A theoretical investigation into the inelastic behavior of metal-matrix composites

Abstract : Various self-consistent analysis have been proposed and used to approximately evaluate the elastic stiffness and elastic-plastic behavior of metal-matrix composites. Such analysis have generally relied on very simple theoretical models for the matrix inelastic stress-strain response. This was perhaps substantiated on the basis of a lack of combined stress state experiments. Weng (1988) successfully approximated the inelastic behavior of spherical particle-reinforced utilizing a modified self-consistent model called the equivalent inclusion-average stress (EIAS) method. Noting the overly stiff response of the basic EIAS model, he developed the 'secant modulus' method to correct for the overconstraining power of the matrix. The purpose of this thesis is to reexamine the problem in the context of more sophisticated nonlinear kinematic hardening rules for the matrix. An EIAS method which incorporates a tangent stiffness formulation based on incremental plasticity is proposed.