The objective of this work is to evaluate the stress concentration induced by longitudinal and transverse plain dents on steel pipelines under cyclic internal pressure. This work is within a study to propose a new methodology to assess the fatigue life of dented steel pipelines based on the current high cycle fatigue theory. This methodology employs stress concentration factors induced by plain dents, which are used to modify material S-N curves of metallic structures under high cycle fatigue loadings. The proposed assessment methodology was validated according to small-scale fatigue test results of steel pipe models with spherical dents under cyclic internal pressure. Here, stress concentration factors induced by longitudinal and transverse plain dents on steel pipes under internal pressure are obtained from a previously developed finite element model. Several finite element analyses are carried out in a parametric study. Analytical expressions are developed to estimate stress concentration factors for these two different dent geometries as function of pipe and dent geometric parameters. With the inclusion of these expressions, the proposed assessment methodology is improved and is now able to deal with three different plain dent geometries: spherical, longitudinal and transverse dents.

This content is only available via PDF.
You do not currently have access to this content.