Degradation Modeling of Compressive Mechanical Properties of Delamination-Defective Composites Considering Heteroscedastic Dispersion

Due to the limitations of composite manufacturing processes, the mechanical properties of composite materials are significantly affected by defects such as delamination and porosity. Current degradation analyses of composite materials under defect conditions are mostly based on average or minimum performance, neglecting dispersion analysis, which restricts the generalization ability of the models. This paper takes ZT7H/5428 carbon fiber composite materials as the research object and proposes a compressive performance degradation prediction model that considers the size and location of delamination defects. By combining the heteroscedastic characteristics of the degradation process, the quantitative analysis of the uncertainty in degradation is conducted. The proposed model has been well validated with experimental data, achieving prediction R² of 0.917, Root Mean Square Error (RMSE) of 364.96, and a prediction interval coverage probability (PICP) of 97.14% under 95% confidence. The proposed model provides guidance for the design, maintenance, and production process control of composite material structures.