Exploring the dynamics of viscoelastic adhesion in rough line contacts

Abstract

Modeling the adhesion of viscoelastic rough surfaces is a recent challenge in contact mechanics. Existing models have primarily focused on simple systems with smooth topography or single roughness scale due to the co-action of roughness and viscoelasticity leading to elastic instabilities and rate-dependent behavior, resulting in complex adhesion dynamics. In this study, we propose a numerical model based on a fnite element methodology to investigate the adhesion between a randomly rough profle and a viscoelastic half-plane. Approach-retraction simulations are performed under controlled displacement conditions of the rough indenter. The results demonstrate that viscous efects dampen the roughness-induced instabilities in both the approach and retraction phases. Interestingly, even when viscous efects are negligible, the pull-of stress, i.e., the maximum tensile stress required to detach the surfaces, is found to depend on the stifness modulus and maximum load reached during the approach. Furthermore, when unloading is performed from a relaxed state of the viscoelastic half-plane, both adhesion hysteresis and pull-of stress are monotonic increasing functions of the speed. Conversely, when retraction begins from an unrelaxed state of the material, the maximum pull-of stress and hysteretic loss are obtained at intermediate velocities.