Curved pipes subjected to mechanochemical corrosion under pressure: Analytical and numerical estimates of the lifetime

Abstract

For the estimates of durability of curved pipes, solutions for toroidal shells are often utilized. This paper discusses several available approximate closed-form static solutions for toroidal shells under pressure, and tests them against finite elements computations. Modifications of the considered solutions, relevant to improving accuracy in strength analyses are developed and approximate analytical solutions for the lifetime of toroidal shells subjected to one- or double-sided mechanochemical corrosion under internal and external pressures are obtained, for the first time. The maps of discrepancies between the analytical and numerical solutions for static and evolutionary problems are built, reasons for these discrepancies and applicability of both approaches being discussed. The study highlights how pipe curvature and mechanochemical effect can influence stress distribution and corrosion progression, offering insights for corrosion monitoring strategies. It is shown, in particular, that due to mechanochemical effect, the location of the maximum stresses at the inner surface may shift from the intrados towards the torus crown, resulting in intensification of the internal corrosion in the area between the intrados and the crown.