What is Tribology? Explain in detail Historical background of Tribology
a
b. Explain the industrial importance of Tribology.
(08 Marks)
OR
List out different types of viscometers. Explain any one with neat
What are the functions of lubricants? Explain.
(08 Marks) (08 Marks)
Module-2
Click here to join us on Social Media for getting instant update on every noticea. Define Friction. What are different types of Friction? Explain. b. What are the different methods of measuring frictional force? Explain any one.
(08 Marks)
(08 Marks)
OR
a. List out wear mechanisms. Explain any one wear mechanism? b. List out various wear testing methods clearly, mentioning their standards
(08 Marks) (08 Marks)
Module-3 Derive Reynolds 2D equation with assumptions.
(16 Marks)
a Derive an equation for load carrying capacity for a Idealized Journal bearing. (10 Marks)
b. An Idealized full Journal bearing has the following specifications:
OR
a
b
Diameter of the Journal 50 mm, Speed of the Journal = 1200 rpm,
Viscosity of lubricant -11 CP.
Length of the bearing 62.5 mm Radial clearance= 0.025 mm
Attitude, -0.8
Calculate bearing
(i) Load carrying capacity (ii) Co-efficient of friction (i) Power loss of the (06 Marks)
Module-4
a Derive an expression for load carrying capacity of a plane slider bearing with a fixed shoe.
b. A slider bearing has a pivoted shoe by the following data:
Length of the shoe in the direction of motion= 50 mm
(10 Marks)
Width of the shoe- 64 mm
Slider velocity-5.5 m/s Load on the bearing = 8025 N
Viscosity of the lubricant - 31 CP
Determine minimum oil film thickness, power loss and coefficient of
friction of bearing? 106 Marks)
The inclination of the surface corresponds to minimum co-efficient of friction?
8
OR
a. Derive an expression for hydrostatic step bearing pressure distribution. b. A hydrostatic step bearing has the following specifications:
Diameter of the shaft - 152 mm Diameter of the pocket = 102 mm
Vertical thrust on the bearing 65000 N
External pressure=0 Shaft speed 900 rpm
Viscosity of lubricant 24 15 CP
Oil film thickness = 0.127mm, Find (1) Supply pressure (ii) Quantity of oil flow (iii) Power loss in the bearing Frictional force (v) Co-efficient of friction.
(iv)
9
Module-5
List the characteristics of bearing materials. Explain any two.
h. Determine the common bearing alloys. Explain any two alloys.:
OR
10 a What is Surface Engineering? Write a brief history of Surface Engineering? b. List out Traditional Coating Techniques? Explain any two..
a. Define the term Tribology. Discuss industrial importance of tribology. b. Discuss major properties of an ideal lubricant.
(06 Marks) (10 Marks)
OR
a Define Viscosity. State and explain Newton's law of viscosity, with a neat sketch. (06 Marks) b. Explain Construction and Operating principle of Falling Sphere Viscometer and Flower's Viscometer, with neat sketches.
(10 Marks)
Module-2
a. Define the term friction. Explain measurement of friction by an inclined plane test rig.
b. Explain Bowden and Tabor's Adhesion theory of friction.
(08 Marks) (08 Marks)
OR
4 a Define the term Wear. Explain in brief classification of wear in relation to wear mechanism.
b. Explain Delamination theory of wear in brief
(08 Marks) (08 Marks)
Module-3 Derive the Reynold's equation in two dimensions.
(16 Marks)
OR
6 a. A full joumal bearing has an equal length and diameter of 0.05m. The diametral clearance ratio is 0.001 and the operating viscosity of the lubricant is 0.05 par sec. If the journal speed is 950 rpm and if the bearing sustains a load of 100kN, determine eccentricity ratio and
thickness of the lubricant. (08 Marks) b. A full journal bearing operates under a load of 1.75 kN at a speed of 900 rpm. The diameter of journal is 37.5mm and the length of bearing is 46.8mm. The minimum oil film thickness must not be less than 0.009375mm. Assume diametral clearance ratio to be 0.001 and average operating temperature as 95°C Determine the type of lubricant and power loss in the bearing by considering end leakages into account. (08 Marks)
Module-4
Derive an equation for load carrying capacity of an idealized plane slider bearing
(08 Marks)
2
3
pivoted shoe
with
b. A square shape pivoted shoe slider bearing has the following specifications Load carrying capacity 13344 N Velocity of moving member 5.08 m/s Viscosity of oil used = 15Cp. Permissible minimum oil film thickness 0.01905mm. Assume q 1.2 and determine coefficient of friction and power loss. Neglect effect of end flow from the bearing (08 Marks)
8
B
ADV
A Derive an equation for rate of flow of oil through a hydro static step bearing. (09 Marks) b. A hydro static step bearing has the following specifications Journal diameter 100mm. Diameter of pocket-50mm. Vertical thrust on bearing 18.16 kN External pressure 1.013 bar. Journal speed 60 rpm, Desirable oil film thickness 0.1mm. Viscosity of lubricant-8.5 Cp. Determine energy lost in pumping and coefficient of friction (08 Marks)
Module-S
Explain major properties of typical bearing materials b. Explain principal methods of physical vapour deposition sketch.
in surface coating with a neat
28%
OR 10 a Explain the basic requirements to be satisfied by any component for selection of a particular surface coating b. Explain in brief any five common surface hardening processes.