A simplified multiscale model of degenerate graphite clusters in grey cast iron

To take into account the weakening effect of defects clusters in real microstructures, we propose a multiscale model in a two-dimensional setting. At a small scale, single defects are described as elliptical voids randomly distributed and randomly oriented in an isotropic matrix. Using an effective field method proposed by Tandon and Weng [5,6], the effective properties of a porous equivalent material can be estimated in a simple closed form. At a larger scale, defects clusters are modelled as single large elliptical inclusions characterized by the weakened effective properties calculated in the first step and embedded in an infinite, elastic, isotropic matrix under remote loading. The method allows to examine the dependence of defects interaction on some basic microstructure parameters (porosity density, voids aspect ratio, inclusion aspect ratio).