Finite element modeling of girth welded pipe with multiple defects

Due to the expansion of the pipeline network in the transportation of petroleum and its derivatives, it has been essential to develop studies to evaluate and guarantee the safety condition, as well as the reliability of such facilities. Welded pipelines have been widely used, and they are susceptible to corrosion. Since the heating at the welded point may leads to structural and compositional modifications in the material, which may generate corrosion. The present paper presents a nonlinear computational model burst pressure assessment in API X70 girth welded pipes with multiple defects, created by corrosion, which may represent a great risk for gases and fuel leakage during transportation. In this study, the computational model has been developed by the finite element method considering the isotropic hardening model and contact conditions between different materials involved in the analysis, with corrosion simulated as a rectangular defect. The corroded pipe and the efficiency of the computational model have been analyzed by varying the width of the heat-affected zone (HAZ), and the depth of single and multiple defects. The results obtained by using the finite element analysis have been compared with the semi-empirical methods and literature results. The computational model developed by the present work has presented satisfactory results.