Damage analysis during full-scale testing of F-15 airframe using arrays of optical fiber sensors

We discuss fatigue test results using extrinsic Fabry-Perot interferometric (EFPI) strain gages on a F-15 fighter within a full-scale test frame at the Structures Test Facility, Wright Patterson Air Force Base, Ohio. A linear array of EFPI sensors were surface-mounted to the trailing edge of the F-15 wing to monitor strain concentration along the inboard flap hinge. Two types of EFPI strain gages and strain gage support systems were employed; linearized output from the standard, differential EFPI sensor system determined dynamic strain on the flap hinge during the application of load, whereas, absolute EFPI strain sensors were implemented to measure residual strain or cracks in the aluminum hinge.