Pipeline Corrosion Monitoring by Fiber Optic Distributed Strain and Temperature Sensors

Brillouin-scattering-based fiber optic distributed strain and temperature sensors (DSTS) has been applied to measure the longitudinal and hoop strain in an internally pressurized 1.8 m long end-capped steel pipe with wall thinning defects. The preembedded defects, which constitute 50-60% of inner wall thickness to simulate the structural degradation by corrosion in pipes, are discriminated by use of the corresponding strain measurements in the axial and hoop directions along the pipe with our distributed strain and temperature sensor system using 10 cm spatial resolution. The locations of structural indentations are found and distinguished by use of their corresponding strain-pressure data. These results are quantified in terms of the fiber orientation, defect size and depth, and behavior relative to those of unperturbed pipe sections.