Burst Pressure Prediction of Dent-Cracked Steel Pipeline Subjected to Tensile Force

The dent-crack defect is considered to be one of the fatal defects in a pipeline system. The pipelines often face the presence of external loadings like tension during service life. In this study, the burst pressure of an X70 steel pipeline having a dent-crack defect has been analyzed using the Extended Finite Element Method (XFEM) when the pipe was subject to an axial tensile force. The Maximum Principal Strain (Maxpe) criterion was considered for crack initiation, and the Fracture Energy criterion was used for damage evolution. The dent-cracked pipes were modeled considering different crack sizes but one dent size. The pipes were pressurized internally up to the failure subjecting to a specified axial tensile force. The study reveals that the crack size and axial force evidently reduce the burst pressure of the pipe, where crack depth plays the leading role in reducing the pressure compared to the crack length. Finally, four interaction curves between normalized burst pressure and normalized crack area have been developed. The interaction curves might be the useful tools to predict the remaining strength of the defected pipe in terms of internal pressure.