STUPIDSID
1 (a)
Explain the following Terms:
(i)Viscosity Index (ii)Profilometry (iii) Friction (iv) Wear (v)Hydro-static lubrication
(vi) Squeeze film lubrication (vii) Bearing modulus
7 M
1 (b)
Define 'Tribology'. Give brief history of Tribology. Discuss basic methods of
solutions of Tribological problems.
7 M
2 (a)
What are the types of lubricants? Discuss the role of lubricants in solution of
Tribological problem using suitable example.
7 M
Solve any one question from Q2(b) & Q2(c)
2 (b)
What are the geometrical properties of the surface? Discuss parameters of measurements of roughness of the surface.
7 M
2 (c)
A typical profilometer trace show a uniform triangular surface asperities having
0.05mm height and 0.25mm pitch. If the sample length taken is 2 mm then determine
CLA and RMS value.
7 M
Solve any two question from Q3(a), Q3(b) & Q3(c), Q3(d)
3 (a)
Explain different methods of measurements of friction.
7 M
3 (b)
Write a short notes on: (i)Fretting (ii) Corrosive wear
7 M
3 (c)
Derive the following equation for adhesive wear mechanism assuming spherical
Asperities: \( V= \dfrac {1}{3} \dfrac {W \ x}{H} \) where, W = Load on asperity, H= hardness of material, x = distance.
7 M
3 (d)
State the laws of friction. Write a short note on ploughing friction.
7 M
Solve any two question from Q4(a), Q4(b) & Q4(c), Q4(d)
4 (a)
Derive the equation of pressure distribution for infinite width tapered-pad bearing. State the assumptions made.
7 M
4 (b)
A 360° hydrodynamic short journal bearing of is to be designed to support a radial
load of 5.5 KN. The rotation of journal is 5000rpm. The eccentricity ratio is 0.6. If the
viscosity of lubricating oil is 45×10-9 Ns/mm2 and supplied at a rate of 0.5 l/min to the bearing, Determine the dimensions of the journal, bearings and minimum oil film
thickness. Take l/d ratio as 0.4.
7 M
4 (c)
Derive the equation of pressure distribution for hydrostatic step bearing. State the assumptions.
7 M
4 (d)
A guide-way bearing of machine tool is having a width of 140mm, length of 700mm
with a sliding velocity 2.5 m/s. The minimum oil film thickness is 16 μ. Absolute
viscosity of oil is 0.025×10-9 MPp-s. Assuming film thickness ratio as 2, determine the load carrying capacity, co-efficient of friction, power lost in friction and film thickness at a distance of 450mm from leading edge.
7 M
Solve any two question from Q5(a), Q5(b) & Q5(c), Q5(d)
5 (a)
Differentiate between hydro-static and hydro-dynamic lubrication.
7 M
5 (b)
Write a short note on bearing materials.
7 M
5 (c)
Write a short note on lubrication in metal working.
7 M
5 (d)
Explain with neat sketch working principle of:(i) EHD lubrication (ii) Gas lubrication
7 M
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