Disc brake squeal has been a major issue of ongoing research and a very strong challenging problem for the automobile manufacturer especially in the last few decades. Despite intense effort and progress has been done by many researchers around the world on the possibility of eliminating brake squeal in vehicle in order to improve vehicle users’ comfort, reduce the overall environmental noise level, prevent passenger complaints and significantly optimize the warranty costs, still no general solution exists. Therefore, it is one of the most important issues that require a detailed and in-depth study for prediction as well as eliminating brake squeal.

The motivation for the present work lies in the fact that the brake squeal is a complicated problem and depends on a large number of parameters. Hence, using traditional parametric studies by changing one factor at a time is not sufficient for evaluation the brake system. The need of a new approach to investigate the effects of combination of several factors on squeal generation and its interactions is very much required to help improve the design of brake components.

In this book a new approach based on integrating finite element (FE) simulations, a preferred method to investigate the brake squeal, with design of experiments (DOE) technique which is widely used in many engineering fields is conducted. The first part of this work deals with an improved three-dimensional FE model of the disc brake corner which includes the disc brake assembly and the steering knuckle assembly. The present research is considered the FE model of the brake corner and used more validation stages than have been used by other researchers. Stability analysis of the disc brake assembly is performed to predict unstable frequencies using complex eigenvalue analysis (CEA). In order to increase the prediction accuracy of the CEA the effects of friction damping, negative friction-velocity slope and real pad surface roughness are considered. The predicted results are corrected using the experimental squeal test and non-linear dynamic transient results.

This book also presents a significant method for reducing disc brake squeal through structural modifications of brake components. Several types of materials for disc brake components as found in practice are simulated to reduce brake squeal. Furthermore, a number of different geometrical modifications for the brake rotor and pads are evaluated. In addition, the effect of pad shim/insulator through FE model and validating it by experimental method is carried out.

This book also covers DOE approaches to investigate the effects of several factors on squeal generation and its interactions to improve the design of brake components. Two approaches of DOE are combined with FE simulations, namely response surface methodology (RSM) to investigate various geometrical configurations of the brake pad on the disc brake squeal and Taguchi method to determine optimal materials of disc brake components for minimization of squeal propensity. The DOE results showed deviations between predicted and simulation results show a reasonable agreement and also the adequacy of the developed model in prediction squeal propensity.

Chapter 1:

INTRODUCTION, BACKGROUND AND LITERATURE REVIEW

  1.1 INTRODUCTION

  1.2 BACKGROUND ON AUTOMOTIVE DISC BRAKE SYSTEMS

  1.3 LITERATURE REVIEW

     1.3.1 Problem Definition

     1.3.2 Classifications of Brake Noise

     1.3.3 Mechanisms of Brake Squeal

     1.3.4 Investigations into Brake Squeal Problem

         1.3.4.1 Experimental approaches

         1.3.4.2 Theoretical approaches

         1.3.4.3 Finite element approaches

     1.3.5 Squeal Reduction Methods

  1.4 MAJOR OBSERVATIONS FROM LITERATURE REVIEW

  1.5 OBJECTIVES OF THE PRESENT WORK

  1.6 ORGANISATION OF THE BOOK

  1.7 CONCLUDING REMARKS

Chapter 2:

RESEARCH METHODOLOGY OF PRESENT STUDY

  2.1 INTRODUCTION

  2.2 DEVELOPMENT AND VALIDATION OF FE MODEL

     2.2.1 Construction of A Disc Brake Corner

     2.2.2 Validation of FE Model

  2.3 EVALUATION OF BRAKE SQUEAL

     2.3.1 Complex Eigenvalue Analysis

     2.3.2 Dynamic Transient Analysis

     2.3.3 Experimental Squeal Test

  2.4 SQUEAL REDUCTION METHODS

     2.4.1 Material Modifications

     2.4.2 Geometric Modifications

     2.4.3 Damping Shim

  2.5 DESIGN OF EXPERIMENTS

     2.5.1 Taguchi Method

     2.5.2 Response Surface Methodology

         2.5.2.1 First Phase: Screening FFD of experiments

         2.5.2.2 Second Phase: RSM-CCD of experiments

         2.5.2.3 Validation of the model

  2.6 CONCLUDING REMARKS

Chapter 3:

MODAL ANALYSIS OF A DISC BRAKE ASSEMBLY

  3.1 INTRODUCTION

  3.2 EXPERIMENTAL MODAL ANALYSIS

     3.2.1 Equipment for Experimental Analysis

     3.2.2 Experimental Procedure

     3.2.3 Performing Impact Hammer Test

     3.2.4 Extraction of Modal Parameters

     3.2.5 Results of Experimental Modal Analysis

         3.2.5.1 Experimental modal analysis of brake components

         3.2.5.2 Experimental modal analysis of disc brake assembly

  3.3 MODAL ANALYSIS USING FINITE ELEMENT TECHNIQUE

     3.3.1 Mesh Sensitivity

     3.3.2 FE Model Updating

     3.3.3 FE Modal Results

         3.3.3.1 FE modal analysis of brake components

         3.3.3.2 FE modal analysis of brake assembly

  3.4 CONCLUDING REMARKS

Chapter 4:

EVALUATION OF DISC BRAKE SQUEAL

  4.1 INTRODUCTION

  4.2 EXPERIMENTAL SQUEAL TEST

     4.2.1 Brake Test Rig Set-up

     4.2.2 Squeal Testing Methodology and Results

  4.3 COMPLEX EIGENVALUE ANALYSIS

     4.3.1 Theory of Complex Eigenvalue Analysis

     4.3.2 Prediction of Squeal using CEA

     4.3.3 Influence of Friction Coefficient

     4.3.4 Mode-Coupling Mechanism

     4.3.5 Verification of the CEA Results

         4.3.5.1 Influence of positive damping

         4.3.5.2 Influence of negative damping

         4.3.5.3 Influence of real pad surface

  4.4 DYNAMIC TRANSIENT ANALYSIS

  4.5 CONCLUDING REMARKS

Chapter 5:

PARAMETRIC STUDIES AND SQUEAL REDUCTION METHODS

  5.1 INTRODUCTION

  5.2 MATERIAL MODIFICATIONS

     5.2.1 Influence of Rotor Material

     5.2.2 Influence of Pad Material

     5.2.3 Influence of Caliper Material

     5.2.4 Influence of Anchor Bracket Material

  5.3 GEOMETRICAL MODIFICATIONS

     5.3.1 Rotor Geometry Modification

     5.3.2 Pad Geometry Modification

  5.4 EFFECT OF PAD INSULATOR

  5.5 CONCLUDING REMARKS

Chapter 6:

A STUDY ON DISC BRAKE SQUEAL USING DESIGN OF EXPERIMENTS

  6.1 INTRODUCTION

  6.2 TAGUCHI METHOD

     6.2.1 Description of Taguchi Method

     6.2.2 Selection of Variables and their Levels

     6.2.3 Taguchi Design Array

     6.2.4 Signal-to-Noise Ratio

     6.2.5 Results of Taguchi Method

  6.3 RESPONSE SURFACE METHOD

     6.3.1 RSM Methodology

         6.3.1.1 Setting up of fixed factors

         6.3.1.2 Selection of controllable factors

         6.3.1.3 First Phase: Screening FFD of experiments

         6.3.1.4 Second Phase: RSM -CCD of experiments

         6.3.1.5 Analysis Of Variance (ANOVA)

         6.3.1.6 Testing of model

  6.4 CONCLUDING REMARKS

Chapter 7:

CONCLUSIONS AND RECOMMENDATIONS

  FOR FUTURE WORK

  7.1 INTRODUCTION

  7.2 CONCLUSIONS AND MAJOR OBSERVATIONS

  7.3 RECOMMENDATION FOR FURTHER RESEARCH

REFERENCES