Repair of Dents Subjected to Cyclic Pressure Service Using Composite Materials

Abstract

For the better part of the past 15 years composite materials have been used to repair corrosion in high pressure gas and liquid transmission pipelines. This method of repair is widely accepted throughout the pipeline industry because of the extensive evaluation efforts performed by composite repair manufacturers, operators, and research organizations. Pipeline damage comes in different forms, one of which involves dents that include plain dents, dents in girth welds and dents in seam welds. An extensive study has been performed over the past several years involving multiple composite manufacturers who installed their repair systems on the above mentioned dent types. The primary focus of the current study was to evaluate the level of reinforcement provided by composite materials in repairing dented pipelines. The test samples were pressure cycled to failure to determine the level of life extension provided by the composite materials relative to a set of unrepaired test samples. Several of the repaired dents in the study did not fail even after 250,000 pressure cycles were applied at a range of 72% SMYS. The results of this study clearly demonstrate the significant potential that composite repair systems have, when properly designed and installed, to restore the integrity of damaged pipelines to ensure long-term service.

Materiales, métodos y normativa para refuerzos de material compuesto en reparación de tuberías y equipos a presión

“…El hecho es que cuando se consideran todos los atributos de este sistema, tales como: el corto tiempo de reparación, la inversión de un mínimo de recursos para su instalación (muy poca logística) y la versatilidad de los materiales que pueden ser utilizados en tuberías de cualquier forma y tamaño, permiten considerar el uso de los FRP como una opción bastante atractiva. Por otra parte, la reducción de la rigidez por fluctuaciones de presión de los materiales compuestos en comparación con los de acero, hace que su uso en cargas cíclicas sea menos extendido, siendo el desempeño en el largo tiempo un tema de continuo interés [9], [10], [11].…”

Comparison of fiber-reinforced polymer wrapping versus steel sleeves for repair of pipelines

“…Work is currently being conducted to better define the long-term performance of composite repairs (Alexander, 2009;Alexander and Bedoya, 2010). Cyclic strains in the defect area may cause the defect to grow and eventually fail in subsequent service.…”

Experimental-Numerical Investigation of a Steel Pipe Repaired with a Composite Sleeve

“…When faced with the need to repair an operating pipeline, there are often a variety of in-service repairing strategies available to pipeline operators for a given repairing situation [14]. While the use of metallic materials to repair damages is nowadays a mature technology (the use of full-encirclement steel sleeves for pipeline repair was developed in the early 1970s [15,16]), the use of non-metallic composite for pipeline repairs has only recently attracted considerable interest [17][18][19][20][21][22]. The first commercially available system was Clock Spring ® , which consisted of an E-glass/polyester resin-based composite material preformed into a multilayer coil installed using an adhesive.…”