Fatigue-crack initiation and growth in notched 2024-T3 specimens monitored by a video tape system

摘要: Fatigue-crack initiation and early stages of growth in notched 2024-T3 aluminum alloy sheet specimens were monitored during constant-amplitude fatigue tests conducted for a range stress ratios. A video tape system was developed to detect cracks 0.1 mm length on the surface monitor their growth. Fatigue initiated either at notch corner or surface. Most first started as notch-corner cracks, crack-initiation period defined number cycles which crack For each ratios used, results showed that low levels, constituted least 90 percent lives. However, negative high about 40