6. Extension of the Greenwood and Williamson contact model

Greenwood and Williamson's model has been around for almost 50 years, but over the years it has proved to be incredibly modern, thanks to a good compromise between simplicity of use and reasonable validity of results.

In the interests of performance, many improvements inspired by this model have been proposed. It would be utopian to review them all. In this section, we will attempt to present the main types of existing work, complementary to this model, and to quantify their contributions. Complementary work on the description of microgeometry will be analyzed in turn, followed by work on the behavior of materials in contact.