Study on Adhesive Friction Process Considering Electrostatic Interaction

Adhesive friction considering electrostatic interaction is an important problem in practical engineering. However, the friction mechanism considering electrostatic interaction and adhesion of elastoplastic materials on the contact interfaces remains poorly understood. A sliding friction model considering the van der Waals attraction, repulsive and electrostatic interactions is established in this work. The effect of charge density on the normal force, friction force, contact area and stress distribution is thoroughly investigated. And the repeated sliding friction process is also quantitatively analyzed. It is shown that adhesion enhances with the increase of surface charge density. Moreover, the contribution of electrostatic interaction to adhesion in the contact process is always greater than that to friction in the sliding friction process under the conditions studied. In the initial stage of friction, the friction will gradually increase and the normal force will gradually decrease. It is also found that a higher charge density results in a lower normal force in the friction process. Furthermore, the increase of charge density leads to a bigger contact diameter and the increased asymmetry of stress field, resulting in the increase of friction force, equivalent plastic strain and friction coefficient. In addition, both normal force and friction force arrive at a steady state after several repeated friction circles for elastoplastic materials, which is due to the fact that the contact diameter tends to be constant because of the accumulation of plastic deformation. This work reveals the contribution of electrostatic interaction to friction during adhesive sliding process and provides some insights into the adhesive friction problem considering electrostatic interaction.