Tribology JNTU previous years question papers



Time: 3 hours

Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

1. Explain basic mechanism of friction with suitable sketches. [16]

2. (a) Can hybrid hydrostatic and hydrodynamic bearings be developed and used to advantage?
(b) Give examples of operating conditions under which the application of hydrostatic bearings would be necessary or highly desirable. [8+8]

3. With the help of a neat sketch explain the construction and working of capillary viscometer. [16]

4. (a) What are the assumptions proposed by Reynolds in theory of hydrodynamic lubrication?
(b) Explain the mechanism of load support in hydrodynamic lubrication. [8+8]

5. Design a journal bearing with the following speci cations:
Journal diameter=100mm
Journal speed=3000rpm
Radial load=15kN. [16]

6. Classify various bearing materials. [16]

7. A rectangular slider bearing with xed shoe is operating under the following conditions:
Bearing length=150mm
Sliding speed=2.0m/s
Absolute viscocity of oil=0.02Pa s
Minimum oil lm thickness=0.02mm
Maximum oil lm thickness=0.05mm
(a) The load carrying capacity
(b) The pressure at a distance 50mm measured from the maximum lm thickness point. Neglect side leakage. [16]

8. Give the design aspect of extremely pressurized bearings. [16]




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