轴向含多处椭圆缺陷管道的屈曲失稳分析

Buckling analysis of pipelines with multiple elliptical defects in the axial direction

由铺设、非均匀海床支撑和落物撞击引起的海底管道缺陷往往是轴向非均匀、非一致且多处分布的。出于简化分析的需要,一般将轴向含多处椭圆缺陷管道的屈曲失稳分析模型简化为轴向含均匀椭圆缺陷管道或轴向含单一局部椭圆缺陷管道。但针对这三种模型计算结果的差异及其工程适用性的研究仍然较少。本文基于数值仿真方法研究含三种椭圆缺陷管道的屈曲失稳行为,利用RIKS方法求解管道的屈曲压力,并与DNVOS-F101计算结果进行对比,重点分析轴向含多处椭圆缺陷管道屈曲失稳的激发位置及影响参数。研究结果表明,含不同椭圆缺陷管道模型所求解的屈曲压力差异明显,其大小顺序为:含均匀椭圆缺陷管道屈曲压力<DNV规范理论解<含多处椭圆缺陷管道屈曲压力<含单一局部椭圆缺陷管道屈曲压力。对于轴向含多处椭圆缺陷管道的屈曲失稳分析,若简化为轴向均匀椭圆缺陷管道模型则偏于保守,简化为轴向含单一局部椭圆缺陷管道模型则偏于危险。轴向含多处椭圆缺陷管道的屈曲压力受到椭圆缺陷大小、椭圆缺陷间距和椭圆缺陷长度的综合影响。

The defects of a submarine pipeline caused by laying,non-uniform seabed support and impact of falling objects are often distributed in many places.In order to simplify the analysis,the buckling model of a pipeline with multiple elliptical defects in the axial direction is generally simplified as the pipeline with uni⁃form elliptical defects or the pipeline with a single local elliptical defect in the axial direction.However,there are few studies on the differences of these three models and their application in engineering.Based on the nu⁃merical simulation,this paper presents a study on the buckling and instability behavior of the pipeline with three kinds of elliptical defects.The RIKS method was used to solve the buckling pressure of the pipeline,and compared with the calculation results of DNV-OS-F101,focusing on the analysis of the excitation posi⁃tion and influence parameters of the buckling and instability of the pipeline with multiple elliptical defects in the axial direction.The results show that the buckling pressure of the pipeline model with different elliptical defects is obviously different,and the order is the buckling pressure of the pipeline with uniform elliptical de⁃fects<the theoretical solution of DNV-OS-F101<the buckling pressure of the pipeline with multiple ellipti⁃cal defects<the buckling pressure of the pipeline with single local elliptical defects.For the buckling analy⁃sis of the pipeline with multiple elliptical defects in the axial direction,if the pipeline model is simplified with axial uniform elliptical defects,it is more conservative.However,if the pipeline model is simplified with axial single local elliptical defects,it is more dangerous.Besides,the buckling pressure of the pipeline with multiple elliptical defects is affected by the size of elliptical defects,the distance between elliptical defects and the length of elliptical defects.