Effect of imperfect coating on the elastohydrodynamic lubrication: Dislocation-like and force-like coating-substrate interfaces

Abstract The commonly existed imperfect coatings may cause the displacements and forces transmitting discontinuously at the coating-substrate interface. This paper reports an elastohydrodynamic lubrication (EHL) model of ball-coated half space with coupled dislocation-like and force-like coating-substrate interface. Reynolds equation is solved to obtain the pressure. The surface elastic deformation and subsurface stress are calculated with the discrete convolution and fast Fourier transform (DC-FFT) method with the influence coefficients (ICs) obtained through corresponding frequency response functions (FRFs). The model is validated by the available data, and then implemented to study the pressure, film thickness, and subsurface stress distributions under imperfect coating-substrate interfaces of dislocation-like, force-like, and the coupled conditions, with various displacements and stresses jumping coefficients.