Abstract:
The sealing performance serves as a critical indicator for spacecraft rubber sealing systems, where the degradation behavior of rubber materials directly determines the service life of these systems. Current research on rubber sealing performance evolution primarily focuses on qualitative studies of macroscopic contact properties or specific mechanical property variations, with limited quantitative investigations on leakage rate calculations based on seal leakage channels. This paper establishes a microscopic leakage model for spacecraft-grade ethylene-propylene-diene monomer (EPDM) rubber by analyzing interfacial leakage channels and molecular flow characteristics of the gas, with theoretical leakage rate calculations validated through experimental measurements. The compression set of rubber materials was tested using time-temperature equivalence theory, and a thermal-oxidative aging mathematical model was developed for lifespan prediction. Stress-strain constitutive relationships were obtained for rubber materials subjected to various thermal-oxidative aging conditions, with the measured relationships incorporated into finite element models for sealing performance analysis. A microscopic leakage model considering thermal-oxidative aging effects was established by analyzing pre-/post-aging surface micro-morphology and calculating contact pressure/width variations. Leakage rates under different thermal-oxidative aging conditions were calculated, with experimental leakage rate measurements validating the theoretical results.