Modeling fatigue hysteresis behavior of unidirectional C/SiC ceramic-matrix composite

In this paper, the fatigue hysteresis behavior of unidirectional C/SiC ceramic-matrix composite at room and elevated temperatures in air atmosphere has been investigated. The fatigue hysteresis modulus and fatigue hysteresis loss energy corresponding to different cycles have been analyzed. An approach to model fatigue hysteresis loops of unidirectional ceramic composites considering fiber failure has been developed. Based on the damage mechanism of fiber slipping relative to matrix under fatigue loading, the unloading interface counter-slip length and reloading interface new slip length are determined by fracture mechanics approach. The interface shear stress and broken fibers fraction corresponding to different cycles are obtained through comparing the experimental fatigue hysteresis loss energy with theoretical computational value considering fiber failure. The fatigue hysteresis loops of unidirectional C/SiC composite have been predicted for different number of cycles.