Reducing Uncertainty for Fatigue Life Limits at Notches in Two Structural Alloys

Fatigue life variability is modeled as a combination of a mean-lifetime and a dominant life-limiting crack growth mechanism in two materials: a powder metal nickel-base superalloy IN100 and a cold rolled plate of aluminum alloy 7075-T651. Specimens of both materials had a common double-edge notch ge...

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Bibliographic Details
Published in:AIP conference proceedings 2012-03
Main Authors: Buchanan, Dennis, Larsen, James, Rosenberger, Andrew, John, Reji, Jha, Sushant, Hutson, Alisha, Porter, W John
Format: Article
Language:English
Subjects:
Alloys
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Summary:Fatigue life variability is modeled as a combination of a mean-lifetime and a dominant life-limiting crack growth mechanism in two materials: a powder metal nickel-base superalloy IN100 and a cold rolled plate of aluminum alloy 7075-T651. Specimens of both materials had a common double-edge notch geometry with a stress concentration factor of Kt = 1.89. Fatigue tests were conducted under constant amplitude loading at temperatures of 23 degree C and 650 degree C for the 7075-T651 and IN100, respectively. Fatigue failure initiated at sites located either along the notch surface or at the notch corner. Crack growth behavior was predicted for both of these initiation sites using a weight function solution and the cyclic and residual stress profiles from three-dimensional finite element analysis The predicted fatigue lives for a range of stress levels correlated well with the observed experimental data and the minimum (1 in 1000 probability of failure) lifetime limit for both materials.
ISSN:0094-243X