Numerical analysis of the performances of bonded composite repair with adhesive band in pipeline API X65

The technique of adhesively bonded composite patch repair has been successfully applied in pipeline of API X65 components repair and has recently been expanded to commercial pipeline industry. In the present paper, the crack growth behavior of cracked pipeline API X65 repaired with bonded composite patch was investigated. The finite element approach was applied in order to analyses the circumferential crack's behavior repaired by a carbon-epoxy composite patch. The effects of the properties of the patch on the evolution of the stress intensity factor, according of angle crack tip, were discussed. The adhesive properties were optimized to increase the performance of the repair of structures by such reinforcement. Moreover, a relatively new method was developed to stop the external corrosion and the structurally reinforce steel pipes by external wrapping of damaged sections, using fibre reinforced polymer (FRP) materials. The results indicated that the defect width around the circumference had little impact on the ultimate rupture pressure of the repaired vessel. On the other hand, it was found that the defect width around the circumference was affected by the stress state in the underlying pipe substrate.