Abstract
The close relationship between sequence-sensitive near-tip residual stress and threshold stress intensity raises questions about load interaction models currently in use to estimate fatigue crack growth under variable amplitude loading. In an attempt to address them, experiments were performed on an Al-Cu alloy under specially designed load sequences with periodic overloads. Fractographic evidence from these tests confirms that fatigue crack closure, together with sequence sensitive variation in threshold stress intensity appear to explain all observed results. The fractographic data provide quantitative inputs for improved modeling of variable-amplitude fatigue, particularly at near-threshold crack growth rates. This study appears to suggest that conventional approaches based on the Wheeler and Willenborg residual stress models can provide reasonable estimates only by coincidence. They model the wrong parameter at lower fatigue crack growth rates and may simply not be valid at other growth rates.
Original language | English |
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Pages (from-to) | 667-675 |
Number of pages | 9 |
Journal | International Journal of Fatigue |
Volume | 82 |
DOIs | |
Publication status | Published - 1 Jan 2016 |
Keywords
- Crack closure
- Near threshold fatigue
- Near-tip residual stress
- Variable-amplitude loading
ASJC Scopus subject areas
- Industrial and Manufacturing Engineering
- Mechanical Engineering
- Mechanics of Materials
- Materials Science(all)
- Modelling and Simulation