The effect of adhesion on the elastic-plastic deformation of sliding contacts was examined with the finite element method. The adhesive interaction of a rigid asperity moving over a homogeneous elastic-plastic half-space was modeled by nonlinear springs obeying a constitutive law derived from the Lennard-Jones potential. The effects of the work of adhesion, interaction distance (interfacial gap), Maugis parameter, and plasticity parameter (defined as the work of adhesion divided by the half-space yield strength and the intermolecular equilibrium distance) on the evolution of the normal and friction forces, subsurface stresses, and plastic deformation at steady-state sliding are interpreted in light of finite element results of displacement-control simulations of sliding contact. The normal and friction forces and the rate of energy dissipation due to plastic deformation at steady-state sliding sharply increase with the interaction distance. Although a higher work of adhesion produces a lower normal force, it also intensifies the friction force, enhances material pile-up ahead of the sliding asperity, and exacerbates the asymmetry of both the deformed surface profile and the normal stress field. The variation of the normal force with the plasticity parameter is explained by the dominant effect of subsurface plastic deformation above a critical plasticity parameter. Simulation results are shown to be in good agreement with those of previous experimental and numerical studies.
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