Strain transfer effect on measurements with distributed fiber optic sensors

Strain transfer phenomenon in distributed fiber optic sensors (DFOS) has shown significant effects on sensor survival and measurement of strain distributions as well as detection and quantification of cracks in health monitoring and condition assessment of civil infrastructure. This review aims to establish a holistic understanding on the strain transfer effect for measurement using DFOS. The reviewed contents cover the fundamental mechanisms, influencing factors, practical solutions, and applications of strain transfer models. Both forward and inverse strain transfer analysis of DFOS are elaborated. Challenges and opportunities of strain transfer analysis for DFOS are discussed. This review shows that the forward and inverse strain transfer analysis are capable of accurately determining the strain distributions and cracks in host structures subjected to arbitrary strain fields. The clarification of the strain transfer effect will facilitate the applications of fiber optic sensors in civil infrastructure.