Reliability Modeling of Single-Sided Aluminized Polyimide Films during Storage Considering Stress-Induced Degradation Mechanism Transition

Single-sided aluminized polyimide films (SAPF) are widely used in thermal management of aerospace systems. Although the reliability of SAPF in space environments has been thoroughly studied, its reliability in ground environments during storage is always ignored, potentially leading to system failure. This paper aims to investigate the reliability of SAPF in storage environments, focusing on the effects of temperature and relative humidity. Firstly, the relationship between the performance degradation of SAPF and aluminum corrosion is identified. Next, considering the presence of two distinct stages in the influence of temperature on aluminum corrosion, a novel degradation model accounting for the degradation mechanism transition is developed. Additionally, a parameter analysis method is proposed for determining SAPF degradation mechanism based on experimental data. Then, a statistical analysis method incorporating an improved rime optimization algorithm is employed for parameter estimation, and the reliability model is established. Experimental results demonstrate that the proposed method effectively identifies two distinct stages in the impact of temperature on SAPF performance degradation. Furthermore, the proposed degradation model outperforms traditional degradation models with unchanged degradation mechanism in terms of degradation prediction accuracy, extrapolation capability and robustness, indicating its suitability for describing the degradation pattern of SAPFs.