双点腐蚀缺陷管道剩余强度的有限元分析

Finite Element Analysis on Residual Strength of Two Point Corrosion Defect Pipeline

以X60管线钢双点腐蚀缺陷管道作为研究对象,根据油气管道的本身特点以及腐蚀机理,借助ANSYS有限元分析软件,考察双点蚀缺陷管道应力云图分布规律,通过改变双点蚀缺陷半径、深度和腐蚀间距,考察其对剩余强度和等效应力的影响规律.结果表明,最大等效应力出现在双点腐蚀缺陷周围区域;随着内压的增大,在未达到屈服极限时,等效应力与内压呈线性关系,当等效应力达到屈服极限时,随着内压的增加,等效应力维持不变,当等效应力超过屈服极限时,随着内压的增大,等效应力增加;随着双点蚀缺陷半径的增大,剩余强度呈增加的趋势,安全性提高;随着双点蚀缺陷深度的增加,剩余强度呈减小的趋势,安全性降低.所得结论对油气管道腐蚀与防护有一定的指导意义和参考价值.

Based on the characteristics and corrosion mechanism of X60 pipeline steel pipeline with two point corrosion defects,stress distribution of pipeline with two point corrosion defects is investigated by means of ANSYS finite element analysis software. The residual strength and equivalent effect are investigated by changing radius,depth and corrosion spacing of two point corrosion defects. The results show that the maximum equivalent stress appears in the area around the two point corrosion defect,and the relationship between equivalent stress and internal pressure is linear when the yield limit is not reached with the increase of internal pressure. We find when the equivalent stress reaches the yield limit,the equivalent stress remains unchanged with the increase of internal pressure,and when the equivalent stress exceeds the yield limit,the equivalent stress is increased with the increase of internal pressure. This paper proves with the increase of two point defect radius,the residual strength is increased and the safety is improved,and with the increase of two point defect depth,the residual strength is decreased and the safety is decreased. The conclusion has the certain guiding significance and reference value for corrosion and protection of oil and gas pipelines.