Distributed Diagnosis of Composite Structures Using Integrated Optical Fibers

"The use of optical fibers to provide a distributed diagnosis of the status and health of composite structures is a very promising and innovative development that could have prevented a number of catastrophic failures in the past. However, although thetechnology has been studied for a number of years, it is still not developed to the level required for either military or commercial routine applications. The proposed R&D effort will (1) determine the quantitative relation between strain, degradation,and fatiguing in the host composite material (the causal event) and the observed response in the optical fiber network (the effect)over the life of a series of test structures-from initiation to failure, and (2) develop a data display technique that will enable rapid, real-time scanning of the extremely large number of simultaneous and continuous measurements that will be generatedby the multiple large arrays of diagnostic optical fibers required in an operational system. The general technique of measuring strain and breaks in optical fibers has been developed sufficiently by previous research and the communications industry that,with the addition of the two developments anticipated to result from the proposed R&D effort (e.g., a clear correlation between observed optical effects and degradation of the host composite structure, and a powerful display technique allowing rapid andeffective scanning of the volumous data set produced), a com