1 WHAT IS ENGINEERING?


1


machines = goods e.g., cars, food


faster, better machines e.g., assembly line better quality – computer story


2


metal fatigue


3 causes 19th term


repeated stress loading


planes


Comet 1954 = 2 crashes


= failure of cabin window 4 History of ME


early 18thC — Ind. Rev. (Eng.) 1712 — Th. Newcomen (Eng.) = steam engine 1765 — J. Watt (Eng.) = better engine therefore mech. engineers needed: 1847 — Inst. M.E. (Eng.)


5 Functions of mechanical engineers


principles RDDp production management of mech. sc.


goods/power


1. dynamics 2. auto. control 3. thermodynamics 4. fluid flow 5. heat transfer 6. lubrication 7. props. of mats.


6


elec. system ✓✗ r eliable economy life


power weight top speed


internal comb. ✓✓ four stroke - SSBB ✓✓ start comb.


POINTS Petrol Vs diesel engine PETROL DIESEL spark compress. accidents


trains factory machinery


effects


building collapse


Environmental control


1. History of ACs heating = thous. of years old Anc. Ind. = wet mats at window - cool by evap. 1922 — first AC in theatre in LA (US) - W. Carrier 1930s — freons = better ACs 1935 — AC on Am. trains 1950 — window AC (US)


2. How ACs work - heat pump r efrig. — coils air from room over coils r efrig. evap. = cools air cool air to room r efrig. — compressor pressurized another set of coils — outside air r efrig. condenses


Mechanical Engineering machines = power


e.g., electricity, nuclear water, wind – steam –


internal combustion engine – nuclear – renewable


weapons


e.g., guns e.g., jet


environmental control e.g., heating, cooling drainage


irrigation water out of mines


air into mines r efrigeration central heating


11


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