TY - JOUR
T1 - Response of fiber Bragg gratings bonded on a glass/epoxy laminate subjected to static loadings
AU - Mulle, Matthieu
AU - Moussawi, Ali
AU - Lubineau, Gilles
AU - Durand, Samuel
AU - Falandry, Didier
AU - Olivier, Philippe
N1 - KAUST Repository Item: Exported on 2020-10-01
PY - 2015/4/25
Y1 - 2015/4/25
N2 - Fiber Bragg gratings (FBG) may be used to monitor strain over the surface of a structure as an alternative technology to conventional strain gauges. However, FBG bonding techniques have still not been established to yield satisfactory surface measurements. Here, two adhesives were investigated, one with low viscosity and the other with high viscosity for bonding FBGs on glass/epoxy sandwich skins. First, instrumented elementary specimens were tested under tension. FBG strain results were analyzed together with digital image correlation (DIC) measurements. The influence of the bonding layer on the measured strain and on the integrity of the sensor was investigated by considering different regions of interest. Next, an instrumented structural sandwich beam was tested under four-point bending. FBG rosettes were compared to conventional strain gauge rosettes. The high viscosity adhesive demonstrated behaviors that affected FBG accuracy. Brittleness of the bonding layer and poor interface adhesion were observed using DIC and X-ray tomography. By contrast, the low viscosity adhesive demonstrated satisfactory results. The FBG strain measurements appeared to be consistent with those of DIC. The accuracy is also adequate as the FBGs and the conventional strain gauges had similar results in three directions, under tension and under compression.
AB - Fiber Bragg gratings (FBG) may be used to monitor strain over the surface of a structure as an alternative technology to conventional strain gauges. However, FBG bonding techniques have still not been established to yield satisfactory surface measurements. Here, two adhesives were investigated, one with low viscosity and the other with high viscosity for bonding FBGs on glass/epoxy sandwich skins. First, instrumented elementary specimens were tested under tension. FBG strain results were analyzed together with digital image correlation (DIC) measurements. The influence of the bonding layer on the measured strain and on the integrity of the sensor was investigated by considering different regions of interest. Next, an instrumented structural sandwich beam was tested under four-point bending. FBG rosettes were compared to conventional strain gauge rosettes. The high viscosity adhesive demonstrated behaviors that affected FBG accuracy. Brittleness of the bonding layer and poor interface adhesion were observed using DIC and X-ray tomography. By contrast, the low viscosity adhesive demonstrated satisfactory results. The FBG strain measurements appeared to be consistent with those of DIC. The accuracy is also adequate as the FBGs and the conventional strain gauges had similar results in three directions, under tension and under compression.
UR - http://hdl.handle.net/10754/550711
UR - http://linkinghub.elsevier.com/retrieve/pii/S0263822315003062
UR - http://www.scopus.com/inward/record.url?scp=84929486148&partnerID=8YFLogxK
U2 - 10.1016/j.compstruct.2015.04.015
DO - 10.1016/j.compstruct.2015.04.015
M3 - Article
SN - 0263-8223
VL - 130
SP - 75
EP - 84
JO - Composite Structures
JF - Composite Structures
ER -