The sliding contact problem for an orthotropic coating bonded to an isotropic substrate

We consider the sliding contact problem of an orthotropic coating/substrate system. The coating/substrate system is pressed by a rigid flat or cylindrical stamp. For the orthotropic coating, the principal material directions are assumed to be parallel and perpendicular to the contact surface. The governing integral equations corresponding to the mentioned contact problem are extracted by means of the Fourier transform technique. Later, the numerical solution of the singular integral equations is provided by applying the Gauss-Chebyshev integration method. The main goal of this study is to obtain analytical benchmark solutions in order to examine the effect of material orthotropy parameters, relative stiffness, the coefficient of friction and the coating thickness on the stress distribution at the surface of the orthotropic coating. The behavior of the surface in-plane stress intensity factor is analyzed as well. For a constant value of the applied load, the results indicate that the stiffness ratio and the shear parameter have a more pronounced effect on the surface stress components than the effective Poisson's ratio. Also, the stress intensity factor at sharp edges of the flat punch decreases as the coating softens with respect to the substrate and/or the coating thickness decreases.