Self-Calibrating Ultrasonic Methods for In-Situ Monitoring of Fatigue Crack Progression

摘要: Ultrasonic sensors permanently affixed to aluminum coupons are used monitor progression of damage during fatigue testing with the long term goal structural health monitoring for diagnostics and prognostics. Necessary success proper design ultrasonic methods, robust transducer mounting techniques, real‐time signal processing determining state structure. It is also highly desirable overall system be self‐calibrating built‐in in order detect compensate sensor degradation or failure. Self‐calibrating techniques applied cracks initiating propagating from inaccessible inner diameters rivet holes where transducers mounted on accessible specimen surface. Angle beam methods utilized that suitable detecting small defects critical local regions high stress. Results presented subjected low cycle demonstrate u...