Distributed fiber strain sensor based on Brillouin scattering for inspection of pipeline buckling

A distributed strain sensor based on Brillouin scattering has been employed to inspect localized pipe-wall buckling on a length of 2.58 m and diameter of 0.75 m steel pipe by measuring the axial strain distributions along the outer surface of the pipe. An optical fiber with 10 sections was laid along the longitudinal direction of the pipe. Both compressive load and bending load were applied on both end of tested pipe up to 2,013 and 300 kIPS respectively, to induce the localized pipe-wall buckling. The buckling locations comprising tension and compression of the pipe wall are found and distinguished using their corresponding strain distribution data. The compressive strains of - 4330 and - 6856 με measured by our distributed strain sensor on the bending load of 220 and 300 kIPS, respectively, at one location near buckling point, match the readings from strain gauge at the same location where the strain gauge attached. The tensile strain happened at different sides of the pipe are found too.