Modeling of fatigue hysteresis loops in C/SiC composite under multiple loading stress levels

In this paper, the tensile fatigue hysteresis behavior of unidirectional C/SiC ceramic-matrix composite under multiple loading stress levels has been investigated. The fatigue hysteresis loops and fatigue hysteresis loss energy corresponding to different number of applied cycles have been analyzed. Based on the fatigue damage mechanism of fiber slipping relative to matrix in the interface debonded region upon unloading/reloading, the unloading interface counter-slip length and reloading interface new-slip length are determined by fracture mechanics method. The fatigue hysteresis loops models corresponding to different interface slip cases under multiple loading stress levels have been developed. The relationships between fatigue hysteresis loops, fatigue hysteresis loss energy and interface slip have been analyzed. The fatigue hysteresis loops of unidirectional C/SiC composite corresponding to different number of applied cycles under multiple loading stress levels have been predicted.