Pipelines are one of the primary modes to transport hydrocarbon products throughout the world. A majority of these pipeline systems are buried, which are susceptible to ground movement that imposes axial forces and bending moments on the pipeline section. As a result of these forces and moments pipeline section may experience localized deformation that result in wrinkling, buckling and other damage mechanisms. This may impair the pipeline mechanical performance with respect to local stress concentration, lower strength and reduced fatigue life. Cyclic operational loads or ground movement events may result in strain reversals within the pipeline section that may lead to fracture through low cycle fatigue process.
In this study, physical testing was conducted to examine the strength and fatigue life performance characteristics of hot rolled steel (44-W). The effects of the test sample bend radius, wall thickness and imposed displacement stroke range on fatigue performance were examined. The data was used to develop and refine continuum finite element modeling procedures that can be used to assess the influence of pipeline damage on fatigue life in a more detailed numerical simulation framework.