ELASTIC STRESS FLUCTUATIONS IN RANDOM STRUCTURE PARTICULATE COMPOSITES

We consider a linear elastic composite medium, which consists of a hom ogeneous matrix containing a homogeneous and statistically uniform ran dom set of ellipsoidal inclusions. All components of the statistical s econd moment tensor of the stress fields, averaged over the volume of the components, is obtained. The micromechanical approach is based on the Green function technique as well as on the ''multiparticle effecti ve field'' method (MEFM), previously proposed for estimating stress fi eld averages in the components. The application of the theory is demon strated by the construction of overall yield surfaces of composite mat erials. For the particular case of porous isotropic materials the comp arison of results obtained by the proposed method with other ones is s hown.