Analysis of internal bonded fibre reinforced composite repair systems for corroded steel pipelines

Steel pipelines are widely used in the oil and gas industry. Over time, many pipelines experience internal metal loss, mainly due to corrosion, and some form of repair is required in order to reinstate the original operating capacity and maintain structural integrity. Fibre reinforced composites offer solutions with broad applicability and efficiency for internal repair of these pipelines. Analysing and understanding the behaviour of composites is important in order for them to be used effectively as an internal repair system for corroded steel pipelines. This paper presents the analyses of internal composite bonded repair systems for long steel pipes with an axisymmetric defect, based on Lame's equation. Optimum internal composite repair thicknesses using biaxial carbon and glass fibre composites were determined for different levels of corrosion, following the Von Mises yielding and Tsai-Hill failure criterion approaches. Design nomographs for internal composite repair systems have been developed.