New method for studying the macro-micro contact properties between smooth metal and silicone rubber

Silicone rubber seals are widely used in the aerospace field due to the excellent chemical and mechanical properties. The contact properties of the silicone rubber have a great influence on the static sealing performance. In this paper, the macro-micro contact properties of silicone rubber are investigated by the experimental and finite element method. Firstly, a sinusoidal profile is used to describe the microscopic topography of the silicone rubber, and a simplified contact model is used to analyze the influence of the rubber roughness on static sealing properties based on the Hertz theory. Then, a new tester of macro contact properties of rubber seals is developed for measuring the contact area and contact force in real time. Finally, a micro contact model is developed by a finite element method for analyzing the influence of surface roughness parameters Ra and Rsm. Results show that the effect of Rsm on sealing properties cannot be ignored when the surface roughness is large. When the Ra increases, the contact pressure increases; when the Rsm increases, the contact pressure decreases. With the decreasement of Ra, the contact area increases, which is opposite to the variation of Rsm. The finite element analysis results are in good agreement with the test and theoretical conclusions, which provides reference for the seal design.