Coupled Field Finite Element Analysis of Car Disc Brake Rotors
TABLE OF CONTENTS
Chapters
Page No.
ACKNOWLEDGEMENT
ABSTRACT
CHAPTER 1: INTRODUCTION
06
1.1 Fundamentals of Braking System
1.1.1 Principle of braking.
1.1.2 Coefficient of friction
07
08
1.2 Braking systems.
1.2.1 Brake types in cars.
1.2.1.1 Drum Brake.
08
1.2.1.2 Disc Brake.
08
1.2.1.3 Antilock Braking System (ABS)
08
1.2.2 Air brakes.
09
1.2.3 Exhaust brakes.
09
1.2.4 Electric brakes.
09
1.2.5 Parking brakes.
10
1.3 Braking system components.
1.3.1 Brake pedal.
10
1.3.2 Brake lines.
10
Dept. of Mechanical Engineering SDMCET, Dharwad
Coupled Field Finite Element Analysis of Car Disc Brake Rotors
1.3.3 Brakes fluid.
10
1.3.4 Master cylinder.
11
1.3.5 Divided systems.
11
1.3.6 Tandem master cylinder.
12
1.3.7 Power booster or brake unit.
12
1.3.8 Hydraulic brake booster.
12
1.3.9 Electrohydraulic braking (EHB).
12
1.4 Disc brake systems.
1.4.1 Disc brake operation.
13
1.4.2 The rotor.
15
1.4.2.1 Brake fade
16
1.4.2.2 Rotor Metallurgy
16
1.4.2.3 Rotor Surface finish
17
1.4.3 Disc brake pads.
17
1.4.4 Disc brake calipers.
18
CHAPTER 2: LITERATURE REVIEW
19
CHAPTER 3: MATERIAL PROPERTIES OF DISC BRAKE
ROTORS
25
3.1 Materials used
Dept. of Mechanical Engineering SDMCET, Dharwad
25
2
Coupled Field Finite Element Analysis of Car Disc Brake Rotors
3.2 Cast Iron
25
3.3 Specifications of car and Material Properties of Gray cast iron
3.3.1 Solid disc brake rotor
3.3.1.1 The specifications of car
26
3.3.1.2 The materials properties
26
3.3.2 Ventilated disc brake rotor
3.3.2.1 The specifications of car
27
3.3.2.2 The materials properties
27
CHAPTER 4: THEORY AND CALCULATIONS
4.1 Assumptions.
29
4.2 Stopping distance.
29
4.3 Weight transfer.
30
4.4 Braking efficiency.
31
4.5 Kinetic energy and Heat flux.
4.5.1 Approaches
32
4.5.2 Macroscopic model approach
32
4.6 Calculations
4.6.1 Calculations for heat flux application time
33
4.6.2 Calculations for kinetic energy heat flux time
4.6.2.1 Solid disc brake rotor
33
Dept. of Mechanical Engineering SDMCET, Dharwad
Coupled Field Finite Element Analysis of Car Disc Brake Rotors
4.6.2.2 Ventilated disc brake rotor
35
CHAPTER 5: GEOMETRIC MODELING
5.1 Pro e Wildfire 4.
37
5.2 Module 2 - Part Modeling.
37
5.3 Module 5 - Drawing.
38
5.4 Modeled and drafted components.
38
CHAPTER 6: FINITE ELEMENT MODELING
41
6.1 Meshed components
42
6.2 SOLID90
43
6.2.1 SOLID90 Element Description
43
6.2.2 SOLID90 Input Data
44
6.2.3 SOLID90 Input Summary
44
6.2.4 SOLID90 Output Data
45
6.2.5 SOLID90 Assumptions and Restrictions
45
CHAPTER 7: FINITE ELEMENT ANALYSIS
7.1 Introduction.
47
7.2 Steps in FEA.
7.2.1 General Steps.
47
7.2.2 Steps in ANSYS.
47
Dept. of Mechanical Engineering SDMCET, Dharwad
Coupled Field Finite Element Analysis of Car Disc Brake Rotors
7.3 Coupled field analysis.
48
7.3.1 Thermal Structural Analysis
49
7.3.2 Thermal and Structural Boundary Conditions
49
7.4 Modal analysis.
50
7.5 Procedure adopted for thermal analysis
of disc brake rotors.
50
7.6 Procedure adopted for structural analysis
of disc brake rotors.
51
7.7 Procedure adopted for modal analysis
of disc brake rotors.
51
CHAPTER 8: RESULTS
8.1 Inputs and results of ANSYS 11
52
8.2 Plots of Results
8.2.1 Solid disc brake rotor
53
8.2.2 Ventilated disc brake rotor
61
CHAPTER 9: CONCLUSION
69
CHAPTER 10: FUTURE SCOPE
70
REFERENCES
Dept. of Mechanical Engineering SDMCET, Dharwad
Coupled Field Finite Element Analysis of Car Disc Brake Rotors
CHAPTER 1
INTRODUCTION
At the end of the 19th century the development of a brake system for the newly
invented automobile vehicles was needed. From that moment on, brake system which
makes use of several components (the brake disc among them), was developed. It was
after the beginning of the Second World War, in 1938, that the brake system
technological advance got great impulse due to the aeronautics industry necessity. Around
1886, in Germany, Gotlieb Daimler and Carl Benz would change the history of the world
forever, because they created, independently, the first prototypes of internal combustion
automobiles. This invention gave rise to the development of several automobile
components, and among them was the brake system. In the United States, in 1890,
according to Hughes, the American Elmer Ambrose Sperry invented a brake similar to the
present disc brake. An automotive brake disc brake rotor is a device for slowing or
stopping the motion of a wheel while it runs at a certain speed. In this project work the
complete study of brake systems used in cars is studied and the actual dimensions of the
solid and ventilated disc brake rotors of TATA indica cars are taken which are used to 3D
modeling of rotors in Pro e Wildfire 4. The model is then converted to iges format and
imported to Altair Hypermesh 7 for meshing. After meshing it is imported to ANSYS 11
with element for meshing defining as SOLID 90. Here coupled field finite element
analysis and modal analysis is carried using general purpose finite element analysis. Then
the results are compared for both solid and ventilated disc brake rotors and alternate
materials are also suggested.
The goals of our project are as follows:
i.
Complete study of braking system in car.
ii.
Conceptualization of working of the disc rotor.
iii.
To carry out coupled-field analysis i.e., thermal to static structural analysis which
gives thermal stresses and their corresponding displacements in the disc brake
rotor due to the application of temperature.
Dept. of Mechanical Engineering SDMCET, Dharwad
Coupled Field Finite Element Analysis of Car Disc Brake Rotors
iv.
To predict natural frequencies and associated mode shapes by considering density
of the disc material.
v.
Comparison of solid and ventilated rotor based on the above results.
vi.
Suggesting the suitable material for disc brake rotor and checking whether the
design is safe or not based on the above results.
1.1 Fundamentals of Braking system
1.1.1 Principle of braking:
A basic braking system of a car has:
Brake pedal.
Master cylinder to provide hydraulic pressure.
Brake lines and hoses to connect the master cylinder to the brake assemblies.
Fluid to transmit force from the master cylinder to the wheel cylinders of the
brake assemblies, and
Brake assemblies drum or disc that stop the wheels.
The driver pushes the brake pedal; it applies mechanical force to the piston in the
master cylinder. The piston applies hydraulic pressure to the fluid in the cylinder, the
lines transfer the pressure which is undiminished in all directions within the brake lines
to the wheel cylinders, and the wheel cylinders at the wheel assemblies apply the brakes.
Force is transmitted through the fluid. For cylinders of the same size, the force
transmitted from one is the same value as the force applied to the other. By using
cylinders of different sizes, forces can be increased or reduced. In an actual braking
system, the master cylinder is smaller than the wheel cylinders, so the force at all of the
wheel cylinders is increased. When brakes are applied to a moving vehicle, they absorb
the vehicles kinetic energy. Friction between the braking surfaces converts this energy
into heat. In drum brakes, the wheel cylinders force brake linings against the inside of the
brake drum. In disc brakes, pads are forced against a brake disc. In both systems, heat
spreads into other parts and the atmosphere, so brake linings and drums, pads and discs
must withstand high temperatures and high pressures.
Dept. of Mechanical Engineering SDMCET, Dharwad
