Bonded composite repair of metallic pipeline using energy release rate method

摘要

A methodology of repair in pipes involving bonded joints, manufactured through the wrappage of a composite around the pipe, is becoming a common practice in the industry for a series of associated advantages. The prediction of failure pressure in bonded repaired pipes is vital to guarantee a good quality of adhesion in this type of repair. Nowadays, the failure pressure is usually evaluated using hydrostatic tests that demand complex preparation to pressurize a section of the pipe and that are also dangerous for possible debris during rupture. With this fact in mind, this research purpose is to verify a simpler and more efficient methodology to predict the failure pressure applying energy release rate concepts. Double Cantilever Beam (DCB) and Width Tapered Double Cantilever Beam (WTDCB) tests were used to obtain the energy release rate of dissimilar specimens constituted with the same material as the most common repairs (steel/glass fiber reinforced polymer). Through a design equation that relates the energy release rate and the failure pressure presented in Standards ISO/PDTS 24817 and ASME PCC-2, it is possible to predict a value of failure pressure using DCB and WTDCB energy release rate results. The failure pressure predicted value was compared with the experimental hydrostatic tests results and analyzed. Results showed a good agreement between these two values, indicating that the methodology developed in this research might be used, in the future, to predict the failure pressure in bonded repaired pipes.