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Predictions of two nonlinear viscoelastic constitutive relations for polymers under multiaxial loadings
Author(s) -
Ellyin F.,
Vaziri R.,
Bigot L.
Publication year - 2007
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20731
Subject(s) - viscoelasticity , materials science , constitutive equation , rheology , anisotropy , nonlinear system , deformation (meteorology) , hydrostatic equilibrium , stress (linguistics) , composite material , uniaxial tension , compression (physics) , polymer , hydrostatic pressure , tension (geology) , mechanics , thermodynamics , physics , ultimate tensile strength , finite element method , linguistics , philosophy , quantum mechanics
Two viscoelastic constitutive relations in differential form are further developed here to include material nonlinearity and distinction between loading and unloading regimes, which is a characteristic of polymers. The effects of hydrostatic pressure and anisotropy in tension and compression on the deformation response of polymers are accounted for through the definition of a pressure‐dependent equivalent stress. In the uniaxial stress state, these constitutive relations reduce to the two well‐known mechanical analogue representations: “Kelvin–Voigt‐type” and “Maxwell‐type” rheological models. The predictive capabilities of these constitutive relations are then assessed against a wide range of experimental results, which include both uniaxial and biaxial stress states subjected to quasi‐static and cyclic‐loading conditions. The predictions of both models are found to be in good agreement with the test data. POLYM. ENG. SCI., 47:593–607, 2007. © 2007 Society of Plastics Engineers.