Prevention of serious damage of composite structures might be achieved by inspecting the structural integrity during exploitation. This paper decribes the design and development of a promising optical fiber
sensor system for low velocity impact detection in unidirectional composite that does not have a laminate structure. Obtained results showed that light in multimode fibers embedded in glass-fiber reinforced
epoxy unidirectional composites is attenuated during the time of the impact load. Microstructural analysis of the fracture surfaces obtained from mechanically fractured samples was carried out to examine
the failure mode of the composite host with embedded optical fibers.