Composites Materials Used in Pipeline Repairs

Maintenance of oil and gas pipelines presenting corrosion damage can be done following conventional routes as cutting and substitution of the damage parts or double sleeve welded method. Recently, the use of composite materials for repair of damaged pipelines is increasing due to the advantages presented by this process like the ease application and the possibility of performing the repair without interrupting the use of the line. As the pipe operates under hydrostatic pressure, it is important to make a stress analysis in order to know the stresses transferred to the composite material repair. In the present work, a microstructural and mechanical characterization of two composite materials used in pipe repair is made. One of the composites is made of continuous fiber glass and the other of a fiber glass fabric, both with polymeric matrix. The first was pulltruded and the second was processed by hand lay up. The microstructural characterization was done through optical microscopy and the mechanical properties were evaluated by tensile tests. From the mechanical properties of the composite materials and models available in the literature, the stresses acting in the composite repairs due to the hydrostatic pressure were evaluated. The main objective of the paper is to correlate the microstructural and mechanical characteristics of the composite materials with the circunferencial stresses acting in the pipes repaired using the studied composite materials.