含缺陷海底管道横向屈曲行为的数值模拟

海底管道在制造、敷设及运行过程中不可避免地会产生局部或整体初始几何缺陷。为了研究海床表面敷设的含缺陷管道横向屈曲行为,建立了含5种初始几何缺陷管道的横向热屈曲非线性数值计算模型,并验证了有限元模型的准确性,重点分析了缺陷类型、不直度对管道横向屈曲行为的影响。结果表明:横向屈曲变形是海底管道安全运行的一个重要威胁,不直度越大,临界温升越小,管道越容易发生横向热屈曲;在不直度相同的条件下,管道初始几何缺陷中心处曲率绝对值越小,抗横向热屈曲能力越强。基于无量纲分析法,提出了适用于含多种通用的初始几何缺陷海底管道的临界温升计算一般表达式,以期为海底管道抗热屈曲工程设计提供参考。(图10,表1,参23)

Numerical simulation on transverse buckling behavior of submarine pipeline with defects

Local or overall initial geometric defects may inevitably occur in the manufacturing,laying and operation of submarine pipelines.To study the transverse buckling behavior of pipelines with defects laid on the seabed surface,the nonlinear numerical model for transverse thermal buckling of pipelines with 5 kinds of initial geometric defects was established firstly,and then the accuracy of the finite element model was verified.The influence of defect types and nonstraightness on the transverse buckling behavior of pipelines was emphatically analyzed.The results show that the transverse buckling deformation poses a great threat to the safe operation of submarine pipelines.The greater the nonstraightness,the smaller the critical temperature rise will be,and the more prone the pipelines will be to the transverse thermal buckling.Under the condition of the same nonstraightness,the smaller the absolute value of curvature at the center of the initial geometric defect of the pipeline,the stronger the transverse thermal buckling resistance will be.Finally,based on the dimensionless analysis method,the general expression was proposed for calculating the critical temperature rise of submarine pipelines with various common initial geometric defects,and it is anticipated to provide a reference for the thermal buckling design of submarine pipelines.