Engineered Products

Skills of the Engineer

• Problem solvers

• Designers

• Communicators

• Project managers

Problem Solvers

• Presented with a challenge or problem and then come up with a solution

Designers

• Final design would be tested then evaluated

Communicators

• Verbal, writen and graphical forms

• CAD, pictorial, orthogonal and assembly

Project Managers

• Ensure al parts of the project occur at the right time and on the right schedule and within constraints on materials and cost

Historical Development

Lawn Mowers

Car Development

Lawn Mower

• Mulch n catch mower

• Wrought iron and cast iron

• Steel

• Fabricated steel frame

• Polyethelyne catcher

Car Development

• First car- Gotleib Daimler

• Mass Produced using production line method

• Volkswagen- Most popular car

• Citroen DS19

• Transverse engine

Effect of Engineering on Peoples lives

• Lawn mowers

• Cars

Effect of Lawn mowers on peoples lives

• The sunbeam mower 1947, that any heavier than air pollutant were deposited directly on the ground

Effect of Cars on peoples lives

• Slow, noisy and expensive

• Development of 4 wheel brakes on in the mud to late 1930’s starts to make the car a much safer travel option

• Innovative suspension systems and disc brakes improved by dynamic safety

• By all 1972 all cars sold in Australia must have seatbelts

• 21st Century: Hybrid Car

Environmental Implications (Petrol Engine 4)

• Induction

• Compression

• Ignitiiton (Power)

• Exhaust

1. Induction

• The valves open

2. Compressin

• Valves are closed

3. Power

• Spark Plug igniting the compressed fuel mixture

4. Exhaust

• Exhaust valves open pushing the gases out of the cylinder

Nature and Types of forces

Resultants and Equilibrants

Principle of transmissibility of forces

Three force rule for equilibirum ( Calculation)

Moment ( Calculation)

Couples ( Calculation)

Engineering Materials

Modification of Materials

• Work hardneing

• Heat Treatment

• Alloying Materials

Work Hardening

• Work hardening is when a metal becomes stronger and harder after being plastically deformed (bent, stretched, hammered), at its “ recrsytillisation temperature”

• Makes it stronger but less flexible

As the metal deforms, the atoms slide across the shearplane, and dont move as they are encounter grain boundaries

Heat Treatement

• Heat treatment is the process of heating and cooling a metal in a controlled way to change its properties (like strength, hardness, or flexibility).

Steel ( Heat Treatment)

• Heated until red hot (1000 degree celscius) then quenched in water, the steel will become hard but brittle *easy to break.

Martensite

• Very hard structure formed when steel is rapidly cooled/ quenched

Tempered Martensite

• Quenched steel that has been reheated to reduce brittleness and increase toughness

Heat Treatment Process “ Steel”

1. Annealing

• Steel is heated about 900 degrees and then cooled very slowly (usually in a furnace)

• Results in an unstressed grain structure consisting of ferrite and pearlite

Ferrite: Soft, ductile form of iron in steel

Pearlite: Layered structure of ferrite and cementite that increases strength

2. Process Annealing

• Lower-temperature heating around 550-650 degrees on mild steel

• Ferrite phase undergoes recovery and recrystallisation, being unstressed

• Pearlite is less affected because its layered structure is more stable at these temperatures.

3. Normalising

• Steel heated up to 900 degrees to relieve stress, then cooled in air

• Produces a finer grain structure then annealing