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Transcript of Trib Ology
TribologyScience and engineering of interactive surface in relative motion.Presented by: Mukut ch. Medhi Somnath Dey Dhiru Kamal Deka Md Shaifuddin Dept. of Mechanical Engineering Tezpur University
Tribology Tribology (origin in 1960s) Tribology= tribos+logos
RubPrinciple or logic
Browns 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 Frictiono Static friction o Frictional heat, resistance against movement (friction force), loss of energy.
Wearo Material 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
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.
Classification Depending on type of frictionSliding contact bearing Rolling 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
Different types of bearings
Water lubricated bearing Water lubricated polymer bearing
Application Industrial Process Tribology in biological science Tribology in engines
Industrial process Rolling-Sheet metal Wire drawing Tube expansion Deep drawing
Tribology in biological science
Tribology in engines Lubrication of engine
Lubrication of engineSump1Valve train
Degradation of lubricant
Piston Piston Assembly Sump
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