Numerical modeling of thermal aging in steady state rolling tires

In this contribution, thermal material degradation in steady state rolling tires is numerically studied. A phenomenological time-dependent thermal damage approach from the field of continuum damage mechanics (CDM) is implemented into a modular simulation environment (Behnke & Kaliske, 2015), which allows the thermo-mechanically coupled analysis of axisymmetric tires in steady state motion via the finite element method within an Arbitrary Lagrangian Eulerian framework. Within the numerical model, rubber compounds of the tire are represented by their temperature-dependent viscoelastic properties at finite deformations. Energy losses as heat source terms, computed on a physical basis from the dissipative material properties (non-equilibrium stresses), are used to predict the heat build-up in the tire under severe service conditions. Model parameters for the time-dependent thermal damage approach are identified from previously published experimental investigations on thermally aged rubber compounds in order to link the temperature increase and the evolution of thermal damage (thermal aging). The thermal damage approach qualitatively captures the irreversible changes of the rubber compounds' mechanical properties, which, in turn, lead to an alteration of the entire structural response of the thermally damaged tire.