What is lambda ratio in Stribeck curve?

What is lambda ratio in Stribeck curve?

The tribology concept of the lambda ratio (λ) — the ratio of lubricant film thickness (h) to composite surface roughness (σ) — has existed for over 50 years.

What is a good lambda ratio?

We all know that perfect combustion requires an air/fuel ratio of approximately 14.7:1 (by weight) under normal conditions. Thus a lean air/fuel ratio of, say, 16:1 would translate to a lambda value of 1.088.

How is the Stribeck curve used in tribology?

Stribeck curve is a fundamental and one of the most widely known concepts in tribology and lubrication fields. The concept represents the friction behavior in lubricated contacts as a function of viscosity of the lubricant, entertainment speed and roughness (sometimes, just roughness).

Which is the easiest way to measure the Stribeck curve?

The easiest way to measure Stribeck curve is to measure friction coefficient in a tribosystem as a function of speed. This parameter is the easiest to change, since there is no need to change the samples (as in case if you would like to alter friction via surface roughness) or lubricant (in case if you would like to change viscosity).

Who are the pioneers of the Stribeck curve?

Richard Stribeck along with Mayo Hersey are accredited as the pioneer researchers of the 20 th century, who introduced Stribeck curve by extending their work on the topic of friction within the railway industry; however the results of the research were in coherence with the previous researches.

When did Richard Stribeck discover the friction coefficient?

The degree of such reduction hugely depends on the so called lubrication regime established in the contact of rotating elements. In 1902 Richard Stribeck studied the friction in hydrodynamic bearings and reported existence of a minimum of friction coefficient as function of operating conditions [1,2].