Structural Design Of Low Temperature Metal Rubber Components

Metal rubber is a new type of homogeneous porous elastic material made of metal wire.It has the advantages of wide working temperature adaptability,strong corrosion resistance,excellent aging resistance,large bearing capacity,long service life and high reliability.Metal rubber has been used in aerospace,marine engineering,petrochemical and other engineering fields.However,compared with traditional rubber,the stiffness change of metal rubber during loading is more drastic and much higher than that of traditional rubber.Therefore,it is of great significance to study the preparation process of metal rubber and obtain metal rubber that can replace traditional rubber at low temperature through structural design.In this paper,the influence of wire diameter and relative density on mechanical properties was analyzed and the mechanical properties of metal rubber and EPDM rubber at low temperature were compared and studied.Through the finite element method,the influence of typical structural elements on the mechanical properties of metal rubber components was analyzed,and the constitutive relationships of metal rubber components with different structures were established.The simulation results have been verified through experiments,which provided a theoretical basis for the engineering application of metal rubber instead of traditional rubber in low temperature environment.In this paper,the compression experiments,compression cycle experiments and stress relaxation experiments were carried out on metal rubbers prepared with different relative densities and different wire diameters.By comparing its mechanical properties,it was found that when the diameter of the wire was the same,with decrease of the relative density,the compression strain,the energy loss coefficient and the stress relaxation rate increased,and the compression modulus decreased.At the same time,when the relative density of the metal rubber was the same,with the increased of the wire diameter,the compression strain and the energy loss coefficient increased,the compression modulus decreased,the stress relaxation rate remained basically the same.In this paper,the mechanical properties of metal rubber and EPDM rubber were tested under low temperature environment to further study the mechanical properties of metal rubber.The mechanical properties of metal rubber at low temperature-45 ℃ basically did not change,the compression strain decreased by 0.57%,the compression modulus increased by 20.49%,and the stress relaxation rate decreased by 1.72%,indicating that the metal rubber materials had excellent low temperature resistance.The mechanical properties of EPDM rubber deteriorated at low temperature-45 ℃,the compression strain decreased by 9.27%,the compression modulus increased by 155.12%,the stress relaxation rate increased by 95.28%,and the EPDM rubber material had poor low temperature resistance.Based on the experiments results,the constitutive relationship of the metal rubber was deduced,and the influence of the structural size of the typical unit(cross-section ○-type,□-type,△-type)on the mechanical properties was analyzed by finite element numerical simulation.The constitutive relationship between the mechanical properties of different components and the size of the components was derived.According to the constitutive relationship,it was found that the mechanical performance parameters of the metal rubber component were related to the length ratio of the inner and outer sides of the component(the ratio of the inner diameter to the outer diameter).With the increase of the ratio between the inner length and outer length(the ratio between the inner diameter to the outer diameter),the elastic modulus of the member decreased and the linear elastic strain increased.The ○-type member had greater linear elastic strain and the □-type member had better damping performance.Based on the mechanical properties of the EPDM rubber sealing member,using the deduced constitutive model of the metal rubber member,a ○-type metal rubber with a relative density of 0.2,an outer diameter of 10 mm,and an inner and outer diameter ratio of 0.524 was designed and prepared to replace EPDM rubber for using at low temperature.The test results of the mechanical properties of ○-type metal rubber components showed that the calculation results and the mechanical experimental data was nearlythe same,and the variance of the two curves was 0.08435,which proved the correctness of the finite element model and the mathematical model.By comparing the mechanical properties of metal rubber components and EPDM rubber components at low temperature,it was found that the mechanical properties of metal rubber at low temperature were basically unchanged.