Modelling Viscoelastic Adhesion and Friction in Sliding Contact Mechanics

We present our recent study on rough adhesive contacts of viscoelastic materials in steady-state sliding, focusing on the interplay between adhesion and viscoelasticity by means of a novel energy approach. We investigate tribological features over a wide range of velocity values, exploring the effect of small- and large- scale viscoelasticity on the overall contact behavior. The former is associated with viscoelastic dissipation close to the adhesive neck at the contact edges; the latter refers to material hysteresis involving the entire bulk of the solid. Depending on the sliding velocity, we predict highly enhanced adhesive strength compared to the purely elastic conditions, increased friction compared to the adhesiveless case, and non-monotonic trend of the energy release rates at the contact leading and trailing edges. Most of our results are supported by existing experiments.