Analytical Modeling, Analysis and Experimental Verification of Degradation Characteristics of Ceramic Matrix Composite Thin Plates in an Extremely High-Temperature Condition

The dynamic degradation behaviors of ceramic matrix composite (CMC) thin plates due to long-term an extremely high-temperature environment may cause structure failure or catastrophic accidents. Therefore, in this paper, an analytical model considering the temperature and degradation time effects is proposed to study its dynamic characteristics. The effectiveness of the proposed modeling approach is verified by comparing it with the experimental testing, demonstrating maximum errors of 7.9% for natural frequencies and 11.8% for resonant responses under [Formula: see text]C and [Formula: see text]C at varying degradation stages. The Rayleigh-Ritz approach, incorporating the classical laminated plate theory and the complex modulus method is used to construct such a model. Then, a dynamic transmissibility index is introduced to quantitatively estimate the structural degradation level. Finally, the effects of temperature and degradation time on the structural natural frequencies and dynamic responses are systematically analyzed. The results indicate that the proposed method can effectively evaluate the structural degradation resistance, which can provide efficient guidance for fault diagnosis and health monitoring of similar structures.