Nondestructive Testing of Composite Materials by OTDR in Imbedded Optical Fibers

Abstract

Optical fiber waveguide imbedded between plys of graphite-epoxy composite materials is used to determine the dynamic three-dimensional strain within the materials by OTDR and subsequent signal processing. This paper describes methods used for imbedding optical fiber within composites, results of the fiber measurements of internal strain location, and inherent limitations on the spatial, temporal, and strain amplitude domain resolutions of the technique.