Dents in buried pipelines occur due to a number of potential causes; the pipe resting on rock, third party machinery strike, rock strikes during backfilling, amongst others. The long-term integrity of a dented pipeline segment is a complex function of a variety of parameters, including pipe geom-etry, indenter shape, dent depth, indenter support, pressure history at and following indentation. In order to estimate the safe remaining operational life of a dented pipeline, all of these factors must be accounted for in the analysis. In order to characterize the severity of a dent on the integrity ...
Dents in buried pipelines occur due to a number of potential causes; the pipe resting on rock, third party machinery strike, rock strikes during backfilling, amongst others. The long-term integrity of a dented pipeline segment is a complex function of a variety of parameters, including pipe geom-etry, indenter shape, dent depth, indenter support, pressure history at and following indentation. In order to estimate the safe remaining operational life of a dented pipeline, all of these factors must be accounted for in the analysis. In order to characterize the severity of a dent on the integrity of a pipeline system, there must first be sufficient information available describing the behavior of the deformed pipe when subjected to typical loading scenarios. While there have been a number of full scale test programs that have been used to develop general trends in the behavior of dented pipe subjected to cyclic pressure loads, these programs have not produced sufficiently detailed information in terms of material properties, dent and pipe response to pressure loading, to form the basis of a severity assessment criterion. The objective of the current project was to generate full scale dent fatigue test data necessary to develop, validate and/or evaluate dent models capable of predicting cyclic internal pressure related failures of a pipe segment. The data generated included: detailed material characterization of the pipes involved in full scale test program, dent profile measurement, dent strains during dent for-mation and cyclic loading and recording of the details of fatigue crack location and orientation within a dent. The test program developed detailed experimental data for: - Unrestrained plain dents, - Restrained plain dents, - Dents interacting with welds and - Dents interacting with metal loss.