Conclusions

Roughness on the surface of the parts disturbs the contact between them, making it discontinuous. As a result, the actual contact between two parts is only a small fraction of the apparent contact. The presence of this strong discontinuity is at the origin of specific contact behaviors. These specific behaviors concern, for example, mechanical aspects (stress, deformability of the contact), thermal or electrical phenomena (presence of additional resistance at the contact), as well as sealing and even lubrication for contacts with relative movement. To analyze these specific interface behaviors, it is essential not only to have a reliable description of the actual morphology of the contact under load, but also to define its contribution to the phenomenon under study.

More than 50 years ago, Greenwood and Williamson proposed a statistical theory for describing microgeometries,...