An Efficient Approach to Estimate Critical Value of Friction Coefficient in Brake Squeal Analysis

2006 ◽  
Vol 74 (3) ◽  
pp. 534-541 ◽  
Author(s):  
Jinchun Huang ◽  
Charles M. Krousgrill ◽  
Anil K. Bajaj
Keyword(s):  
Friction Coefficient ◽  
Coupled System ◽  
Expansion Method ◽  
Critical Value ◽  
System Stability ◽  
Design Parameters ◽  
Complex Eigenvalue ◽  
Brake Squeal ◽  
Eigenvalue And Eigenvector ◽  
Brake Noise

Automotive brake squeal generated during brake applications has become a major concern in automotive industry. Warranty costs for brake noise related complaints have been greatly increasing in recent years. Brake noise and vibration control are also important for the improvement of vehicle quietness and passenger comfort. In this work, the mode coupling instability mechanism is discussed and a method to estimate the critical value of friction coefficient identifying the onset of brake squeal is presented. This is achieved through a sequence of steps. In the first step, a modal expansion method is developed to calculate eigenvalue and eigenvector sensitivities. Different types of mode couplings and their relationships with possible onset of squeal are discussed. Then, a reduced-order characteristic equation method based on the elastically coupled system eigenvalues and their derivatives is presented to estimate the critical value of friction coefficient. The significance of this method is that the critical value of friction coefficient can be predicted accurately without the need for a full complex eigenvalue analysis, making it possible to determine the sensitivity of system stability with respect to design parameters directly.

Estimation of Critical Value of Friction Coefficient for Brake Squeal Analysis

2005 ◽  
Author(s):  
Jinchun Huang ◽  
Charles M. Krousgrill ◽  
Anil K. Bajaj
Keyword(s):  
Friction Coefficient ◽  
Expansion Method ◽  
Critical Value ◽  
System Stability ◽  
Design Parameters ◽  
Complex Eigenvalue ◽  
Brake Squeal ◽  
Modal Expansion ◽  
Eigenvalue And Eigenvector ◽  
Brake Noise

Automotive brake squeal which is generated during brake application has become a major concern in automotive industry. Warranty costs for brake noise have been greatly increasing in recent years. Brake noise and vibration control are important for the improvement of vehicle quietness and passenger comfort. In this work, the mode coupling instability mechanism is discussed, and a method to estimate the critical value of friction coefficient is presented to predict the onset of brake squeal. A modal expansion method is developed to calculate eigenvalue and eigenvector sensitivities. Different types of mode couplings and their relationships with squeal are discussed. A reduced-order characteristic equation method based on the statically coupled eigenvalues and their derivatives is presented to estimate the critical value of friction coefficient. The significance of this method is that the critical value of friction coefficient can be predicted accurately without the need for a full complex eigenvalue analysis, making it possible to determine the sensitivity of system stability with respect to design parameters directly.

Sensitivity of Critical Value of Friction Coefficient for Brake Squeal Analysis

2007 ◽  
Author(s):  
Jinchun Huang ◽  
Charles M. Krousgrill ◽  
Anil K. Bajaj
Keyword(s):  
Sensitivity Analysis ◽  
Friction Coefficient ◽  
Structural Modification ◽  
Critical Value ◽  
System Stability ◽  
Mode Shapes ◽  
Frequency Variation ◽  
Complex Eigenvalue ◽  
Brake Squeal ◽  
Complex Eigenvalue Analysis

Brake squeal has been a major concern throughout the automotive industry. Structural modification is a practical and effective way to reduce brake squeal. However, few if any, systematic techniques exist to guide in this structural modification. In this work, a sensitivity analysis for brake squeal control is presented. The critical value of friction coefficient is used as a measure of squeal propensity. Based on the reduced-order characteristic equation method which can accurately estimate the critical value of friction coefficient, a sensitivity analysis of system stability with respect to lining stiffness and lining geometry is presented for a drum brake system. The sensitivity analysis can be conducted without creating new system models or performing a full complex eigenvalue analysis. Furthermore, the sensitivity analysis reveals the regions of contact area which have strong influence on squeal. It is shown that the separation of elastically coupled frequencies is influenced by the grooves in lining material, and the frequency variation can be related to the mode shapes of the drum and the shoes.

Stability Based Robust Eigenvalue Design for Tolerance

2009 ◽  
Vol 131 (8) ◽  
Author(s):  
XinJiang Lu ◽  
Han-Xiong Li
Keyword(s):  
Robust Design ◽  
Design Method ◽  
Integrated Approach ◽  
System Stability ◽  
Design Parameters ◽  
Complex Eigenvalue ◽  
Sensitivity Matrix ◽  
Eigenvalue Sensitivity ◽  
Design Systems ◽  
Robust Design Method

A novel integrated approach is developed to design systems for stability and robustness. First, design parameters with large variation bounds are chosen to maintain system stability. Then, a robust eigenvalue design problem is considered to make the dynamic response less sensitive to parameter variations. A new complex sensitivity matrix is derived from the system dynamics with the eigenvalue variation approximated into a first-order model by means of the eigenvector orthogonal theory. Through a proper transformation, the complex eigenvalue sensitivity of the Jacobian matrix can still be processed by the traditional robust design approach. By minimizing the eigenvalue sensitivity, design parameters can be obtained for stability as well as robustness. Furthermore, the tolerance space of the selected parameters can be maximized to improve robust performance. A Laval rotor example is used to demonstrate the effectiveness of the proposed robust design method.

Light duty automotive drum brake squeal analysis using the finite-element method

2021 ◽  
pp. 146442072110359
Author(s):  
Anderson L Dias ◽  
Rômulo do N Rodrigues ◽  
Roberto de A Bezerra ◽  
Pierre Lamary ◽  
Matheus HP Miranda
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Friction Coefficient ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Brake Squeal ◽  
Positive Real ◽  
Drum Brake ◽  
Light Duty ◽  
Element Method

The method presented in this work intends to analyze drum brake design parameters of a light duty automotive drum brake system. The main objective of this work is to correlate brake materials and unstability parameters to identify which condition will effectively reduce squeal propensity. The methodology involves (a) the finite-element method of the brake components, namely, drum, shoes, and frictional linings, (b) static calculations to get a pre-stress state around which (c) is computed the complex eigenvalues of the system. Hence, positive real parts indicate dynamic instabilities which are explored by varying parameters, namely, the modulus of elasticity of the materials and the friction coefficient at the contact of the shoes with the drum. According to calculations, it was observed that there exist a given range of values for Young’s modulus and friction coefficient that are favorable to reduce drum brake squeal occurrence. In addition, the method proposed delivered results that match with brake squeal literature.

Preventing Drum Brake Squeal through Lining Modifications

2013 ◽  
Vol 471 ◽  
pp. 20-24 ◽  
Author(s):  
Muhammad Ridhwan Abd Rahman ◽  
Gregory Vernin ◽  
Abd Rahim Abu Bakar
Keyword(s):  
Finite Element Method ◽  
Complex Eigenvalue ◽  
Frequency Range ◽  
Brake Squeal ◽  
Positive Real ◽  
Drum Brake ◽  
Warranty Costs ◽  
Squeal Noise ◽  
Brake Noise

Drum brake squeal is one of the most common and annoying types of brake noise and it usually falls in the frequency range between 0.5-16 kHz. Brake squeal continues to confront vehicle manufacturers where it not only leads to significant increase in the warranty costs but also may affect customers perception on quality of the vehicle. Thus this paper attempts to prevent drum brake squeal by means of lining modifications. In doing so, finite element method is first employed and squeal noise will be then predicted using complex eigenvalue (CE) analysis. A good lining modification should be able to stabilize the drum brake assembly by shifting or reducing positive real parts toward zero or negative real parts in the eigenvalue analysis. Finally, laboratory squeal tests are conducted on the four proposed modifications to verify its effectiveness against squeal.

Bearing-Rotor Coupled System Stability Optimization Design Based on Genetic Algorithm

2011 ◽  
Vol 199-200 ◽  
pp. 1130-1133
Author(s):  
Yu Feng Ding ◽  
Lin Gan ◽  
Jun Bo Zhou ◽  
Bu Yun Sheng
Keyword(s):  
Genetic Algorithm ◽  
Optimization Design ◽  
Mutual Coupling ◽  
Coupling Effect ◽  
Coupled System ◽  
System Stability ◽  
Design Parameters ◽  
Sliding Bearing ◽  
Design Variables ◽  
Algorithm Theory

The structure parameter of sliding bearing has significant influence on entire shafting. The structural optimization of elliptical sliding bearing based on the genetic algorithm theory is studied in the paper. Shafting logarithmic decrement is taken as the objective function, the bearing width-diameter ratio, relative clearance and main design parameters such as ellipticity is taken as design variables. Mutual coupling effect between sliding bearing and rotor is considered in the optimization model. An elliptical sliding bearing of shafting has been optimized, and the solution result shows that the shafting stability has been increased, it indicates this method is feasible.

scholarly journals Influence of Material-Dependent Damping on Brake Squeal in the Specific Disc Brake System

2021 ◽  
Author(s):  
Juraj Úradníček ◽  
Miloš Musil ◽  
Ľuboš Gašparovič ◽  
Michal Bachratý
Keyword(s):  
Finite Element ◽  
Complex Model ◽  
System Stability ◽  
Dynamical Instability ◽  
Brake Disc ◽  
Disc Brake ◽  
Complex Eigenvalue ◽  
Brake Squeal ◽  
Friction Forces ◽  
Finite Element Software

The connection of two phenomena - non-conservative friction forces and dissipation-induced instability can lead to many interesting engineering problems. The paper studies general material-dependent damping influence on dynamical instability of disc brake systems leading to brake squeal. The effect of general damping is demonstrated on a minimal and complex model of a disc brake. A complex system including material-dependent damping is defined in the commercial finite element software. The finite element model validated by experimental data on the brake-disc test bench is used to compute the influence of a pad and a disc damping variations on system stability by complex eigenvalue analysis. Analyzes show a significant sensitivity of the experimentally verified unstable mode of the system to the ratio of the damping between the disc and the friction material components.

Brake Squeal Analysis by Finite Elements and Comparisons to Dyno Results

1999 ◽  
Author(s):  
W. V. Nack
Keyword(s):  
Friction Coefficient ◽  
Finite Elements ◽  
Stiffness Matrix ◽  
Approximate Analysis ◽  
Stability Evaluation ◽  
Analysis Method ◽  
Brake Squeal ◽  
Complex Modes ◽  
Baseline Solution ◽  
Test Schedule

Abstract An approximate analysis method for brake squeal is presented. Using MSC/NASTRAN a geometric nonlinear solution is run using a friction stiffness matrix to model the contact between the pad and rotor. The friction coefficient can be pressure dependent. Next, linearized complex modes are found where the interface is set in a slip condition. Since the entire interface is set sliding, it produces the maximum friction work possible during the vibration. It is a conservative measure for stability evaluation. An averaged friction coefficient is measured and used during squeal. Dynamically unstable modes are found during squeal. They are due to friction coupling of neighboring modes. When these modes are decoupled, they are stabilized and squeal is eliminated. Good correlation with experimental results is shown. It will be shown that the complex modes baseline solution is insensitive to the type of variations in pressure and velocity that occur in a test schedule. This is due to the conservative nature of the approximation. Convective mass effects have not been included.

Characteristic Measures for the Representation of Manufactured Surface Quality

1996 ◽  
Author(s):  
Irem Y. Turner ◽  
R. S. Srinivasan ◽  
Kristin L. Wood
Keyword(s):  
Surface Characterization ◽  
Fourier Spectrum ◽  
Expansion Method ◽  
Design Parameters ◽  
Machining Processes ◽  
Wavelet Representation ◽  
Design And Manufacturing ◽  
Surface Precision ◽  
Signal Characterization ◽  
Generate Characteristic

Abstract In this paper, we investigate four methods that yield mathematical measures to analyze the precision of surfaces of manufactured parts. These four methods, namely the autocorrelation function, the Fourier spectrum, the Karhunen-Loève expansion, and a fractal-wavelet representation, are applied to surfaces produced from grinding processes. The first two methods are standard methods used in the surface analysis literature for qualitative signal characterization. The Karhunen-Loève expansion method, used in various signal processing applications, has never been applied to the field of surface characterization and representation. The fractal-wavelet representation has been previously proposed by the authors; its suitability to generate characteristic measures is investigated in this paper. The existence of characteristic measures of surface precision should aid designers in choosing process and design parameters and in comparing the precision between competing machining processes. The use of such measures is essential in taking a forward step towards integrating the fields of design and manufacturing.

Sign in / Sign up

Export Citation Format

Share Document