Braking Systems - aceh.b-cdn.net › re20 › c › Braking Systems Investigation Report.pdf1 Contents Page Abstract Page 2 History Page 3-4 Material Analysis Page 5-6 ... 1953 on

Braking Systems

H S C P r e l i m i n a r y

E n g i n e e r i n g S t u d i e s

A s s e s s m e n t T a s k 2

B r a k i n g S y s t e m s

D Olsen Engineering Consultants Braking Systems

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Contents Page

Abstract Page 2

History Page 3-4

Material Analysis Page 5-6

Material Alternatives Page 7-8

Material Modification Page 9-10

Anti-Lock Braking system Page 11

Regenerative Braking system Page 12

Pascal’s principle Page 13

Archimedes Principle Page 14

OH&S Issues Page 15

Glossary Page 16-19


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Abstract:

This report presented by D Olsen Engineering Consultants covers a range of information in relation to braking systems. A disc brake has been collected and then examined for various analyses, including the history of the disc brake, material analysis, material alternatives that could have been used and material modification that took place on the component prior to assembly. The relevant OH&S issues associated with the manufacturing and material modification that took place on the disc brake is also highlighted. Other area’s this report covers includes a mechanical analysis which I have solved five assigned questions, a detailed overview of the ABS and Regenerative braking systems and their effectiveness also societiesacceptance to the systems. Pascals Principle is also highlighted in this report. It is explained how Archimedes and Pascal’s principle can be applied to the hydraulic braking system. Glossary at the end of this report covers all references and sources where information was sourced from.


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Analysis:

History:

A disc-styled braking system was first introduced into the automobile world in the 1890’s. The first calliper-type automobile disc brake was implemented by Frederick William Lanchester in his Birmingham, UK factory in 1902 and used successfully on Lanchester cars. The limited availability of different metals at the time meant the Lanchester had to use Copper as the braking medium acting on the disc.

Due to the condition of the roads at the time, which consisted mainly of dirt and gravel roads,caused the copper to wear quickly. This made the disc brakes “non-viable” as stated in the Lanchester Legacy. Another problem that Lancaster encountered was the noise the brakes made, the noise of the metal crunching against metal was another to turn many customers off.

The problem was solved in 1907 when Herbert Frood, another Englishman, came up with the idea of lining pads with asbestos. The new material was quickly adopted by car manufacturers on both drum and disc brakes. Asbestos linings also outlasted other friction materials by a wide margin. This latest development meant that cars could last 10,000 miles before a brake change was needed.

Half a century later, the Chrysler crown imperial was implementing the disc brakes as standard equipment on 1949 models. The Chrysler Disc brake was expensive and extremely complex but was very reliable and efficient.

Reliable Calliper-type disc brakes were developed in the UK by Dunlop and first appeared in 1953 on the Jaguar C-Type racing car. The 1955 Citroën DS featuring powered inboard front disc brakes was the first French application of this technology, while the 1956 Triumph TR3 was the first English production car to feature modern disc brakes.

In 1954 the first production car was released which had Disc brakes on all four tyres. This was the Austin-Healey 100S. This was a significant development in the history of the disc brakes and this led to other companies also not long after fitting disc brakes on all production cars.


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Timeline of Development:


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Material analysis:

Brake Disc:

The brake disc is the disc component of a disc brake against which the brake pads are applied. The material the brake disc is made out of varies depending on the size and power ofthe vehicle they are implemented on. A “ventilated” disc design is usually used on heavier vehicles that require more stopping power, the ventilated design allows the heat generate to dispense quickly. Initially, when the disc brakes were introduced cast iron was the popular material to use due to its availability. Now days, an aluminium alloy is most commonly used to maximise different properties that aluminium and the other materials present in the alloy.

Another method was drilling many holes in the solid cast iron; this was done on many high performance race cars and also heavier vehicles which allowed heat dissipation to take place.

Based on the properties, potential candidate materials forAutomotive brake disc were selected as:

Gray cast iron (GCI) Ti-alloy (Ti-6Al-4V) 7.5 wt% WC and 7.5 wt% TiC reinforced

Ti-composite (TMC) 20% SiC reinforced Al-composite (AMC

1) 20% SiC reinforced Al-Cu alloy (AMC 2)

To the right is the microstructure of greycast iron.

Environmental effects during:

Production of the material: During the production of the cast iron, there were many stages in the manufacturing that could affect the environment. Some of these include: when steel was initially heated, gasses would have been released into the atmosphere. In result of the CO2 levels increasing, greenhouse gasses would increase, resulting in the Global warming process.

Manufacturing of the product: Furthermore, during the production of the Brake Disc a variety of processes could have substantial effects on the environment. The Brake disc would need to be cut and eventually welded and grinded to achieve finished product. Each process would be releasing gasses, using up electricity which results in more electricity to be produced which also results in the emissions of Co2 gasses. Another major effect would be the waste which the manufacture needs to dispose of.


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Below are further examinations of other key parts of the Disc Braking system:

Brake Pads:

Brake pads are steel backing plates with friction materialbound to the surface that faces the disk brake rotor. Overtime the material the pads are made out of has changed inrelation to advancements in technology. The pads havebeen made out of Asbestos, organic matter and semi-metallic formulations. All these materials have advantagesand disadvantages which led to the usage of and timeperiod of that material.

Rotor disc:

The rotor is the attached to the hub which the brake pads squeeze to create heat which dispenses the kinetic energy from the moving car. Most rotor discs are precisely machined from premium aluminium alloys for high strength and attention to minimized weight. Rotors in this category feature threaded rotor mount holes for use with standard through-hole mount rotors.

Calliper:

The calliper is the device which holds the brake pads whichis attached above the rotor. This device is crucial in thebreaking system. Callipers are generally made from threecommon casting metals: magnesium, aluminium and castiron. Callipers are made of different materials the mostcommon are aluminium and cast iron. The material used inthe callipers becomes important to help eliminate deflection,deflection results in a spongy pedal. The microstructure ofAluminium can be found on the right.

Material Alternatives for the Brake disc:


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Older brake discs were constructed from cast iron, now most are made from an aluminium alloy. Other material alternatives include:

- Mild steel:

Advantages:

- Stronger

- More durable

- Readily available in large quantities

- Take long time to wear down

Disadvantages:

- Too heavy to use in vehicles

- Harder to machine

- Expensive

- Need more force to lift and transport because it is heavier

- Kevlar reinforced polymer:

Advantages:

- Light

- Easy to work with

- Readily available

Disadvantages:

- Wear down to quickly

- Expensive

- Complex material

- Could release harmful toxins when worn down


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Polymer:

Advantages:

- Light weight

- Cheap to manufacture

- Easy to work with

- Readily available in large quantities

Disadvantages:

- Wear down very quickly

- Could release harmful toxins when worn down

- Expensive because consistent replacing would be required, due to a high rate of wear

Ceramic:

Advantages:

- Readily available

- Cheap to manufacture

- Easy to manufacture

- Renewable resource

Disadvantages:

- Very brittle, wouldn’t withstand pressure of the brake pads

- Wear down very quickly

- Costly, as constant replacing would be needed

- Hard to work with when set


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Material Modification:

Work hardening:

Work hardening, also known as strain hardening or coldworking, is the strengthening of a metal by plasticdeformation. This strengthening occurs because ofdislocation movements within the crystal structure of thematerial.

Annealing:

Annealing is the when a metal undergoes heating or coolingto produce the softest state. Different reasons for annealinginclude a metal could be to soften the metal for furtherworking or machining, to produce a uniform grain structureor to relieve internal stresses.

Normalizing:

Normalizing is the process when a metal is heated to red hotand then allowed to cool in room temperature. It uses highertemperature than the annealing process and this allows themetals to cool faster. The purpose of normalizing is to refinethe grain structure. This results in smaller grains creatingstronger steel than the annealing process.

Tempering:

Tempering involves heating the hardened steel to a hightemperature but below 723 C, it is then soaked to removeinternal stresses and to allow all structural changes to goto equilibrium followed by slow cooling to room


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temperature. The higher the tempering temperature the lower the tensile strength, stress and hardness but increases the metals ductility.

Quenching:

Quenching is the rapid cooling of a material to achievea desired property. Different media’s used to increasethe severity of the quench include, air, brine (saltwater), oil and water. Quenching can reducecrystallinity and thereby increase toughness of bothalloys and plastics (produced through polymerization).

Case Hardening:

Case or surface hardening is the process of producing ahardened, wear resistant surface and a relatively soft,tough inside called the core. Three different methods ofcase hardening:

1. Carburising; soaking the metal at red hot in acarbonaceous material or atmosphere whichincreases the carbon content.

2. Flame and induction hardening; is done throughelectric currents and only used on small jobs like axels, shafts and cams.

3. Nitriding; changing surface compound by diffusing nitrogen into it to produce hard nitride compounds.


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ABS and Regenerative Braking:

ABS (Anti-skid braking system):

How it works:

Without the ABS braking system when a person hits the brake pedal in a car, the wheels would lock up and skid. With ABS installed its primary function is to grab and let go of the brakes very quickly. This is proven to work better and bring the car to a stop quicker than a car without ABS.

The ABS controller knows that such a rapid deceleration is impossible, so it reduces the pressure to that brake until it sees acceleration, then it increases the pressure until it sees the deceleration again. It can do this very quickly, before the tire can actually significantly change speed. The result is that the tire slows down at the same rate as the car, with the brakes keeping the tires very near the point at which they will start to lock up. This gives the system maximum braking power.

-Effectiveness with reference to society’s acceptance of these technologies:

When the ABS was first introduced, a large proportion of society didn’t want anything to do with it. Most people had no idea how, a computer controlling the brakes could depressurise and pressurise the brakes in seconds which would be beneficial to the car when braking rapidly. Furthermore, after time when a large majority of automobiles started implicating ABS standard on their cars, society’s acceptance of ABD grew rapidly, as more and more science proved that the ABS could actually stop a car quicker than a car without ABS in any conditions.


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Regenerative Braking System:

How it works:

The regenerative braking systems can be found in mostly electric cars due to their requirement for electricity to run the motors. In all moving automobiles, kinetic energy is apparent as it is created in the movement action. When a person brakes a car, the brake pads press against the rotor which causes heat which is a way of the kinetic energy to leave the car.The regenerative braking system however, is specially designed to capture that kinetic energyand turn it back into electricity which could be used to power the car.

In a car which has the Regenerative braking system fitted, it acts very differently to a car in the braking stage of a journey. When the brakes are applied the motor is ran the opposite waywhich in term applies the brakes and stops or slows down the car. However, when the brakes are applied the motor acts as a generator which creates electricity which can be sent directly to batteries or used to power the motor.

-Effectiveness with reference to society’s acceptance of these technologies:

In introduction of the electric cars in the late 20th century, early 21st century has caused great advancements in greener energy technology. However, although the electric car might be the way of the future; many people around the world are still showing ignorance about adapting to electric cars. Therefore, making the regenerative braking system (which is mostly implicated on the electric cars), not very popular as society is still reluctant to try new ways.


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Pascals Principle:

Pascal’s principle:

“Pressure applied to a confined liquid is transmitted equally throughout the liquid.” Blaise Pascal (1623-1662)

The hydraulic braking system in motor vehicles makes use of this principle to provide even braking forces to each wheel. Pascal's Law deals with the way fluids act in a closed hydraulicsystem. Without this closed hydraulic system, no pressure can be developed in the brake system.

Pascal's Law states that, because fluids are virtually non-compressible, any force applied to a closed hydraulic system will be felt equally and instantly throughout the entire system. It goes on to show that when a force is applied to one cylinder of a closed system, the output is directly proportionate to the ratio of the input to output pistons.


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Archimedes Principle:

“The buoyant force on a body immersed in a fluid is equal to the weight of the fluid displacedby that object.” Archimedes (287?-212 BC)

With a submerged object the difference between the pressure at the top and the bottom of a submerged object produces a net force upwards which is the force of buoyancy. The weight of the displaced fluid can be found mathematically. The fluid displaced has a weight W = mg.The mass can now be expressed in terms of the density and its volume, m = pV. Hence, W = pVg.

Archimedes’ principle applies to object of all densities. If the density of the object is greater than that of the fluid, the object will sink. If the density of the object is equal to that of the fluid, the object will neither sink nor float. If the density of the object is less than that of the fluid, the object will float.

For example, when an object is immersed in water, it feels lighter. In a cylinder filled with water, the action of inserting a mass in the liquid causes it to displace upward.


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OH&S Issues:

Health and safety issue relating to the disc brake:

The main health and safety issues relating to the Disc Braking system is within the Disc pads.The linings they have used in the pads include: Asbestos, organic matter and semi-metallic formulations. The first lining used was Asbestos, which was used for over twenty years before ramifications of the elaborate use of this product were discovered. The microscopic particles that hold the Asbestos together, when they undergo wear from the breaking rotor its can emit the particles into the air. It is proven that these particles were small enough to infiltrate the body and has caused severe illness to many people around the world. Most commonly they illness called Asbestosis.

Even today the particles released from the wear of the disc pads could be found out in the future to be harmful to the human body.

Advancements in the braking are have improved the safety of all vehicle users around the world. The introduction of such engineering innovations as the ABS has increased the safety of all road users.


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Glossary:

-Wilwood Website

http://www.wilwood.com/Hats/HatList.aspx

Viewed on the 18th of June 2012

-Wikipedia Website

http://en.wikipedia.org/wiki/Work_hardening

Viewed on the 22nd of June 2012

-Wikipedia Website

http://en.wikipedia.org/wiki/Disc_brake

Viewed on the 15th June 2012

-Wikipedia website

http://en.wikipedia.org/wiki/Quenching

Viewed on the 22nd of June 2012

-Engineering Studies “A student’s workbook.” Textbook

Textbook Pages from 3-2 to 3-8

Viewed on the 16th of June 2012, Viewed on the 19th June 2012, Viewed on the 23rd June 2012

-How stuff works website

http://auto.howstuffworks.com/auto-parts/brakes/brake-types/anti-lock-brake3.htm

http://auto.howstuffworks.com/auto-parts/brakes/brake-types/regenerative-braking6.htm

http://www.wilwood.com/Hats/HatList.aspx



http://auto.howstuffworks.com/auto-parts/brakes/brake-types/anti-lock-brake3.htm

http://en.wikipedia.org/wiki/Quenching

http://en.wikipedia.org/wiki/Disc_brake

http://en.wikipedia.org/wiki/Work_hardening


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-E How website

http://www.ehow.com/about_5381517_understanding-car-brakes.html


-library Quest Webiste

http://library.thinkquest.org/27948/archimede.html


-Google images

http://www.google.com.au/imgres?q=work+hardening+metal&num=10&um=1&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&biw=1081&bih=685&tbm=isch&tbnid=bsWS-wZl3OUnvM:&imgrefurl=http://metal-artist-sculptor.blogspot.com/2010/10/tortoise-sculpture-copper-forming-and.html&docid=-izj-C5Qx-bxYM&imgurl=http://3.bp.blogspot.com/_HIyQjhSsIsc/TLuZaKcFYPI/AAAAAAAAAgg/4xFKH867Q-U/s1600/turtle%252Bsculpture%252B3.JPG&w=1600&h=1200&ei=kJLmT_K1Do2wiQeYuvxY&zoom=1&iact=hc&vpx=283&vpy=198&dur=2986&hovh=194&hovw=259&tx=125&ty=109&sig=114693966222838540771&sqi=2&page=1&tbnh=152&tbnw=170&start=0&ndsp=15&ved=1t:429,r:1,s:0,i:73

http://www.google.com.au/imgres?q=annealing+metal&um=1&hl=en&client=firefox-a&sa=N&rls=org.mozilla:en-US:official&tbm=isch&tbnid=PdVufRZ3JfJhLM:&imgrefurl=http://silverandsteelsite.com/blacksmith-tools-and-techniques/a-peek-at-metal-work-techniques.html/attachment/annealing&docid=pTcUADF5qDYpeM&imgurl=http://silverandsteelsite.com/wp-content/uploads/2011/02/annealing.jpeg&w=640&h=480&ei=9pLmT8LaAeefiAfhrelY&zoom=1&iact=hc&vpx=394&vpy=216&dur=854&hovh=194&hovw=259&tx=199&ty=120&sig=109680410154147592613&page=1&tbnh=150&tbnw=222&start=0&ndsp=14&ved=1t:429,r:1,s:0,i:75&biw=1081&bih=685

http://www.google.com.au/imgres?q=Normalizing+metal&um=1&hl=en&client=firefox-a&sa=X&rls=org.mozilla:en-US:official&tbm=isch&tbnid=hcPL-

http://www.google.com.au/imgres?q=Normalizing+metal&um=1&hl=en&client=firefox-a&sa=X&rls=org.mozilla:en-US:official&tbm=isch&tbnid=hcPL-qNPcjWeQM:&imgrefurl=http://www.indiamart.com/metaltreatind/heat-treatment-process.html&docid=Q2u5fnQFrzwgLM&imgurl=http://2.imimg.com/data2/VE/XT/MY-2730932/normalizing-250x250.jpg&w=250&h=250&ei=RpPmT4_ADtOgiQfNu7BY&zoom=1&iact=hc&vpx=312&vpy=157&dur=1947&hovh=200&hovw=200&tx=116&ty=125&sig=109680410154147592613&page=1&tbnh=155&tbnw=114&start=0&ndsp=14&ved=1t:429,r:1,s:0,i:75&biw=1081&bih=685








http://library.thinkquest.org/27948/archimede.html

http://www.ehow.com/about_5381517_understanding-car-brakes.html


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qNPcjWeQM:&imgrefurl=http://www.indiamart.com/metaltreatind/heat-treatment-process.html&docid=Q2u5fnQFrzwgLM&imgurl=http://2.imimg.com/data2/VE/XT/MY-2730932/normalizing-250x250.jpg&w=250&h=250&ei=RpPmT4_ADtOgiQfNu7BY&zoom=1&iact=hc&vpx=312&vpy=157&dur=1947&hovh=200&hovw=200&tx=116&ty=125&sig=109680410154147592613&page=1&tbnh=155&tbnw=114&start=0&ndsp=14&ved=1t:429,r:1,s:0,i:75&biw=1081&bih=685

http://www.google.com.au/imgres?q=tempering+metal&um=1&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&tbm=isch&tbnid=LNT6WufWm9irgM:&imgrefurl=http://www.dragosroua.com/tempered-steel/&docid=4W4cU9kUbX9IVM&imgurl=http://www.dragosroua.com/wp-content/uploads/2010/10/tempered-steel.jpg&w=480&h=323&ei=kpPmT9LnGI64iAfu_5VY&zoom=1&iact=hc&vpx=128&vpy=166&dur=556&hovh=184&hovw=274&tx=184&ty=95&sig=109680410154147592613&page=1&tbnh=157&tbnw=209&start=0&ndsp=15&ved=1t:429,r:0,s:0,i:72&biw=1081&bih=685

http://www.google.com.au/imgres?q=quenching+metal&um=1&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&tbm=isch&tbnid=DJnsjwFp9JAU7M:&imgrefurl=http://news.bbc.co.uk/local/sheffield/hi/people_and_places/arts_and_culture/newsid_8468000/8468068.stm&docid=Rj0vxtIuyNlyDM&imgurl=http://news.bbc.co.uk/media/images/47319000/jpg/_47319350_scissors_quenched1.jpg&w=766&h=511&ei=85PmT5_7IcbYigeb1OBZ&zoom=1&iact=hc&vpx=298&vpy=217&dur=371&hovh=183&hovw=275&tx=200&ty=97&sig=109680410154147592613&page=1&tbnh=141&tbnw=186&start=0&ndsp=15&ved=1t:429,r:1,s:0,i:75&biw=1081&bih=685

http://www.google.com.au/imgres?q=case+hardening+metal&um=1&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&tbm=isch&tbnid=6Wq9iVaG5Lfn0M:&imgrefurl=http://blog.iqsdirectory.com/iqsdirectory/the-toughest-metals-on-earth-get-stronger/&docid=YC0COR0QeFYGUM&imgurl=http://www.blog.iqsdirectory.com/wp-content/uploads/files/heat%252520treating%2525202.JPG&w=221&h=165&ei=PZTmT5bXHsLYigfA0Pxa&zoom=1&iact=hc&vpx=178&vpy=220&dur=1833&hovh=132&hovw=176&tx=99&ty=98&sig=109680410154147592613&page=2&tbnh=132&tbnw=176&start=15&ndsp=20&ved=1t:429,r:0,s:15,i:122&biw=1081&bih=685














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Braking Systems - aceh.b-cdn.net › re20 › c › Braking Systems Investigation Report.pdf1 Contents Page Abstract Page 2 History Page 3-4 Material Analysis Page 5-6 ... 1953 on