Abstract: A micro mechanics approach to predict low cycle tensile-tensile fatigue life of fiber reinforced ceramic matrix composites is presented. When first loading to fatigue maximum stress, matrix cracking, fiber/matrix interface de-bonding occur, and partial fibers fracture. The statistical approach is used to determine the percentage of fracture fibers. Upon cycling, fiber slips relative to matrix in the interface de-bonding region, which makes interface shear stress decreased. By combing fiber failure model and interface wear model, the relationship between the percentage of fiber failure and interface, or cycles, is determined. Residual strength of ceramic matrix composites decreases as fiber failure. When residual strength is lower than fatigue maximum stress, the material fails. The residual strength approach is used to predict the S-N curve of ceramic matrix composites, the S-N curve agrees well with experiment data.

Key words: Ceramic matrix composites, Fiber failure, Interface wear, Life prediction, S-N curve