Thermal Effects On Fiber Optic Strain Sensors Embedded In Graphite-Epoxy Composites

Smart structures deployed in low earth orbit will be exposed to a hostile environment which will include temperature extremes during each orbit as the platform moves from the day to the night side. The stresses due to thermal cycling may compromise the performance of embedded fiber optic strain sensors because of differential thermal expansion of the fiber and the composite material. We have investigated the effects of elevated temperature and thermal cycling on the performance of a fiber optic strain sensor embedded in a graphite-epoxy tube for temperatures from 65 to 220 ° F. The results indicated that the fiber optic strain sensor measurements correlated well with conventional resistance strain gauges attached to the tube.