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Tribology
Science and engineering ofinteractive surface in relativemotion.
Presented by:Mukut ch. MedhiSomnath DeyDhiru Kamal DekaMd Shaifuddin
Dept. of Mechanical EngineeringTezpur University
Tribology
• Tribology (origin in 1960’s)
Tribology= tribos+logos
Rub
Principle or logic
Brown’s first law of applied Tribology
IF IT'S RUNNING
IT'S WEARING !!!
IF IT'S NOT RUNNING
IT'S PROBABLY WORN!
Tribology
• Two bodies in relative motion .
• Results Friction
oStatic frictionoFrictional heat, resistance against movement
(friction force), loss of energy.
WearoMaterial loss degradation of surface, decreasing
functionality.
Examples of Tribology
• Industrial Tribology– Machine parts/engines
• Lubrication• Oil• Grease
• Friction and wear
• Decreasing performance
Wear Definition
• Most wear is an combination of several mechanisms
Wear Mechanisms
• Adhesive – Low contact pressures – Augmented asperities
• Abrasive – High contact
pressures – Wear tracks
Friction
• Origin of friction– Deforming of the surface : deformation energy– Adhesion of two bodies: non-linear adhesion
hysteresis• Atomic adhesion model• Van Der Waals• Capillary forces
– Electron interactions
• Dynamic friction –static friction
Lubrication
• Lubrication is the process, or technique employed to reduce wear of one or both surfaces in close proximity, and moving relative to each another, by interposing a substance called lubricant.
Types of lubricants
• Liquid lubricants– Lubrication with oil
• Cooling and removal of debris• Protection against metal-metal contact• Hydrodynamic lubrication• Lowering friction=lowering energy input into the surface.
– Lubrication with grease• Oil in wax• Low cooling effect/no hydrodynamic lubrication• Alternative when oil lubrication is impossible
Types of lubricants
• Solid lubricants and self-lubricating materials– Plastics, PTFE, MoS2, , Graphite
Important properties of lubricants
• Wide range of viscosity
• Little change in viscosity with temperature
• Chemical stability
• Sufficient specific heat to carry away frictional heat
• Low cost
• Easily available
Bearings
• It is mechanical element that permits relative motion between two parts such as shaft and housing.
Ball Bearing
Classification
• Depending on type of frictionSliding contact bearingRolling contact bearing
• Depending on type of forceRadial Thrust
Rolling and sliding contact bearing
Rolling contact bearing and sliding contact bearing
Radial and thrust bearing
Rolling contact bearing
• Deep groove ball bearing
• Cylindrical roller bearing
• Angular contact bearing
• Self aligning bearing
• Taper roller bearing
• Thrust roller bearing
Rolling bearing
Propeller bearing
Water lubricated polymer bearing
Water lubricated bearing
Different types of bearings
Application
• Industrial Process
• Tribology in biological science
• Tribology in engines
Industrial process
• Rolling-Sheet metal
• Wire drawing
• Tube expansion
• Deep drawing
Rolling-Sheet metal
Rolling-Sheet metal
Wire drawing
Tube expansion
Deep drawing
Tribology in biological science
Tribology in engines
• Lubrication of engine
Lubrication of engine
Valve train
Sump1
Sump2
Piston assembly
Crank shaft
Degradation of lubricant
Piston Assembly
Sump
Sump
Piston
Piston Assembly
Extraction of Oil from Top Piston Ring
Solutions to tribological problem
• Trial and error method– Material selection– Parameter selection– Lubricant
• Simulation method– Selection of simulation– Material selection– Parameter selection– Field data
Conclusions
• Tribology is a multi-disciplinary science that is based onto experience and common sense.
• Boiler feed pumps: 49% of the failures causing outages were because of tribological components.
• Friction, wear and failure of tribological components are costing industry billions of dollars
Reference
• www.falexint.com
• www.wikipedia.org
• lqme.sjtu.edu.cn
• www.TRIBOLOGY-ABC.com
• Design of machine elements- V.B BHANDARI
• Fundamentals of Tribology-Basu, Sengupta, Ahuja
Thank You
Question’s ?....