Mathematical Modeling of Growth of Stress-Corrosion Cracks in an Oil Pipeline with Regard for Hydroshocks and In-Service Changes in the Characteristics of its Material

We propose a mathematical model for the determination of the period of subcritical crack growth in an oil pipeline operating under the action of constant internal pressure, hydroshocks, and soil corrosion with regard for the degradation of its material. The model is based on the first law of thermodynamics, i.e., on the balance of energy components and the rates of their variations, the mechanisms of electrochemical corrosion, and the analytic dependences of changes in the stress-corrosion characteristics of the material in the course of time (degradation). We determine the residual lifetime of an oil pipeline made of Kh60 steel.