Fatigue Design of a Rough Contact

Abstract

In the aim to build up design tools for mechanical contacts, a curve, allowing to estimate fatigue endurance of a contact between rough surfaces, is presented. The curve gives the tolerable limit value of hertzian pressure in function of the roughness of the contact bodies that is characterised by an opportune parameter. Therefore it separates the zone of infinite fatigue life from the zone of finite fatigue life for any rough contact.

The study has been developed for an elastic dry contact between a smooth plane and a rough cylinder of 100Cr6 steel in absence of friction. The fatigue damage of the contact has been valued by a multiaxial fatigue criterion that also gives the critical directions of first cracks nucleation.
The simplicity of use together with taking into account the most important phenomena in a rolling contact problem, make this curve a helpful tool in the contact design process.