In-Situ Surface Acoustic Wave Monitoring of Fatigue Crack Initiation and Propagation

Material degradation due to pitting corrosion and fatigue crack initiation from pits may trigger widespread fatigue damage in aging aircraft structures. Since corrosion damage is often hidden, the corrosion pits and initiated cracks can remain undetected by surface inspection techniques for long service periods. Therefore, the ability to predict the initiation and propagation of surface damage originating from pitting corrosion is of great importance for the timely maintenance of aging airplanes [1]. Recently, we reported a microradiographic method quantifying pitting corrosion [2] and fatigue life prediction model [3] based on the measured pit depth. These have been applied successfully to A1-2024-T3 alloy