Wrinkling Failure of Lined Pipe Under Bending Available to Purchase

Lining internally a carbon steel pipe with a thin layer of corrosion resistant material is an economical method for protecting offshore tubulars from the corrosive ingredients of hydrocarbons. In applications involving severe plastic bending, such as reeling, the liner can detach from the outer pipe and develop large amplitude buckles that compromise the flow. This paper outlines a numerical framework for establishing the extent to which lined pipe can be bent before liner collapse. The manufacturing process of lined pipes is simulated and a set of 12-inch pipes are plastically bent. The two tubes ovalize and the liner detaches from the outer pipe developing small amplitude wrinkles. The wrinkles initially grow stably but at a higher curvature yield to a diamond-shaped buckling mode that catastrophically collapses the liner. The onset of collapse is shown to be very sensitive to small geometric imperfections in the liner.