REPEATED TENSILE BEHAVIOUR AND DAMAGE EVOLUTION OF A 2.5D C/SiC COMPOSITE CHARACTERISED BY GREY VERHULST MODELS

The microstructure and repeated tensile behaviour of a 2.5D C/SiC composite fabricated by chemical vapour infiltration were examined and the associated damage evolution was characterised by the residual strain and reloading modulus. Both the envelope stress-strain behaviour and the associated damage evolution of the composite can be well characterised by three regimes including the matrix cracking emergence, a multiplication followed by the matrix cracking saturation. The grey Verhulst model and the inverse grey Verhulst model were established for the evolution of the damage characteristics and the constitutive behaviour, respectively. Excellent agreement between the predictions and experimental results was obtained for both the grey models, which indicates the nature of intra-specific competition for these matrix cracks in the composite studied. Such robust relationships can be further applied to facilitate the modelling of the constitutive behaviour of other ceramic composite systems.