Fiber Optic Non-Destructive Evaluation Systems for In-Flight Health Monitoring

Health management technologies are being developed for both current and future aircraft to detect and accommodate cracks and damage to the airframe structure and other aircraft components. Non-destructive evaluation (NDE) systems have been successfully demonstrated in numerous terrestrial applications but have not migrated to flight environments due to the prohibitive cost, size, weight and durability of the conditioning electronics, cable plant, and sensors. However, optical fiber sensors are rapidly emerging as viable alternatives to conventional NDE systems as effective means of detecting and quantifying acoustic emission (AE). Compared to traditional piezoelectric-based sensors, optical fiber sensors offer much smaller size, reduced weight, ability to operate at temperatures up to 2000¿C, immunity to electromagnetic interference, resistance to corrosive environments, inherent safety within flammable environments, and the ability to multiplex multiple sensors on a single fiber. The effort of this program is to further develop fiber optic AE sensors for in-flight health monitoring on both military and commercial aircraft. The areas of proposed activities include 1) developing fiber optic AE sensors specifically for flight application, 2) producing commercially available flight qualified sensors, cable plant and conditioning electronics and 3) developing data integration components to reduce the AE data into a usable form.