A micromechanical damage model for effective elastoplastic behavior of partially debonded ductile matrix composites

A micromechanical damage model considering progressive partial debonding is presented to investigate the effective elastoplastic-damage behavior of pa rtially debonded particle reinforced ductile matrix composites (PRDMCs). Th e effective, evolutionary elastoplastic-damage responses of three-phase com posites, consisting of perfectly bonded spherical particles, partially debo nded particles and a ductile matrix, are micromechanically derived on the b asis of the ensemble-volume averaging procedure and the first-order effects of eigenstrains. The effects of random dispersion of particles are accommo dated. Further, the evolutionary partial debonding mechanism is governed by the internal stresses of spherical particles and the statistical behavior of the interfacial strength. Specifically, following Zhao and Weng (1996), a partially debonded elastic spherical isotropic inclusion is replaced by a n equivalent, transversely isotropic yet perfectly bonded elastic spherical inclusion. The Weibull's probabilistic function is employed to describe th e varying probability of progressive partial particle debonding. The propos ed effective yield criterion, together with the assumed overall associative plastic flow rule and the hardening law, forms the analytical framework fo r the estimation of the effective elastoplastic-damage behavior of ductile matrix composites. Finally, the present predictions are compared with the p redictions based on Ju and Lee's (2000) complete particle debonding model, other existing numerical predictions, and available experimental data. It i s observed that the effects of partially debonded particles on the stress-s train responses are significant when the damage evolution becomes rapid. (C ) 2001 Elsevier Science Ltd. All rights reserved.