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Vers un matériau virtuel pour les composites céramiques

Abstract : In the current age of composite materials, industrial developments are based largely on the use of numerical tools for structures and materials design and optimization. With regard to the scientific challenge posed by the construction of these tools, we propose to collect the work of macro- and micro-mechanics communities. For this, we consider modeling and simulating frameworks large enough to contain all the mechanisms, situated at different scales and belonging to various physics, that drive the mechanical behavior and lifetime of composites. The derived models, called virtual materials, are i) useable in both structural design and material optimization, ii) extrapolating to severe loads and large lifetimes, iii) generic for entire families of materials. The thesis presented here initiates the construction of such a virtual material for self-healing ceramic matrix woven composites developed by Snecma Propulsion Solide, and several bricks are studied. i) At the macroscopic level, the mechanical behavior is analyzed through a model written in the framework of the anisotropic and unilateral damage theory. We first discuss the framework of the theory, several formulations and evolution laws are then compared. Then we discuss the numerical implementation of the proposed models, and examples of industrial structure calculations are presented. ii) At the yarn level, to handle with the inter-yarn cracking, a method based on damage mechanics with limited rate in quasi-static is analysed and illustrated by examples of propagation calculations. iii) Also at this scale, intra-yarn transverse cracking is introduced through a continuous model with inelastic deformation, homogenized from a discrete model with friction situated at the fiber scale. Examples of calculations on realistic fabric are presented. iv) Finally, the key point of the work: the fiber lifetime is analyzed through an innovative approach to the sub-critical propagation of defects in ceramics. It unifies classical and sub-critical propagations, as well as reaction- and diffusion-controlled propagations, through a simple coupling between fracture mechanics and diffusion/reaction problems. It is validated on the case of Hi-Nicalon fiber.
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Contributor : Martin Genet <>
Submitted on : Thursday, April 15, 2010 - 6:22:24 PM
Last modification on : Monday, February 15, 2021 - 10:41:13 AM
Long-term archiving on: : Wednesday, November 30, 2016 - 4:52:36 PM


  • HAL Id : tel-00473030, version 2


Martin Genet. Vers un matériau virtuel pour les composites céramiques. Mécanique []. École normale supérieure de Cachan - ENS Cachan, 2010. Français. ⟨tel-00473030v2⟩



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