Stress–Strain Analysis of a Pipeline With Inner and Outer Corrosion Defects

A numerical simulation method is adopted to analyze the effects of three types of defect geometries ((1) a single defect on the inner surface, (2) a single defect on the outer surface, and (3) double coaxial defects on the inner surface and the outer surface.) on the residual strength of corroded X60 steel pipelines and equivalent stress and plastic strain distribution of the local defect area. The results show that the defect geometry exerts obvious effects on stress–strain distribution. The earliest plastic deformation occurs at the edge of the inner surface defect (type 1), but it occurs on the central part of both the outer surface defect (type 2) and the double defects (type 3). The appearance of defects greatly weakens the stability of the pipeline. For equivalent sum total corrosion defect depth, a single defect is more harmful to the pipeline than double defects.