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

2021 ◽  
Vol 11 (6) ◽  
pp. 2625
Author(s):  
Juraj Úradníček ◽  
Miloš Musil ◽  
L’uboš Gašparovič ◽  
Michal Bachratý
Keyword(s):  
Dynamic Instability ◽  
Friction Material ◽  
System Stability ◽  
Brake System ◽  
Brake Disc ◽  
Disc Brake ◽  
Fe Model ◽  
Brake Squeal ◽  
Friction Forces ◽  
General Material

The connection of two phenomena, nonconservative friction forces and dissipation-induced instability, can lead to many interesting engineering problems. We study the general material-dependent damping influence on the dynamic instability of disc brake systems leading to brake squeal. The effect of general damping is demonstrated on minimal and complex models of a disc brake. Experimental analyses through the frequency response function (FRF) show different damping of the brake system coalescent modes, indicating possible dissipation-induced instability. A complex system including material-dependent damping is defined in commercial finite element (FE) software. A FE model validated by experimental data on the brake-disc test bench is used to compute the influence of a pad and disc damping variations on the system stability using complexe igenvalue analysis (CEVA). Numerical analyses 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.

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.

A Study of Squeal Noise in Vehicle Brake System

2011 ◽  
Author(s):  
Xu Wang ◽  
Sabu John ◽  
He Ren
Keyword(s):  
Experimental Tests ◽  
Brake System ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Squeal ◽  
Design Changes ◽  
Brake Application ◽  
Unstable Vibration ◽  
Squeal Noise ◽  
Brake Noise

Disc brake squeal can be classified as a form of friction-induced vibration. Eliminating brake noise is a classic challenge in the automotive industry. This paper presents methods for analyzing the unstable vibration of a car disc brake. The numerical simulation has been conducted, and its results are compared with those from the experimental tests. The root causes of brake squeal noise will be identified. Potential solutions for elimination of the brake squeal noise will be proposed. Firstly, new materials and technologies for the disc brake application will be explored, secondly, it will be illustrated how to avoid the brake squeal noise problem from the brake system design. Brake disc design changes for improving cooling performance, and service solutions for brake squeal noise will be presented.

scholarly journals Squeal Frequency of a Railway Disc Brake Evaluation by FE Analyses

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
F. Cascetta ◽  
F. Caputo ◽  
A. De Luca
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Experimental Tests ◽  
Numerical Approach ◽  
System Stability ◽  
Brake System ◽  
Physical Parameters ◽  
Disc Brake ◽  
Complex Eigenvalues ◽  
The Stability

This paper deals with the development of a numerical model, based on the Finite Element (FE) theory for the prediction of the squeal frequency of a railway disc brake. The analytical background has been discussed and presented, as well as the most efficient methods for evaluating the system stability; the attention has been paid particularly to the complex eigenvalues method, which has been adopted within this paper to investigate the railway disc brake system. Numerical results have been compared with measurements from experimental tests in order to validate the proposed numerical approach. At the end of this work, a sensitivity analysis, aimed at understanding the effects of some physical parameters influencing the stability of the brake system and the squeal propensity, has been carried out.

Links Between Disc Brake Squeal and Pad In-Plane Motion

2003 ◽  
Author(s):  
Fulun Yang ◽  
Valery Pilipchuk ◽  
Chin An Tan
Keyword(s):  
Degrees Of Freedom ◽  
Time History ◽  
Bending Moment ◽  
Dominant Frequency ◽  
Plane Motion ◽  
Mode Shapes ◽  
Theoretical Interpretation ◽  
Disc Brake ◽  
Brake Squeal ◽  
Friction Forces

This paper is focused on links between disc brake squeal and in-plane vibration of pads. A special experimental setup is developed in order to determine correlation between squeal acoustical signals and longitudinal accelerations of both pads. A strong coherence between spectral properties of squeal and pad vibrations is found and quantified. In particular, the dominant frequency of the acoustical and mechanical responses appears to be same. Essentially unharmonic temporal mode shapes of the pad vibrations are detected. Such mode shapes reveal the information about multiple frequency friction forces applied to the disc and pads with a possibility of resonance with their coupled elastic modes. Experimental time history records also show a significant out-of-phase component in the pad motions, which is associated with a bending moment applied to the disc. Major experimental observations admit theoretical interpretation based on a two degrees of freedom model. Theoretical conclusions and experimental results are found to be in a good agreement.

Dynamic surface characteristics during disc brake squeal: non-linear modelling and simulation

2011 ◽  
Vol 225 (6) ◽  
pp. 1341-1348
Author(s):  
J Kang
Keyword(s):  
Contact Area ◽  
Travelling Wave ◽  
Friction Material ◽  
Brake System ◽  
Surface Pattern ◽  
Disc Brake ◽  
Dynamic Surface ◽  
Stick Slip ◽  
Non Linear ◽  
Lift Off

This article studies the non-linear dynamic behaviour of a disc brake system during squealing induced by a disc doublet mode. The disc brake system is modelled as a rotating annular plate in contact with annular sector-friction material. In order to investigate the possibility of detachment over the contact area between the disc surface and friction material during squealing, the lift-off condition is applied to this model. Also, the non-linearity arising from the contact stiffness is considered on the basis of the load–deflection test for the friction material. Numerical results show that the vibration after the onset of squeal reaches the limit cycle. In the steady-squealing response, several interesting phenomena are observed: the stick-slip and lift-off over the specific regime of the contact area. It is shown that the dynamic surface pattern rotates due to the forward travelling wave of the squealing surface. However, the mark of the surface pattern does not seem to move because the speed of the travelling wave fluctuates at a double frequency of squeal vibration.

scholarly journals Stability Optimization of a Disc Brake System with Hybrid Uncertainties for Squeal Reduction

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Hui Lü ◽  
Dejie Yu
Keyword(s):  
System Stability ◽  
Brake System ◽  
Disc Brake ◽  
Uncertain Parameters ◽  
Design Component ◽  
Optimization Constraints ◽  
Reliability Based Design ◽  
Uncertain Model ◽  
Interval Variables ◽  
Distribution Parameters

A hybrid uncertain model is introduced to deal with the uncertainties existing in a disc brake system in this paper. By the hybrid uncertain model, the uncertain parameters of the brake with enough sampling data are treated as probabilistic variables, while the uncertain parameters with limited data are treated as interval probabilistic variables whose distribution parameters are expressed as interval variables. Based on the hybrid uncertain model, the reliability-based design optimization (RBDO) of a disc brake with hybrid uncertainties is proposed to explore the optimal design for squeal reduction. In the optimization, the surrogate model of the real part of domain unstable eigenvalue of the brake system is established, and the upper bound of its expectation is adopted as the optimization objective. The lower bounds of the functions related to system stability, the mass, and the stiffness of design component are adopted as the optimization constraints. The combinational algorithm of Genetic Algorithm and Monte-Carlo method is employed to perform the optimization. The results of a numerical example demonstrate the effectiveness of the proposed optimization on improving system stability and reducing squeal propensity of a disc brake under hybrid uncertainties.

An Analytical Approach to Model Disc Brake System for Squeal Prediction

2001 ◽  
Author(s):  
Harsh V. Chowdhary ◽  
Anil K. Bajaj ◽  
Charles M. Krousgrill
Keyword(s):  
Equations Of Motion ◽  
Linear Equations ◽  
Coupled System ◽  
Hydraulic Cylinder ◽  
Friction Material ◽  
Brake System ◽  
Disc Brake ◽  
Complex Eigenvalue ◽  
Material Stiffness ◽  
Complex Eigenvalue Analysis

Abstract The squeal noise arising due to friction-induced vibrations in brakes continues to be a major challenge for automotive manufacturers. To predict one of the mechanisms behind disc brake squeal, an analytical model is developed for the disc brake system. The brake rotor is represented by a thin plate of equivalent modal characteristics and the backing plates are modeled as thin annular sector plates using Rayleigh-Ritz approach. The two structural models are then coupled using linear elastic springs and Coulomb friction at the interface, and Lagrangian approach is used to derive the equations of motion of the coupled system. The resulting linear equations are solved by using complex eigenvalue analysis. The study shows that squeal is a flutter-type instability caused by coupling between the modes of structural components with very close natural frequencies. The sensitivity to friction material stiffness and the influence of hydraulic cylinder stiffness at backing plates are also discussed.

Generalized Theory of Brake Noise

1993 ◽  
Vol 207 (3) ◽  
pp. 195-202 ◽  
Author(s):  
M Nishiwaki
Keyword(s):  
Friction Force ◽  
Dynamic Instability ◽  
Equations Of Motion ◽  
The Other ◽  
Disc Brake ◽  
Brake Squeal ◽  
Drum Brake ◽  
Brake Application ◽  
Brake Noise ◽  
Theoretical Analyses

Eliminating brake noises generated during brake application is an important issue in the improvement of comfort in vehicles. Brake noises (frequency 1–15 kHz) are often called brake squeal. On the other hand, brake noises (frequency 200–500 Hz) are often called brake groan noise. The studies on drum brake squeal, disc brake squeal and disc brake groan noise have already been presented in references (2), (3) and (4), where theoretical analyses on these brake noises were described. This paper shows that the equations of motion are represented by the same type of equations. Based on these analyses. It is clear that drum brake squeal, disc squeal and disc brake groan noise are generated by the same cause—dynamic instability of the brake system with friction force variations.

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