Simulating the Effect of Insulators in Reducing Disc Brake Squeele

McDaniel, J. Gregory; Li, Xianhui; Elvenkemper, Andreas; Wegmann, Enrique; Wang, Alex; Chen, Shih-Emn; Flint, John

doi:10.4271/2005-01-3944

Cited by 7 publications

(4 citation statements)

References 1 publication

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“…In most cases, a constant loss factor is applied to the entire frequency range. Other researchers have focused on an accurate modelling of damping sources: friction-induced damping [24][25][26] and shims [27][28][29]. This paper focuses on the effect of damping on the mode-coupling phenomenon involved in brake squeal.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the relationship between damping and mode-coupling patterns in case of brake squeal

Fritz

Sinou

Duffal

et al. 2007

Journal of Sound and Vibration

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International audienceBrake squeal is a friction induced instability phenomenon that has to be addressed during the development process. The mechanism is considered a mode coupling phenomenon also referred to as coalescence. The system eigenvalues have been computed using a technique based on the finite element method. The coalescence patterns were then determined in relation to the friction coefficient. The effects of damping on the coalescence patterns have been investigated. If the two modes involved in the coalescence are equally damped, a "lowering effect" that tends to stabilize the system is observed. If the two modes are not equally damped, both "lowering" and "smoothing" effects occur. If the "smoothing effect" prevails, added damping may act in an unintuitive way by destabilizing the system. To further study this point, stability areas have been plotted and a metric is proposed to find the most stable configuration in terms of damping distribution. In the squeal frequency range, coalescence patterns often involve more than two modes. In this case, the effect of damping is far more complicated since several modes are coupled both in terms of friction and damping

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Section: Introductionmentioning

confidence: 99%

Investigation of the relationship between damping and mode-coupling patterns in case of brake squeal

Fritz

Sinou

Duffal

et al. 2007

Journal of Sound and Vibration

View full text Add to dashboard Cite

show abstract

“…In most cases, a constant loss factor is applied on the whole frequency range. Some other researchers have focused on an accurate modelling of damping sources: friction induced damping [14], [15], [16] and shims [17], [18], [19].…”

Section: Introductionmentioning

confidence: 99%

Effects of damping on brake squeal coalescence patterns – application on a finite element model

Fritz

Sinou

Duffal

et al. 2007

Mechanics Research Communications

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Brake squeal is referred to, in most publications, as a flutter instability trigged by a mode coupling phenomenon. A lot of clues tends to prove that damping would be a key parameter in brake squeal modelling. This study aims at investigating the effects of damping on coalescence patterns, that is to say on the way the modes couple. A finite element model of the whole brake corner has been used to compute the brake modal behaviour. Then a complex eigenvalue analysis has been undertaken to assess the brake stability as a function of the friction coefficient. Different kinds of damping spreading over the modes have been studied. Two main effects have been noticed: a shifting effect and a smoothing effect. The first one always stabilize the brake, whereas this is not the case of the second one. The combination of the two effects may make the brake more unstable depending on the spreading of the additionnal damping.

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“…Modelling of brake shim requires a comprehensive knowledge of material properties of different layers of the shim, some of which are not easy to measure. Also, precisely modelling the boundary conditions of the layers requires an in depth understanding of how these layers interact with each other once in action (Flint et al, 2004;Nishizawa et al, 2007;McDaniel et al, 2005).…”

Section: Shim Modellingmentioning

confidence: 99%

“…Shims are formed of rubber material, adhesive, and usually a sheet of steel in the middle (McDaniel et al, 2005). The simplified model developed in this study is formed of three layers; two layers of rubber on either side and a sheet of steel in the middle.…”

Section: Shim Dampingmentioning

confidence: 99%

Computer aided engineering prediction of brake noise: modeling of brake shims

Esgandari

Olatunbosun

2014

Journal of Vibration and Control

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Brake shims, applied to brake pads, are used for suppressing high frequency noise in disc brake units. Also called brake insulators, they do this mainly by adding more damping to the system in the brake pad area. This reduces the likelihood of the energy transfer between the components which would cause modal coupling. Finite element analysis (FEA), as a simulation and analysis technique, is widely used in the industry to perform squeal analysis as a part of the virtual development of new brake units. However, in most computer aided engineering (CAE) simulations of brake noise, shims are modeled as thin sheets of steel or are not modeled at all. This introduces some inaccuracy because the damping effect and flexibility of the rubber and adhesive material are ignored. Such inaccuracy in predicting system behavior, in the virtual design stage, means the analyst may not be able to locate the right frequencies of any occurring instability in order to decide on a noise fix. Also, the over-prediction of instabilities by complex eigenvalue analysis (CEA) adds to the inaccuracy of the process. This paper introduces a simplified CAE model for the brake shim, which when implemented in brake system modeling helps in highlighting the actual frequencies at which instability occurs in the system by taking into account the correct level of damping in the system in the virtual design stage. The method is confirmed by correlating the analysis predictions with the noise performance of a brake unit in dynamometer tests.

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Simulating the Effect of Insulators in Reducing Disc Brake Squeele

Cited by 7 publications

References 1 publication

Investigation of the relationship between damping and mode-coupling patterns in case of brake squeal

Investigation of the relationship between damping and mode-coupling patterns in case of brake squeal

Effects of damping on brake squeal coalescence patterns – application on a finite element model

Computer aided engineering prediction of brake noise: modeling of brake shims

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