DETERMINING THE PARAMETERS OF THE HEREDITARY KERNELS OF ISOTROPIC NONLINEAR VISCOELASTIC MATERIALS IN COMBINED STRESS STATE

摘要

The relations between the heredity kernels of isotropic nonlinear viscoelastic materials in combined and one-dimensional stress states are derived. The constitutive equations are presented in a form corresponding to the proportional deviator hypothesis. The nonlinearity of viscoelastic properties is described by Rabotnov’s type models. The creep strains and stress relaxation in thin-walled tubular elements subject to a combination of tension and torsion are determined and tested experimentally.