Optical Sensor for Detection of Fatigue Damage Precursors

Reliable and operationally simple methods that can be used in the field are needed for expeditious fatigue damage and corrosion detection. We have developed a strategy for constructing a laser-based nondestructive sensor for fatigue and corrosion damage detection and monitoring in aerospace components. The sensor detects precursors to crack formation occurring as early as the first 10% of fatigue life and, therefore, can be used to identify accumulated fatigue damage prior to crack initiation. The sensor can also be used to detect the state of surface corrosion formation. During Phase I, we will demonstrate the proof-of-concept of a compact, leave-in-place, nondestructive, optical sensor with remote wireless interrogation of the retrieved data and develop a strategy for building a prototype of the instrument. During Phase II, we will further refine our work in modeling the instrument, designing its specific components, assembling it, and establishing its performance envelope. Phase II will culminate in constructing and field-testing the prototype system.