MODELLING THE TENSILE DAMAGE AND FRACTURE PROCESSES OF FIBRE-REINFORCED CERAMIC-MATRIX COMPOSITES UNDER THE EFFECT OF PRE-EXPOSURE AT ELEVATED TEMPERATURES

In this paper, the tensile damage and fracture process of fibre-reinforced ceramic-matrix composites (CMCs) under the effect of pre-exposure at elevated temperatures are investigated. The damage mechanisms of the interface oxidation and the fibre failure are considered in the stress analysis, matrix multi-cracking, interface debonding and fibre failure. Combining the stress analysis and damage models, the tensile stress-strain curves of the fibre-reinforced CMCs for the different damage stages can be obtained. The effects of the pre-exposure temperature and time, interface shear stress, fibre strength and fibre Weibull modulus on the tensile damage and fracture processes are analysed. The experimental tensile damage and fracture process of the fibre-reinforced CMCs with the different fibre preforms are predicted for the different pre-exposure temperatures and times.