Subsurface stress field of a dry line contact

The calculation of the pressure distribution and the subsurface stress field developed at the dry line contact of two cylinders, can be carried out with sufficient accuracy, using the Hertzian theory assuming that both cylinders are smooth. However, for the investigation of surface failures, such as micro-pitting, Hertz’s solution cannot be applied, because the effect of roughness is significant. This paper presents a model for the determination of the asperity pressure distribution at the contact of two rough cylinders, assuming elastic–perfectly plastic deformation. Having determined the surface load, the subsurface stress field is then calculated. The effect of roughness on the stress field is investigated. For this investigation, numerically generated rough surfaces are used. The results show that the maximum shear stresses developed in small depths are significantly higher than those predicted by the Hertzian solution. This conclusion is in good agreement with the small depth of cracks observed on the flanks of gears that have suffered from micro-pitting.