Research On Hyperelastic Constitutive Model Of Metal Rubber And Finite Element Secondary Development

In the design of new metal rubber products,an in-depth study of its constitutive relationship will help to shorten the research and development cycle and save design costs.The existing metal rubber constitutive model contains many parameters,the form is complex,and can not be well combined with the finite element software.In this paper,taking the hollow cylindrical metal rubber component as the research object,the hyperelastic constitutive model of metal rubber with high fitting accuracy and easy to combine with finite element software is established.It not only provides a reference for the performance prediction of metal rubber products,but also provides convenience for the application and promotion of metal rubber in other fields.Based on the theory of continuum mechanics,the static deformation process of metal rubber is equivalent to the uniform deformation of hyperelastic body,in which the constitutive relation of metal rubber is determined by strain energy function.Firstly,the deformation process of metal rubber under static compression is analyzed,and combined with the theory of superelastic constitutive model,the deformation of metal rubber is divided into equal volume part and volume part,and the superelastic constitutive model of metal rubber is established.Then,through the analysis of the static test data,it is concluded that the solid volume fraction and wire diameter have great influence on the accuracy of metal rubber constitutive model,and the change of loading speed in 0.5mm/min ? 50mm/min has little influence on the stiffness of metal rubber.Finally,the form of strain energy function of metal rubber is determined.It is proved that the superelastic constitutive model of metal rubber has better fitting accuracy than the polynomial model,and can predict the constitutive relationship with the change of solid volume fraction and wire diameter.Based on the user subroutine interface in the finite element software ABAQUS,the finite element software for the hyperelastic constitutive model of metal rubber is developed.In order to simplify the process of solving the material parameters of the constitutive model by fitting the experimental data,a software for solving the material parameters is developed based on the GUI tool of MATLAB.Firstly,the user subroutine of strain energy of metal rubber hyperelastic constitutive model is written in Fortran language,and the subroutine is verified by unit compression simulation and hollow cylinder static compression simulation.The verification results show that the subroutine can reflect the static compression characteristics of metal rubber.In the process of combining the secondary development work with the practical engineering application,the static test of the metal rubber vibration isolator is carried out,and the maximum displacement under 4 k N load is about 2.50 mm.Then the static test data are imported into the material parameter solving software to determine the material parameters of the constitutive model.Finally,the compiled user subroutine file is used to simulate the static test of metal rubber vibration isolator.The simulation results show that the maximum displacement under the same load is 2.68 mm,and the maximum error compared with the four groups of test values is 7.6%,which verifies the effectiveness of the secondary development work in practical engineering applications.