Experimental study on strain sensing by small-diameter FBG

Rong-mei Liu; Qiufeng Li; Lujia Zhu; Dakai Liang

doi:10.1117/12.2241497

11 November 2016 Experimental study on strain sensing by small-diameter FBG

Rong-mei Liu, Qiufeng Li, Lujia Zhu, Dakai Liang

Proceedings Volume 10150, Second International Seminar on Photonics, Optics, and Its Applications (ISPhOA 2016); 101500S (2016) https://doi.org/10.1117/12.2241497
Event: Second International Seminar on Photonics, Optics, and Its Applications (ISPhOA 2016), 2016, Bali, Indonesia

Abstract

Fiber Bragg grating (FBG) sensors were attractive in various fields for structural health monitoring. Because of their accurate performance and real time response, embedded FBG sensors are promising for strain monitoring in composite materials. As an optical fiber sensor was embedded inside a composite, interface would form around the embedded optical fiber and the host polymer composite. In order to study the influence of the embedded optical fiber to the mechanical character, finite elemental analysis was applied to study the stress distribution inside the composite. Keeping the resin rich area the same size, laminates with optical fibers in different diameters, which were 250 and 125 micrometers, were analyzed. The simulation results represent that stress singularity would occur around the embedded optical fiber. The singularity value for the laminate with optical fiber at 250 micrometer was higher than that with optical fiber at 125 micrometer. Micro- cracks would arise at the stress singularity point. Therefore, the optical fiber in smaller diameter was preferred since the mechanical strength could be higher. Four points bending test was carried out on a steel beam with a small-diameter FBG on the bottom surface. Besides, a strain gauge was stuck on bottom to validate the monitoring results by FBG sensor. The tested results indicated that the strain monitoring results by the small-diameter FBG sensor almost identical with the theoretical ones and what recorded by strain gauge. The maximum testing error for the designed FBG is less than 2% compared with the theoretical one.

Citation Download Citation

Rong-mei Liu, Qiufeng Li, Lujia Zhu, and Dakai Liang "Experimental study on strain sensing by small-diameter FBG", Proc. SPIE 10150, Second International Seminar on Photonics, Optics, and Its Applications (ISPhOA 2016), 101500S (11 November 2016); https://doi.org/10.1117/12.2241497

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