Would Life Be Possible Without Tribology ????? Dr A. Karpinska 1

Tribology is the science and engineering of interacting surfaces in relative motion 2 S O WHAT IS T RIBOLOGY ? Tribology tries to describe everything that happens when things rub together TRIBOLOGY TRIANGLE

F RICTION What is friction? 3 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 4 F RICTION Let’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?

5 T HE AMAZING FRICTION CHALLENGE! Pick up thousands of rice grains with a single chopstick.

6 T HE AMAZING FRICTION CHALLENGE! Pull apart two books with interwoven pages. 30 s 3 min

M AKING CORNFLOUR SLIME 7 CornflourWaterRatio 50 ml 25 ml2:1

8 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.

foods W HERE IS T RIBOLOGY ? corn flour + water 9 20 s

H IGH F RICTION 10 goodbad

H IGH F RICTION 11 bad

L OW F RICTION 12 goodbad

sport W HERE IS T RIBOLOGY ? 13

sport W HERE IS T RIBOLOGY ? leather or... synthetic? 14

cosmetics W HERE IS T RIBOLOGY ? 15

cosmetics- hair conditioners W HERE IS T RIBOLOGY ? 16

W HERE IS T RIBOLOGY ? 17 mechanisms: gears, bearings, rail wheels

W HERE IS T RIBOLOGY ? 18 According to specifications, the bearings were to have a life of more than 50 years.

nature and human body W HERE IS T RIBOLOGY ? 19

W EAR What is wear? It’s the removal of material from a solid surface by the action of another surface. 20

W EAR 21 goodbad

L UBRICATION Why do we need it? ↓ friction ↓ wear remove heat and contamination lower the friction prevent wear

L UBRICATION Types of lubricants OIL 23

L UBRICATION Types of lubricants 24 GREASE

L UBRICATION Types of lubricants 25 AIR Load Pressurized air

L UBRICATION Types of lubricants 26 SOLID

L UBRICATION Types of lubricants 27 SPECIAL SUBSTANCES

just look around !!! T RIBOLOGY IS EVERYWHERE !!! 28

Dr A. Karpinska 29 Thank you