Theory of viscoelastic adhesion and friction

We present a novel theory of the adhesive contact of linear viscoelastic materials sliding at constant velocity against rough substrates. Despite the non-conservative behaviour of the system, the closure equation, needed to calculate the unknown size of the contact area, can be rigorously formulated in the form of a local energy balance. The results highlight three main peculiar features of the contact, which are strictly ascribable to the interplay of adhesion and viscoelasticity. First, a velocity dependent pull-off force is predicted, whose maximum value occurs at intermediate sliding velocity. Second, the energy release rates G1 and G2 at the contact trailing and leading edges respectively, present a non-monotonic dependence on the indenter sliding velocity. Third, the velocity dependence of the hysteretic friction mu is significantly altered and presents a friction peak much more pronounced compared to the adhesiveless viscoelastic case. Theoretical predictions are in very good agreement with existing experimental data.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

In this article, a novel theory of adhesive contact between linear viscoelastic materials and rough substrates during constant velocity sliding is presented. The closure equation to calculate the unknown contact area is rigorously formulated based on a local energy balance, despite the non-conservative behavior of the system. The results highlight three main peculiar features of the contact, which are strictly related to the interplay of adhesion and viscoelasticity.