Propagation Characteristics of Circumferential Surface Cracks in Long Distance Oil and Gas Pipelines
Long distance oil and gas pipelines often fail under complex loads,and even leak due to cracks.In order to study the propagation characteristics of circumferential surface cracks in long distance oil and gas pipe-lines,taking a long distance oil and gas pipeline containing surface cracks as the research object,the contour inte-gral method was used to calculate the J-integral of the surface crack tip of the long distance oil and gas pipeline.The extended finite element method(XFEM)was used to simulate the propagation process of circumferential sur-face crack.Moreover,the variation characteristics of the crack tip opening displacement(CTOD)were analyzed.The analysis results show that axial load contributes more to the propagation of circumferential surface cracks com-pared to internal pressure.Under the same load,the propagation rate of internal cracks in long distance oil and gas pipelines is greater than that of external cracks.In the process of crack propagation,the initial crack first propa-gates along the circumferential direction and evolves into an elliptical crack.When the length to depth ratio of crack reaches a certain value,the crack rapidly propagates in the direction perpendicular to the tip of the elliptical crack,and the propagation rate at this stage is much higher than that at the stage of forming the elliptical crack.The study results provide reference for further analysis of cracks and fractures in long distance oil and gas pipelines.
long distance oil and gas pipelinecircumferential surface crackJ-integralcrack propagationCTOD
万方数据
维普
