Multiscale approach of mechanical behaviour of SiC-SiC composites : elastic behaviour at the scale of the towReportar como inadecuado

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1 SRMA - Service des Recherches Métallurgiques Appliquées DMN - Département des Matériaux pour le Nucléaire : DEN-DMN 2 Multi-échelle - Modélisation et expérimentation multi-échelle pour les solides hétérogènes NAVIER UMR 8205 - Laboratoire Navier 3 MAT - Centre des Matériaux 4 LMS - Laboratoire de mécanique des solides

Abstract : SiC-SiC composites are candidates for structural applications at elevated temperatures in the context of the development of the 4th generation of nuclear reactors. A multiscale approach is under development to construct a predictive modelling of their complex mechanical behaviour due to their heterogeneous microstructure. This approach is based on two scale transitions: from the fibres-matrix microstructure to the tow and from the tow to the woven composite, each scale presenting a significant residual porosity. This paper focuses on the first scale transition and on the modelling of the elastic behaviour of the tow at room temperature. A microstructural investigation of several tows in a 2D SiC-SiC specimen has been conducted using scanning electron microscopy to get statistical data on microstructural characteristics by image analysis in order to generate a virtual microstructure. The elastic problem of homogenisation is numerically solved by means of finite element techniques. The simulations performed on various volumes show noticeable fluctuations of the apparent behaviour: so separation of length scales is not satisfied in this material. Nevertheless, this problem is neglected in a first approximation and the homogeneous equivalent behaviour is evaluated by averaging the apparent behaviours of several volume elements - smaller than the Representative Volume Element RVE – called Statistical Volume Elements SVEs. Finally, influence of porosity and pores- morphology is quantified.

Autor: Camille Chateau - Lionel Gélébart - Michel Bornert - Jérome Crépin - Daniel Caldemaison -



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