Cyclic plasticity and damage of a metal matrix composite by a gradient-enhanced CDM model

Abstract: Cyclic plasticity and damage of a metal matrix composite have been studied in the framework of continuum damage mechanics. The material was considered as macroscopically homogeneous and a model incorporating damage gradient was applied. Strain-controlled fully reversed low-cycle fatigue uniaxial tests were performed to identifymaterial parameters related to yield stress, isotropic and kinematic hardening, fatigue life and damage diffusion. From previous studies it has been found that in the most general case the parameters of the model are constant or depend exponentially on total strain so that only two or three tests are needed for the characterisation. The results obtained from the application of the model in terms of hysteresis loop shape and fatigue life were compared to the experimental results and to the Manson-Coffin curve. Very good agreement was found, even if the experimental results were much spread, mostly due to the effect of brittle reinforcement clustering.