不同尺寸双点蚀缺陷管道剩余强度分析

Remaining Strength of Pipeline with Different Size Double Pitting Corrosion Defects

现有的双腐蚀缺陷管道剩余强度评价规范大多以轴向均匀腐蚀为研究对象,评价双点蚀缺陷管道时结果偏保守,导致管材浪费严重。利用非线性有限元分析方法,对含有交互影响双点蚀缺陷管道的剩余强度进行分析,验证了分析方法的可靠性。在此基础上,研究轴向间距对带有不同尺寸双点蚀缺陷管道失效压力的影响。分析表明:不同尺寸双点蚀缺陷,可将ls作为交互影响的临界间距,超过此间距,双点蚀缺陷相互作用可以忽略;由于腐蚀坑形状系数n的不同,相比直径差距,双点蚀缺陷深度差距对缺陷管道失效压力的影响明显增加;在双点蚀缺陷交互作用区间0<ld<ls,双点蚀缺陷管道失效压力随轴向间距呈对数函数变化。

The evaluation specifications of pipeline with double corrosion defects makes axial uniform corrosion as the research object,mostly the conservative results on double pipeline pitting defects,leading to serious pipe material waste.Using nonlinear finite element analysis method,to analyze the residual strength of pipeline with double pitting defects,and compared with the experimental data,the reliability analysis method was verified.On this basis,studying the impact of the axial spacing on failure pressure of pipeline with different size double pitting corrosion defect,the analysis shows lscan be as critical spacing of pitting corrosion defect interaction for different size double pitting defects,more than this distance,double pitting corrosion defect interaction can be ignored;Compared with the two pitting corrosion defect diameter difference,double pitting corrosion defect depth gap has greater influence on pipeline failure stress,because of the difference of corrosion pit shape factor n;The changing of double pitting defects pipeline failure stress is a logarithmic function with axial spacing within the range of 0<ld<lswhich is the interaction interval.