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Morphologie microstructurale et comportement mécanique ; caractérisations expérimentales, approches par bornes et estimations autocohérentes généralisées.

Abstract : The prediction of the effective behaviour of heterogeneous random materials as a function of the spatial distribution of the constitutive phases is still an open question. The associated formalism and several micromechanical approaches are presented. An experimental study on two-phase iron/silver and iron/copper blends with a "matrix/inclusions" morphology or with bi-continuous phases shows that the morphological parameters act mainly at the local scale and especially on the local strain heterogeneities, caracterized in terms of phase averages and distribution functions, measured by means of a new microextensometric technique. Since classical models are not able to describe the observed phenomena, a new approach based on the concept of "morphologically representative pattern" is proposed. A first semi-analytical model with multilayered patterns is still insufficient. A more general morphological description can be achieved with ellipsoidally distributed patterns with arbitrary internal structure. It generates rigorous bounds and self-consistent estimates for the effective linear behaviour. The underlying theory is thoroughly described and the actual physical meaning of these models is commented. The effective computation is possible with numerical methods and leads for instance to new results for anisotropic particulate composites, whose local interactions are correctly described. But the description of some long-range interactions which have been observed experimentally in the nonlinear domain remains a open question.
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https://pastel.archives-ouvertes.fr/tel-00113078
Contributor : Michel Bornert <>
Submitted on : Friday, November 10, 2006 - 3:16:10 PM
Last modification on : Wednesday, October 14, 2020 - 4:02:28 AM
Long-term archiving on: : Tuesday, April 6, 2010 - 10:12:34 PM

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  • HAL Id : tel-00113078, version 1

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Michel Bornert. Morphologie microstructurale et comportement mécanique ; caractérisations expérimentales, approches par bornes et estimations autocohérentes généralisées.. Mécanique [physics.med-ph]. Ecole Nationale des Ponts et Chaussées, 1996. Français. ⟨tel-00113078⟩

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