The Contact Mechanics of Coated Elastic Solids: Effect of Coating Thickness and Stiffness

We investigate the adhesive and adhesiveless contact between a rigid regular wavy profile and an elastic substrate coated with an elastic layer. The contact stiffness is strongly influenced by the elasticity and thickness of the coating layer. Specifically, coatings more compliant than the substrate entail larger contact area, and vice versa. Under adhesive conditions, thin soft coatings may lead to complete contact, regardless of the applied load. Moreover, enhanced adhesive strength (toughness) can be achieved at the pull-off by adopting stiff (compliant) coatings. We compare our exact model with the Bec/Tonck model, which is one of the most adopted approximate model for biological tissues contact mechanics. The results show that predictions of the proposed model are in better qualitative agreement with experimental results taken from the literature.