Thermo-Mechanical Behavior of Shear Stiffening Elastomer via Finite Deformation Temperature-Dependent Hyper-Viscoelastic Constitutive Model

Shear stiffening elastomers (SSEs) have gained significant attention as intelligent materials with remarkable rate-enhanced properties, showing great potential in impact protection applications. With the application domains broadening from ambient to elevated temperature regimes, understanding their behavior under coupled thermo-mechanical conditions becomes crucial. In this study, dynamic mechanical thermal analysis and compressive stress relaxation experiments were conducted to systematically investigate the viscoelastic properties of SSE over a temperature range of 30–100[Formula: see text]C. A Neo-Hookean hyper-viscoelastic constitutive model, which accounted for time-temperature effects and was suitable for large strains, was then proposed. The stress evolution equation under uniaxial compression was derived, and the key material parameters of the constitutive model were identified using the Prony series. A shift function based on the Williams–Landel–Ferry (WLF) equation was constructed to account for time-temperature equivalence, and the effects of temperature on the shear modulus, viscoelastic parameters, and relaxation time of SSE were analyzed. A finite element model was subsequently developed, and numerical simulations were validated against experimental results. Finally, the material parameters derived from time-temperature equivalence were used to predict the thermo-mechanical behavior of SSE under varying loading conditions, establishing a robust theoretical framework.