长输油气管道环向表面裂纹扩展特性研究  

Propagation Characteristics of Circumferential Surface Cracks in Long Distance Oil and Gas Pipelines

作　　者：曹敏 汤历平[1] 王锡军 王佳 肖开阳 孙莹 初炳军 Cao Min;Tang Liping;Wang Xijun;Wang Jia;Xiao Kaiyang;Sun Ying;Chu Bingjun(School of Mechanical Engineering,Southwest Petroleum University;Ground Gathering Engineering Company,PetroChina Qinghai Oilfield Company;Training Center,PetroChina Qinghai Oilfield Company)

机构地区：[1]西南石油大学机电工程学院,四川省成都市610500 [2]中国石油青海油田地面集输工程公司 [3]青海油田培训中心

出　　处：《石油机械》2024年第12期125-133,共9页China Petroleum Machinery

基　　金：全国总工会补助项目“油气管道腐蚀机理及防腐措施研究”(2016-2901)。

摘　　要：长输油气管道在复杂载荷作用下失效问题频发,甚至出现因裂纹而泄漏等现象。为研究长输油气管道中环向表面裂纹的扩展特性,以含表面裂纹的长输油气管道为研究对象,基于围线积分法计算了长输油气管道表面裂纹尖端的J积分,基于扩展有限元法(XFEM)模拟了环向表面裂纹的扩展过程,同时分析了裂纹尖端张开位移(CTOD)的变化特性。分析结果表明:相较于内压,轴向载荷对环向表面裂纹的扩展有更大的影响;在相同载荷下,长输油气管道中内裂纹的扩展速率比外裂纹的扩展速率大;在裂纹扩展过程中,初始裂纹首先沿环向扩展演变成椭圆形裂纹,当裂纹长深比达到一定值后,裂纹沿与椭圆形裂纹尖端垂直的方向快速扩展,此阶段扩展速率远大于形成椭圆形裂纹的阶段。研究结果可为分析长输油气管道裂纹与断裂提供参考。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 pipelines,taking a long distance oil and gas pipeline containing surface cracks as the research object,the contour integral 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 surface 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 compared 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 propagates 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.

关 键 词：长输油气管道 环向表面裂纹 J积分 裂纹扩展 裂纹尖端张开位移 

分 类 号：TE832[石油与天然气工程—油气储运工程]