Distributed strain measurement of welded tubular joint with long gauge FBG

H. Murayama; K. Kageyama; K. Ohara; K. Uzawa; M. Kanai; H. Igawa

doi:10.1117/12.786182

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16 May 2008 Distributed strain measurement of welded tubular joint with long gauge FBG

H. Murayama, K. Kageyama, K. Ohara, K. Uzawa, M. Kanai, H. Igawa

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Proceedings Volume 7004, 19th International Conference on Optical Fibre Sensors; 700452 (2008) https://doi.org/10.1117/12.786182
Event: 19th International Conference on Optical Fibre Sensors, 2008, Perth, WA, Australia

Abstract

Strain along a welded joint submitted to a load can fluctuate because of inhomogeneity in thickness or residual stress distributions and defects. Inversely, strain fluctuation may represent such inhomogeneities or defects. We applied the distributed strain sensing technique with a long gauge FBG to monitoring strain distributions along a welded tubular joint of a steel pipe. By using this sensing technique, we can measure a strain distribution at an arbitrary position along a FBG with the high spatial resolution less than 1 mm. In the tensile test of the steel pipe, we could successfully measure the strain distribution along the weld line of about 100 mm in length. We also observed the strain fluctuating sharply in some areas and acoustic emissions were simultaneously detected by the other sensors. In some areas where sharp fluctuations occurred, defects were observed by also computer tomography carried out after the tensile test. Applications for the sensing technique include health monitoring for other joint configurations, such as fastening and bonding.

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H. Murayama, K. Kageyama, K. Ohara, K. Uzawa, M. Kanai, and H. Igawa "Distributed strain measurement of welded tubular joint with long gauge FBG", Proc. SPIE 7004, 19th International Conference on Optical Fibre Sensors, 700452 (16 May 2008); https://doi.org/10.1117/12.786182

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