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Proceedings Paper

In situ monitoring of curing and ageing effects in FRP plates using embedded FBG sensors
Author(s): Guijun Xian; Chuan Wang; Hui Li
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Paper Abstract

In recent years, fiber reinforced polymer (FRP) composites have been widely applied in civil engineering for retrofitting or renewal of existing structures. Since FRP composite may degrade when exposed to severe outdoor environments, a serious concern has been raised on its long term durability. In the present study, fiber Bragg grating (FBG) sensors were embedded in glass-, carbon- and basalt-fiber reinforced epoxy based FRP plates with wet lay-up technology, to in-situ monitor the stain changes in FRPs during the curing, and water immersion and freeze-thaw ageing processes. The study demonstrates that the curing of epoxy resin brings in a slight tension strain (e.g., 10 ~ 30 με) along the fiber direction and a high contraction (e.g., ~ 1100με) in the direction perpendicular to the fibers, mainly due to the resin shrinkage. The cured FRP strips were then subjected to distilled water immersion at 80oC and freeze-thaw cycles from -30°C to 30°C. Remarkable strain changes of FRPs due to the variation of the temperatures during freeze-thaw cycles indicate the potential property degradation from fatigue. The maximum strain change is dependent on the fiber types and directions to the fiber. Based on the monitored strain values with temperature change and water uptake content, CTE (coefficient of thermal expansion) and CME (coefficient of moisture expansion) are exactly determined for the FRPs.

Paper Details

Date Published: 8 April 2010
PDF: 9 pages
Proc. SPIE 7649, Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2010, 764909 (8 April 2010); doi: 10.1117/12.847386
Show Author Affiliations
Guijun Xian, Harbin Institute of Technology (China)
Chuan Wang, Harbin Institute of Technology (China)
Hui Li, Harbin Institute of Technology (China)


Published in SPIE Proceedings Vol. 7649:
Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2010
Peter J. Shull; Aaron A. Diaz; H. Felix Wu, Editor(s)

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