Measurement accuracy of FBG used as a surface-bonded strain sensor installed by adhesive

Abstract

Material and dimensional properties of surface-bonded fiber Bragg gratings (FBGs) can distort strain measurement, thereby lowering the measurement accuracy. To accurately assess measurement precision and correct obtained strain, a new model, considering reinforcement effects on adhesive and measured object, is proposed in this study, which is verified to be accurate enough by the numerical method. Meanwhile, a theoretical strain correction factor is obtained, which is demonstrated to be significantly sensitive to recoating material and bonding length, as suggested by numerical and experimental results. It is also concluded that a short grating length as well as a thin but large-area (preferably covering the whole FBG) adhesive can enhance the correction precision.

Gecko-inspired self-adhesive packaging for strain-free temperature sensing based on optical fibre Bragg gratings

“…This is highly undesired in many real applications, as for instance for monitoring microelectronic or chip devices 7,8 . While the effects of different kinds of glues for FBG sensing have been investigated in the literature [9][10][11] , in all cases the strain transfer provided by the glue would affect temperature sensing, making it difficult to reach strain-free thermal monitoring. On the other hand, removing glued FBG sensors from a structure might result in adhesive residuals that remain in the structure; this is normally unwanted in many cases.…”

Radiation impact on strain transfer efficiency of bonded FBGs

“…In addition, FBGs offer some great advantages: they are small and weight light, unsensitive to electromagnetic fields, and they allow multi-points measurements which can be remotely acquired (with the electronics far from harsh environments for instance). In order to accurately measure the strain distribution within a structure, the FBG can either be integrated in a complex sensor system 2 , either it can be incorporated in the structure to be measured 3 , or can be bonded directly to the structure's surface 4 . Even if the latter seems to be the easiest way to do strain measurement, choosing the right adhesive, the one which transfers maximal strain from the host material to the FBG, is not obvious.…”

Numerical and experimental analysis of the reliability of strain measured by surface‐mounted fiber‐optic sensors based on Bragg gratings

“…The advantages of FOSS based on Bragg gratings and typical schemes for their application are widely covered in the literature, in particular in previous papers 1–4 . In a number of works, the results of measurements recorded with FOSS based on Bragg gratings are compared with data obtained by other strain measurement systems 5–8 …”

“…[1][2][3][4] In a number of works, the results of measurements recorded with FOSS based on Bragg gratings are compared with data obtained by other strain measurement systems. [5][6][7][8] It is necessary to have estimates of the reliability of the strain measurement results when using any sensors, including FOSS based on Bragg gratings. These estimates depend on various factors.…”