基于ANSYS有限元法的含双点及组合腐蚀缺陷管道应力分析

Stress analysis of corroded pipelines with double-point and combined defects based on ANSYS

以大庆采油六厂埋地管道实测腐蚀缺陷为依据,用ANSYS有限元软件模拟了含双点及组合腐蚀缺陷管道表面的应力状态,研究方形、椭圆形两种双点腐蚀缺陷及组合腐蚀缺陷尺寸对管道最大等效应力的影响规律。结果表明:双点方形、椭圆形腐蚀缺陷间距分别大于60、40 mm,两缺陷相互独立,对管道剩余强度无影响;在干涉距离内,双点方形腐蚀缺陷深度对等效应力影响最大,而双点椭圆形缺陷的深度、长度和宽度影响均较大;随组合腐蚀缺陷深度增加,管道模拟等效应力增加,大尺寸缺陷深度对等效应力影响程度较大。

The surface stress state of external pipeline with double-point and combined corrosion defects in Daqing Oil Recover Plant No.6 was analysed by ANSYS software. The effects of the defect length, width and depth on maximum equivalent stress of pipeline were studied. The results show that the double-point square defects are independent with each other when the span is higher than 60 mm, and for the double-point elliptic defects, the span is higher than 40 mm. Within the interface interfering distance, the depth of double-point square defects is proportional to the equivalent stress, which is one of the most important factors for failure. For the double-point elliptic defects, the depth, width and length are all proportional to the equivalent stress. The equivalent stress increases with the depth of combined corrosion defects, and the larger dimension exhibits greater effects.