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Effet des fortes contraintes hydrostatiques sur la tenue en fatigue des matériaux métalliques

Abstract : This work treats the effect of high hydrostatic stress on the high cycle fatigue resistance of metallic materials. The aim is to understand the effect of the mean stress (and more specifically very high mean stresses or load ratios), as well as the effect of a biaxial stress state (where biaxial implies two normal stresses). A vast experimental campaign was undertaken in which high cycle fatigue tests were performed on two materials, a cast aluminum alloy AlSi7Cu05Mg03 and a wrought aluminum 2024-O. The effect of the mean stress and the biaxiality on the fatigue behavior is investigated. Fatigue damage mechanisms are particularly studied. A literature review of different criteria found in the scientific literature is undertaken, with the aim of evaluating the capability of these different models to predict the effect of the mean stress and the biaxiality. A fatigue criterion for predicting the specific behavior of the cast aluminum alloy is proposed. Based on a probabilistic approach, this criterion takes into account the competition between the different damage mechanisms observed. It appears to efficiently predict the fatigue behavior for the two loading types studied. Observations conducted on different metal alloys, show that for very high load ratios, material damage created in the first ¼ cycle can modify the conditions under which fatigue cracks initiate. Consequently, a second fatigue criterion based on coupled plasticity and damage at the mesoscopic scale is put forward. It is shown that this approach is capable of reproducing the major experimental trends and in particular those relative to biaxial loading conditions.
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https://pastel.archives-ouvertes.fr/pastel-00599125
Contributor : Imade Koutiri <>
Submitted on : Wednesday, June 8, 2011 - 3:21:29 PM
Last modification on : Friday, July 17, 2020 - 2:58:26 PM
Long-term archiving on: : Friday, September 9, 2011 - 12:05:57 PM

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  • HAL Id : pastel-00599125, version 1

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Imade Koutiri. Effet des fortes contraintes hydrostatiques sur la tenue en fatigue des matériaux métalliques. Mécanique des matériaux [physics.class-ph]. Arts et Métiers ParisTech, 2011. Français. ⟨NNT : 2011ENAM0015⟩. ⟨pastel-00599125⟩

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