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.

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.

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.

scholarly journals A Hybrid Model for Predicting Steering Brake Squeal Based on Multibody Dynamics and Finite Element Methods

2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Lijun Zhang ◽  
Yongchao Dong ◽  
Dejian Meng ◽  
Wenbo Li
Keyword(s):  
Finite Element ◽  
Hybrid Model ◽  
Multibody Dynamics ◽  
Finite Element Methods ◽  
Lateral Force ◽  
Steering Wheel ◽  
Complex Eigenvalue ◽  
Brake Squeal ◽  
Complex Eigenvalue Analysis ◽  
Stress And Deformation

In recent years, the problem of automotive brake squeal during steering braking has attracted attention. Under the conditions of squealing, the loading of sprung mass is transferred, and lateral force is generated on the tire, resulting in stress and deformation of the suspension system. To predict the steering brake squeal propensity and explore its mechanism, we established a hybrid model of multibody dynamics and finite element methods to transfer the displacement values of each suspension connection point between two models. We successfully predicted the occurrence of steering brake squeal using the complex eigenvalue analysis method. Thereafter, we analyzed the interface pressure distribution between the pads and disc, and the results showed that the distribution grew uneven with an increase in the steering wheel angle. In addition, changes in the contact and restraint conditions between the pads and disc are the key mechanisms for steering brake squeal.

Superelement Reduction of Industrial Finite Element Brake System for a Constrained Harmonic Balance Method

2012 ◽  
Author(s):  
Paul Villard ◽  
Samuel Nacivet ◽  
Jean-Jacques Sinou
Keyword(s):  
Finite Element ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Experimental Tests ◽  
Balance Method ◽  
Brake System ◽  
Complex Eigenvalue ◽  
Brake Squeal ◽  
Element System ◽  
Complex Eigenvalue Analysis

Brake squeal is a ubiquitous disturbance in automotive systems. Facing the complexity and the cost of experimental tests, simulations of brake squeal have become essential as well as to provide a predictive numerical method. Two major approaches exist in the numerical analysis of this phenomenon, the transient analysis and the complex eigenvalue analysis. In this study, the Constrained Harmonic Balance Method is applied on an industrial finite element system in order to estimate the nonlinear stationary responses due to friction induced vibration. This paper aims at explaining how a finite element system was adapted to the CHBM and at analyzing the results. First of all, the method used to reduce a finite element brake system is examined and the contact issue is particularly emphasized. Then, a brief summary of the CHBM is made. Finally, limit cycles are obtained close to the Hopf bifurcation.

scholarly journals A Reduced-Order Model for Complex Modes of Brake Squeal Model and Its Application to a Flexible Pin-on-Disc System

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Lijun Zhang ◽  
Jun Wu ◽  
Dejian Meng
Keyword(s):  
Design Optimization ◽  
Sufficient Accuracy ◽  
Reduced Order Model ◽  
Complex Eigenvalue ◽  
Brake Squeal ◽  
Order Model ◽  
Reduced Order ◽  
Complex Modes ◽  
Pin On Disc ◽  
Complex Eigenvalue Analysis

Brake squeal is often analytically studied by a complex eigenvalue analysis of linearized models of the brake assembly that is usually quite large. In this paper, a method for determining those frequencies having the most effect on the pair of coupling frequencies that saves much time is put forward and a reduced-order model is presented based on the complex modes theory. The reduced-order model is proved to be effective when applied to a flexible pin-on-disc system; even damping and nonlinearity are taken into consideration. This reduced-order model can predict the onset of squeal as well as the squeal frequency with sufficient accuracy and largely reduced amount of calculation and gives us a practical guide to perform design optimization in order to reduce brake squeal.

Instability analysis of friction oscillators with uncertainty in the friction law distribution

2015 ◽  
Vol 230 (6) ◽  
pp. 948-958 ◽  
Author(s):  
Z Zhang ◽  
S Oberst ◽  
JCS Lai
Keyword(s):  
Operating Conditions ◽  
Brake System ◽  
Analysis Tool ◽  
Complex Eigenvalue ◽  
Brake Squeal ◽  
Stick Slip ◽  
Number Of Factors ◽  
Friction Models ◽  
Complex Eigenvalue Analysis ◽  
Noise Vibration

Despite substantial research efforts in the past two decades, the prediction of brake squeal propensity, as a significant noise, vibration and harshness (NVH) issue to automotive manufactures, is as difficult as ever. This is due to the complexity of the interacting mechanisms (e.g. stick-slip, sprag-slip, mode coupling and hammering effect) and the uncertain operating conditions (temperature, pressure). In particular, two major aspects in brake squeal have attracted significant attention recently: nonlinearity and uncertainty. The fugitiveness of brake squeal could be attributed to a number of factors including the difficulty in accurately modelling friction. In this paper, the influence of the uncertainty arising from the tribological aspect in brake squeal prediction is analysed. Three types of friction models, namely the Amonton-Coulomb model, the velocity-dependent model and the LuGre model, are randomly assigned to a group of interconnected oscillators which model the dynamics of a brake system. The complex eigenvalue analysis, as a standard stability analysis tool, and the friction work calculation are performed to investigate the probability for instability arising from the uncertainty in the friction models. The results are discussed with a view to apply this approach to the analysis of the squeal propensity for a full brake system.

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