De la rupture des materiaux à comportement fragile

Abstract : The rupture of brittle materials is due to initial flaws. In the case of monolithic materials, the latter lead to catastrophic failures. On the other hand, in the case of fiber reinforced ceramics, the final rupture is due to gradua1 fiber fiagmentation. Experiments were conducted on specimens made of two different ceramics and on concrete. They demonstrate the influence of the stress field pattern and the initial flaw distribution upon the failure stresses. A first approach to take these initial flaws into account is through an initial value of a scalar damage variable, randomly distributed within the structure according to the flaw distribution. It allows to get the value of the cumulative failure probability. A second approach assumes that interactions between flaws and their influence on the macroscopic stress field is negligible. This approach is implemented as a post-processor to a F.E. code. It also enables to derive a closed-form expression of the cumulative failure probability related to initial flaw distributions. An extension to cyclic loading is given. Lastly, al1 these considerations can be utilized to derive a constitutive equation of fiber reinforced ceramics in the fi-amework of continuum damage mechanics. By using the localization theory, the condition of macroscopic rupture can be described by a critical value of a scalar anisotropic damage variable related to the Weibull modulus.
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https://tel.archives-ouvertes.fr/tel-00460367
Contributor : François Hild <>
Submitted on : Saturday, February 27, 2010 - 11:02:44 PM
Last modification on : Friday, May 17, 2019 - 1:23:54 AM
Long-term archiving on : Wednesday, November 30, 2016 - 2:25:54 PM

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  • HAL Id : tel-00460367, version 1

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François Hild. De la rupture des materiaux à comportement fragile. Sciences de l'ingénieur [physics]. Université Pierre et Marie Curie - Paris VI, 1992. Français. ⟨tel-00460367⟩

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