Contact Anaysis And Leakage Theory Research Of Metal Rubber Seal For Static Sealing

Seals are key fundamental components for advanced equipment in the aerospace,oil exploration,and nuclear power industry fields.Metal seals are used to solve sealing problems under harsh working conditions such as high temperature,low temperature,and high pressure.As a kind of entangled functional material,metal rubber material has been widely used in the aerospace field.The metal rubber material and metal seal are combined to design a new type of metal rubber seal.Compared with traditional metal seals,metal rubber seal has better strength,elasticity,and bearing capacity.However,the leakge theory and contact property of metal rubber seals are undeveloped.The main problems include the mechanism of the metal rubber material and the formation principle of the leakage gap in the sealing interface.This paper conducts theoretical and experimental research on metal rubber seals.The purpose is to fully understand the sealing mechanism of metal rubber seals and lay a theoretical foundation for the application of metal rubber seals under harsh conditions.It has important theoretical and engineering practical significance.The mechanical properties of metal rubber materials are an important basis for the application of metal rubber,but the constitutive models of metal rubber materials can be used for accurate and efficient numerical simulation calculations in undeveloped.First,the internal microscopic characteristics of the metal rubber material were observed with a 3D X-ray scanning microscope,and the non-linear and anisotropic characteristics of the metal rubber material and its influencing factors were analyzed through uniaxial compression tests.The elasticity matrix is adopted to express the nonlinearity and anisotropy of MR.An artificial neural network(ANN)model is built,trained,and tested to output the current elastic moduli for the elasticity matrix.Then,we combine the constitutive ANN model with the finite element method(FEM)simulation to calculate the mechanics of the MR component.Finally,the statics and dynamics simulation calculations of metal rubber components are carried out.By comparing the test results under the same conditions,the feasibility and accuracy of the proposed model and simulation method are verified.Maintaining sufficient contact stress in the sealing interface is an important condition for sealing,and clarifying the macroscopic contact stress is an important basis for the analysis of the leakage channel’s formation process.The contact stress of the metal rubber seal comes from its elastoplastic deformation,and there is an interaction between the stainless steel jacket and the metal rubber inner core.the macro-contact FEM model of the metal rubber seal was established by using the metal rubber ANN material model,and the static simulation analysis of the metal rubber seal was presented.The uniaxial compression test verified the accuracy of the FEM simulation results.The mechanism of the metal rubber inner core was explained by comparing the elastoplastic deformation characteristics and contact stress distribution pattern of metal C-ring,metal O-ring,and metal rubber seals.The influences of structural parameters on elastoplastic deformation and contact stress distribution were analyzed.The macroscopic contact performance provides a theoretical basis for the design of metal rubber seals and provides a prerequisite for analyzing the formation of leakage channels.The elastic-plastic contact of the two rough surfaces between the sealing interface is the direct cause of the leakage channel,and numerical analysis is the most intuitive and effective method to study this problem.By establishing a mathematical model,the elastoplastic contact problem of rough surfaces is transformed into a mathematical problem for numerical solutions.A numerical analysis method of elastoplastic contact based on the conjugate gradient method and three-dimensional fast Fourier transform is proposed,which fully considers the plasticity flow of the surface asperity.The accuracy of the method is verified by comparing the results of the elastoplastic contact with a single rough peak.An experiment of elastoplastic contact of the rough surface is designed.The surface morphology before and after the test is observed by a white light surface interferometer and then compared with the theoretical calculation results.The applicability and accuracy of the presented method to the elastoplastic contact problem of rough surfaces are verified.This method provides an important theoretical basis for analyzing the formation of leakage channels of metal rubber seals.The essence of leakage is the process of the sealed fluid flowing through the leakage channel under pressure.By simplifying the fluid flow in the leakage gap between the sealing interfaces to Poiseuille flow,an equivalent leakage rate calculation formula that is suitable for metal rubber seals is proposed,and the influence factors of the leakage rate for metal rubber seals are analyzed.Based on the elastoplastic contact numerical analysis method,the influence of contact stress,material mechanical properties,and surface roughness on the leakage path is studied.Finally,leakage tests of metal rubber seals for radial and axial applications were carried out respectively,and the experimental results were compared with the theoretical calculation results to verify the correctness of the theoretical analysis.