FATIGUE LIFE PREDICTION METHOD FOR A PLAIN WOVEN C/SiC COMPOSITE AT HIGH TEMPERATURE

Abstract

In this study, the concept of effective stress was proposed to reflect the effect of carbon fibre oxidation on the macroscopic properties of a plain woven C/SiC composite. Based on the creep test data under constant loading at high temperature, the relationship among the growth rate of the effective stress, applied stress and temperature was established. On this basis, a fatigue life prediction method for woven C/SiC composite at high temperature was proposed based on the effective stress. After determining the effective stress of each loading cycle, the fatigue lives were predicted by using the stress-life curve (S-N curve) at room temperature and the linear damage accumulation law. The comparison between the predicted and experimental lives of the plain woven C/SiC composite showed that the proposed method has a high predicted accuracy. In addition, the fatigue lives of the C/SiC composite were also predicted by the creep damage considered method, which has been widely used for predicting the fatigue life of metallic materials under isothermal or thermo-mechanical loading, and the applicability and accuracy of this method were also discussed.

Keywords

• plain woven c/sic composite
• fatigue life prediction
• high temperature
• effective stress
• creep damage