Running-in of rolling contacts

This thesis deals with running-in of the pure rolling contact situation operating in the boundary lubrication regime, so that normal plastic deformation due to the contact between asperities is the main aspect. The change of the surface topography during the running-in process and the run-in surfaces are predicted locally. The main theme concerns the elastic-plastic asperity contact model. An asperity micro-contact model was considered due to its analytical nature and a well-ploughed study. A new single elliptic elastic-plastic asperity contact model has been proposed and demonstrated as the best prediction to the experimental results among the other models. Plastic deformation appears when the applied load is removed; therefore, the developed asperity contact model was extended to the unloading case.