Damage development in fiber-reinforced ceramic-matrix composites under cyclic fatigue loading using hysteresis loops at room and elevated temperatures

In this paper, the damage development behavior in fiber-reinforced ceramic-matrix composites (CMCs) with different fiber architectures, i.e., unidirectional, cross-ply and 2D woven, under cyclic fatigue loading at room and elevated temperatures has been investigated using fatigue hysteresis loops, i.e., fatigue hysteresis modulus, fatigue hysteresis dissipated energy, and fatigue hysteresis dissipated energy-based damage parameter. The relationships between fatigue hysteresis loops, fatigue hysteresis modulus, fatigue hysteresis dissipated energy and fatigue hysteresis dissipated energy-based damage parameter have been established. The effects of fiber volume content, fatigue peak stress, fatigue stress ratio, matrix crack spacing, multiple matrix cracking modes, and woven structures on the damage evolution in fiber-reinforced CMCs have been investigated. The experimental fatigue hysteresis modulus, fatigue hysteresis dissipated energy and fatigue hysteresis dissipated energy-based damage parameter versus cycle number have been predicted for unidirectional, cross-ply and 2D woven CMCs at room and elevated temperatures. It was found that the damage parameters derived from the fatigue hysteresis loops can effectively monitor the damage development and predict the fatigue life of fiber-reinforced CMCs.