Roughness in elastohydrodynamic contacts

Surface roughness can reduce the life of any elastohydrodynamically lubricated (EHL) component. However, the process is complex with details of the operating conditions, relative surface slip, fluid rheology, as well as surface topography influencing the behaviour. Because of this, it is unlikely than any generally applicable rules will be found which can be used to relate surface roughness to life. Instead, an approach that enabled rapid predictions of the contact pressures and clearances stresses in EHL contacts was developed by the authors and is extended here to include the calculation of the subsurface stresses.