On the Interaction of Viscoelasticity and Waviness in Enhancing the Pull-Off Force in Sphere/Flat Contacts

Abstract Motivated by roughness-induced adhesion enhancement (toughening and strengthening) in low modulus materials, we study the detachment of a sphere from substrate presence both viscoelastic dissipation at contact edge, roughness form single axisymmetric waviness. We show that found Guduru coworkers for elastic case (i.e. very small speeds) tends to disappear with increasing speeds, where effect dominates problem approaches smooth sphere. This is qualitative agreement original experiments Guduru’s group gelatin. The cross-over velocity two separate effects are comparable. Viscoelasticity effectively damps instabilities makes their much less important. Graphical