AbstractA new approach for predicting the Young's modulus of two phase composites has been proposed based on a topological transformation and the mean field theory. The new approach has been applied to Co/WCp,Al/SiCp, and glass filled epoxy composites. It is shown that the new theoretical predictions are well within the Hashin and Shtrikman lower and upper bounds (the HS bounds) and are in closer agreement with the experimental results for the corresponding composite systems than both the HS bounds and the predictions of the mean field theory. An advantage of the present approach over other continuum approaches is that it can predict not only the effect of volume fraction of the reinforcing phase, but also the effects of microstructural parameters such as grain shape and phase distribution on the stiffness of composites. It is also shown that the classical linear law of mixtures is a specific case (where the reinforcing phase is continuous and perfectly aligned) of the present approach. In contrast to the classical linear law of mixtures, the present approach can be applied to a two phase composite having any volume fraction, grain shape, and phase distribution. It is shown that in a particulate composite having a given volume fraction of reinforcement, the Young's modulus of the composite increases with increasing contiguity of the constituent phases and this increment is dependent on the stiffness ratio of the constituent phases. Furthermore, the present approach can provide a simple and effective solution to the problem of interaction between particles of the same phase.MST/1587