7.design and Analysis of Disk Brake PDF
7.design and Analysis of Disk Brake PDF
7.design and Analysis of Disk Brake PDF
Abstract: The disc brake is a device for slowing or stopping the rotation of a wheel. Repetitive braking of the vehicle leads
to heat generation during each braking event. Transient Thermal and Structural Analysis of the Rotor Disc of Disk Brake is
aimed at evaluating the performance of disc brake rotor of a car under severe braking conditions and there by assist in disc
rotor design and analysis. Disc brake model and analysis is done using ANSYS workbench 14.5. The main purpose of this
study is to analysis the thermomechanical behavior of the dry contact of the brake disc during the braking phase. The
coupled thermal-structural analysis is used to determine the deformation and the Von Mises stress established in the disc for
the both solid and ventilated disc with two different materials to enhance performance of the rotor disc. A comparison
between analytical and results obtained from FEM is done and all the values obtained from the analysis are less than their
allowable values. Hence best suitable design, material and rotor disc is suggested based on the performance, strength and
rigidity criteria.
Keywords: Disc Flange, ANSYS Workbench, Structural, Thermal Analysis, Disc Brake
I. INTRODUCTION
In today’s growing automotive market the competition for better performance vehicle is growing enormously. The
racing fans involved will surely know the importance of a good brake system not only for safety but also for staying
competitive. The disc brake is a device for slowing or stopping the rotation of a wheel. A brake disc usually made of cast
iron or ceramic composites includes carbon, Kevlar and silica, is connected to the wheel and the axle, to stop the wheel [1-
3]. A friction material in the form of brake pads is forced mechanically, hydraulically, pneumatically or electromagnetically
against both sides of the disc. This friction causes the disc and attached wheel to slow or stop. Generally, the methodologies
like regenerative braking and friction braking system are used in a vehicle . A friction brake generates frictional forces as
two or more surfaces rub against each other, to reduce movement. Based on the design configurations, vehicle friction
brakes can be grouped into drum and disc brakes. If brake disc are in solid body the heat transfer rate is low [4-6]. Time
taken for cooling the disc is low. If brake disc are in solid body, the area of contact between disc and pads are more. In disc
brake system a ventilated disc is widely used in automobile braking system for improved cooling during braking in which
the area of contact between disc and pads remains same [7,8]. Brake assembly which is commonly used in a car as shown in
fig1.
d
u2
= 56.18 m
2 μg
(c) To calculate deceleration time v u at
Deceleration time = Braking time = 4s
(d) Braking Power: Braking power during continued braking is obtained by differentiating energy with respect to time
Pb = K.E/ t = 32366.25 W
(e) Calculate the Heat Flux (Q): Heat Flux is defined as the amount of heat transferred per unit area per unit time, from
or to a surface.
Q=Pb/A = 1201084.422 W/m2
The contact area between the pads and disc of brake components, heat is generated due to friction. For calculation
of heat generation at the interface of these two sliding bodies, two methods are suggested on the basis of “law of
conservation of energy which states that the kinetic energy of the vehicle during motion is equal to the dissipated heat after
vehicle stop” [7]. The material properties and parameters adopted in the calculations are as shown in table1 [9].
0.527 q t
Single stop temperature rise is the temperature rise due to single braking condition .
Tmax Tamb
( ρ.c.k )
The relative brake temperature after the nth brake application can be calculated using relation,
1 e ( nhAtc ) ( cv )
t
Troa Ti
1 e
( hAtc ) ( cv )
The compressive stresses ‘ ’developed in the surface of a disc from sudden temperature increases is
σ α T
E
1 v
III. FINITE ELEMENT ANALYSIS
The finite element method has become a powerful tool for the numerical solutions of a wide range of engineering
problems. It has been developed simultaneously with the increasing use of the high- speed electronic digital computers and
with the growing emphasis on numerical methods for engineering analysis. In this step it defines the analysis type and
options, apply loads and initiate the finite element solution. This involves three phases:
Pre-processor phase
Solution phase
Post-processor phase
The ANSYS Workbench, together with the Workbench projects and tabs, provides a unified working environment for
developing and managing a variety of CAE information and makes it easier for set up and work with data at a high level.
Workbench includes the following modules “ANSYS Design Space” is referred to as Simulation “ANSYS AGP” is
referred to as Design Modeler and ”ANSYS Design explorer” referred to as Design explorer. Workbench provides
enhanced interoperability and control over the flow of information between these task modules. Various tools and
techniques are incorporated for efficiently manage to large models. Like tree filtering tagging tree Objects, connections
worksheet, object generator, submodeling. Data can be transferred from a 2D coarse model [Full Model] to a 3D submodel.
Submodeling is available for structural and thermal analysis types with solid geometry.
Fig.3 FEA Model Mesh Model for solid disc and ventilated disc
Fig.4 Thermal and Structural Boundary Conditions for solid and ventilated disc
condition of the constant hydraulic pressure P =1Mpa and angular velocity = 50 rad/s (drag brake application) during 10
To validate the present models, a transient thermal analysis behavior of disc brake was performed for the operating
seconds. The ANSYS simulation is obtained in 6 repeated brake applications. One cycle is composed of braking time of
4sec and constant speed driving. The time step Δt =0.001 sec was used in the computations. In each process, the heat flux
distribution on the friction surfaces after time t=4 sec does scarcely occur and then the steady state is reached. The
hydraulic pressure was assumed to linearly increase to 1MPa by 1.5 sec and then kept constant until 4sec. Also, the angular
velocity was assumed to decay linearly and finally become zero at 4sec. The results obtained from analytical and FEM
solutions are compared for both transient thermal and structural behavior of the model. Finally the best model is suggested.
In addition, based on disc brake performance a ventilated radial vanes disc brake analysis of two different materials is
carried out for 6 braking conditions. Comparisons of solid discs case I and ventilated discs case II are performed to validate
the results.
CASE I: Solid Disc
1.Stainless Steel Temperature Results 2.Cast Iron Temperature Results
Fig.5 SS Disc 1st Braking Temperature Contours Fig.8 C I Disc 1st Braking Temperature Contours
During each braking cycle, the temperature on surface of the disc is raises. During 1st braking, the temperature rises from
ambient temperature 22 to 166 . Similarly for alternate braking applications, during 3rd braking and 6th braking it rises to
289 and 446 for solid stainless steel disc respectively. Similarly in the cast iron solid disc 1st, 3rd and 6th braking
applications the temperature rise is 152 , 267 and 412 respectively. The maximum temperature rise is indicated in red
color and green color shows average temperature rise at the friction surface around the circumference of the disc as shown
in figures 5,6,7,8,9,10.
Stainless Steel Deformation and Stress Contours Cast Iron Deformation and Stress Contours
Fig.11 stainless steel Brake Deformation Contours Fig.13 Cast Iron Brake Deformation Contours
Fig.12 stainless steel Brake Von Misses Contours Fig.14 Cast Iron Brake Von Misses Contours
The distribution of the total distortion in solid stainless steel cast iron disc brake is shown in fig11. The scale of values of
the deformation varies from 0 µm with 0.06mm which corresponds to the time of braking. After the 6 th braking, the
maximum deflection induced is 0.0608mm in SS disc and 0.059 in C I disc, which is less than the allowable deflection
0.5mm. During the total time simulation of braking for a full disc presents the distribution of the constraint equivalent of
Von Mises Stresses to various moments of simulation as shown in fig12. The scale of values varies from 0 MPa to 255MPa
in stainless steel disc and 142 MPa in cast iron disc, which is the maximum thermal stress induced at maximum temperature
rise after 6th braking application.
Fig.15 SS Disc 1st Braking Temperature Contours Fig.18 C I Disc 1st Braking Temperature Contours
Fig.16 SS Disc 3rd Braking Temperature Contours Fig.19 C I Disc 3rd Braking Temperature Contours
Fig.17 SS Disc 6th Braking Temperature Contours Fig.20 C I Disc 6th Braking Temperature Contours
During each braking cycle, the temperature on surface of the disc is raises. During 1st braking, the temperature rises from
ambient temperature 22 to 187 . Similarly for alternate braking applications, during 3 rd braking and 6th braking it rises to
281 and320 for solid stainless steel disc respectively. Similarly in the cast iron solid disc 1st, 3rd and 6th braking
applications the temperature rise is 157 , 242 and 283 respectively. The maximum temperature rise is indicated in red
color and green color shows average temperature rise at the friction surface around the circumference of the disc as shown
in figures15,16,17,18,19,20.
Stainless Steel Deformation and Stress Contours Cast Iron Deformation and Stress Contours
Fig.21stainless steel Brake Deformation Contours Fig.23 Cast Iron Brake Deformation Contours
The distribution of the total distortion in stainless steel and cast iron ventilated disc brake is shown in fig21. The scale of
values of the deformation varies from 0 µm to 0.0128mm and which corresponds to the time of braking. After the 6 th
braking, the maximum deflection induced is 0.0128mm in SS ventilated disc and 0.098mm in C I ventilated disc, which is
less than the allowable deflection 0.5mm. The distribution of the constraint equivalent of Von Mises Stresses The scale of
values varies from 0 MPa to 288MPa for in stainless steel disc and 110 MPa in cast iron disc. Which is the maximum
thermal stress induced at maximum temperature rise 320 and 283 after 6th braking application respectively.
Comparing the different results of temperature rise, deflection, and stress field obtained from analysis it shows that
the ventilated cast iron disc has reduction in temperature, deflection and stresses. It is concluded that ventilated type cast
iron disk brake is the best for the present application.
VI. CONCLUSIONS
Comparing the different results of temperature rise, deflection, and stress field obtained from analysis it shows that
in the ventilated cast iron disc reduction in temperature, stresses and deformation by 31.47% and 22.5% 8% respectively
than the solid disc. It is concluded that ventilated type disk brake is the best for the present application. All the values
obtained from the analysis are less than their allowable values. Hence the brake disk design is safe based on the strength
and rigidity criteria.
REFERENCES
[1] Ameer Fareed Basha Shaik, Ch.Lakshmi Srinivas, “Structural and Thermal Analysis of Disc Brake With and Without Cross drilled Rotor of Race
Car”, International Journal of Advanced Engineering Research and Studies, Vol.1, PP 39-43, 2012.
[2] S. Sarip, “Design Development of Lightweight Disc Brake for Regenerative Braking and Finite Element Analysis”, International Journal of Applied
Physics and Mathematics, Vol. 3, PP 52-58, 2013.
[3] Guru Murthy Nathil, T N Charyulu, “Coupled Structural/ Thermal Analysis of Disc Brake” IJRET, Vol.2, PP 539-553, 2012.
[4] V. Chengal Reddy, M. Gunasekhar Reddy, “Modeling and Analysis of FSAE Car Disc Brake Using FEM” International Journal of Emerging
Technology and Advanced Engineering, Vol.3, PP 383-389, 2013.
[5] Michal Kuciej, Piotr Grzes, “The Comparable Analysis of Temperature Distributions Assessment in Disc Brake Obtained Using Analytical Method
and FE Model”, Journal of KONES Powertrain and Transport, Vol.18, PP 236-250, 2011.
[6] Antti Papinniemi, Joseph C.S. Lai, “Disc Brake Squeal, Progress And Challenges” ICSV14, Australia, PP 1-8, 2007.
[7] F.Talati, S.Jalalifar, “Investigation of heat transfer phenomenon in a ventilated disk brake rotor with straight radial vanes” journal of applied science
Vol.8 PP 3583-3592, 2008.
[8] Ali Belhocine, Mostefa bouchetara, “Thermal behavior of dry contacts in the brake discs” international journal of automotive engineering, Vol.3, PP
9-17, 2011.
[9] Limpert Rudolf, “Brake Design and Safety”, Society of Automotive Engineers. Warrandale, Inc, Second Edition, USA, PP 11-157, 1992.
[10] Catalin Spulber, Stefan Voloaca, “Aspects regarding the disc brake's thermal stress simulation by using Infrared Thermography” International
Conference on Optimization of the Robots and Manipulators Romania, ISBN 978, 26-2011.
[11] Dr.Mushtaq Ismael Hasan, “Influence of Wall Axial Heat Conduction on The Forced Convection Heat Transfer In Rectangular Channels” Basrah
Journal for Engineering Science Vol.1, PP 31-43, 2011.
[12] G. Babukanth, M.Vimla Teja, “Transient Analysis of Disk Brake by using ANSYS Software” International Journal of Mechanical and Industrial
Engineering, Vol-2, PP 21-25, 2012.
[13] Muhamad Ibrahim Mahmod, Kannan M. Munisamy, “Experimental analysis of ventilated brake disc with different blade configuration”
Department of mechanical Engineering, Vol. 1, PP 1-9, 2011.