Recent Advances and Tendencies Regarding Fiber Optic Sensors for Deformation Measurement: A Review

Deformation is a crucial factor to be employed for evaluating the health state of the equipment structure. Electrical-based sensors have been widely used for structural deformation monitoring. However, they are difficult to achieve accurate measurements in some harsh environments, such as those with strong magnetic fields, corrosion, and high-speed rotations. Compared with electrical-based sensors, fiber optic sensors (FOSs) possess the inherent advantages of being small and having passive sensing, anti-electromagnetic interference, etc ., which endows them with great potential for deformation sensing. In this review, fiber optic deformation sensors (FODSs) are divided into contact and non-contact types according to the spatial location relationship between them and the objects being monitored. Related FOS sensing principles, including wavelength, phase, and intensity modulations are introduced. Also, cutting-edge designs of contact and non-contact FODS are discussed. Recent achievements in applying FODS are investigated and their limitations and development prospects analyzed.