摘要
疲劳裂纹扩展是导致连续管失效的主要原因。针对试验法研究连续管用钢裂纹扩展过程较为繁琐的问题,引入扩展有限元法进行分析。应用工程软件模拟CT110钢裂纹扩展过程,计算了不同应力比R下的裂纹扩展门槛值。研究结果表明:利用扩展有限元法模拟裂纹扩展得到的循环次数与试验法测得的循环次数比较接近,最大相对误差为17.67%,验证了用扩展有限元法模拟CT110钢裂纹扩展的可行性;随着应力比R的增大,其裂纹扩展门槛值减小,在R=0.50时,其门槛值仅为R=0.02时的0.63倍;基于Paris公式和分析结果得到的拟合公式,可对稳定扩展阶段内不同应力比下的疲劳裂纹扩展速率进行预测。研究结果对预测连续管使用寿命和保证现场安全作业有一定指导意义。
Fatigue crack propagation is the main cause of coiled tubing failure.To address the cumbersome testing study work of the crack propagation process of steel for coiled tubing,the extended finite element method(XFEM)was introduced for analysis.The engineering software was used to simulate the crack propagation process of the CT110 steel,and the crack propagation thresholds at different stress ratios R were calculated.The results show that the number of cycles obtained by the extended finite element method of crack propagation simulation was close to that measured by the testing method.The maximum relative error was 17.67%.The feasibility of simulating crack propagation of the CT110 steel by extended finite element method was thus verified.As the stress ratio R increases,the crack propagation threshold decreases.Under R=0.50,the threshold is only 0.63 times that of R=0.02.Based on the Paris formula and the fitting formula obtained by the analysis results,the fatigue crack propagation rate under different stress ratios in the stable expansion phase can be predicted.The study has certain guiding significance for predicting the service life of the coiled tubing and ensuring operation safety.
作者
石建刚
蒋振新
向冬梅
张洁
管锋
王振
Shi Jiangang;Jiang Zhenxin;Xiang Dongmei;Zhang Jie;Guan Feng;Wang Zhen(Engineering Technology Research Institute,Xinjiang Oilfield Company;School of Mechanical Engineering,Yangtze University)
出处
《石油机械》
北大核心
2019年第11期104-110,共7页
China Petroleum Machinery
基金
国家科技重大专项“中深层砂砾岩致密油优快钻井基础研究及应用”(2017ZX05070-005)
国家自然科学基金项目“含缺陷连续管残余承载能力评估与分析方法研究”(51604039)
湖北省技术创新重大专项“深部地热资源综合开发利用关键技术”(2016ACA181)
长江大学长江青年科技创新团队基金项目“油气高效钻井工具技术研究”(2016cqt01)
关键词
扩展有限元法
裂纹扩展门槛值
应力比
CT110钢
裂纹扩展速率
extended finite element method
crack propagation threshold value
stress ratio
CT110 steel
crack propagation rate
