In view of the characteristics of strong randomness of corrosion defect location distribution and community characterization of defects in long-distance pipelines,the finite element models of symmetrical and asymmetrical double-defect pipelines were established.The interaction between double defects arranged axially and circumferentially and its influence on pipeline failure pressure were investigated.The influences of defect size and spacing on pipeline failure pressure under different arrangements of defects were determined,and the interaction criterion between defects suitable for asymmetric defects was proposed.The results show that the interaction between longitudinally aligned defects and circumferentially aligned defects with different depths increases nonlinearly with the increase of defect spacing.For circumferentially aligned defects with the same depth,the interaction between defects decreases first and then increases with the increase of defect spacing,and the minimum value is obtained when the circumferential spacing is 0.01πD.The interaction between asymmetric defects is generally weaker than that of symmetric defects,and the failure pressure of pipeline for asymmetric defects is determined by the serious corrosion defect.The axial interaction distance between defects is determined by the defect length.The increase of the length will reduce the axial interaction limit distance between defects.When the defect length exceeds 8.36√Dt,the interaction between defects can be ignored.The limit distance of the circumferential interaction between adjacent defects equals to 0.18πD.This study provides a new method for evaluating the failure pressure of pipelines with interaction defects.
关键词
管道/双缺陷/有限元模型/相互作用准则/失效压力
Key words
pipeline/double corrosion defects/finite element model/interaction rule/failure pressure
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