Influence Of Surface Effects On Nano-frictional Contact Behavior

In the present paper, based on the surface elasticity theory, we study the effects of surface stress and friction on nanosized contact problems. The Fourier integral transform method of stress function is adopted to derive the singular integral equation of the problem. By using the Gauss-Chebyshev quadrature formula, the singular integral equation is solved numerically to obtain the numerical solution of the problem. Finally, the numerical results indicate the influences of surface effect and friction on the contact pressure, stress and displacement at the flat surface. The main contents include the following two aspects:(1) The frictional contact problem of rigid flat indenter slipping on an elastic half plane. The results show that the influence of surface stress is notable and it significantly decreases the displacement on the half plane. In addition, with the decrease in the indenter size, surface effect gradually eliminates the singularities of pressure and stress on the contact edge. And it makes the displacement gradient continue across the loading boundary. But in the case of considering the surface effect, the impact of friction on the pressure distribution, surface normal stress and displacement is almost negligible.(2)The frictional contact problem of cylinder indenting on an elastic half plane. The results illustrate that the existence of surface effect obviously reduces the contact width and tends to make the pressure distribution in the whole contact region more uniform. Additionally, both the contact stress and the displacement gradient on the deformed surface vary smoothly across the contact fringe as a result of surface effect, but still can ignore the friction on the pressure distribution, surface normal stress and displacement.