The work presented in this paper shows that Fiber Bragg Grating (FBG) optical fiber sensors\ncan potentially be used as receivers in a long-range guided wave torsional-mode pipe inspection\nsystem. Benefits over the conventional pulse-echo method arise due to reduced total travel distance\nof the ultrasonic guided wave reflections, since reflections from defects and structural features do not\nneed to propagate a full round trip back to the transmitting collar. This is especially important in\npipe configurations with high attenuation, such as coated and buried pipelines. The use of FBGs as\nreceivers instead of conventional piezoelectric or magnetostrictive elements also significantly reduces\ncabling, since multiple FBG receivers can be placed along a single optical fiber which has a diameter\non the order of only around 100 �¼m. The basic approach and sample results are presented in the\npaper. Additionally, a brief overview of some topics in ultrasonic guided waves is presented as a\nbackground to understand the inspection problem presented here.
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