Manufacturing/in-service Health Monitoring Of Composite Structures

ADVANCED COMPOSITE MATERIALS HAVE EVOLVED TO BE THE CLASS OF MATERIALS WHICH MEET THE STRICT REQUIREMENTS OF MANY GROUND- AND SPACE-BASED CRITICAL STRUCTURES. SYSTEMS WHICH INCORPORATE THESE NOVEL MATERIALS ARE FREQUENTLY EXPOSED TO HARSH ENVIRMENTS DURING SERVICE, AND MUST THEREFORE BE MANUFACTURED USING HIGH QUALITY STANDARDS. NOT ONLY IT IS DESIRABLE TO MONITOR AND CONTROL THE FABRICATION PROCESS USING EMBEDDED SENSORS, BUT IT IS ALSO NECESSARY TO INSTRUMENT THESE STRUCTURES WITH DEVICES WHICH ALLOW IN-SERVICE HEALTH MONITORING. OPTICAL FIBER SENSORS HAVE BEEN INVESTIGATED FOR THESE PURPOSES OVER A NUMBER OF YEARS, BUT HAVE YET TO BE REDUCED TO PRACTICE IN AN INTEGRATED, MULTI-PARAMETER, SPATIALLY-MULTIPLEXED FORMAT. IT IS PROPOSED TO DEMONSTRATE THE FEASIBILITY OF AN OPTICAL TIME DOMAIN FIBER STRAIN- AND TEMPERATURE-MONITORING NETWORK THAT CAN BE INTEGRATED WITH A NOVEL FIBER OPTIC-PROCESS MONITORING SYSTEM FOR COMPOSITE MATERIALS. THE PROOF-OF-CONCEPT TEST CONSISTS OF FABRICATING A THERMOSET COMPOSITE LAMINATE WHICH CONTAINS A MULTI-SEGMENT OPTICAL FIBER SENSOR NETWORK, MONITORING THE STATE OF CURE DURING THE FABRICATION OF THE LAMINATE, AND DETERMINING STRAIN AND TEMPERATURE DURING TESTS PERFORMED AFTER FABRICATION. SOFTWARE WILL BE WRITTEN TO INTERFACE A COMMERCAILLY AVAILABLE OPTICAL TIME DOMAIN MONITORING SYSTEM TO A PERSONAL COMPUTER.