A hysteresis loop model for fiber-reinforced ceramic matrix composites considering interface oxidation under high temperature

Fiber-reinforced ceramic matrix composites (FRCMCs), valued for superior high-temperature mechanical properties, are promising thermo-structural materials frequently exposed to cyclic loads. The hysteresis loop’s shape and position are correlated with internal damage accumulation in FRCMCs, making hysteresis loop model vital for structural health monitoring and material design optimization. To model hysteresis loops in high-temperature oxidation environments, each loading cycle is divided into six stages to reflect evolution of newly formed positive/negative slip region. Then, the axial stress distributions of fiber considering interface oxidation at each stage are calculated using shear-lag theory, and cycle-dependent matrix crack spacing and volume fraction of failure fibers are obtained. Finally, a hysteresis loop model for FRCMCs considering interface oxidation under high temperature is proposed according to intact fibers’ stress-strain relationship. Model validation against experimental data confirms its predictive accuracy for FRCMCs, and quantitative effects of multiple parameters on the hysteresis loop are investigated by the model.