Influence of Dynamic Stiffness in Contact Region on Disk Brake Squeal

Oura, Yasunori; Kurita, Yutaka; Matsumura, Yuichi

doi:10.1299/jee.4.234

Cited by 10 publications

(5 citation statements)

References 3 publications

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“…Therefore, the dynamic stiffness of pads in the squeal-frequency bandwidth was measured by adding vibration with the same amplitude and frequency of squeal. The results clarified that the pads became rigid when the pressure applied to them was increased (8) . Thus, it is…”

Section: Introductionmentioning

confidence: 85%

“…Figure 6 shows the apparatus we used for measuring the dynamic stiffness of the pad (8) . A constant pressure that imitates thrust pressure on the brake was applied to the pad with a thrust screw in the upper part of the apparatus.…”

Section: Apparatus For Measuring Dynamic Stiffnessmentioning

confidence: 99%

“…To effectively prevent squeal, it is necessary to measure the rigidity and to clarify what influences the generation of squeal. We have been examining what influence the spring characteristics of the friction-contact surface have on squeal (6) - (8) . First, a squeal test was carried out by using a testing machine that simplified pad-calipers so that they had a symmetrical structure to clarify what influence the friction-contact surface had on squeal (6) .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of Brake Pad Thickness on Disk Brake Squeal

Oura¹,

Kurita²,

Nishizawa³

et al. 2010

JSDD

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A squeal test using a pad with a different thickness demonstrated that a squeal with a higher frequency can be generated if a thin pad is used. The factors that changed as a result of pad thickness were termed 'difference of pad rigidity' and 'dimension difference in the thickness direction of the pad,' and the influence each factor exerted on the squeal was clarified. First, the dynamic stiffness of the pads used for the squeal tests were measured by adding a vibration that imitated the frequency and amplitude of the squeal. The measurement showed that the pad rigidity becomes hard when the pad thickness becomes thin. In addition, the pad vibrated with the same amplitude and the same phase from the frictional contact surface to the back plate in the thickness direction. The pad rigidity is in inverse proportion to the pad thickness because the pad can be viewed as springs in series in the thickness direction. Next, the influence that pad thickness exerted on squeal was analyzed by using a surface-contact-analysis model that reproduced the pad rigidity with a distributed spring and the dimension difference in the thickness direction of the pad with distance from the contact surface to the rotational center of the pad. Results showed that the squeal frequency becomes high when the pad rigidity becomes hard. If the dimension in the thickness direction of the pad becomes small, the squeal is not generated easily; however, the dimension does not influence the squeal frequency.

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Section: Introductionmentioning

confidence: 85%

Section: Apparatus For Measuring Dynamic Stiffnessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Brake Pad Thickness on Disk Brake Squeal

Oura¹,

Kurita²,

Nishizawa³

et al. 2010

JSDD

Self Cite

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show abstract

“…The latter can be expressed by f ¼ kðy d À y p À lU p Þ ¼ k:y where k is the stiffness of the friction pad, including the interface. k can be discretized as a function of the pressure P (which is deduced from the finite element analysis) according to k ¼ KP n (see Oura et al (2009)), where n is the parameter of non-linearity, K is the coefficient of rigidity related to n, the non-linearity parameter. The values are summarized in Table 1.…”

Section: Lumped-mass Model For Modal Analysismentioning

confidence: 99%

“…The values are summarized in Table 1. The material is an organic friction pad inspired by the Oura et al (2009). This non-linear contact approach makes it possible to consider the non-linear behavior of the friction material near the surface.…”

Section: Lumped-mass Model For Modal Analysismentioning

confidence: 99%

Influence of geometry imperfections on squeal noise linked to mode lock-in

Bonnay

Magnier

Brunel

et al. 2015

International Journal of Solids and Structures

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International audienceNumerical studies of squeal in brake systems are carried out with unreal perfect surfaces. In this paper, a methodology to introduce geometric imperfections in the multi-scale contact problem is proposed. Two kinds of geometric imperfections are taken into account separately: the first is “disc thickness variation” as function of the disc while the second is the “plateau” as function of the friction pad. A complete resolution strategy is proposed with a combination of finite element analysis and a lumped-mass model for a simplified pin-on-disc system. A complex modal analysis is performed for different static configurations in which only the contact pressure evolves. Parametric studies for both cases are performed to study the influence of these geometric imperfections on mode lock-in. It is shown that the introduction of both kinds of geometrical imperfections have an influence on dynamic behavior and mode lock-in (through modification of the eigenfrequencies of the system). The pad mode is mostly influenced by bumping which modifies the contact localization. Considering plateaus on the pad surface highlights the importance of the theoretical contact length parameter

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Mechanism and suppression of friction-induced vibration in catenary-pantograph system

Amano,

Kobayashi,

Yabuno

et al. 2024

Nonlinear Dyn

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An unexplained instability phenomenon in railways is known to be caused by sliding friction in a catenary-pantograph system at low speeds. This is an important engineering problem because this instability phenomenon contributes to increased wear of contact wires and requires a train driver to confirm safety, which leads to train delays. Tribological analyses have found an increase in the friction coefficient at low speeds. Pantograph models based on the finite element method, multibody dynamics, and pin-disk model have been proposed for kinematic analyses. However, the mechanism is still uncertain, and no experimental investigations have been conducted. In this study, experimental and numerical investigations are conducted on the instability phenomenon caused by sliding friction. A method for estimating the friction coefficient for an actual pantograph is proposed and applied to experimentally investigate the instability phenomenon. A dynamic model is constructed based on various experiments. The frequency and the stable-unstable boundary of the instability phenomenon obtained in the simulations agree with those obtained in the experiment. From the dynamic model, it is found that the instability is a flutter-type instability caused by the asymmetry of the stiffness matrix due to Coulomb friction. Countermeasures for preventing the instability phenomenon based on the determined mechanism are proposed, and their effectiveness is verified by simulations and experiments. The results could contribute to the design of new pantographs to improve stability and the development of countermeasures for existing pantographs that experience instability.

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Influence of Dynamic Stiffness in Contact Region on Disk Brake Squeal

Cited by 10 publications

References 3 publications

Influence of Brake Pad Thickness on Disk Brake Squeal

Influence of Brake Pad Thickness on Disk Brake Squeal

Influence of geometry imperfections on squeal noise linked to mode lock-in

Mechanism and suppression of friction-induced vibration in catenary-pantograph system

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