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Journal ArticleDOI

Modelling of automotive disc brake squeal and its reduction using rotor design modifications

08 Jun 2011-International Journal of Vehicle Noise and Vibration (Inderscience Publishers Ltd)-Vol. 7, Iss: 2, pp 129-148

Abstract: This paper proposes a numerical approach to reducing disc brake squeal through rotor design modifications using the finite element method (FEM). The finite element (FE) model is validated based on the measured data extracted from experimental modal analysis for individual brake components in free-free boundary condition and brake assembly under applied pressure. The FE model is used to investigate brake squeal through two numerical approaches namely complex eigenvalue analysis and dynamic transient analysis. Experimental squeal tests are performed using a brake test rig for verification of the predicted results. It is observed that the results of both the complex eigenvalue analysis and dynamic transient analysis agree well with experimental squeal frequencies. In order to reduce brake squeal, a number of structural modifications on the disc are evaluated. The predicted results show that the squeal noise of disc brake is influenced by the natural frequency of the brake rotor and its mode shape. It is also found that a good choice of rotor geometry in the pre-design stage could help in reducing squeal noise.
Topics: Disc brake (61%), Brake (61%), Rotor (electric) (51%)
Citations
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Journal Article
01 Jan 1999-SAE transactions
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, linearised 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 neighbouring modes. When these modes are decoupled, they are stabilised and squeal is eliminated. Good correlation with experimental results is shown. It will be shown that the complex modes base-line 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.

114 citations


Journal ArticleDOI
Sebastian Oberst1, Joseph C. S. Lai1Institutions (1)
Abstract: In automotive disc-brake squeal, most numerical studies have been focussed on the prediction of unstable vibration modes in the frequency domain using the complex eigenvalue analysis. However, the magnitude of the positive real part of a complex eigenvalue is an unreliable indicator of squeal occurrence. Although nonlinearities have been shown to play a significant role in brake squeal, transient nonlinear time domain analyses have rarely been applied owing to high computational costs. Here the complex eigenvalue analysis, the direct steady-state analysis and the transient nonlinear time domain analysis are applied to an isotropic pad-on-disc finite element model representing a simple model of a brake system. While in this investigation, in-plane pad-mode instabilities are not detected by the complex eigenvalue analysis, the dissipated energy obtained by the direct steady-state analysis of the model subjected to harmonic contact pressure excitation is negative at frequencies of pad modes, indicating a potential for instabilities. Transient nonlinear time domain analysis of the pad and disc dynamics reveal that in-plane pad vibrations excite a dominant out-of-plane disc mode. For intermittently chaotic pad motion, the disc dynamics is quasi-periodic; and for chaotic motion of the pad, a toroidal attractor is found for the disc׳s out-of-plane motion. Nonlinear interactions between the pad and the disc highlight that different parts in a brake system display different dynamic behaviour and need to be analysed separately. The type II intermittency route to chaos could be the cause for the experimentally observed instantaneous mode squeal.

62 citations


Journal ArticleDOI
Mohamad S. Qatu1Institutions (1)
Abstract: Vehicle noise, vibration and harshness (NVH) is usually among the top five attributes in terms of its priority in the design of automotive vehicles. Its priority in other types of vehicles (e.g., aerospace) is also important. Like other attributes of safety, performance, dynamics, fuel economy, NVH has to be considered closely in the design process. This manuscript presents a summary of recent research in the general area of NVH with an emphasis in the automotive field. It follows up on a previous review and classifies the phenomena by the main sources of NVH into powertrain, road and tyre, wind and other NVH. The last includes brake and chassis, squeak and rattle, electromechanical NVH, exterior (or drive-by) NVH and others. The paper provides a review of some of the recent literature in this field.

39 citations


Journal ArticleDOI
Abstract: This paper is concerned with the disc brake squeal problem of passenger cars. The objective of this study is to develop a finite element model of the disc brake assembly in order to improve the understanding of the influence of Young’s modulus on squeal generation. A detailed finite element model of the whole disc brake assembly that integrates the wheel hub and steering knuckle is developed and validated by using experimental modal analysis. Stability analysis of the disc brake assembly is conducted to find unstable frequencies. A parametric study is carried out to look into the effect of changing Young’s modulus of each brake’s components on squeal generation. The simulation results indicate that Young’s modulus of the disc brake components plays an important role in generating the squeal noise.

24 citations


Journal ArticleDOI
Belhocine Ali1, Nouby M. Ghazaly2Institutions (2)
Abstract: THIS PAPER IS CONCERNED WITH THE DISC BRAKE SQUEAL PROBLEM FOR PASSENGER CARS. THE OBJECTIVE OF THE PRESENT RESEARCH IS DEVELOPING A FINITE ELEMENT MODEL OF THE DISC BRAKE ASSEMBLY IN ORDER TO IMPROVE UNDERSTANDING OF THE INFLUENCE OF YOUNG€™S MODULUS ON SQUEAL GENERATION. A DETAILED FINITE ELEMENT MODEL OF THE WHOLE DISC BRAKE ASSEMBLY THAT INTEGRATES THE WHEEL HUB AND STEERING KNUCKLE IS DEVELOPED AND VALIDATED USING EXPERIMENTAL MODAL ANALYSIS. STABILITY ANALYSIS OF THE DISC BRAKE ASSEMBLY IS ACCOMPLISHED TO FIND UNSTABLE FREQUENCIES. A PARAMETRIC STUDY IS CARRIED TO LOOK INTO THE EFFECT OF CHANGING YOUNG€™S MODULUS OF EACH BRAKE COMPONENTS ON SQUEAL GENERATION. THE RESULTS OF SIMULATION INDICATED THAT YOUNG€™S MODULUS OF DISC BRAKE COMPONENTS PLAY A SUBSTANTIAL ROLE IN GENERATING THE SQUEAL NOISE.

22 citations


Cites methods from "Modelling of automotive disc brake ..."

  • ...There are two numerical methods that are used to study this problem namely; transient dynamic analysis (Nouby et al., 2011; Hu et al., 1999) and complex eigenvalue analysis (Kung et al., 2000; Abdo et al., 2010; Liu et al., 2007; Abu-Bakar and Ouyang, 2008)....

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  • ...There are two numerical methods that are used to study this problem namely; transient dynamic analysis (Nouby et al., 2011; Hu et al., 1999) and complex eigenvalue analysis (Kung et al....

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References
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Journal ArticleDOI
Abstract: This paper reviews numerical methods and analysis procedures used in the study of automotive disc brake squeal. It covers two major approaches used in the automotive industry, the complex eigenvalue analysis and the transient analysis. The advantages and limitations of each approach are examined. This review can help analysts to choose right methods and make decisions on new areas of method development. It points out some outstanding issues in modelling and analysis of disc brake squeal and proposes new research topics. It is found that the complex eigenvalue analysis is still the approach favoured by the automotive industry and the transient analysis is gaining increasing popularity.

371 citations


"Modelling of automotive disc brake ..." refers background or methods in this paper

  • ...Comparison between CEA and DTA is given in detail by Ouyang et al. (2005). In the following section, CEA and DTA done for validating the findings of the experimental squeal test are described....

    [...]

  • ...There are two main categories of numerical approaches (Ouyang et al., 2005) that are used to study this problem: 1 complex eigenvalue analysis (CEA) 2 dynamic transient analysis (DTA)....

    [...]

  • ...In general, there are two main FE approaches that are used to simulate squeal phenomena: complex mode analysis and dynamic transient analysis (DTA) (Ouyang et al., 2005)....

    [...]


Proceedings ArticleDOI
01 May 1989-SAE transactions

215 citations


"Modelling of automotive disc brake ..." refers background or methods in this paper

  • ...Therefore, many researchers and engineers preferred complex eigenvalue analysis (CEA) to investigate disc brake squeal (Bajer et al., 2003; Dai and Lim, 2008; Liles, 1989; Liu et al., 2007; Mario et al., 2008; Nouby et al., 2009; Abdo et al., 2010)....

    [...]

  • ...Throughout the analysis, a tuning procedure (also known as FE updating) was used to reduce relative errors between the predicted and experimental results (Liles, 1989)....

    [...]


Journal ArticleDOI
Norbert Hoffmann1, Lothar Gaul2Institutions (2)
Abstract: The mode-coupling instability has generally been acknowledged as one of the most prominent mechanisms leading to self-excited oscillations in sliding friction systems. The influence of structural damping on this type of instability mechanism however has not yet been fully clarified. The objective of the present work therefore is to investigate qualitative and quantitative aspects of the mode-coupling instability in the presence of structural damping, which will be assumed as linear viscous. For the sake of simplicity a two-degree-of-freedom minimal model is set up and analyzed. It is shown that under specific conditions the mode-coupling instability may be regarded as a viscous instability in the sense that an increase in structural damping may render a stable system unstable. An explanation for this behavior is given by two lines of argument: First a description and explanation is given in terms of eigenvalue-analysis. Due to the mathematical formality of this approach, the insight gained remains phenomenological. Second, a feedback-loop formalism is developed that allows a more detailed understanding of the underlying mechanical processes. Based on this formalism, necessary and in sum sufficient conditions for the onset of instability can be deduced and also the role of damping can be clarified.

209 citations


Journal ArticleDOI
Abd Rahim AbuBakar1, Huajiang Ouyang1Institutions (1)
Abstract: There are typically two different methodologies that can be used to predict squeal in a disc brake, i.e., complex eigenvalue analysis and dynamic transient analysis. The positive real parts of complex eigenvalues indicate the degree of instability of the disc brake and are thought to associate with squeal occurrence or noise intensity. On the other hand, instability in the disc brake can be identified as an initially divergent vibration response using transient analysis. From the literature it appears that the two approaches were performed separately, and their correlation was not much investigated. In addition, there is more than one way of dealing the frictional contact in a disc brake. This paper explores a proper way of conducting both types of analyses and investigates the correlation between them for a large degree-of-freedom disc brake model. A detailed three-dimensional finite element model of a real disc brake is developed. Three different contact regimes are examined in order to assess the best correlation between the two methodologies.

147 citations


"Modelling of automotive disc brake ..." refers background in this paper

  • ...Since the limit-cycle motions can be determined only by a very time-intensive transient analysis, it is not an approach favoured by the automotive industry and only a few researchers have used it (AbuBakar and Ouyang, 2006)....

    [...]


Journal Article
01 Jan 1999-SAE transactions
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, linearised 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 neighbouring modes. When these modes are decoupled, they are stabilised and squeal is eliminated. Good correlation with experimental results is shown. It will be shown that the complex modes base-line 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.

114 citations


Performance
Metrics
No. of citations received by the Paper in previous years
YearCitations
20171
20161
20153
20131
20123
19991