Photo-curable Biodegradable-based Tissue Solders containing a Photochromic Endpoint Indicator

Systems Planning and Analysis, Inc. (SPA) proposes to develop a temperature compensated Bragg grating based acoustic emission crack detection (AECD) sensor system based on our proprietary temperature compensation technique for matched Bragg grating sensorsystems. Leveraging previous work by the sponsor, we will perform analytical and experimental analysis to determine optimal system parameters for the AECD system. The analytical models will involve the transmission of an acoustic wave within a compositelaminate and the interaction of the wave with a surface mounted and embedded Bragg grating sensor. Composite test specimens conforming to the American Society for Testing and Materials standards (ASTM D5528 and ASTM D5766) will be fabricated and tested inthe Phase I SBIR program. Testing of these specimens will provide an empirical method of determining optimal system parameters and validating the analytical models derived during the Phase I effort. System refinements will be implemented and tested tofacilitate a risk reduction in pursuing follow on Phase II funding. Temperature compensation tests will be performed in an environmental chamber in a temperature range of 40 to 120 degrees Fahrenheit. The temperature compensation and system optimizationof the acoustic emission crack detection system will enhance the present Bragg grating based technique currently considered by the technical sponsors. Through the use of fiber optic sensors, integration into composite structures will be a seamlesstransition into many fields beyond monitoring crack events on aircraft. This technology will enable a real-time monitoring of composite structures during operation and establish condition-based maintenance (CBM) practices for the fleet.