fluid-project_report

Project Guide: Dr. Guldiken
Project by:
1. Aditya Yadav (CFD and
Design)
2. Sudesh Jadhav (CFD)
3. Nishant Sule (Design)
4. Krishna Aravinthan
(Design)
Brake System Design and Brake Fluid Flow
Comparison
Group ID-10

HYDRAULIC BRAKING SYSTEM
2
Table of Contents
List of Figures............................................................................................................................3
Introduction .............................................................................................................................. 4
Abstract......................................................................................................................................4
Background ...............................................................................................................................5
Classification.............................................................................................................................9
Design Procedure.....................................................................................................................13
Stress Calculations and Analysis.............................................................................................15
Conclusion and Reference .....................................................................................................25

3
List of Figures
Figure 1: Example of the Lever Brake.................................................................................. 6
Figure 2: Example of a Disk & Drum Brake.........................................................................7
Figure 3: Brake Rotors..........................................................................................................8
Figure 4: Brake Pads ............................................................................................................9
Figure 5: Foot Actuated Brake.............................................................................................10
Figure 6: Hand Actuated Brake...........................................................................................10
Figure 7: Air Brake...............................................................................................................10
Figure 8:Electric Brake ……….............................................................................................11
Figure 9:Hydraulic Brake.....................................................................................................11
Figure 10: Mechanical Brake........................................................................................... ...12
Figure 11:Vaccume Brake....................................................................................................12
Figure 12: Principle of Braking ..........................................................................................13
Figure 13: Tandem Master Cylinder...................................................................................15
Figure 14:Pedal Orientation...............................................................................................16
Figure 15: Pedal Design & Mounting.................................................................................16
Figure 16: Stresses in Disc..................................................................................................17
Figure 17: Deformation in Disc..........................................................................................17
Figure 18:Stresses in Pedal ................................................................................................17
Figure 19:Deformation in Pedal.........................................................................................17
Figure 20: Notation of Various Parameters....................................................................... 18
Figure 21:Simplified stopping Period Graph .....................................................................19
Figure 22: 2D Space Model………………….......................................................................22
Figure 23:Mesh ..................................................................................................................22
Figure 24:CFD of OEM Brake System...............................................................................24
Figure 25: CFD of Customize Braking System..................................................................25

4
Introduction
In this Project we are comparing Original Equipment Manufacturer (OEM) brake design with
our custom design. The main objective of this project is to calculate the pressure at the caliper
end and compare it with our model by using Computational Fluid Dynamics (CFD). There
are two types of braking systems such as Disc Brakes and Drum Brakes out of which we have
done analysis on Disc Brake which uses hydraulic fluid to stop the vehicle. There are three
types of disc brakes such as rotating axis, symmetrical disc and stationary pads. In hydraulic
braking system the fluid which is in master cylinder is used to put pressure at the caliper end
to stop the vehicle by pressing the pedal. The disc brakes have immediate stopping response
as compare to drum brakes.
There are various components in the disc brake that we have designed and while designing
there were several factors that we have consider. First, the braking system should bring the
vehicle to quick and safe stop and all four vehicles should lock in static condition. The design
of the braking system is such that for every wheel we have provided independent hydraulic
circuits in our design which makes this design more efficient because even if there is a
leakage at any wheel the barking power will remain the same.
We have used the Pascal’s law in our project to calculate the pressure which says that
“Pressure exerted anywhere in a mass of confined liquid is transmitted undiminished in
all directions throughout the liquid”.
There are several assumptions that we have considered in terms of brake force applied,
vehicle gross weight and coefficient of friction. Also, there are other measurements such as
length, diameter and pedal ratio which we have assumed to make our own design. In CFD we
have defined the boundary conditions to analyze the fluid flow through master cylinder brake
liner. In our final CFD results we found out pressure values at caliper end and we compared it
with OEM results. While comparing CFD results the value of pressure we got was lower than
OEM brake system.

5
ABSTRACT
The current tendencies in automotive industry need intensive investigation in
problems of interaction of active safety systems with brake system equipment’s. The same
time, the chances to diminish the power take-off of single parts,
disc brake systems. Disc brakes are a flat, disc-shaped metal rotor that rotates with the rim.
At the point when the brakes are connected, a caliper crushes the brake pads against the disk
should as you would stop a turning circle by squeezing it between your fingers, abating the
wheel. The disk brake utilized as a part of the vehicle is separated into two parts a rotating
axis symmetrical disk, and the stationary pads. The hydraulic disk brake is a course of action
of braking component which utilizes brake fluids, normally containing ethylene glycol, to
transfer pressure from the controlling unit, which is usually near the operator of the vehicle,
to the actual brake instrument, which is generally at or close to the wheel of the vehicle.
The frictional heat, which is created on the interface of the disk and pads, can cause high
temperature during the braking. Therefore, the vehicles for the most part use disc brakes
on the front Drum brakes on the rear wheels. The disk Brakes have good stopping and
are usually more secure and more productive than drum brakes. The four-wheel circle brakes
are more well known, swapping drums on everything except the most basic vehicles. Many
two wheel automobiles configuration utilizes a drum brake for the rear wheel.
Brake that came into its peak existence in the 60's to proficiently deliver
adequate braking for automobiles has ended in an industry where brakes run from sufficient
to downright sensation. One of the initial steps taken to enhance braking came in the mid 70's
when manufacturers, on a widespread scale, switched from drum to disc brake. Therefor it
has set a mark that the braking begins with the front wheels and only those were modernized
to disk during most of the period. Hence then, many manufacturers have received four-wheel
circle brakes on their top of the line and execution models too as their low-line economy
autos. Very often, the manufacturers go back to the drum brakes framework for the behind
wheels of auto so as to reduce the manufacturing and buying cost.

6
Background
The principle documented instance of brakes being used was in old Rome. These brakes were
made from a lever that when pulled, squeezed a wooden square onto the outside of a metal
lined wheel. The essential power for braking with this gadget was friction. This technique
was successful because of the low velocities at which the cart moved; in any case, it was a
lacking type of abating runaway carts. This strategy for braking was utilized for quite a long
time with little design change.
Figure 1: Example of the Lever Brake
At the point when the Michelin siblings designed rubber-covered wheel wooden blocks were
substituted with drum brakes. Louis
Renault developed drum brakes in 1902.
Rather than applying a square to the
outside of the wheel, drum brakes were
mounted within the wheel center points.
This limited dirt blockage and diminish
the loss in braking friction. Drum brakes
are still being used in autos as handbrakes
because of the substantial large measure
of power required to conquer the brake
constrain while at equilibrium. Figure 1: Lever Brake
With the presentation of the mechanical production system, autos wound up noticeably
heavier and quicker, which made a requirement for a more capable braking mechanism.
Malcolm Loughead made a four-wheeled hydraulic Braking mechanism. The hydraulic
system utilizes lines loaded with pressure driven liquid as opposed to cable braking
mechanisms. The fundamental favorable position to hydraulic Braking mechanisms is that
they can apply a more noteworthy braking power than cable system. cable brakes weakness
quicker than hydraulic brakes because of the steady pressure that the cable is under. hydraulic
brakes enabled the driver to apply less power onto the brake pedal while yet stopping in a

7
similar short distance. All through braking history the issue of overheating has been a steady
issue. Heating happens when the brake cushions interact with the braking surface. The key
factor in scattering heat is having a bigger surface area for the brake to cool off.
Disk brakes have a vast surface region exposed to the air, which causes it to stay cooler.
There are holes and grooves cut into the rotor of the Braking mechanism to enable water and
dirt to be moved off the braking surface and limit interference, which causes loss of braking
power.
Figure 2: Disc and Drum Brakes
Disk brakes did not begin getting to be mainstream in vehicles until the point that the 1950's
even though they were invented around 1902. Disk brakes are appended inside the rim of the
vehicle and turn as one with the wheel. At the point when constrain from the driver's foot is
connected to the brake pedal the brake liquid goes through hydraulic cables and progresses
toward becoming enhanced by the power Braking mechanism appended to the engine; this
thusly drives the brake liquid against the caliper which utilizes frictional power to slow the
vehicle.
Fast vehicles require brake pads and calipers to be made of various materials to reproduce the
same braking system needed to stop slower less advanced vehicles, because of the more
prominent measure of idleness that is attempting to be stopped.

8
There are five primary materials utilized as a part of brake rotors. The five materials most
normally found in brake rotors are solid metal, steel, layered steel, aluminum, and high
carbon irons. Production cars utilize cast iron brakes because of the measure of mishandle
that they can deal with without splitting or failing. Steel brakes have a lighter weight and heat
limit, yet lack durability in repeated employments. Heat can scatter quicker with layered steel
brakes on the grounds that adding layers to basic steel brakes takes into account a more
grounded material that can withstand a more thorough workload. Aluminum brakes have the
most minimal weight of all vehicle rotors. Heat is scattered faster, however the aggregate
with respect to heat absorption is lower than in steel brakes; this is the reason aluminum is
most generally utilized as a part of bikes and other little vehicles. The last sort for brake
material that is utilized is high carbon iron. High measures of carbon take into consideration
expanded heat diffusion, which makes this kind of brake most normally utilized as a part of
high performance vehicles.
Figure 3: Brake Rotors
Brake pads have been made with various materials during the time contingent upon the
utilization. Asbestos was the most mainstream material because of its capacity to absorb and
emit heat. After logical investigations, asbestos has been observed to be an exceedingly
dangerous material and has been prohibited from use in vehicles in the United States. With
asbestos unlawful to utilize, brake producers were compelled to make more secure brakes
from a material that won't hurt the overall population. Organic brakes are produced using
materials that can withstand heat, for instance; glass and rubber are blended with heat
resilient resin to deliver more secure brakes. The upsides of utilizing natural brake cushions
are that they are typically calmer and are simpler to arrange. All things considered, natural
Turner Motorsport

9
brakes are not normally utilized since they wear effectively, and clean particles gather
between the cushion and wheel, which diminishes the braking surface.
Figure 4: Brake Pads
With a lighter weight to back off, bikes utilize natural and ceramic brake pads. Ceramic brake
pads are the best kind of brake pads however are the most expensive. The most widely
recognized sort of brake pads is made with a blend of a few sorts of metals. These metallic
brakes are sturdy while yet being cost proficient. The negative elements for utilizing metallic
brakes are that they work best when warm and it might take more time to slow at first when
driving in cool climate. With inventions in material science, brakes will keep on improving to
coordinate the advances in auto innovation.
Amazon.com

10
Classification of Brakes
1. Mode of Actuation
(also, called the main brake) (also called parking brake)
Operated by foot Operated by hand
2. Modes of Power
1. Air Brakes
Air is the abundant in nature where hydraulic fluid is limited. Air brakes are used inn
abundance in trains, trailers and buses and they do not require
hydraulic fluid as other automobiles, which can be exhausted
when there is a leakage. Safety is also concerned where larger
automobiles like trains busses and trailers carry large amount of
cargo and passengers where air brakes are safer medium in
utmost environments unlike fluids. A high-speed automobile
can turn dangerous when the fluid braking system incurs a leak.
The triple value system is used in airbrakes and this system fills a supply tank and uses air
pressure to release the brakes. The Triple value system is in operation until the air is exerted
out completely from the system. As the medium is air it is less expensive.
Figure 7: Air Brake
Figure 6: Hand BrakeFigure 5: Hand Brake
YouTube Auto | HowStuffWorks
Wikipedia

11
2. Electric Brakes
In electromagnetic brakes electric motor is the essential part which uses electricity as a mode
to generate heat which stops the vehicle. Instead of motor some vehicles use retarder which
generates braking force by internal short-circuit. In this braking system magnetic force act as
a braking force which is also called as mechanical braking system. Eddy current brakes also
uses same principle instead of using drag force it uses electromagnetic force between magnet
and an object which is a conductor of the electricity.
Brake are one the key parts of any vehicle, without which it
is basically impractical to use the vehicle for travel. Clearly,
a brake, which serves to slow the vehicle, should not be
excessively weak. in any case, strikingly, when designing a
Braking mechanism, it ought to likewise be taken care that it
is not very productive. An excessively solid a brake would
open us consistently to the ill effects of a sudden brake
application in transport or auto. on the off chance that a vehicle is halted unexpectedly
or strongly, the traveler may hit the front seat or whatever
is there. Thus, excessively productive a brake system isn't required.
3. Hydraulic Brakes
Hydraulic braking system follows a simple principle where the forces applied at one point is
transmitted to another through an incompressible fluid. In this system, we address this
incompressible fluid as break liquid. In hydraulics, the initial force applied to operate the
system multiplies through the process. Times of multiplication can be found by the point on
each end. For instance, the pistons which drives the
fluid is comparatively smaller than the piston that
operates the brake pad, this way the force is multiplied
resulting in efficient and convenient braking. The Pipe
containing the fluid can be of any size length or shape
which allows it to travel through the system anywhere.
It is also possible to split them, therefore allowing them
to connect to master cylinder and two or more slave master cylinder if required.
Figure 9: Hydraulic Brake
Figure 8: Electric Brake
Etrailer
YouTube

12
4. Mechanical Brakes
They are most normal and can be separated extensively into "shoe" or
"pad" brakes, using an explicit wear surface, and hydrodynamic brakes, such as parachutes, w
hich utilize contact in a working liquid and don't expressly wear.
Basic arrangements incorporate shoes that a contract to rub
outwardly of a rotating drum, for example, a band brake; a rotating
drum with shoes that extend to rub the inside of a drum, normally
called a "drum brake", Other drum designs are possible; such as
rotating caliper which is connected to pads which pushes rotating disc hence the name disc
brake is given to the system. The principle behind frictional braking is it generates heat when
friction force is applied to the braking system which apposes the motion by giving reduction
in velocity. In frictional braking kinetic energy gets converted into thermal energy when
applied to the moving parts of the vehicle.
5. Vacuum Brakes
Air brakes and vacuum brakes are controlled by a brake pipe that connects the braking device
in every vehicle and the brake valve. Each vehicle braking operation is different depending
upon the state of vacuum created inside the pipe by an ejector or exhauster. Ejector- Steam or
Exhauster- electric power on trains removes atmospheric
pressure formed in the pipes and creating vacuum. When
the brake is released then it has full vacuum, the
atmospheric pressure is present then there is no vacuum the
pressure is applied and braking takes place. Motor driven
exhauster creates and maintains the vacuum. High speeds
and low speeds are the two quantities achieved by using the
exhauster. High speed is to create a vacuum and thus braking
and low speed keep the vacuum at a level and gradual
releasing. This maintains the vacuum from small leaks
and proper functioning for safer and efficient performance.
commons.wikimedi
a.org
Figure 10: Mechanical Brake
Figure 9: Vaccum Brake

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Working Principle
In this project we have used the principle of Pascal’s Law which says that “Pressure exerted
anywhere in a mass of confined liquid is transmitted undiminished in all directions
throughout the liquid”.
What pascal’s law basically says that in any closed system when the pressure is applied at
one point it should give the same pressure value on the other end of the system.
In above fig.2 we can see the same principle used where
two gas cylinders are there and they are connected to a
closed system at one cylinder when the force is applied
to the piston it moves downward by exerting pressure
on the oil inside the cylinder. When this pressure is
exerted the other cylinder, which is connected to the oil
filled pipe moves upwards due to the same amount of Fig 12: Principle of Braking
pressure which is transferred through the close system
which in this case is oil filled pipe which proves the Pascal’s law relation with pressure.
Working of Hydraulic Braking System
In a braking system, frictional force is used to stop the vehicle which utilizes moving energy
of the vehicle to convert into heat. The frictional force causes resistance between two parts
which depends on types of material in contact and pressure holding them together. In a
hydraulic braking system, incompressible fluid is used to transmit the force applied at one
point to another point. In the disc braking system, there is a metal caliper instead of a drum to
generate frictional force between wheel and shoe. When we put force on the brake pedal it
cause fluid inside the master cylinder to get pressurized. This pressurized fluid then moves
through the hose pipe which is connected to the master cylinder. The fluid from the hose pipe
then reaches to the brake pad which is fixed against brake rotor and puts pressure on it. The
entire pressure of the fluid causes frictional force between rotor and brake pad causing
vehicle to stop.
YouTube

14
Design procedure
While starting the design, our main concern were the assumptions to be made, like what
should be the value of different variable involved in the design procedure such as coefficient
of friction, pedal force applied by the driver, vehicles gross weight etc. After a lot of detailed
discussions and brainstorming sessions, it was decided to go for a thorough study as well as
survey regarding each and every variable in picture. For example: for deciding the value of
coefficient of friction (µ), a detailed survey was carried out regarding the coefficient of
friction (µ) of all the tires related to off road vehicles such as trucks, tractors, dirt bikes,
commercial ATV’s etc. Once the data was gathered, the value of coefficient of friction was
determined by taking the average of all the value. The coefficient of friction came out to be.
In the similar manner all other variables were determined.
Coming back to our design methodology, our braking system was designed significantly and
effectively. In this system we decided to use a single tandem master cylinder of bore ¾ inch
because of the result of our market survey which was based on many factors such as
availability, cost, bore size, easy replacements, weight etc. We decided to go for a self-design
customised pedal box with swing mount pedals having optimum pedal ratio of 5:1. The main
reasons behind this major change are weight reduction, ergonomics, aesthetics, compactness
and space constraints. Finally coming to the splits, we installed both F/R & diagonal split in
our previous design, we came to conclusion that in case of any failure, F/R split yields better
& safer results as compared to diagonal split.
Designing of various braking components
Brake disc
Brake discs were logical components to design in the early stages of the total system design
because the range of possible diameter is already limited by other parts of the vehicle.
Because the brake circuit is an outboard system, the assemblies dwell inside the rims of the
wheels, the disc diameter is limited by the inner diameter of the rims and the clearance of the
calipers with respect to rims. We are used a 10”-5” rim with a 3”-2” offset.
After modelling the rims in Creo 2.0, we came across the maximum size of the brake disc
around 7 inches. In order to generate the required torque, we decided to use optimum brake
discs of size 175mm for front as well as rear. Static structural as well as thermal analysis was
done.

15
Master Cylinder
The major decision that has to be made when selecting a master cylinder is whether to use
separate cylinders for the front and rear circuits or to use one tandem cylinder that serves
both. But the problem faced when using two separate cylinders was that it required a bias bar
system. So instead, we used a tandem master cylinder and to create biasing effect we used
calipers of different sizes for front and rear.
Fig 13: Tandem Master Cylinder
After doing a market survey, we found out that the most easily available and smallest tandem
master cylinder was of 3
/4 inches.
Fig 14. Pedal orientation
The above image shows the possible orientation of pedal with respect to master cylinder.
Considering the above two choices we concluded that the first choice was better due to
proper space utilization and ease of mounting

16
Brake Calipers
Once the master cylinder and brake disc size was decide, the other two parameter, which we
could vary, were pedal ratio and caliper size. Due to dynamic weight transfer, more braking
force is required at the front as compared to rear. Hence, after performing a number of
iterations, we came to a conclusion of using a 38mm bore brake caliper in front and a 32mm
brake caliper in rear. It also ensures proper brake force distribution as well as brake force
balance.
Fig 15: Pedal design & its mounting
To begin the design process views and opinions were taken from each and every individual of
the braking design team. Dimensions and geometry the same was designed in Creo2.0. This
pedal setup was design significantly with optimum dimensions, to keep the robustness &
ergonomics of the entire system intact. It has swing mount pedals with a single tandem
master cylinder of bore ¾ inches. Certain amount of material was removed for improving the
aesthetics without compromising with the strength of different elements of the system.

17
Stress calculation & analysis:
While designing the brake disc static as well as thermal consideration were taken into
account. Using ANSYS 14.5, thermal as well as static structural analysis were performed.
Brake clamping force, heat flux, rubbing area and total braking time were taken as inputs.
The figures below shows the result obtained.
Fig 16.Stress in Disc Fig 17: Deformation in Pedal
Fig 18.Stresses in Pedal Fig19: Deformation in Pedal

18
Calculations
Pedal ratio = 5:1
Master cylinder bore diameter = 19.05mm
Brake rotor: Front = 175mm
Rear = 175mm
Weight distribution = 45:55
Total weight = 161 Kg
Wheel base = 56 inches
Drivers weight = 75Kg
C.G height = 17.14”
Static weight distribution: FzF = 105.75 Kg
FzR = 129.25 Kg
Figure 20. Notations of various
parameters
Lf =
FzR∗L
W
= 30.8”
LR = L-Lf
= 25.2”
Ψ =
FzR
W
= 0.55
Dynamic axle load:
FzF , dyn = (1-ψ + χa)W
Where, χ =
C.G height
Wheel base
=
h
L
χ = 0.3060
∆dyn wt transfer = χaW
a = 4.94 m/s2
, a = µg, µ = 0.503
Therefore, ∆dyn =
h
L
* a * W =36.211Kg
FzF,dyn = 141.961Kg (1392.63N)
FzR,dyn = 93.039Kg (912.712N)
Front axle Braking force:
FxF = µ * FzF , dyn = 947.841 N
FxR = µ * FzR, dyn = 638.8988 N
Torque:
TxF =
FxF∗10.33"∗25.4
1000
= 255.7807 Nm
TxF = 127.89036 Nm (single)
TxR =
FxR∗10.33"∗25.4
1000
= 166.6355 Nm
TxR = 83.8177 Nm (single)
System Design:
Master cylinder bore: 19.05mm
Area of master cylinder: 2.85*10-4
m2
Brake rotor;
F: 175mm (72.5mm effective radius)
R: 175mm (72.5 m effective radius)
Caliper front:38mm(area=1134.1149mm2
)

19
Also,
Vtr
a
= ts
So, Stotal = Vtrtr +
Vtr
2
2𝑎
Where, Vtr = initial vehicle velocity
tr = driver reaction time
ta = brake system application time
ts = braking time
a = deceleration
Now,
Vtr = 40Km/h = 11.11m/s
tr = 1 sec
ta = 0.25 sec
tb = 0.3 sec
a = µ*g=0.7*9.81
a= 6.867m/s2
So,
Stotal = 11.11*1+
11.112
2∗6.867
=20.097m
Leverage efficiency=0.
Fmc = P.R*P.F*0.8
= 1000N
Pmc =
Fmc
Amc
= 35.08489 bar
=3508489.318 N/m2
Fcaliper = Pmc * Acaliper * ηwc
Fcaliper front = 3899.054349 N
Force on disc = 2*0.4*3899.05
= 3119.243479 N
Fcaliper rear = 2765.260575 N
Force on disc = 2*0.35*2765.260
= 1995.682403 N
Torque generated
Torquefront = 226.145122 Nm
Torquerear = 140.3369742 Nm
Torque generated at the front and rear is greater than
the required torque.
STOPPING DISTANCE:
SIMPLIFIED:
Figure 21. Simplified stopping
distance time period
Stotal = Vtrtr+
Vtrt 𝑠
2

20
DETAILED:
Stotal = Vtr (tr + ta +
tb
2
)+
V1
2
2amax
-
amax∗tb
2
24
=11.11(1 + 0.25 +
0.3
2
) + (
11.112
2∗6.867
) + (
6.867∗0.32
24
)
=15.554 + 8.9873 – 0.02575
Stotal = 24.5155m
TOTAL TIME = tr + ta +
tb
2
+
Vtr
2amax
=2.2089 sec
Sizing of master cylinder:
SIMPLIFIED
VF=4[(Awc)F*(B.F)F+(Awc)R*(B.F)R
=4(907.36+562.954)
VF=5.881256 cm3
Bore diameter of master cylinder used =
19.05mm
Maximum stroke length = 36mm
Vmc =
𝜋
4
* 19.052
* 36
Vmc =10.260cm3
Since Volume of master cylinder is greater
than volume required. Hence, selection of
master cylinder is justified.
DETAILED:
Amc=
2FpLpηpηc[(Awc∗BFr)F:(Awc∗BFr)R∗SL
aWR;2(Awc∗BFr)R∗Pk(1;SL)∗ηc
Where,
Fp= pedal force, N
Lp= pedal lever ratio
Pk= knee point pressure, N/cm2
ηc= wheel cylinder efficiency
ηp= pedal level efficiency
Awc= Area of wheel cylinder
SL= reducer slope
r= rotor radius
R= tyre effective radius
W= vehicle total weight
a = deceleration
Amc=
2FpLpηpηc[(Awc∗BFr)F:(Awc∗BFr)R∗SL
aWR;2(Awc∗BFr)R∗Pk(1;SL)∗ηc
SL=0; ηp=0.8; ηc=0.98; Fp=250N; Lp=5:1;
r= 72.5mm; BFF = 0.8; BFF = 0.7;
(Awc)F=1134.2 mm2
; (Awc)R=804.22mm2
;
R=11.5”; a=0.9; W=235Kg; Pk=0.

21
Amc=
2∗250∗5∗0.8∗0.98[(1134.2∗0.8∗72.5):(804.22∗0.7∗72.5)∗0
0.9∗2305.35∗292.1
=
1960[65783.6:0]
606053.4615
=212.746670 mm2
Amc =2.1274 cm2
Area of master cylinder selected is 2.85cm2
Detailed Volume Analysis:
5. Pad rotor clearance:
Front Caliper = 115.2347 mm3
Rear Caliper = 81.7067 mm3
Total clearance volume = 115.2347+ 81.7067
=196.9414mm3
=0.1969 cm3
6. Brake line expansion:
VBL=
0.79D3LPL
tE
Where,
D=outer diameter= 4mm
T=wall thickness of pipe= 0.7
E= elastic modulus= 2.05*107
N/cm2
PL=brake line pressure=350.8489N/cm2
L= length of brake line=54”
Therefore,
VBL=
0.79∗(0.4)3∗137.16∗350.8489
0.07∗2.05∗107
VBL =1.69551*10-3
cm3
7. Brake hose expansion:
VH=KH*LH*PL=4.39*10-6
*460*350.8489
VH = 0.7085cm3
1. Master cylinder losses:
Vmc=Kmc*PL
Kmc = specific master cylinder volume
loss cm3
/N/cm2
Vmc= 150*10-6
*350.8489
Vmc=0.05262cm3
2. Caliper deformation:
Vc= KcPL + Vr
Vc = volume loss in caliper, cm3
,
Vr = residual air volume
For diameter between 38 and 60mm,
Kc=482*10-6
dwc-1632*10-6
cm3
/N/cm2
dwc = wheel cylinder diameter, cm,
Kc,F.C= 482*10-6
*3.81-1632*10-6
=204.42*10-6
cm3
/N/cm2
Vc=204.42*10-6
*350.8489+0.31
Vc =0.762cm3
3. Brake pad compression:
Vp=4Σ[(Awc)*Cs*PL]
Awc= wheel cylinder area, cm2
Cs = brake shoe compressibility, cm/(N/cm2
)
=4*19.3842*18*10-6
*350.8489
Vp=0.48966 cm3
4. Brake fluid compression:
VA=Vo+4Σ[(Awc).W] cm3
Vo = brakefluid volume with new shoes, cm3

22
Where, lo = pushrod travel to overcome
pushrod play
lp = pedal ratio.
Sp = (
4.5363
2.85
+ 0.2) * 5
=8.9585 cm
= 3.5269”
The total travel considering all the losses
is in accepted range. Hence, the selection
of master cylinder is justified.
Vo=master cylinder volume+ volume of front
caliper+ volume of rear caliper+ volume of
rigid brake hose+ volume of flexible brake
hose
Vo= 136.0227 cm3
VFL=VA*CFL*PL
W=wear travel of shoes=0.635 cm
CFL= brake fluid compressibility factor = 5*10-
6
cm2
/N
at 422 K
VA= 136.0227+4(19.3842*0.635)
VA=185.258568 cm3
VFL=VA*CFL*PL
=185.258568*5*10-6
*350.8489
VFL=0.324985
8. Air or Gas in the brake system:
VGL=
VGT
To
(1−Po)
(PL+Po)
VGL=2 cm3
These calculations are done for cold brake;
hence the residual air volume is taken as
2cm3
.
9. Fluid losses in hydrorac (booster)
=0 cm3
Total Volume Requirement:
ΣVi=0.0016955+0.7085+0.05262+2+0
.762+0.48966+0.324985+0.1967
ΣVi =4.5363
Sp=[Σ
Vi
Amc
+ lo] * lp
(
4.5363
+ 0.2)

23
CFD
 For CFD we have considered doing 2-D Analysis in Ansys 18.2
 The 2D sketch was drawn in space claim as shown in the figure
1
5
6
4
3
2
1
1. Brake Pedal
2. Fluid Reservoir
3. Master Cylinder
4. Brake line
5. Caliper Pad
6. Disc/Rotor
• Element Size: 1
mm
• Type of Mesh:
Quads & Trias
• Number of
Elements:
13160
• Number of
Nodes: 13955
Figure 22: 2D Space Model
Figure 23: Mesh

24
 We can see that if we apply a force of 35 bar at the inlet we get the output as 28.69
bar
 The force is found to be 3900 N at the caliper end
 Thus the braking efficiency is optimized for the this system
Fig. 24:OEM Brake System

25
 We can see that if we apply a force of 35 bar at the inlet we get the output as 22 bar
 The force is found to be 3100 N at the caliper end
 Thus the braking efficiency is less than compared to the Braking system already there
in the market.
Input Output
Pressure
35.08489 bar 22.35 bar
Force
3100.90N
Fig 25: Customize Brake System

26
Conclusion:
The hydraulic brake system should follow the Pascal’s law, which in turn
doesn’t happen due to all the losses in the braking system during actual
braking. Therefore we considered a braking system of a vehicle which is
currently there in the market and calculated the pressure at caliper end.
Further, we designed our own braking system using Creo 2.0 and calculated
the pressure at the caliper end. We concluded that our design needs to be
more optimized as the results clearly shows that the efficiency of the OEM
braking system is more than our design.
References:
• Limpert Rudolf (2011), “Brake design and Safety”, Society of
Automotive Engineers, Inc.
• Walker James (2005), “The Physics of Braking system.” Stop tech:
High performance braking system
Software’s used:
• PTC Creo 3.0
• Solidworks
• Space Claim
• Ansys 18.2
Future Work:
• To Improvise Design by modifying the design
• To perform the transient CFD Analysis on the system to calculate
more accurate results.

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