A novel method for auto-correction of fiber optic distributed temperature sensor using anti-Stokes Raman back-scattering and its reflected signal is presented. This method processes two parts of measured signal. One part is the normal back scattered anti-Stokes signal and the other part is the reflected signal which eliminate not only the effect of local losses due to the micro-bending or damages on fiber but also the differential attenuation. Because the beams of the same wavelength are used to cancel out the local variance in transmission medium there is no differential attenuation inherently. The auto correction concept was verified by the bending experiment on different bending points.
In this paper, the feasibility of real-time monitoring of the
fatigue damage of composite laminates under fatigue loading using the embedded
intensity-based optical fiber (IBOF) sensors was evaluated. The IBOF sensor
system used in this study has a relatively simple sensing principle. Thus the
system can be composed of inexpensive components compared with other optical
fiber sensors such as Fabry-Perot and Bragg grating sensors. The performance
of the fabricated IBOF sensors was evaluated by comparison with a
surface-mounted extensometer. The process of conversion of the detected IBOF
sensor signal into the stiffness was proposed. Experimental results showed
that the sensing response of embedded IBOF sensors showed good agreement with
that of the surface-mounted extensometer. The IBOF sensor system showed good
potential as a health monitoring system which can give composite structures
the capability of fatigue damage monitoring by detecting the stiffness change
of the composite structures under fatigue loading. The IBOF sensors showed
relatively good durability under fatigue loading compared with commercial
electrical strain gages.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.