Résumé
This study deals with the determination of effective elastic properties of random porous ceramics. Ceramic-matrix composites with bi-modal pore shape (spherical and ellipsoidal pores randomly distributed) are considered. For such a microstructure, various micro-mechanical estimates are compared to three dimensional numerical simulations based on periodic homogenization. Effective elastic moduli are derived as a function of matrix properties, porosity and pore shape. In the case of nuclear fuel ceramics, spherical and ellipsoidal pores are identified to inter-granular and intra-granular pores respectively, and obtained effective elastic properties are compared to experimental micro-acoustic data.