ELASTIC PROPERTIES OF 2-PHASE COMPOSITES

Simple expressions were derived to predict the elastic properties of two-phase systems containing discontinuous reinforcements, on the basis of approximation of composite microstructure to a unit cell incorporating isostrain and isostress type elements, arranged in two different ways. The bounds on elastic modulus obtained in this manner have been shown to accurately describe the variation of elastic modulus as a function of volume fraction of one of the phases, for a wide variety of two-phase composites. The present expressions offer predictions of elastic modulus that are much closer to experimental data than the commonly used Hashin and Shtrikman bounds, particularly for composites with constituents having large differences in elastic moduli. Similarly, it has been shown that the shear moduli and the Poisson's ratios of composites as a function of second-phase volume fraction can also be predicted. The present unit-cell-based method of calculation presents a promising approach for the prediction of properties of multiphase materials, especially for those consisting of more than two dissimilar phases.