Influence of Thermal Cycle on Viscoelastic Material Response

The present work aims to study the temperature cycle influence on a general viscoelastic (VE) material constitutive response. The time-dependent behaviour of VE material is modelled by Prony exponential series. A novel method, providing non-negative Prony coefficients, is used and successfully validated against various creep and relaxation experiment results. Displacement control experiments (relaxation) are difficult for stiff materials; load control experiments (creep) are thus performed in general. It is, therefore, essential to correctly convert creep compliance into relaxation modulus and vice versa. A correct inter-conversion novel method is thus derived in detail and successfully validated against various experimental results. A time-temperature superposition (TTS) is used to obtain a master curve for VE material by horizontal shift factors. Williams–Landel-Ferry equation constants are computed to obtain VE material properties at any temperature value within the available experimental range by linearising horizontal shift factors. The correctness of these constants is validated in a novel manner, thus highlighting the limitation of the linearisation process, which is generally adopted in the literature. The temperature dependence of VE material is finally coupled with a VE stress update algorithm through pseudo-time concept (without considering damage and ageing).