Based on the energy approach previously developed by the authors, the problem of determining the residual life of an oil pipeline pipe with a surface semi-elliptical microcrack, into which the soil corrosive medium penetrates, is solved. A turbulent flow of oil moves along such a pipe, which causes two-frequency loading of its wall. Microdefects and the plastic material of the pipe, which degrades during crack propagation, are considered. Therefore, the solution to the problem, using the energy approach, is reduced to a nonlinear differential equation for the crack opening function at its pre-fracture zone with variable coefficients. The equation together with the initial and final conditions (crack opening on the inner surface of the pipe and its depressurization) is a mathematical model for determining the residual life of the pipe. The crack opening function is found approximately using the method of equivalent stress states and the limit interpolation method developed earlier by the authors. The dependences of the residual life of the oil pipeline pipe made of X70 steel, considering its material’s degradation, are obtained.

基于作者先前开发的能量方法，解决了土壤腐蚀介质渗入表面具有半椭圆形微裂纹的石油管道剩余寿命的确定问题。油的湍流沿着这样的管道移动，这会导致其壁产生双频载荷。考虑了微缺陷和管道的塑料材料在裂纹扩展过程中的降解。因此，使用能量方法将该问题的解简化为具有变系数的预断裂区裂纹张开函数的非线性微分方程。该方程与初始条件和最终条件（管道内表面的裂纹张开及其减压）一起构成了确定管道剩余寿命的数学模型。利用作者早期开发的等效应力状态法和极限插值法近似求出裂纹张开函数。得到了考虑材料退化情况下X70钢制石油管线管剩余寿命的依赖性。