Strain measurement and stress analysis in the vicinity of a fiber Bragg grating sensor embedded in a composite material

• Published in: Composite structures 2020-05, Vol.239, p.111844, Article 111844
• Main Authors: Fedorov, A.Y., Kosheleva, N.A., Matveenko, V.P., Serovaev, G.S.
• Format: Article
• Language: English
• Subjects: Composite laminate; Fiber Bragg grating (FBG); Fiber-optic sensor; Finite element analysis (FEA); Strain calculation; Stress concentration
• ISSN: 0263-8223
• DOI: 10.1016/j.compstruct.2019.111844

The paper presents the results of a numerical analysis of the stresses in a polymer composite material (PCM) in the vicinity of an optical fiber embedded in the material, and the results from estimating the reliability of the strain values calculated on the basis of fiber-optic sensor data. A comparative analysis was carried out for the PCM represented as a homogeneous medium and as a laminated material for different directions of the prepreg reinforcements relative to the fiber and for different geometrical parameters of the resin pocket in the vicinity of the fiber. The situation associated with the presence of stress singularity at the mouth of a resin pocket was analyzed and the effect produced by the geometric parameters of the resin pocket on the level of stress concentration was estimated. A series of numerical experiments were proposed for estimating errors in the strain value calculations made on the basis of the data recorded by a fiber-optic sensor embedded in the material. The accuracy of the strain value calculations was estimated depending on the variants of the complex stress state in the fiber Bragg grating (FBG) zone.