Multiscale three-dimensional stress analysis of voids clusters for the modelling of degenerated graphite in cast iron

We propose a multiscale three-dimensional model for the stress analysis of a cluster of degenerated graphite in spheroidal cast iron. The model allows to study the effect of graphite microstructure on the average stress distribution inside the cluster. At the microscale, precipitates of degenerated graphite are modelled as spheroidal voids. At the mesoscale, clusters of degenerated graphite are viewed as spheroidal inclusions made of equivalent porous elastic material. The equivalent elastic properties of the porous material are calculated using an approach proposed by Tandon and Weng and based on Eshelby's equivalent principle and the Mori-Tanaka's estimate. FE simulations at the microscale and at the mesoscale are performed in order to numerically validate the multiscale model.