MODULE 2 (1.2) - TRIBOLOGY PRINCIPLES

Question 1

actual contact between two rubbing surfaces involves asperities of the softer material of the two contacting surfaces, and their yield pressure balances the total load, in the absence of a fluid film between them

Answer 1

Dry Sliding

Question 2

unevenness, roughness or ruggedness of a surface

Answer 2

Asperity

Question 3

The greater the load, the
_______ is the contact!

Answer 3

greater

Question 4

a film of separating fluid is being drawn into a converging, wedge shaped zone by the self acting pumping action of a moving surface

Answer 4

Hydrodynamic lubrication

Question 5

on mating surfaces under shock load and is time dependent, applicable on higher loads

Answer 5

Squeeze film hydrodynamic lubrication

Question 6

the lubricating fluid film is forced between surfaces by an external pressure

Answer 6

Hydrostatic lubrication

Question 7

the pressure betwen the mating surface are large enough to cause significant elastic deformation of the lubricated surfaces

Answer 7

Elastohydrodynamic lubrication

Question 8

the mating surfaces are so close together that surface interaction between fluid lubricant film and solid asperities dominates the contact, usually when the load between the mating surface is increased and lubricant viscosity significantly decreases

Answer 8

Boundary lubrication

Question 9

the transition between boundary and hydrodynamic/elastohydrodynamic lubrication, wherein the coefficient of friction is steadily decreasing

Answer 9

Mixed lubrication

Question 10

a plot of a fluid lubricated bearing system that presents the coefficient of friction, 𝑓, as a function of the product of the absolute viscosity, 𝜇 in 𝑁∙𝑠/𝑚𝑚^2, and rotational speed, 𝑁 in 𝑟𝑒𝑣/𝑠, divided by the load per unit projected bearing area, 𝑃 in 𝑁/𝑚𝑚^2

Answer 10

Stribeck curve