ME-802-B Tribology & Maintenance Engineering - May 2023 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 4 Marks
   aWhat are the historical developments and industrial significance of tribology?
   How to answer

   • Define tribology as study of friction, wear and lubrication
   • Outline historical developments from early civilizations to Jost report 1966
   • Explain industrial significance: energy saving, reliability, maintenance cost
   • Give examples of applications in bearings, gears, manufacturing
2. 3 Marks
   bDifferentiate between conforming and non-conforming contact.
   How to answer

   • Define conforming contact with large contact area
   • Define non-conforming contact with point/line contact
   • Compare on contact area, pressure, load capacity
   • Give examples: journal bearing vs ball bearing
3. 4 Marks
   cExplain Stick slip phenomenon.
   How to answer

   • Define stick-slip as cyclic sticking and slipping
   • Explain role of static vs kinetic friction
   • Describe mechanism with spring-mass model
   • Mention effects and control measures
4. 3 Marks
   dHow to reduce adhesive component of friction?
   How to answer

   • Define adhesive component of friction
   • Explain role of junction growth and surface films
   • List methods: lubrication, coatings, material selection
   • Explain surface hardening and contamination control
5. 4 Marks
   aWhat is meant by Elastic half spheres?
   How to answer

   • Define elastic half spheres in Hertzian contact context
   • Explain assumptions of elastic half-space
   • Mention contact of spheres as model for non-conforming contact
   • State relevance to stress and deformation analysis
6. 3 Marks
   bExplain the classification of bearing based on the applied load.
   How to answer

   • State basis of classification by load direction
   • Explain radial, thrust and combined load bearings
   • Give examples of each type
   • Mention load capacity implications
7. 4 Marks
   cExplain different types of bearing based on film thickness.
   How to answer

   • Define role of lubricant film thickness
   • Explain thick film, thin film, boundary lubrication bearings
   • Differentiate hydrodynamic and hydrostatic types
   • Give applications of each
8. 3 Marks
   dWhat are the advantages and disadvantages of cylindrical roller bearings?
   How to answer

   • Describe construction of cylindrical roller bearing
   • List advantages: high radial load, rigidity, low friction
   • List disadvantages: sensitivity to misalignment, noise
   • Mention typical applications
9. 4 Marks
   aWhat are the laws of friction and explain the exceptions of these laws?
   How to answer

   • State Amontons-Coulomb laws of friction
   • Explain proportionality to normal load and independence of area
   • Explain exceptions at very low/high loads and clean surfaces
   • Give examples of adhesion and lubrication effects
10. 3 Marks
    bExplain Bowden Tabor's theory of friction.
    How to answer

    • State Bowden and Tabor adhesion theory
    • Explain real area of contact and asperity junctions
    • Give friction force relation $F = A \cdot \tau$
    • Mention ploughing component
11. 4 Marks
    cExplain any two factors affecting friction.
    How to answer

    • Identify factors: load, surface roughness, speed, temperature
    • Select any two for detailed explanation
    • Explain mechanism of influence on friction
    • Give practical examples
12. 3 Marks
    dDescribe the Physical vapour deposition technique with the help of a sketch.
    How to answer

    • Define physical vapour deposition (PVD)
    • Describe steps: evaporation, transport, condensation
    • Include neat labelled sketch of PVD chamber
    • Mention applications and advantages
13. 7 Marks
    aList out any three friction measuring equipment. Explain any one of the methods in detail.
    How to answer

    • List three devices: pin-on-disc, four-ball tester, block-on-ring
    • Describe construction and working of one method
    • Explain measurement of friction force/coefficient
    • Mention standards and applications
14. 7 Marks
    bSuggest any two coating methods to improve high temperature oxidation and corrosion.
    How to answer

    • Identify need for high temperature oxidation resistance
    • Suggest two coatings: diffusion aluminide, MCrAlY overlay
    • Explain process and protective oxide formation
    • Compare suitability and limitations
15. 4 Marks
    aWhat is meant by electro plating?
    How to answer

    • Define electroplating as electrodeposition process
    • Explain principle using electrolyte and electric current
    • Give examples: Ni, Cr, Zn plating
    • Mention purpose: wear and corrosion protection
16. 6 Marks
    bExplain its three advantages and three disadvantages of electroplating method.
    How to answer

    • List advantages: low cost, uniform coating, corrosion resistance
    • List disadvantages: hydrogen embrittlement, waste disposal, slow rate
    • Explain each briefly
    • Conclude with applications
17. 4 Marks
    cExplain any five micro structural treatments.
    How to answer

    • Define microstructural treatments for surfaces
    • Explain five: carburizing, nitriding, induction hardening, shot peening, laser hardening
    • Mention effect on hardness and wear
    • Give applications
18. 6 Marks
    aExplain any three geometrical parameters of coating.
    How to answer

    • Define geometrical parameters: thickness, roughness, porosity
    • Explain any three with measurement methods
    • Discuss influence on coating performance
    • Give acceptable ranges/examples
19. 4 Marks
    bDescribe the hard facing coating technique with the help of a sketch.
    How to answer

    • Define hardfacing as wear-resistant overlay
    • Describe process: welding, thermal spray with sketch
    • Include labelled diagram of torch/substrate
    • Mention materials and applications
20. 4 Marks
    cSuggest any two methods of coating to acidic environments.
    How to answer

    • Identify acidic corrosion problem
    • Suggest two coatings: PTFE, rubber lining, Ni-Cr plating
    • Explain chemical resistance mechanism
    • Mention limitations and selection criteria
21. 6 Marks
    aExplain hydrodynamic and elastro-dynamic lubrication.
    How to answer

    • Define hydrodynamic lubrication with thick fluid film
    • Define elasto-hydrodynamic lubrication with elastic deformation
    • Compare pressure, film thickness, applications
    • Give examples: journal bearing vs gears/cams
22. 4 Marks
    bList the assumptions in the Hertzian analysis of contact between surfaces.
    How to answer

    • State Hertzian contact assumptions
    • List: elastic, homogeneous, smooth, small contact area
    • Explain frictionless and half-space assumption
    • Mention limitations
23. 4 Marks
    cState Amonton's laws of friction.
    How to answer

    • State Amonton's two laws of friction
    • Explain proportionality to normal load
    • Explain independence from apparent contact area
    • Mention kinetic friction independence from velocity
24. 7 Marks
    aDefine wear and explain any two types of wear.
    How to answer

    • Define wear as progressive material loss
    • Explain any two: adhesive, abrasive, corrosive, fatigue wear
    • Describe mechanism with diagrams
    • Give prevention methods
25. 7 Marks
    bMention any five factors affecting wear and explain them.
    How to answer

    • List five factors: load, speed, hardness, lubrication, environment
    • Explain influence of each on wear rate
    • Give Archard wear relation
    • Suggest control measures