Optimisation of 3D RVE for anisotropy index reduction in modelling thermoelastic properties of two-phase composites using a periodic homogenisation method

Abstract : In the present paper, a periodic homogenisation method is used to predict the thermomechanical properties of heterogeneous ceramics containing randomly dispersed inclusions (or pores) by modelling this complex microstructure by a Representative Volume Element (RVE) composed of a small number of inclusions (or pores). The combination of suitable RVE geometries is used to find 3D arrangements as less anisotropic as possible, in the case of ceramics with glass matrix and either alumina inclusions or pores. It is shown that anisotropy indices, in terms of elastic stiffness and thermal expansion of face-centred cubic (F.C.C.) and hexagonal close-packed (H.C.P.) arrangements are very close to the isotropic case. Therefore, these arrangements have, then, been assumed to be isotropic for the calculation of the isotropic thermoelastic properties of the model materials. A good agreement with the experimental and analytical results is observed, validating the proposed methodology.