In Situ Evaluation of 3-D Woven Composite Structural Performance Using Fiber Optic Sensors

"Three-dimensional textile reinforcement architectures with straight in-plane fibers and optimized through thickness fiber content are considered as efficient solutions for the next generation of light weight, damage tolerant, high strength compositesallowing for cost-effective manufacturing solutions. The 3-D weaving process is gentle to the fibers, thus making automated fiber optic sensor insertion feasible. 3-D woven preforms do not allow delamination, thus providing a safe environment for embeddedfiber opric sensors. Principal objectives of the project are (i) develop commercial, automated placement of fiber optic sensors into 3-D woven fabric preforms; (ii) develop resin infusion techniques suitable for processing composite structures withembedded optical sensors; (iii) demonstrate the functionality of embedded sensors in the 3-D woven composite panels with open holes and composite bolted joints, and (iv) validate some of the advanced 3-D stress/strain and failure analysis tools bycomparison with embedded fiber optic sensor data. The effort will include specific modification of current 3-D weaving processes, development of suitable and reliable sensor connectors, manufacturing of open hole and bolted joint composite specimens, theirmechanical testing, and comparison of theoretical versus experimental results. Success of these efforts will validate applicability of fiber optic sensors to continuous health monitoring of composite structures."