Deformation monitoring in prestessing tendons using fibre Bragg gratings encapsulated in metallic packages

An investigation into the capability of deformation monitoring using fibre Bragg gratings encapsulated in metallic packages is presented in the paper. The proposed approach relies on a grating inscription into a metal coated fibre and brazing the fibre into a metal capillary using induction heating. A metal rod instrumented with encapsulated FBG strain and temperature sensors is placed in an electromechanical tester and stressed up 80 % of its ultimate tensile strength. It is demonstrated through a 60 h experiment that the sensors are capable of real-time deformation monitoring