Contact Behavior of Phenyl Silicone Rubber Material Under the Condition of High-Altitude Environment

Phenyl silicone rubber is widely used in aircraft seals for its high- and low-temperature tolerance and chemical stability. However, intense UV radiation and elevated ozone at high altitudes accelerate aging, threatening seal reliability. The accelerated aging tests of phenyl silicone rubber seals have been carried out under UV and ozone to examine their mechanical, microstructural, and chemical evolution. Then, a finite element contact model of phenyl silicone rubber seals was developed considering the influence of UV and ozone aging. Both conditions increased hardness and elastic modulus but reduced tensile strength and elongation at break, with UV degradation markedly more severe. UV exposure caused a 29% maximum loss in elongation (compared to 16% under ozone) and a hardness rise of 2.30 HA, roughly 1.7 times that of ozone aging (1.35 HA). The contact pressure increases by approximately 15.2% and 10.7%. These findings provide a theoretical basis for performance evaluation and service-life prediction of these seals in high-altitude environments.