Pressurized line pipe wall thinning detection using a distributed fiber-optic sensing system

Wall thinning defects in steel pipes are usually localized and are difficult to detect using traditional sensors that have a small coverage and limited measuring range. A distributed fiber sensor, based on the Brillouin backscattering sensing system, has been demonstrated to be able to measure the strain and detect the defect in a pipe accurately. A 1.8 m pipe segment that contains artificial thinning from 13 to 60% of wall thickness at various positions was subjected to an internal pressure of 350 kgf/cm2. Hoop strain distribution along the whole pipe segment was monitored by a single optical fiber. The measured strains compared favorably with strain gauge results. The method proposed in this study shows promising results for the detection of the existence and location of wall thinning defects in long distance pressurized pipe.