6. Lubricated Friction
What you'll learn
- Lubricated friction and how to calculate it
- Lubricants and lubricant properties (viscosity)
- The dynamics of lubricated friction
- The effects of surface texture in lubricated systems
- Elastohydrodynamic (EHD/EHL) lubrication
- No prerequisites. However, we recommend Module (4 Dry Friction) of the Surface Texture and Tribology Short Course
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.
To understand friction in lubricated systems we need to look at the complex relationships between film thickness, temperature, pressure, materials, surface texture and more. In this module we discuss the basic mechanisms and physics of lubricated friction and how it is calculated. We look at the relationships between surface texture (surface roughness) and lubricated friction, introducing the concepts of hydrodynamic, elastohydrodynamic, mixed and boundary regimes and how friction and lubrication differ in these regimes. Finally, we look at the mechanics of lubrication with help from a short video from Vern Wedeven (used with permission), who has written a number of excellent books on this topic as well.
Following this module we encourage you to watch the modules on Dry Friction and Rolling Friction for a more complete view of friction.
This is Module 6 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.
Who this course is for:
- Scientists, engineers, technicians and students in the fields of automotive, medical device, aerospace, materials, polymers, and others
In 1994, Dr. Cohen established Michigan Metrology to help engineers and scientists solve problems related to “Squeaks, leaks, friction, wear, appearance, adhesion and other issues,” using 3D Surface MicroTexture Measurement and Analysis.
Dr. Cohen is a past Chairman of the STLE-Detroit section and has been active with the ASME B46.1 committee on surface texture since 1988, having served as Chair from 2005-2011. Dr. Cohen is also a Subject Matter Expert for the ISO surface metrology activities.
Dr. Cohen has an undergraduate degree in Physics from the University of Michigan, Dearborn, and graduate degrees in Physics and Optical Sciences from the University of Arizona. Early in his career, Dr. Cohen worked with IBM on optical disk drive development. He later joined WYKO Corporation as Product Manger and later became Vice President, leading the development of 3D surface texture metrology instrumentation.
Dr. Cohen has developed this class over the past 20 years having presented the material at numerous client locations as part of his training and consulting activities. Typically once a year the class is offered to a general audience in the Livonia, MI area.