shallow dents and shallow dents interacting with corrosion features and a large population of these features exist...
With the improvement in ILI technologies, there is an increase in detection of shallow dents and shallow dents interacting with corrosion features and a large population of these features exist currently in operating pipelines. Previous full-scale dent fatigue testing (MD 4-2 & others) did not consider shallow restrained dents. The objective of the current project is to develop understanding of shallow dents and shallow dents interacting with shallow corrosion features.
Full scale dent fatigue tests were carried out to generate data on shallow dents and validate finite element (FE) models. The fatigue test data was also generated to evaluate the effect of metal loss on shallow dent fatigue life.