a karpinska tribology
TRANSCRIPT
Would Life Be Possible Without
Tribology?????
Dr A. Karpinska
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Tribology is the science and engineering of interacting surfaces in relative motion
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SO WHAT IS TRIBOLOGY?Tribology tries to describe everything that
happens when things rub together
TRIBOLOGY TRIANGLE
FRICTION What is friction?
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It’s a FORCE.Occurs whenever two objects are IN CONTACT with
each other.It’s the resistance to movement. It SLOWS objects
down.
higher friction
lower friction
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FRICTIONLet’s use THE SAME FORCE to move the box on:
wooden floor
ice
Which one will slide further?In which case friction is higher?WHY?
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THE AMAZING FRICTIONCHALLENGE!
Pick up thousands of rice grains with a single chopstick.
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THE AMAZING FRICTIONCHALLENGE!
Pull apart two books with interwoven pages.
30 s
3 min
MAKING CORNFLOUR SLIME
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Cornflour Water Ratio50 ml 25 ml 2:1
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Cornflour is made up of lots of tiny (<0.01mm) angular starch particles, these are very attracted to water so the water gets in amongst them very quickly.
The water acts as a lubricant, so when you move it slowly the particles have time to move past each other and they can flow like a liquid. However if you apply a rapid force it causes the particles to move slightly causing the particles that are almost touching to jam together. and the water that was between them moves sideways slightly into the gaps.
Now instead of having lots of lubricated individual particles you have a solid structure of lumps touching each other which can't flow.
HIGH FRICTION
10good bad
HIGH FRICTION
11bad
LOW FRICTION
12good bad
sportWHERE IS TRIBOLOGY?
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sportWHERE IS TRIBOLOGY?
leather or ... synthetic?
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cosmeticsWHERE IS TRIBOLOGY?
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cosmetics- hair conditionersWHERE IS TRIBOLOGY?
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WHERE IS TRIBOLOGY?
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mechanisms: gears, bearings, rail wheels
WHERE IS TRIBOLOGY?
18According to specifications, the bearings were to have a life of more than 50 years.
nature and human bodyWHERE IS TRIBOLOGY?
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WEAR What is wear?
It’s the removal of material from a solid surface by the action of another surface.
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WEAR
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good bad
LUBRICATIONWhy do we need it?
↓ friction
↓ wear
remove heat and contamination
lower the friction prevent wear
LUBRICATION Types of lubricants
OIL
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LUBRICATION Types of lubricants
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GREASE
LUBRICATION Types of lubricants
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AIR
Load
Pressurized air
LUBRICATION Types of lubricants
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SOLID
LUBRICATION Types of lubricants
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SPECIAL SUBSTANCES
just look around !!!TRIBOLOGY IS EVERYWHERE !!!
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Dr A. Karpinska
29 Thank you