DAMAGE PATTERNS AND CONSTITUTIVE RESPONSE OF RANDOM MATRIX-INCLUSION COMPOSITES

Out-of-plane responses of disordered matrix-inclusion composites are s tudied as spatially cooperative phenomena of initiation and propagatio n of cracks; both phases (of matrix and inclusions) are locally isotro pic and elastic-brittle, The tool is a numerical simulation method bas ed on a very fine two-dimensional spring network, whereby damage evolu tion is simulated by sequentially removing/breaking bonds in this latt ice in accordance with the local state of stress/strain concentrations . Two parameters-stiffness ratio and strain-to-failure ratio of both p hases-define a damage plane onto which various aspects of the system's response are being mapped, thereby resulting in damage maps. The main focus of the study is on a basic classification and statistical scatt er of effective constitutive responses, as well as on the accompanying geometric patterns of damage. Additionally, an investigation of the d amage sensitivity of periodic composites to very weak perturbations in geometry and material properties is carried out. The paper concludes with a proposal for a model of stress-strain responses by a jump Marko v process. (C) 1997 Elsevier Science Ltd.