含矩形腐蚀缺陷管道剩余强度的有限元分析

Finite Element Analysis of Residual Strength of Pipeline With Rectangular Corrosion Defect

为了提高油气管道剩余强度的准确性,以常用的X70管线钢为研究对象,借助ANSYS工具,首先考察缺陷尺寸如缺陷长度和缺陷宽度对等效应力的影响,其次考察了内压对等效应力和等效应变的影响,并基于应力和应变进行剩余强度的拟合。结果表明:随着缺陷长度、缺陷深度和内压的增加,最大等效应力呈增加的趋势,内压和等效应力基本呈正比例关系;随着缺陷宽度的增加,最大等效应力呈减小的趋势;通过线性拟合得到了基于应力和应变的剩余强度求解算法,其中,基于应力的剩余强度求解算法下降速度高于基于应变的剩余强度求解算法。所得结论对管线钢剩余强度的计算有一定的借鉴意义。

In order to improve the accuracy of residual strength analysis of oil and gas pipelines, taking common X70 pipeline steel with the rectangular defect as the investigation object, the influence of defect size, such as defect length and defect width, on the equivalent stress and equivalent strain was firstly investigated by using ANSYS finite element software. Then, the effect of internal pressure on the equivalent stress and equivalent strain was investigated, and residual strength was fitted based on the stress and strain. The results showed that, with the increase of defect length, defect depth and internal pressure, the maximum equivalent stress increased, and the equivalent stress was basically proportional to the internal pressure;with the increase of defect width, the maximum equivalent stress decreased;through linear fitting, the residual strength algorithm based on the stress and strain was obtained Among them, the descent speed of residual strength algorithm based on the stress was faster than that based on the strain. The conclusion can provide some reference in the calculation of residual strength of pipeline steel.