Fatigue life prediction of needled ceramic matrix composite under variable amplitude loading

•S-N curve was proposed based on the normalized fatigue loading parameter.•Relationship between normalized loading and fatigue life was obtained.•Fatigue life prediction method was developed under variable amplitude loading.•Influence of needled fiber bundle on the fatigue life dispersion was identified. The fatigue loading parameter-life (S-N) curve of the needled composite was proposed by constant amplitude fatigue tests first, and then the variable amplitude fatigue tests of needled C/SiC ceramic matrix composite were completed. Combined with the rainflow counting method, the Goodman line, the constant amplitude S-N curve and the linear damage accumulation rule, the fatigue life of the needled C/SiC composite was predicted under tensile variable amplitude block loading. According to the ratio of the width containing needled fiber bundle to the specimen width, the influence of needled fiber bundle on the fatigue life dispersion was quantitatively analyzed for the specimens with different fatigue lives.