Modeling and characterization of thermo-viscoelastic behavior of rubber compounds

Viscoelasticity as a unique property of rubber materials, has a significant influence on the product performance, for example, on the wet grip and the rolling resistance of tires. The viscoelasticity of rubber materials has been described by mathematical models and characterized by experimental approaches. In many existing models, the viscous behavior is usually assumed to be independent or linearly dependent on temperature. This simplification leads to inaccurate predictions under real operating conditions, especially when temperature-sensitive ingredients like resins are added to rubber compounds. Moreover, such models are rarely validated against experimental results. This work addresses these limitations by developing a modelling and testing framework for filled rubber compounds that consistently integrates mathematical modeling, parameter identification, and experimental validation. Firstly, a thermo-viscoelastic model that explicitly captures the nonlinear temperature dependence of viscosity was developed Then, the parameters of the developed model were identified by fitting the model to the experimental data obtained from the Dynamic Mechanical Analysis (DMA) measurements, where the constrained optimization problem was solved. To apply the material model in structure analysis, the developed model was implemented in the Finite Element Method (FEM) scheme. Finally, the developed material model was successfully validated by comparing the model prediction results with the experiments including the Temperature Scanning Stress Relaxation (TSSR) measurements. With the thermo-viscoelasticity model, the dynamic properties of the rubber compound at higher frequencies can be predicted without master curve creation, which offers a faster and more physically accurate route to assess dynamic properties such as tire wet grip.