Continuum Models and Discrete Systems (Ed. K.Z.Markov), pp. 140-147, 1996

ELASTIC-PLASTIC BEHAVIOR OF ELASTICALLY HOMOGENEOUS MATERIALS WITH A RANDOM FIELD OF INCLUSIONS

V.A. Buryachenko and F.G. Rammerstorfer

Institute of Lightweight Structures and Aerospace Engineering,
TU Wien, Vienna, Austria


Abstract - A two-phase material is considered, which consists of a homogeneous elastic-plastic matrix containing a homogeneous statistically uniform random set of ellipsoidal elastic-plastic inclusions. The elastic properties of the matrix and the inclusions are the same, but the so-called "stress free strains", i.e. the strain contributions due to temperature loading, phase transformations, and the plastic strains, fluctuate. A general theory of the yielding for arbitrary loading (by the macroscopic stress state and by temperature) is employed. The realization of an incremental plasticity scheme is based on averaging over each component of the nonlinear yield criterion. Usually averaged stresses are used inside each component for this purpose. In distinction to this usual practice physically consistent assumptions about the dependence of these functions on the component's values of the second stress moments are applied. The application of the proposed theory to the prediction of the thermomechanical deformation behavior of a model material is shown.


(hjb,960709)