The adhesion of viscoelastic bodies with slightly wave surfaces

Adhesive contact of viscoelastic bodies is a challenging problem due to its rate-dependent nature. In this work, we formulate a theoretical model to describe the pulling process of a slightly wavy indenter from a soft medium, comparing predictions with numerical simulations. A cohesive approach is adopted to formulate the theory based on the assumption that viscoelastic dissipation is confined to a small region around the contact edge. The resulting increase in surface energy is related to the quasi-static work of adhesion through the creep compliance. Theoretical findings match quite good numerical results. However, when separation arises from complete contact, the pull-off force can be estimated only if a small flaw is postulated at the interface.