Fatigue tests were performed on lugs in five cases with stress ratio R = 0.1 and maximum load Fmax = 44 kN. However, it was found that there was a remarkable scatter of fatigue lives even in identicals tests. Fractography of the fractures lugs has shown that each crack initiated at one origin, which was on the hole surface and near one side of the lug. Stress analysis has demonstrated that the crack origins locate in a high stress region and the fatigue stresses make the lugs fail in range of 105 - 106 cycles. Detailed examination of the microstructure of the lugs has shown that the recrystallization degrees in the lugs vary. It is the scatter of recrystallization degree that increases the fatigue lives of lugs. A further analysis has indicated that the scatter of recrystallization degree may result from the differences of original bar stock sizes and deformation in die forging.
Fatigue life scatter of aluminum alloy helicopter lugs
Engineering Failure Analysis ; 7 , 4 ; 239-247
2000
9 Seiten, 8 Bilder, 2 Tabellen, 5 Quellen
Article (Journal)
English
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