Fiber Optic Grating Sensor Distributed Adhesive Bond Monitoring Systems

An innovative distributed multi-axis fiber optic based strain sensor system will be used to measure transverse strain, longitudinal strain, and strain gradients in adhesive bonds to track the onset of failure. This system which is based on advanced fiber grating technology allows multiplexing of large numbers of sensors, Synergy with the communications industry allows the unit cost of the sensors to be low, This program is directed toward the demonstration of (1) the first usage of a single point multi-axis strain grating sensor to monitor an adhesive bond, (2) the effectiveness of measuring transverse strain gradients in tracking the onset of damage in adhesively bonded joints, (3) localization of damage by measuring multi-dimensional strain field changes, (4) the strategic placement of fiber grating sensors in bonded joints does not degrade joint strength and, (5) fiber grating sensors can be used to monitor the curing process of an adhesive bond.