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Effets de taille et d'interphase sur le comportement mécanique de nanocomposites particulaires.

Abstract : The aim of this work is the development of predictive tools to account for the effect of particle size on the mechanical behaviour of particulate nanocomposites. An introduction of specific information at the atomic scale, via Molecular Dynamics (MD) simulations, into homogenization models of the overall mechanical behaviour of heterogeneous materials (micromechanical approach) is proposed here. The interest of the method proposed in this work lies in the fact that it could be extended to the more general case of taking! into account characteristic length in heterogeneous materials. Studying virtual nanocomposites using MD simulations reveals the existence of an interphase of disturbed matrix surrounding the inclusions. The virtual systems are composed of silica inclusions embedded in a polymer matrix. The range of perturbation to the structure of the polymer chains is independent of the particle size and volume fraction of inclusions, but decreases with increasing temperature. By considering that the interphase surrounding the nanoparticles has a fixed thickness, a particle size effect has been introduced into micromechanical models of the effective mechanical properties of the nanocomposites. In the case of low volume fractions of inclusions, the use of just a 3-phase pattern is sufficient. The study of the mechanical behaviour of virtual nanocomposites, using non-equilibrium MD, reveals a reinforcement effect on the composite moduli and a particle size effect. Confrontation with 3+1-phase micromec! hanical models and the determination of the interphase elastic moduli by inverse techniques allows the stiffening effects observed by MD to be explained in the case of an interphase softer than the matrix.
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https://pastel.archives-ouvertes.fr/pastel-00001804
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Submitted on : Wednesday, July 28, 2010 - 10:31:14 AM
Last modification on : Thursday, September 24, 2020 - 4:00:22 PM
Long-term archiving on: : Friday, October 29, 2010 - 10:01:37 AM

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  • HAL Id : pastel-00001804, version 1

Citation

Vincent Marcadon. Effets de taille et d'interphase sur le comportement mécanique de nanocomposites particulaires.. Mécanique des matériaux [physics.class-ph]. Ecole Polytechnique X, 2005. Français. ⟨pastel-00001804⟩

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