Sensitivity of the Stribeck curve to the pin geometry of a pin-on-disc tribometer

A considerable number of surface texture investigations is based on pin-on-disc tribometers. This work shows that a crucial role in the reproducibility of the results, e.g. Stribeck curves, is played by the geometry of the pin surface. The investigation is based on an elastohydrodynamic model of a pin-on-disc tribometer which is validated with experimental data. Characteristic roughness and pin shapes are introduced in this model to evaluate the sensitivity of the Stribeck curve to these operating conditions. The obtained significant variations in the friction coefficient indicate that studies which aim at quantifying the influence of surface textures in the mixed lubrication regime need to provide information about the pin geometry in order to enable a meaningful comparison among literature data.