WELD DEFECT ANALYSIS IN A PRESSURE PIPELINES USING 2D AXISYMMETRIC FINITE ELEMENT ANALYSIS IN ABAQUS

Weld defects challenge the structural integrity of internally loaded pipelines used for pressurized oil and gas transportation. The butt weld was examined in ABAQUS software considering the 2D axisymmetric finite element analysis (FEA) modeling technique assuming identical behavior along the circumferential direction. The principal objectives were to investigate the stress concentration behavior of butt weld, to conduct mesh convergence analysis to ensure FEA accuracy, such as optimal mesh element type and size, to analyze the stress concentration effect with weld defect depth, and to determine the stress distribution along the defect edge. The methodology included modeling the pipeline system in three components: left pipe, butt-weld bead, and right pipe. The mesh convergence analysis and parametric analysis on weld geometry showed that quadrilateral quadratic elements with a 0.1 mm mesh size provide stabilized results at around 232.637 MPa with minimal variation. Parametric analysis depicts the direct correlation between stress concentration and weld defect depth. It showed that at deeper defect depths, higher stress concentrations can cause potential failure and crack initiation. This study concludes the significance of carefully selecting mesh element types and sizes. Quadrilateral quadratic elements capture detailed stress distribution in the curved geometries. The stress produced in weld defects is lower than the material’s strengths and is within safe limits. This research highlights the importance of managing the integrity and safety assessment of pipelines.