Modelling of the viscoelastic layer effect in rolling contact

The three-dimensional quasi-static contact problem for an elastic sphere rolling over a thin viscoelastic layer bonded to an elastic half-space is considered. The Kelvin model is used to describe the layer viscoelastic properties in tangential direction. The layer compliance in normal direction is described by the modified Winkler model. The contact region is assumed to consist of a stick and slip subregions, which boundaries are unknown in advance. The Coulomb law is used to describe the relation between the contact pressure and shear stresses in the slip subregions of the contact region. The contact pressure distribution is evaluated with the method of successive approximations. Calculation of shear stresses distribution in the contact region is based on the strip method. The contact and internal stress distributions are studied for various values of relative slippage, the layer viscosity parameter and sliding friction coefficient. The dependence of the adhesion coefficient on the relative slippage is analysed for various values of surface layer viscosity parameter. The results of the contact and internal stresses analysis for various layer properties can be used for better understanding and future prediction of the friction modifiers effect in wheel-rail rolling contact.