*Int.J.Sol.Struct.* **37**, 3177-3200, 2000

### ON THE THERMO-ELASTO-STATICS OF COMPOSITES

WITH COATED RANDOMLY DISTRIBUTED INCLUSIONS

V.A. Buryachenko¹ and F.G. Rammerstorfer ²

¹Air Force Research Laboratory, Materials Directorate,

AFRL/MLBC, Wright-Patterson AFB, Dayton, OH

²Institute of Lightweight Structures and Aerospace
Engineering,

TU Wien,
Vienna, Austria

**Abstract** -
We consider a linearly elastic composite medium with stress free strains,
which consists of a homogeneous matrix containing a homogeneous and
statistically uniform random set of coated ellipsoidal inclusions having
all the same form, orientation and mechanical properties.
We are using the main hypothesis of many micromechanical methods, according
to which each inclusion is located inside a homogeneous so-called effective
field.
It is shown, in the framework of the effective field hypothesis, that from a
solution of the pure elastic problem (with zero stress free strains) for the
composite the relations for the effective thermal expansions, stored energy
and average thermoelastic strains inside the components can be found.
This way, one obtains the generalization of the classical formulae by Rosen
and Hashin (1970, Int.J.Engng.Sci. 8, 157-173), which are exact for
two-component composites.
The proposed theory is applied to the example of composites reinforced with
particles with thin inhomogeneous (along inclusions surface) coatings.
For a single coated inclusion the micromechanical approach is based on the
Green function technique as well as on the interfacial Hill operators.

(hjb,000417)