Degradation Modeling of Composite Interfacial Properties Under Coupled Humidity and Thermal Conditions

Under the influence of coupled humidity and thermal conditions, the interfacial properties of composite materials undergo significant degradation. While current research mainly focuses on the mechanisms of degradation, quantitative modeling of interfacial property loss under these coupled conditions remains a major challenge. This study investigates the CCF300/5428 carbon fiber composite through hygrothermal coupling tests conducted at 25° C, 130° C, and 150° C. Based on the experimental data, a residual strength model incorporating temperature-induced stress was developed to quantify the degradation of composite interfacial properties. The model demonstrated superior fitting performance, with an R2 value of 0. 9 7 9 4. Compared to traditional power-law models, the proposed model showed admirable improvements by reductions of 11.68 % in AIC and 7.13 % in BIC. Furthermore, key parameters, such as activation energies and temperature-dependent terms, were quantified to elucidate the roles of resin plasticization, microcracking, and interfacial debonding in property degradation. The proposed model provides a robust framework for predicting mechanical degradation in composites under diverse hygrothermal conditions, offering valuable insights for optimizing material design in aerospace and marine applications.