Advanced viscous model for viscous friction between rough rubber and smooth ice

The improvement of tractive performance on ice is one of the most challenging aspect in the nowadays tire industry. For this reason, a model which can predict the friction coefficient on ice can be useful in the winter-tire design. However, the highly multiphysics nature of the interaction between rubber and ice [1-4], as well as the magnitude of the dimensions involved make the development of a numerical model a quite complex issue. In this work, a first step for the prediction of the friction coefficient on ice is proposed using the finite element method. The subject of this analysis is the transient phase of the sliding interaction between a rubber block and an ice surface. The User Define Friction module of LS-DYNA has allowed to implement the suitable friction law for contacts with ice, widely used in the literature [3, 5], which follows a microscopic approach and it is based on a viscous formulation. Considering again the dimensions involved and the duration of the transient phase, it is impossible to directly validate the model through experimental detection [3]. However, in the subsequent steady-state phase, which involves higher amounts of water and longer time, the experimental measurements are easier. To compare the results, in the literature an indirect procedure was used in order to provide a qualitative validation, using the strict link between the transient phase and the steady-state one. The final comparison between the LS-DYNA results and the literature results has shown a good correlation level.