Thermo-Solid Coupling Analysis Of Metal Rubber Seal System In Low Temperature Environment

With the widespread use of liquid hydrogen and liquid oxygen fuels in the aerospace field,strict requirements have also been put forward for seals used in lowtemperature environments.Metal rubber is a kind of homogeneous porous elastic material with high,low temperature,high pressure and corrosion resistance.It is of great significance to use it to solve the sealing problem under the harsh working conditions in the aerospace field.Metal rubber and other materials can be combined to produce a variety of coated metal rubber seals,its sealing performance is closely related to the resilience performance and the contact stress distribution between the sealing interface,and these two aspects are affected by the mechanical properties of the seals themselves.At present,the effect of low temperature on the resilience performance of metal rubber seals is not yet clear,and when the seal is used to seal the cryogenic medium,the thermo-solid coupling deformation under the action of temperature load and mechanical load will affect the contact stress distribution of the seal interface.Therefore,this paper carried out experiments and simulation studies on the mechanical properties,resilience performance of metal rubber seals under low temperature environment and the effect of thermo-solid coupling deformation on the contact stress distribution of the seal interface.In this paper,the low temperature tests of the metal rubber seal components—the coating layer and the metal rubber inner core were carried out separately.The low temperature hysteresis characteristic test was carried out on the metal rubber sample,and the variation rules of hysteresis loop,Young’s modulus and energy dissipation coefficient were analyzed at low temperature.The low temperature tensile test of coating layer was completed and the mechanical properties at room temperature and low temperature were studied.The finite element model of the rubber seal was established,and the simulation analysis of the cooling process was carried out.The simulation results showed that the deformation caused by the thermal expansion of the seal had little influence on the resilience performance of the seal within the range of 20℃(normal temperature)～-50℃.Simulation analysis of the compression and rebound process at different temperatures and different compression ratios,the simulation results showed that the resilience performance of the seals was closely related to the compression rate at work and in the range of normal temperature to-50℃,the rebound rate increases with the decrease of temperature;The distribution of contact stress in the springback process at different temperatures was compared.The simulation analysis of sequential coupling and full coupling thermo-solid coupling in the compression process of metal rubber seals is carried out and the calculation process of sequential thermo-solid coupling simulation is established.The finite element model of the metal rubber sealing system was established according to the application conditions of the metal rubber seals.The sequential coupling simulation method was used to simulate and analyze the model under different working conditions,the temperature field and thermo-solid coupling deformation of the sealing system are studied,and the contact stress distribution at the sealing interface between the seals and the upper and lower flanges is analyzed,the contact stress distribution between the sealing interface changes with the temperature and pressure of the sealing medium was obtained.The influence of the contact stress distribution width and the maximum contact stress on the leakage rate was analyzed.