Engineering Studies notes

Andrew Harvey

HSC ENGINEEING STUDIES

Syllabus Notes 2007

1st Edition

_____________________________________________________________________________________________________ HSC ENGINEERING STUDIES SYLLABUS NOTES 2007 – ANDREW HARVEY iii

Copyright © Andrew Harvey 2007 Students and teachers may copy, distribute and transmit this work freely so long as this work is not used for commercial purposes; and that this work is attributed in a manner that clearly acknowledges the copyright of this work. First Edition published November 2007. If you have any queries on this document, I can be contacted at [email protected] I would appreciate and welcome your comments/corrections/suggestions, please send them to my e-mail. This publication contains extracts from the Board of Studies, NSW Stage 6 Engineering Studies Syllabus 1999, ISBN 0 7313 4313 1. These extracts are Copyright © Board of Studies NSW. Also the orange and blue headings, (the syllabus dot points) are Copyright © Board of Studies NSW. Some diagrams and text in this document may have been sourced from other sources that may or may not be copyright. Any material from another source has been referenced. Any copyright for that diagram or text is vested in the owner. If you are the copyright owner of a diagram, image or extract of text used in this document and wish for it to be removed from this document, please contact me and I will willingly make the changes.

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CONTENTS ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

_____________________________________________________________________________________________________ HSC ENGINEERING STUDIES SYLLABUS NOTES 2007 – ANDREW HARVEY iv

CCOONNTTEENNTTSS CONTENTS ......................................................................................... iv

1. CIVIL STRUCTURES .......................................................................... 1 1. Historical and societal influences ..................................................................................................................................... 2 2. Engineering mechanics and hydraulics ............................................................................................................................ 2 3. Engineering materials ....................................................................................................................................................... 5 4. Communication ................................................................................................................................................................. 7

2. PERSONAL AND PUBLIC TRANSPORT ................................................. 9 1. Historical and societal influence ..................................................................................................................................... 10 2. Engineering mechanics and hydraulics .......................................................................................................................... 10 3. Engineering materials ..................................................................................................................................................... 11 4. Engineering electricity/electronics ................................................................................................................................. 13 5. Communication ............................................................................................................................................................... 13

3. LIFTING DEVICES ........................................................................... 14 1. Historical and societal influences ................................................................................................................................... 15 2. Engineering mechanics and hydraulics .......................................................................................................................... 15 3. Engineering materials ..................................................................................................................................................... 15 4. Engineering electricity/electronics ................................................................................................................................. 15 5. Communication ............................................................................................................................................................... 15

4. AERONAUTICAL ENGINEERING ........................................................ 16 1. Scope of the profession .................................................................................................................................................. 17 2. Historical and societal influences ................................................................................................................................... 17 3. Engineering mechanics and hydraulics .......................................................................................................................... 17 4. Engineering materials ..................................................................................................................................................... 17 5. Communication ............................................................................................................................................................... 18

5. TELECOMUNICATION ...................................................................... 19 1. Scope of the profession .................................................................................................................................................. 20 2. Historical and societal influences ................................................................................................................................... 20 3. Engineering materials ..................................................................................................................................................... 20 4. Engineering electricity/electronics ................................................................................................................................. 20 5. Communication ............................................................................................................................................................... 20

REFERENCES/ RESOURCES ................................................................. 22

1. CIVIL STRUCUTRES ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

_____________________________________________________________________________________________________ HSC ENGINEERING STUDIES SYLLABUS NOTES 2007 – ANDREW HARVEY 1

11..

CCIIVVIILL SSTTRRUUCCTTUURREESS



1. Historical and societal influences

1. historical developments of civil structures

Beam Bridges Arch Bridges Suspension Bridges

2. engineering innovation in civil structures and their effect on people’s lives

Large buildings have allowed for apartments and businesses to work in a good environment. Bridges allowed people to cross water ways easily and quickly.

3. construction and processing materials used in civil structures over time

Timber Stone – Strong in compression, heavy Cast Iron Steel – Corrodes, strong in tension and compression Concrete

4. environmental implications from the use of materials in civil structures

Timer – Deforestation Stone – Needs to be quarried Steel – Pollutants from smelting Concrete

1. outline the history of technological change as applied to civil structures

2. investigate the construction processes and materials used in civil structures from a historical point of view

3. critically examine the impact of civil structures on society and the environment

2. Engineering mechanics and hydraulics

1. stress and strain

– shear stress

Shear stress occurs when you apply shear force. Eg. If a bolt is supporting a load perpendicular to the bolt of 10N, and it has a diameter of 10mm, what is the shear stress?

Shear Stress = kPaAreaShear

ForceShear127

23105

10

π

– engineering and working stress

Engineering stress is the stress a material is undergoing without taking into account the change in area.

– yield stress, proof stress, toughness, Young’s modulus, Hooke’s law, engineering applications

Yield stress occurs when there is an increase in strain without an increase in stress. Proof stress is the amount of stress necessary to bring a permanent strain in the material. Toughness is a measure of the ability of a material to absorb energy.

Hooke’s law is

E , it calculates Young’s modulus of elasticity.

– factor of safety

A factor of safety is how many times stronger the material or structure is than it needs to be.

area



Ductileyield

allowableSofF

BrittleUTS

allowableSofF

– stress/strain diagram

2. truss analysis

– method of joints

This involves working around the truss, finding the forces in most of the members.

– method of sections

This involves cutting the truss so that you can calculate just the forces you want.

3. bending stress induced by point loads only

– concept of shear force and bending moment

– shear force and bending moment diagrams

Here is a beam (top), with the corresponding shear force diagram (middle), and bending moment diagram (bottom),



– concept of neutral axis and outer fibre stress

The neutral axis has no stress in it. If the beam is bent the maximum stress occurs at the top and bottom faces of the beam.

– bending stress calculation (second moment of area given)

σ =My

I

σ = Bending Stress (Pa) M = Bending Moment (Nm-1)

y = depth of beam

2 (distance from neutral axis to outer surface) (m)

I = Second moment of area (m4) (Always given in the question) (if in mm4 use 𝑥4

then change units then x4)

4. uniformly distributed loads

The load is distributed along the whole beam, so there is no point on the beam with the most loading; it is equal the whole way along. A uniformly distributed load will result in a non-horizontal or vertical lines of shear force diagrams, and curves on bending moment diagrams.

5. crack theory

– crack formation and growth

Cracks form due to strain energy, which is internal stress. They also form by movement and vibration. They create areas of high stress, these areas of high stress create more cracks.

neutral axis

+

SF

-

+

BM

-



They grow because the further they penetrate the less force needed to continue the crack.

– failure due to cracking

As the crack penetrates further the material will crack completely and fail.

– repair and/or elimination of failure due to cracking

Cracks can be repaired by: filling the crack reinforcing with another material replacing it

Cracks can be eliminated for forming by:

High factor of safety (making the material much stronger than it needs to be) Using the best design. eg. adding webs and fillets

1. apply mathematical and/or graphical methods to solve problems related to the design of civil structures

2. evaluate the importance of the stress/strain diagram in understanding the properties of materials

3. calculate the bending stress on simply supported beams involving vertical point loads only

4. describe the effect of uniformly distributed loads on a simple beam, without calculations

5. examine how failure due to cracking can be repaired or eliminated

3. Engineering materials

1. testing of materials

– x-ray

X-ray testing will show any holes in the material, as if there are hole more X-rays will penetrate and this will show up on the photographic film.

– specialised testing of engineering materials and/or systems

Testing of materials can either be destructive or non-destructive. Each can be used for different purposes and situations.

2. ceramics

– structure and property relationship, applications

Ceramics are used because of their: Heat resistance Compressive strength Wear resistance Water resistance Non conductivity

– glass

Glass has low toughness and is brittle and weak in tension. Glass may be toughened to increase toughness. To toughen glass it is blasted with cold air on the surface, and then the outer layers are placed in compression.

crack



– cement

3. composites

– timber

Plywood is a composite. It consists of layers of wood in alternating grain directions, with glue to bind it together.

– concrete (reinforced and prestressed)

Concrete is composed of sand, cement, aggregate and water.

Concrete macrostructure

Concrete is strong in compression, but weak in tension. To prevent the concrete from cracking when in tension, it is reinforced with steel rods or steel mesh. The steel rods or mesh are strong in tension and prevent the concrete from cracking. Prestressed concrete is when concrete is poured into rods which are in tension. Once the concrete has set the rods are released and they create compressive stress in the concrete.

Post-stressed is where the steel rods are stressed once the concrete has set.

If concrete is prefabricated, then it is cast separately then placed in its final position, it can be cast on and off site. This is contrasted to cast in situ, where the concrete is cast in its final resting place.

– asphalt

Asphalt is a composite of aggregate and bitumen. It is used mainly on roads.

– laminates

Laminates are materials with layers of other materials to change the properties. Laminated glass is used to create shatter resistant glass. It is produced by rolling two sheets of glass with a vinyl sheet in between them. Plywood is also a laminate as it consists of layers of wood glued together, this increases compressive strength and toughness.

rods held at one end, they are inside tubes, concrete is set then they are stressed in tension and anchored at the other end.

concrete poured

rods in tension, then released when concrete is set

concrete poured when rods are in tension

big aggregate

sand

cement



– geotextiles

Geotextiles are woven polymers or ceramic fibres. For example they are used to stop dirt from a construction site going into the drain.

4. corrosion

– corrosive environments

Corrosion is most likely to occur in materials that are subjected to water. Salt in the air or water will increase the effects of corrosion and make it happen faster,

– dry corrosion, wet corrosion, stress corrosion

Corrosion in the form of rust needs water. Corrosion occurs more at areas of high stress.

5. recyclability of materials

1. describe basic testing conducted on civil structures

2. examine the properties, uses and appropriateness of materials used in civil structures

3. make appropriate choices of materials and processes for use in civil structures

4. investigate the structure and property relationships in materials

5. explain the special properties produced by composite materials

6. experiment with simple pretensioned and post-tensioned structures

7. evaluate the significance of corrosion problems in civil structures

Concrete cancer is a form of corrosion problem which affects concrete. It occurs when the reinforcing steel rods corrode. When they corrode they expand, which causes the concrete to crack

8. describe methods used for recycling materials when civil structures are replaced

4. Communication

1. Australian Standard AS1100

2. orthogonal assembly drawings

3. development

– development of transition pieces

Take the length from one view and the height from the other, the resulting line is the true length.

4. graphical mechanics

– graphical solutions to complex engineering problems

5. computer graphics

6. research methods including the Internet, CD-ROM and libraries

7. collaborative work practices

Engineers from different fields need to work with one another to ensure all the parts and components fit and work together correctly, safely and in it best way.

8. Engineering Report writing

• produce orthogonal drawings applying appropriate Australian Standard (AS 1100)

• apply appropriate computer technology to the preparation of reports

• construct the development of noncircular transition pieces

length

height true

length



• apply graphical methods to the solutions of relevant problems

• apply research methods to collect and analyse data

• work with others and appreciate the value of collaborative working

• complete an Engineering Report based on the analysis and synthesis of an aspect of civil structures using appropriate software

2. PERSONAL AND PUBLIC TRANSPORT ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬


22..

PPEERRSSOONNAALL AANNDD

PPUUBBLLIICC TTRRAANNSSPPOORRTT



1. Historical and societal influence

1. historical developments in transport systems

The bicycle has developed due to the availability of new and better materials; and the changing need, and use of the bicycle over the ages.

Bicycle Train Car Bus Aeroplane

2. effects of engineering innovation in transport on people’s lives

Allow people to get from one place to another quickly and easily.

3. construction and processing materials over time

Early bicycles were made of timber, latter iron was used, then steel, then aluminium, and recently alloys and titanium and carbon fibre.

4. environmental effects of transport systems

Combustion of fossil fuels in petrol cars and steam engine trains.

5. environmental implications from the use of materials in transport


1. static friction

𝐹 = 𝜇𝑁 𝜇 = tan𝜑

– concept of friction and its use in engineering

Static friction is a force that opposes the motion of two objects in contact.

– coefficient of friction

Different materials in the same situation have different frictional forces. To account for this a coefficient of friction is given to different materials. Eg. Ice = 0.1 , rubber = 0.9.

– normal force

The normal force is the component (usually of weight) that is normal to the surface of friction.

– friction force

The frictional force is the force which acts to oppose the motion.

– angle of static friction

– angle of repose

2. energy, power

– potential energy, kinetic energy, work, power

𝐾𝐸 =1

2𝑚𝑣2

KE = Kinetic Energy (J) m = mass (kg) v = velocity (ms-1)

𝑃𝐸 = 𝑚𝑔ℎ PE = Potential Energy (J) m = mass (kg) g = acceleration due to gravity (9.8ms-2)

φ

F

N



h = height above surface (m)

𝑊 = 𝐹𝑠 = ∆𝑃𝐸 + ∆𝐾𝐸 W = Work (J) F = Force (N) s = distance (m)

𝑃 =𝑊

𝑡

P = Power (J/sec) W = Work (J) t = time (sec)


1. testing of materials

– x-ray

– specialised testing of engineering materials and/or systems

2. Heat treatment of ferrous metals

– heat treatment of steels

Alters the properties of steels.

– annealing

Heating then cooled slowly in furnace. Relieves any stress from distorted grains. Large grains.

– normalising

Heated then cooled in air. Smaller equiaxed grains.

– hardening and tempering

Hardening results in the material becoming hard and brittle. Cannot harden low carbon steel. If toughness and hardness is required a steel is hardened then tempered. This results in slightly less hard materials but much greater toughness.



Toughened Microstructure Tempered Microstructure

– structure property relationships

3. structure/property relationship in the material forming processes

– forging

Forging involves physically bashing it to shape. Can be done by hot or cold forging.

– rolling

Cold rolling results in elongated grains and hot rolling results in equiaxed grains.

– casting

Casting is making a shape from a mould. Casting refers to metals. Injection moulding is different and used for plastics.

– extrusion

Direct and indirect. Forces the metal out a die. The same shape the whole way along.

– powder forming

4. non-ferrous metals

– aluminium and its alloys, aluminium silicon, aluminium copper, aluminium siliconmagnesium

– brass, bronze

Brass is an alloy of copper and zinc. Shiny corrosion resistant.

elongated grains



Bronze is an alloy of copper and tin.

– structure/property relationship

– annealing, strengthening

5. ceramics and glasses

– semi-conductors

– laminating and heat treatment of glass

When tempered glass is smashed it separates into many little pieces.

6. polymers

– structure/property relationships and applications

– engineering textiles

– manufacturing processes for polymer component

4. Engineering electricity/electronics

1. power generation/distribution

– electrical energy and power

2. AC/DC circuits

AC > Alternating Current DC > Direct Current

3. electric motors used in transport systems

– principles

– applications

4. control technology

– digital technology

5. Communication

1. freehand sketching, designs, pictorial, orthogonal


3. computer graphics, Computer Assisted Drawing applications solving problems


5. collaborative work practices


3. LIFTING DEVICES ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬


33..

LLIIFFTTIINNGG DDEEVVIICCEESS

I DISCONTINUED STUDY OF THIS SUBJECT AT THE START OF THIS TOPIC

3. LIFTING DEVICES ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬



1. historical development of lifting devices

2. engineering innovation in lifting devices and their effect on people’s lives


1. conditions of equilibrium for non-concurrent coplanar forces

2. fluid mechanics

– Archimedes’ and Pascal’s principles

– hydrostatic pressure

– applications to lifting devices


1. testing of materials used in lifting devices

– tension, compression

– hardness

– impact

2. structure/property relationships in heat treatment processes

– normalising

– hardening and tempering

3. structure/property relationships in forming processes

– forging

– casting

– extrusion

– rolling

– powder forming


1. applications found in appropriate lifting devices

– motors

– motor control

2. electrical safety

5. Communication


2. sectioning of orthogonal views

3. orthogonal assembly drawings

4. computer graphics/computer assisted drawing


6. work collaboratively when appropriate


4. AERONAUTICAL ENGINEERING ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬


44..

AAEERROONNAAUUTTIICCAALL

EENNGGIINNEEEERRIINNGG

© NASA 2005



1. Scope of the profession

• nature and scope of the aeronautical engineering profession

• current projects and innovations

• health and safety issues

• training for the profession

• career prospects

• unique technologies in the profession

• legal and ethical implications

• engineers as managers

• relations with the community


• historical developments in aeronautical engineering

• the effects of aeronautical innovation on people’s lives and living standards

• environmental implications of flight


• forces – lift drag, weight, thrust

• basic aerodynamics

– Bernouli’s principle

• bending stress – airframes

• propulsion systems (jet, turboprop)

• fluid mechanics

– hydrostatic and dynamic pressure

– applications to aircraft components

– application to aircraft instruments


• specialised testing of aircraft materials

– dye penetrant

– x-ray

– magnetic particles

– ultrasonic

• aluminium and its alloys used in aircraft

– aluminium silicon, aluminium silicon – magnesium, aluminium copper

– structure/property/application relationships

– heat treatment of applicable alloys

• polymers

– structure/property relationships and applications

– modifying materials for aircraft applications

– engineering textiles

• composites

– types and applications in aircraft

– structure/property relationships

• corrosion

– common corrosion mechanisms in aircraft structures



– pit and crevice corrosion

– stress corrosion

5. Communication

• freehand and technical drawing

– pictorial and orthogonal projections

• Australian Standard AS1100

• graphical mechanics

– graphical solution to basic aerodynamic problems

• computer graphics, computer assisted drawing (CAD)

• research methods including the Internet, CD-ROM and libraries

• collaborative work practices

• Engineering Report writing



1. Scope of the profession

• nature and scope of telecommunications engineering

• health and safety issues

• training for the profession

• career prospects

• relations with the community

• technologies unique to the profession

• legal and ethical implications

• engineers as managers

• current applications and innovations


• historical development within the telecommunications industry

• the effect of telecommunication engineering innovation on people’s lives

• materials and techniques used over time


• specialised testing

– voltage, current, insulation

• copper and its alloys used in telecommunications

– structure/property relationships

• ceramics as insulation materials

• semiconductors

– types and uses in telecommunications

• polymers

– insulation materials

• fibre-optics

– types and applications


• telecommunications

– analogue and digital systems

– modulation, demodulation

– radio transmission (AM, FM)

– television transmission (B/W, colour)

– telephony – fixed and mobile

– transmission media – cable, microwave, fibre-optics

• satellite communication systems, geostations

5. Communication

• freehand and technical drawing, pictorial and dimensioned orthogonal drawings

• Australian Standard AS1100

• computer graphics, computer assisted drawing (CAD)

– for use in the presentation of reports

– in the solution of problems

• collaborative work practices

• research methods including the Internet, CD-ROM and libraries



• Engineering Report writing

REFERENCES/RESOURCES ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬


RREEFFEERREENNCCEESS//

RREESSOOUURRCCEESS Stage 6 Engineering Studies Syllabus 2002, © Board of Studies Engineering: The Definitive Guide Volume 2 (2nd Edition) Paul L. Copeland © Anno Domini 2000 Pty Ltd

REFERENCES/RESOURCES ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬


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