A look a fluid mechanics in lifting devices. References Images http://www.superstock.com http://www.lovelybike.blogspot.com.au http://www.ustudy.in/node/3432 http://www.motoristpassion.com/2011/05/braking-system-enhancer-producing.html http://www.allstar.fiu.edu/aero/hydr02.htm http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0016531.html http://www.dreamstime.com/royalty-free-stock-photography-royalty-free-stock-photography-motorbike-disc-brake-image11518937 http://www.advancedhandling.com/overhead_lifting_equipment/overhead_handling_equipment.ht http://www.bristol-business.net/bristols-sharklets-make-their-first-flight/m Websites http://www.maritime.org/fleetsub/hydr/chap1.htm http://www.atzonline.com/index.php;do=show/site=a4e/sid=15216829664fcada747c79e679887491/alloc=1/id=34 http://auto.howstuffworks.com http://www.youtube.com/watch?v=UuK3ESGgbqk http://www.rohitbhargava.com/2011/07/the-wingtip-vortex.html Printed text Learning Materials Production Open Training and Education Network-Distance Education NSW Department of Education and Training 2000. 51 Wentworth Rd. Strathfield NSW 2135. Revised 2003.

1. FLUID MECHANICS
Braking systems & Lifting Devices.

2. CASE STUDIES RELEVANT TO THE
ENGINEERING STUDIES STAGE 6 SYLLABUS
BOARD OF STUDIES NSW
• Note to teachers.
• – Case Studies relate to two separate modules found in the current Engineering Studies
syllabus. One engineering application module (3) – Braking systems, can be found on the
preliminary course 30 hours indicative. The second can be found as a focus module (3) –
Aeronautical engineering, found in the HSC course 30 hours indicative.
• Other parts of the syllabus can be linked to this digital teacher resource.
• Fluid mechanics :
The scientific study of static and dynamic actions of liquids and
gasses in motion (fluid dynamics) and at rest (Hydrostatic). Fluid
mechanics as a topic also investigates internal and external forces
and how these forces affect the flow properties of fluids.

3. LIQUID AND GAS
• Liquid is a fluid that will spread out but remain in pools if poured
onto a flat surface. Liquid poured into a container will fill the
container in any shape starting from base.
• Gas will disperse in all directions if released. If forced into a
container gas will fill the shape making contact with all surfaces.

4. SECTION ONE – BRAKING SYSTEMS.
• Syllabus outcomes: P2.1,P3.1,P4.1
• If all the systems of a vehicle were to be broken down and prioritised the braking system
would have to be one the most important.
• Fluid Mechanics- are linked with basic hydraulics found in braking systems. Early
mechanical braking systems such as levers and cables, were not only unreliable and
unsafe, they also inadequate in providing equal braking pressure to the braking system.

5. BLAISE PASCAL
Hydraulic systems work on the principle that confined fluid under pressure, will be transmitted
undiminished and equally in all directions.

6. UNDER NORMAL CONDITIONS LIQUID CANNOT
BE COMPRESSED.

7. Here we can see the weight putting force on the
liquid; this force is acting in all directions thus
increasing the pressure on all sides of the container.
The pressure being the same at all points.

8. This image shows that liquid takes the shape of any
container; the whole area is occupied filling it in
between two weights.

9. Applying force to the left cylinder or weight
demonstrates that the liquid is not compressible so
its volume stays the same.

10. The effect is that the force gets transferred to the
opposite cylinder.
Where only the weight is free to move, due to the
shape of the container. What we can also see is that
both cylinders are equal thus the pressure exerted in
each force is the same.

11. Pascals theory – mathematically
F2
F1
A1 A2
F1 F2
=
A1 A2

12. A similar or relevant principle can be explained by
this man, Archimedes investigated density and
buoyancy over 2000 years ago.

13. Archimedes Principle states that the buoyant force on a submerged object is equal
to the weight of the fluid that is displaced by the object.
Or………..The weight of the displaced liquid is equal
to the weight of the floating object click on the link to
watch a short clip.

14. THE USE OF HYDRAULIC PRINCIPLES IN PERSONAL AND
PUBLIC TRANSPORT
- BRAKING SYSTEMS
• Syllabus outcomes: P1.1,P2.1,P3.1,P4.1,P4.2P4.3.
PASSENGER CAR
Here’s an example of a disc
braking system, commonly found
in passenger cars, motorcycles
and light duty trucks.

15. Hydraulic drum brakes using Pascals
principle.

16. MOTORCYCLE
Hydraulic disc brakes
An attempt to slow or stop the rotation of a wheel by friction,
brake pads are used to clamp to a disc connected to the wheel.

17. DIFFERENCE BETWEEN HYDRAULIC AND AIR
BRAKES IS THAT AIR CAN BE COMPRESSED.
From a scientific point of view liquid
cannot be compressed.

18. INNOVATIONS IN BRAKING SYSTEMS.
• Syllabus outcomes:P1.1,P2.1,P3.1,P3.3,P4.1,P4.2,P4.3
• One of the most common innovations in braking
systems would have to be
ABS- Antilock Braking System.
In 1988 BMW introduced the first ABS system for a
motorcycle. An electro-hydraulic brake servo and adaptive
brake-power distribution system which was the first of its
kind in the world.

19. How is the BMW
Integral ABS
innovative?
• The hand-brake lever and pedal-
operated brake act simultaneously
on both wheels
• To ensure optimum decaccellartion
• When reaching the wheel lock limit,
the brake power is distributed and
regulated electronically
• Two seperate brake servos relieve
pressure build up on both wheels.

20. WHY HYDRAULIC DISC BRAKES SUPERCEED DRUM BRAKES
Motorcycle disc brakes :
• Usually made from different materials such as stainless steel , to prevent rust
• They are drilled and slotted to dissipate water from the road or rain
• The drilled brake or slotted wholes also act as a heat sink under heavy
braking
• can be electronically controlled to include ABS
Bicycle disc breaks:
• Range from simple cable systems to expensive six-piston hydraulic systems
• Can be manufactured from aluminium and titanium for weight reduction and
durability
Large lightweight trucks, passenger rail cars, some aeroplanes
• Replacing drum brakes
• Less wear and maintenance
• Commonly manufactured out of grey iron due to hardness, chemical
composition, tensile strength

21. SECTION TWO – LIFTING DEVICES
• Syllabus outcomes:P2.1,P4.3,H2.2,H4.1,
Lifting devices can range from simple to computer
controlled machines that are part of our daily lives.

22. EXAMPLES OF COMMON LIFTING DEVICES.
If it’s too heavy or awkward to carry or move a lifting device either
simple or complex will make it easier for you.

23. HOW THREE SIMPLE MACHINES WORK
DIFFERENTLY TO COMPLETE THE SAME TASK
• They all have a screw mechanism two of these designs are force magnifiers.

24. HYDRAULICS & PNEUMATICS &
COMPRESSIBILITY
• Fluid volume can be reduced by an increase of pressure if we
are working with a gas. Due to the molecules being close
together or cohesive (attracted to each other) liquid cannot
compress even if a lot of pressure is applied.
• Gases have molecules that are far apart thus allowing it to
either compress under pressure or compress reducing the
volume of the gas.
• Syllabus outcomes: H4.3,H6.1,

25. THE IMPACT OF LIFTING DEVICES THROUGH
THE DEVELOPMENT OF A SAFER SYSTEM.
• Without hydraulic lifting devices that range from car
jacks to construction cranes it can be said the effort it
would take to move or lift objects heavier than humans
would be near impossible.
• One innovation available that makes lifting a car safer
and more convenient must be the Safe T Jack system.
The bottle jack system if not supported correctly in the
recommended lift area may be unstable and dangerous.

26. The hydraulic floor jack may hold more weight
than the bottle jack however is heavy and takes
up a lot of floor space especially working on a
small car or cramped area.
Features of the Safe T Jack
• Available in 2 and 3 tonne capacities
• A removable power/lifting unit leaving
the jack stand in place
• Transfer between a hydraulic jack to a
mechanical stand
• All components can be assembled to
produce a conventional jack stand.
• Click on the link to learn more.

27. PNEUMATICS & HYDRAULICS IN AN
AERONAUTICAL APPLICATION.
• Syllabus outcomes: H4.1,H4.3,H6.1,H3.2,H3.3
• So far we have understood that a hydraulic system uses the pressure
of a liquid to preform a mechanical function.
• The hydraulic system can also be a force multiplier if one piston is
smaller than the other despite travelling a longer distance a greater
load can be lifted.

28. THE PNEUMATIC SYSTEM
• Create more noise when at work in comparison to hydraulic systems that use oil.
• At first an effort is applied to a piston
• The piston compresses the air in a tank that is connected to a pipe or hose.
• The pipe or hose is fitted with a relief valve that allows the control of air to be turned off
or on the pressure of the controlled air powers gears connected to fans
• Several tools are use available for work in several different applications,
ranging from dentists’ drills to jack hammers.

29. Compressed air is directed through the air inlet.
The system moves the piston in the intended
direction forcing it move in a reciprocating
action.

30. BERNOULLI’S
PRINCIPLE.

31. The use of hydraulics in the aero industry start from the actual production of the
aircraft to the take off and landing .
• Elevators
• Ailerons
• Rudders
• Flaps
• Electronic hydraulic controllers
• computational fluid dynamics CFD

32. AN AERONAUTICAL INNOVATION
• Wing tip devices known as SHARKLETS.
Aerodynamic improvements such as
• 15% reduction in fuel consumption
• Lower operating costs
• Reductions in engine noise & emissions
• Assists with the wing tip vortex creating safer flights for passengers and crew.