Friction is a complex subject that we have broken up into multiple modules in this course. Understanding friction is critical in wide-ranging applications, from automotive and aerospace, to rock climbing and curling. In many cases we try to minimize friction (to improve engine performance, for example), but in other cases a high degree of friction is essential (in brake systems, for example). The concepts have been studied since antiquity, and we continue to invest a great deal of effort and resources to understand and control friction today.

The first case we discuss is the simplest: dry friction, which occurs in systems without lubrication. In this module we discuss the basic mechanisms and physics of dry friction, and the methods we use to measure it. We look at the relationships between surface texture (surface roughness) and dry friction, introducing the concept of "real contact," the actual meeting points of two interacting surfaces. Finally, we revisit some of the surface texture parameters that we discussed in previous modules and show how they relate to, and change with, dry friction.

Following this module we encourage you to watch the next modules on Lubricated Friction and Rolling Friction for a more complete view of friction.

Module 5 of the Surface Texture and Tribology Short Course. The full course is available on udemy, or you can select the individual course modules of interest to you. Enter "surface roughness texture tribology" in the udemy search bar to browse the full course and modules.