THERMOELASTIC STRESS FLUCTUATIONS IN RANDOM-STRUCTURE COATED PARTICULATE COMPOSITES

In this paper linearly thermoelastic composite media are considered, c onsisting of a homogeneous matrix containing a statistically homogeneo us random set of ellipsoidal uncoated or coated inclusions. This study constitutes an extension of the theory regarding the purely isotherma l elastic case and uncoated ellipsoidal inclusions. Effective properti es (such as compliance, thermal expansion, stored energy) and both fir st and second statistical moments of stresses in the components are es timated for the general case of nonhomogeneity of the thermoelastic in clusion properties. The micromechanical approach is based on Green's f unction techniques and on the generalization of the 'multiparticle eff ective field' method (MEFM), previously proposed for the estimation of stress field averages in the components. The application of this theo ry is demonstrated by calculating this overall yield surfaces of compo site materials. The influence of the coating is analyzed both by the a ssumption of homogeneity of the stress field in the inclusion core and the thin-layer hypothesis. (C) Elsevier, Paris.