Fatigue life assessment of damaged pipelines under cyclic internal pressure: Pipelines with longitudinal and transverse plain dents

•A methodology for fatigue life assessment of dented steel pipes is refined.•The methodology concerns high cycle fatigue and uses stress concentration factors.•Stress concentration factors of longitudinal and transverse dents are evaluated.•Expressions for stress concentration factors due to these dent shapes are obtained.•The methodology can deal with spherical, longitudinal and transverse dent shapes.

This ongoing work aims to refine a methodology for fatigue life assessment of dented steel pipelines under cyclic internal pressure. A numerical model is developed to obtain stress concentration factors on dented pipes under internal pressure. A comprehensive parametric study is accomplished and analytical expressions to estimate stress concentration factors for spherical, longitudinal and transverse plain dents as a function of selected geometric parameters are developed. The proposed fatigue assessment methodology is validated from fatigue test results. Here, the analytical expressions are refined to include a more complete dent geometry definition for transverse, longitudinal and short longitudinal dents.