Embedded fiber Bragg grating sensor for internal strain measurements in polymeric materials

In this paper, the essential aspects of fiber Bragg grating (FBG) sensors as a tool for internal strain measurements are discussed. The merits and the limitations are mentioned and experimental results of internal elastic strains measurements are presented in various configurations. These data are used to deduce: (a) bridging forces in a model composite, (b) strains through the thickness of a laminated composite, and (c) residual stresses in an epoxy cylinder. The experimental results are confronted with numerical models of the actual configuration and pertinent theoretical models. The present studies demonstrate that internal strain measurements using embedded FBG sensors, accompanied by appropriate modeling, can be used to characterize deformation and fracture behavior of polymeric materials at various scales.