橡胶材料的非线性黏弹性本构方程

Rubber is a nonlinear viscoelastic material. The nonlinear viscoelastic constitutive equation is the key to design and optimize rubber materials and rubber products. In the paper, a nonlinear viscoelastic constitutive equation based on hyperelastic model and parallel rheological network (PRF) was studied, and the method of fitting the material parameters of the PRF constitutive equation was discussed in detail. Firstly, the hyperelastic model was obtained by fitting the experimental data of uniaxial tensile, and the linear viscoelastic model-Prony series was obtained by fitting the experimental data of stress relaxation, then the Prony series was transformed to the linear PRF model, which was used as initial value and continuously optimized. Finally, the experimental verification was carried out. The results show that the error between the fitting data by the PRF model and the experimental data of stress relaxation under different strains is only 0.067%. The PRF model can accurately describe the nonlinearity of stress relaxation of rubber materials.