Synergistic effects effects of stochastic loading stress and time on stress-rupture damage evolution and lifetime of fiber-reinforced ceramic-matrix composites at intermediate temperatures

摘要

In this paper, the synergistic effects of the stochastic loading stress and time interval on the stress-rupture damage evolution and lifetime of fiber-reinforced ceramic-matrix composites (CMGs) at intermediate temperatures are investigated. The relationships between the stochastic loading stress and stochastic time interval, internal damage evolution, macro strain, broken fiber fraction, and stress-rupture lifetime of fiber-reinforced CMCs are established. The effects of the stochastic loading stress and stochastic time interval, constituent properties, damage condition, and environment temperature on the stress-rupture time, strain evolution, and internal damage of SiC/SiC composite under stress-rupture loading are discussed. The experimental stress-rupture behavior of SiC/SiC composite under constant and stochastic loading condition are predicted. The stress-rupture lifetime decreases with increase of stochastic stress level, stochastic time interval, and environmental temperature, and increases with the fiber volume and interfacial shear stress in the slip region.