Handbook of Friction-Vibration Interactions

3.3.3 Wet friction

Stribeck curve

We have discussed an interface with dry friction surfaces or surface friction without liquid involvement. For many real engineering interfaces, water and moisture are mediated, and for lubrication systems, the grease and oil as well as fatty acid type lubricants can be applied on the surfaces to allow them to slide easily over each other. It is well known that there are possibly four regions of lubrication effect on an interface with a fluid:

1. static friction;

2. boundary lubrication;

3. mixed lubrication (partial fluid and partial solid); and

4. full fluid lubrication.

Figure 3.16 gives the schematic of a generalized Stribeck curve, showing the possible regions.

Figure 3.16 Generalized Stribeck curve ...