Free volume based nonlinear viscoelastic model for polyurea over a wide range of strain rates and temperatures

A series of quasi-static and dynamic uniaxial compression experiments over a wide range temperatures were conducted on polyurea elastomer. The stress-strain response exhibits extreme nonlinearity, temperature strain-rate sensitivity. How to comprehensively describe these complex behaviors regulated by the unique micro-structure is still an open question. In this paper, nonlinear viscoelastic constitutive model for developed. viscoelasticity, entropic energetic elasticity are taken into account, correlated with interaction chain segments, stretch molecular chains covalent bonds from perspective structure. formulated hereditary integral relaxation modulus strain rate time. real time accelerated shift factor, which depends free volume. new mechanism shear-induced increase volume, gives rise nonlinearity proposed, corresponding rate-dependent evolution equation fractional volume Parameters in determined through DMA test. Comparison experimental data, as well data references, verifies ability predict rates. • Quasi-static temperatures. proposed. based established polyurea. predicts