Articoli di riviste: "Brake squeal instability"

1

Nakai, M., e M. Yokoi. "Band Brake Squeal". Journal of Vibration and Acoustics 118, n. 2 (1 aprile 1996): 190–97. http://dx.doi.org/10.1115/1.2889648.

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The purpose of this paper is to investigate the squealing mechanism of band brakes in order to develop effective treatments for the reduction or elimination of squeal noise. With increasing rotational drum speed, squeal frequency increases up to a constant frequency. This constant squeal frequency coincides precisely with the frequency of instability obtained by a linear analysis of the motion of a band on an elastic foundation when the frictional force between the lining of the band and the drum is taken into account. Through experiments and analyses, it will be demonstrated that squeals are induced by the coupling between two modes of the band.

2

Nishiwaki, M. "Generalized Theory of Brake Noise". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 207, n. 3 (luglio 1993): 195–202. http://dx.doi.org/10.1243/pime_proc_1993_207_180_02.

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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.

3

Lü, Hui, Wen-Bin Shangguan e Dejie Yu. "A universal approach to squeal analysis of the disc brakes involving various types of uncertainty". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, n. 6 (28 giugno 2017): 812–27. http://dx.doi.org/10.1177/0954407017709644.

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On the basis of fuzzy random variables, a universal approach to squeal analysis of the disc brakes involving various types of uncertainty is proposed in this paper. In the proposed approach, first, the brake stability analysis function related to reliability is constructed with fuzzy random variables. Next, the fuzziness represented by fuzzy random variables is decomposed into interval uncertainties by using a level-cut strategy. Then, the expectations and the variances of the brake stability analysis function are approximately solved by the random moment method at different cut levels, and the lower bounds and the upper bounds of the expectations and the variances are calculated by using a first-order Taylor expansion and a subinterval analysis. Finally, by combining the different interval solutions with the corresponding cut levels, the fuzzy solutions of the brake stability analysis function are obtained, which can be employed to evaluate the brake squeal instability. The proposed approach provides a universal framework for dealing with various types of uncertainty that may exist in automotive brakes. The universality, the accuracy and the efficiency of the proposed approach to the squeal instability analysis of the brakes involving various types of uncertainty are verified by the analysis results from nine different numerical examples.

4

Huynh, Le Hong Thai, Aleš Dittrich e Ondřej Dráb. "Model Predict Vibration and Noise of Disc Brake". Applied Mechanics and Materials 232 (novembre 2012): 461–64. http://dx.doi.org/10.4028/www.scientific.net/amm.232.461.

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The problem brake squeal is one of the important areas of application in the automotive industry. Most brake squeal is produced by vibration (resonance instability) of the brake components, especially the pads and discs are known as force-coupled excitation. Until now have many research about predict vibration and noise of disc brake but unfortunate the results is not satisfied. This paper presents model for prediction stability of disc brake for a model four degrees of freedom. The result shows stability of system and when occurrence brake squeal.

5

Zhang, Z., S. Oberst e JCS Lai. "Instability analysis of friction oscillators with uncertainty in the friction law distribution". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, n. 6 (19 novembre 2015): 948–58. http://dx.doi.org/10.1177/0954406215616421.

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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.

6

Ouyang, H., e J. E. Mottershead. "A Bounded Region of Disc-Brake Vibration Instability". Journal of Vibration and Acoustics 123, n. 4 (1 giugno 2001): 543–45. http://dx.doi.org/10.1115/1.1394200.

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This paper introduces the velocity-dependent friction law with the Stribeck effect in a moving load model for the vibration and squeal of a car disc brake. Simulated numerical results produce a bounded region of instability for the rotating speed of the disc which is compatible with observed squeal phenomenon.

7

Ghorbel, Ahmed, Becem Zghal, Moez Abdennadher, Lassâad Walha e Mohamed Haddar. "Investigation of friction-induced vibration in a disk brake model, including mode-coupling and gyroscopic mechanisms". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, n. 2-3 (10 maggio 2019): 887–96. http://dx.doi.org/10.1177/0954407019845723.

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The brake squeal reduction has been extensively investigated in many academic and industrial researchers. Friction-induced vibrations can be considered as a dynamic instability problem. Generally, automotive engineers and researchers working in the domain of disk brake noise treat instabilities due to the force of friction as a friction-induced vibration. In the case of squeal noise, mode coupling may cause instability of the system. The aim of this article is to propose a minimal two degree of freedom disk brake model in order to investigate the effects of different parameters on mode-coupling instability. This model takes into account self-excited vibration, gyroscopic effect, friction-induced damping, and brake pad geometry. Thus, a stability analysis of equilibrium by calculating complex eigenvalues is presented to investigate the influence of the main parameters on the stability zone such as the opening angle of the brake pad and preload. For the validation of the stability analysis, squeal index and time domain response are used. The results obtained show the importance of optimizing the physical and geometrical parameters of the brake and that some of these parameters have greater effects compared to the others to reduce noise.

8

Tang, B., JL Mo, X. Zhang, Q. Zhang, MH Zhu e ZR Zhou. "Experimental investigation of the squeal characteristics in railway disc brakes". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 232, n. 11 (16 gennaio 2018): 1437–49. http://dx.doi.org/10.1177/1350650117754002.

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In this study, a bespoke small-scale brake dynamometer was developed to simulate the braking conditions of a railway disc brake system. Braking squeal experiments were performed with this brake dynamometer at different braking pressures and disc rotation speeds, and the influence of these braking parameters on the generation and characterization of the squeal noise was evaluated and discussed. The obtained results show that both the braking pressure and the disc rotation speed have a significant influence on the generation and evolution of the squeal noise. Higher rotation speeds are found to result in higher sound pressures and more complicated squeal noise spectra, except at a particular braking pressure, for which the highest sound pressure level is found at various disc rotation speeds. This phenomenon indicates that a combination of specific braking parameters may lead to a strong instability of the brake system and consequently to squeal noise. Additionally, a possible correlation of the squeal noise characteristics with the pressure distribution at the braking interface was found and discussed.

9

Lai, Van-Vuong, Igor Paszkiewicz, Jean-François Brunel e Philippe Dufrénoy. "Multi-Scale Contact Localization and Dynamic Instability Related to Brake Squeal". Lubricants 8, n. 4 (6 aprile 2020): 43. http://dx.doi.org/10.3390/lubricants8040043.

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Friction-induced vibrations (brake squeal) produced during braking applications have been one of the major problems in the transportation for many years. It can be the most troublesome for passengers because of its high frequency and acoustic pressure. The role of frictional contact surface geometry on the occurrence of squeal was investigated recently by some researchers. However, it has never been systematically studied at different scales simultaneously. Contact localizations are induced on the one hand by macro effects such as thermal dilatation (macroscopic scale) and on the other hand, by the heterogeneity of third body (tribolayer) generated by friction (mesoscopic scale). The aim of this paper is to investigate the effect of contact localization at both scales through stability analysis on a simplified pad on disc system. The model has been developed numerically by the finite element method (FEM) to introduce a non-uniform contact at macroscopic and mesoscopic scales. The results showed a strong dependency between squeal frequencies and effective contact zone at macroscopic and mesoscopic scales for the investigated configuration. Especially, it is found that squeal frequencies depend on the contact area at a macroscopic scale whereas the probability of occurrence of squeal frequency strongly relies on mesoscopic contact distribution.

10

Pan, Gongyu, e Lei Chen. "Impact Analysis of Brake Pad Backplate Structure and Friction Lining Material on Disc-Brake Noise". Advances in Materials Science and Engineering 2018 (2018): 1–9. http://dx.doi.org/10.1155/2018/7093978.

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This study proposes a three-layer brake pad design, on which a six-DOF dynamic model of brake disc-brake pad is established, and the factors affecting the system instability are analyzed. The analysis shows that the change of mass and stiffness of the brake pad will affect the stability of the system. From the linear complex eigenvalue analysis, the unstable vibration modes of the brake system are predicted, and the effectiveness of the complex mode analysis model is verified by the brake system bench test. Brake pads with different structural shapes are designed, and their influence on the stability of the brake system is analyzed. The results show that the design of the three-layer structure and the slotting design of the brake pad can effectively reduce the occurrence of the brake squeal, especially that of the high-frequency squeal noise.

11

Huang, Jinchun, Charles M. Krousgrill e Anil K. Bajaj. "An Efficient Approach to Estimate Critical Value of Friction Coefficient in Brake Squeal Analysis". Journal of Applied Mechanics 74, n. 3 (13 giugno 2006): 534–41. http://dx.doi.org/10.1115/1.2423037.

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Abstract (sommario):

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.

12

Massi, Francesco, Oliviero Giannini e Laurent Baillet. "Brake squeal as dynamic instability: An experimental investigation". Journal of the Acoustical Society of America 120, n. 3 (settembre 2006): 1388–98. http://dx.doi.org/10.1121/1.2228745.

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13

Soh, H. J., e J.-H. Yoo. "Optimal shape design of a brake calliper for squeal noise reduction considering system instability". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 224, n. 7 (14 maggio 2010): 909–25. http://dx.doi.org/10.1243/09544070jauto1385.

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Squeal is a noise phenomenon occurring in the last stage of automobile braking with a high-frequency sound. It is very difficult to express the phenomenon using a mathematical model, since the origin of squeal noise is physically complex. However, the possibility of squeal generation can be predicted by solving the vibration equation of the self-excited system using the complex eigenvalue analysis method. The results of the method are expressed as the magnitude of the unstable mode, and the generation of squeal noise can be prevented by reducing the magnitude of the unstable mode of the brake system. The objective of this research is to determine the optimal design process focused on the calliper housing shape to suppress squeal noise generation by reducing the system instability. The objective function is set to minimize the real part of the complex eigenvalue, i.e. the instability index. In the optimization design process, the design variable for topology optimization is established by focusing on the finger part of the calliper housing, which transmits the braking pressure to the pad lining. To supplement the complex shape generated by the topology optimization process, parametric design variables are selected for the subsequent process. Parameters are set to adjust the housing finger stiffness and are defined by considering the topology optimization result. Finally, the asymmetric shape of the calliper housing is obtained to reduce squeal noise generation.

14

Úradníček, Juraj, Miloš Musil, L’uboš Gašparovič e Michal Bachratý. "Influence of Material-Dependent Damping on Brake Squeal in a Specific Disc Brake System". Applied Sciences 11, n. 6 (16 marzo 2021): 2625. http://dx.doi.org/10.3390/app11062625.

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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.

15

Yavuz, Akif, e Osman Taha Sen. "DISC BRAKE SQUEAL ANALYSIS USING NONLINEAR MATHEMATICAL MODEL". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, n. 2 (1 agosto 2021): 4773–78. http://dx.doi.org/10.3397/in-2021-2834.

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Many academics have examined the disc brake squeal problem with experimental, analytical, and computational techniques, but there is as yet no method to completely understand disc brake squeal. This problem is not fully understood because a nonlinear problem. A mathematical model was created to understand the relationship between brake disc and pad thought to cause the squeal phenomenon. For this study, two degree of freedom model is adopted where the disc and the pad are modeled. The model represents pad and disc as single degree of freedom systems that are connected together through a sliding friction interface. This friction interface is defined by the dynamic friction model. Using this model, linear and nonlinear analyzes were performed. The stability of the system under varying parameters was examined with the linear analysis. Nonlinear analysis was performed to provide more detailed information about the nonlinear behavior of the system. This analysis can provide information on the size of a limit cycle in phase space and hence whether a particular instability is a problem. The results indicate that with the decrease in the ratio of disc to pad stiffness and disc to pad mass, the system is more unstable and squeal noise may occur.

16

Meehan, Paul A. "Prediction and suppression of chaotic instability in brake squeal". Nonlinear Dynamics 107, n. 1 (1 novembre 2021): 205–25. http://dx.doi.org/10.1007/s11071-021-06992-1.

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17

Zhang, Lijun, Wenbo Li e Dejian Meng. "Influence of Heterogeneous Contact Stiffness and Heterogeneous Friction Coefficient on Frictional Squeal". Shock and Vibration 2018 (2018): 1–21. http://dx.doi.org/10.1155/2018/6379201.

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Contact stiffness and friction coefficient are excitation sources and key influencing factors to frictional squeal with obvious inhomogeneous characteristic that is always neglected. In this paper, a multipoint contact flexible pin-on-disc system is established considering tangential stiffness. Then influence of contact stiffness and friction coefficient with heterogeneous distribution on frictional squeal is studied using the complex modal analysis. The research shows that contact stiffness and friction coefficient heterogeneities influence the likelihood of occurrence of the squeal, the frequency of the squeal, and the real part of the complex eigenvalue of the system. And when the contact stiffness and friction coefficient are close to the boundary of the region of mode-coupling instability, flexible pin-on-disc system with homogeneous contact stiffness and friction coefficient cannot predict whether frictional squeal occurs or not. Besides, uncertain distribution of contact stiffness and friction coefficient can induce the uncertainty of brake squeal.

18

Kang, Jaeyoung. "Squeal propensity due to rigid modes of brake pad". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, n. 12 (2 dicembre 2013): 2100–2109. http://dx.doi.org/10.1177/0954406213515200.

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This paper examines the squeal propensity associated with the rigid motion of a brake pad. For the description of the rigid motion, the brake pad is analytically modeled as a composite annular sector plate with both the back plate and friction material rigid. The friction material is subject to friction contact with a rotating disc. The vibration modes of the rigid pad consist of the six rigid modes including three rotation and three translation modes coupled with contact stiffness. The analytical formulation for the dynamic motion of the composite rigid pad is presented. From the numerical calculation, the rigid pad modes are shown to be coupled with one another and thus generate the modal instability in both finite element full model and simplified pad model. It is suggested that the squeal propensity of the rigid pad modes can be estimated by using the simplified pad model and controlled by the certain design modification such as the contact area.

19

Khafaji, Salwan Obaid Waheed, e Noah Manring. "Sensitivity analysis and Taguchi optimization procedure for a single-shoe drum brake". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, n. 10 (8 gennaio 2019): 3690–98. http://dx.doi.org/10.1177/0954406218823799.

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Drum brakes have dominated the braking industry for many years and will most likely continue to do so for the foreseeable future due to their low cost and adequate operating performance. Basic equations for conventional brake are presented, while complicated analysis has been published using finite element methods to predict brake squeal and instability. This paper seeks to step away from the complexity of numerical models to consider the fundamental braking phenomenon of a single-shoe drum brake, using nondimensional, closed-form analysis and a Taylor series expansion to examine the effects of perturbing dimensionless design parameters. In addition, an optimal design for the conventional brake is achieved using Taguchi method. In conclusion, this paper shows that the braking torque is dependent upon only four dimensionless groups, and that two of these groups dominate the physics of braking. Furthermore, it is shown that adjustments to these two dominating groups have a direct impact on the contact pressure between that shoe material and the brake drum, and that this pressure must be kept below the yield strength of the braking material in order to prevent a mechanical failure of the brake. Since the results are nondimensional, they are generally applicable to all single-shoe drum brakes having a design with mechanical features that are similar to the one analyzed in this paper. There is very good agreement between the results of both Taguchi and sensitivity regarding the significance and insignificance of the design parameters.

20

Lee, Junghwan, e Seonghwan Kim. "A Study on the Squeal Noise Instability Analysis on Caliper Brake". Transactions of the Korean Society for Noise and Vibration Engineering 23, n. 11 (20 novembre 2013): 957–65. http://dx.doi.org/10.5050/ksnve.2013.23.11.957.

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Hetzler, Hartmut, e Wolfgang Seemann. "Friction induced flutter instability - on modeling and simulation of brake-squeal -". PAMM 8, n. 1 (dicembre 2008): 10369–70. http://dx.doi.org/10.1002/pamm.200810369.

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22

Lü, Hui, Qianlang Feng, Zicheng Cai e Wen-Bin Shangguan. "An optimization method for brake instability reduction with fuzzy-boundary interval variables". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, n. 12 (25 dicembre 2018): 3209–21. http://dx.doi.org/10.1177/0954407018820192.

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In some special engineering circumstances, it is likely that all parameters of an uncertain automotive structure can only be treated as interval variables due to limited knowledge, but meanwhile their lower and upper bounds can just be modeled as fuzzy variables rather than as deterministic values due to ambiguous information. To handle this dual uncertainties case, a reliability-based optimization method with fuzzy-boundary interval variables is developed in this study, and it is further extended to carry out squeal instability analysis and reduction of brake involving both limited and vague information. In the proposed method, fuzzy-boundary interval variables are utilized to cope with the above dual uncertainties of structure parameters and help to build up the structure response analysis model. First, the structure responses are derived on the basis of α-cut strategy, Taylor series expansion, subinterval analysis, and central difference method. Then, with the aid of fuzzy possibility theory, a reliability analysis model of structure response is developed, which can make use of extra reliability information and thus quantify the reliability more accurately. Next, a reliability-based optimization model involving fuzzy-boundary interval variables is established by integrating the uncertain response analysis model and the reliability analysis model. Finally, the proposed method is extended to carry out automotive brake squeal instability analysis and optimization. The numerical investigations demonstrate the applicability and effectiveness of the proposed method.

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Zhou, Kewei, Cheol Kim e Seoyeon Ahn. "CM-KR-5 Efficient Numerical Method to Predict Brake Squeal Noise Using the Dynamic Instability Technique". Proceedings of Mechanical Engineering Congress, Japan 2012 (2012): _CM—KR—5–1—_CM—KR—5–2. http://dx.doi.org/10.1299/jsmemecj.2012._cm-kr-5-1.

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24

Afferrante, L., M. Ciavarella e J. R. Barber. "Sliding thermoelastodynamic instability". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 462, n. 2071 (6 marzo 2006): 2161–76. http://dx.doi.org/10.1098/rspa.2006.1676.

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Numerous mechanisms can give rise to instabilities and vibrations in sliding systems. These can generally be characterized as either elastodynamic (e.g. ‘brake squeal’) or thermoelastic. The time-scales of these processes differ considerably, so it is usual to neglect coupling between them, i.e. to neglect thermal effects in elastodynamic analyses and to use the quasi-static approximation in thermoelastic analyses. In the present paper, we consider the potential coupling between them in the simplest possible context—a thermoelastodynamic layer sliding against a rigid plane and constrained to one-dimensional displacements. The results show that although the coupling is extremely weak, it has a destabilizing effect on the natural elastodynamic vibration of the layer at arbitrarily low sliding speeds. A numerical solution of the transient equations below the quasi-static critical speed shows that an initial disturbance grows exponentially until periods of separation develop, after which the system approaches asymptotically to a steady state involving periods of contact and separation alternating at the lowest natural frequency of the elastodynamic system. With increasing sliding speed, the proportion of the cycle spent in contact is reduced and the maximum contact pressure increases. It is important to note that neither a quasi-static thermoelastic analysis, nor an elastodynamic analysis neglecting thermal expansion would predict instability in this speed range. Similar instabilities due to thermoelastodynamic coupling are almost certain to occur in more complex practical sliding systems such as brakes and clutches, implying the need for the incorporation of these effects in commercial analysis software. The proposed mechanism might also provide an explanation of reported experimental observations of vibrations normal to the contact interface during frictional sliding.

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Lü, Hui, Kun Yang, Wen-bin Shangguan, Hui Yin e DJ Yu. "Rendering optimal design under various uncertainties". Engineering Computations 37, n. 1 (2 agosto 2019): 345–67. http://dx.doi.org/10.1108/ec-03-2019-0100.

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Purpose The purpose of this paper is to propose a unified optimization design method and apply it to handle the brake squeal instability involving various uncertainties in a unified framework. Design/methodology/approach Fuzzy random variables are taken as equivalent variables of conventional uncertain variables, and a unified response analysis method is first derived based on level-cut technique, Taylor expansion and central difference scheme. Next, a unified reliability analysis method is developed by integrating the unified response analysis and fuzzy possibility theory. Finally, based on the unified reliability analysis method, a unified reliability-based optimization model is established, which is capable of optimizing uncertain responses in a unified way for different uncertainty cases. Findings The proposed method is extended to perform squeal instability analysis and optimization involving various uncertainties. Numerical examples under eight uncertainty cases are provided and the results demonstrate the effectiveness of the proposed method. Originality/value Most of the existing methods of uncertainty analysis and optimization are merely effective in tackling one uncertainty case. The proposed method is able to handle the uncertain problems involving various types of uncertainties in a unified way.

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Yoon, Jungro, Joosang Park e Seungjae Min. "Optimal disc brake design for reducing squeal instability using slip-dependent complex eigenvalue analysis". Mechanical Systems and Signal Processing 177 (settembre 2022): 109240. http://dx.doi.org/10.1016/j.ymssp.2022.109240.

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INOUE, Hayuru, e Takayoshi KAMADA. "Structural instability of friction-induced vibration by characteristic polynomial plane applied to brake squeal". Journal of Advanced Mechanical Design, Systems, and Manufacturing 14, n. 1 (2020): JAMDSM0014. http://dx.doi.org/10.1299/jamdsm.2020jamdsm0014.

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VanderLugt, David N., Charles M. Krousgrill e Farshid Sadeghi. "Experimental observations of coupled-mode instability in disc brake systems leading to squeal vibration". International Journal of Vehicle Noise and Vibration 2, n. 3 (2006): 266. http://dx.doi.org/10.1504/ijvnv.2006.011970.

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Cho, Sangwoon, e Byoungduk Lim. "An Experimental Study on the Squeal Noise Generation due to Dynamic Instability of Brake Pad". Transactions of the Korean Society of Automotive Engineers 24, n. 5 (1 settembre 2016): 520–26. http://dx.doi.org/10.7467/ksae.2016.24.5.520.

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Ostermeyer, Georg-Peter, Michael Müller, Stephan Brumme e Tarin Srisupattarawanit. "Stability Analysis with an NVH Minimal Model for Brakes under Consideration of Polymorphic Uncertainty of Friction". Vibration 2, n. 1 (6 marzo 2019): 135–56. http://dx.doi.org/10.3390/vibration2010009.

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Abstract (sommario):

In brake systems, some dynamic phenomena can worsen the performance (e.g., fading, hot banding), but a major part of the research concerns phenomena which reduce driving comfort (e.g., squeal, judder, or creep groan). These dynamic phenomena are caused by specific instabilities that lead to self-excited oscillations. In practice, these instabilities can be investigated using the Complex Eigenvalues Analysis (CEA), in which positive real parts of the eigenvalues are identified to characterize instable regions. Measurements on real brake test benches or tribometers show that the coefficient of friction (COF), μ , is not a constant, but dynamic, system variable. In order to consider this aspect, the Method of Augmented Dimensioning (MAD) has been introduced and implemented, which couples the mechanical degrees of freedom of the brake system with the degrees of freedom of the friction dynamics. In addition to this, instability prediction techniques can often determine whether a system is stable or instable, but cannot eliminate the instability phenomena on a real brake system. To address this, the current work deals with the quantification of the relevant polymorphic uncertainty of the friction dynamics, wherein the aleatory and epistemic uncertainties are described simultaneously. Aleatory uncertainty is concerned with the stochastic variability of the friction dynamics and incorporated with probabilistic methods (e.g., a Monte Carlo simulation), while the epistemic uncertainty resulting from model uncertainties is modeled via fuzzy methods. The existing measurement data are collected and processed through Data Driven Methods (DDM) for the identification of the dynamic friction models and corresponding parameters. Total Variation Regularization is used for the evaluation of derivatives within noisy data. Using an established minimal model for brake squealing, this paper addresses the question of probabilities for instabilities and the degree of certainty with which this conclusion can be made. The focus is on a comparison between the conventional Coulomb friction model and a dynamic friction model in combination with the MAD. This shows that the quality of the predictive accuracy improves dramatically with the more precise friction model.

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Kang, Jaeyoung, Charles M. Krousgrill e Farshid Sadeghi. "Dynamic instability of a thin circular plate with friction interface and its application to disc brake squeal". Journal of Sound and Vibration 316, n. 1-5 (settembre 2008): 164–79. http://dx.doi.org/10.1016/j.jsv.2008.02.041.

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32

Soobbarayen, K., J. J. Sinou e S. Besset. "Numerical study of friction-induced instability and acoustic radiation – Effect of ramp loading on the squeal propensity for a simplified brake model". Journal of Sound and Vibration 333, n. 21 (ottobre 2014): 5475–93. http://dx.doi.org/10.1016/j.jsv.2014.05.037.

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33

Lü, Hui, Wen-Bin Shangguan e Dejie Yu. "A unified approach for squeal instability analysis of disc brakes with two types of random-fuzzy uncertainties". Mechanical Systems and Signal Processing 93 (settembre 2017): 281–98. http://dx.doi.org/10.1016/j.ymssp.2017.02.012.

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34

Maciel, Mateus Holanda Cardoso, Rômulo do Nascimento Rodrigues, Camilo Augusto Santos Costa, Roberto De Araujo Bezerra, Vanessa Vieira Gonçalves e Thiago Victor Albuquerque de Freitas. "Parametric analysis on temperature influence on brake squeal generation in a single-seater off-road vehicle’s disc brake". Noise & Vibration Worldwide, 20 settembre 2023. http://dx.doi.org/10.1177/09574565231203250.

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Abstract (sommario):

Brakes are a critical component of automobiles, responsible for converting kinetic energy into heat and vibration. The phenomenon of brake squeal, which produces uncomfortable noises, has been extensively studied in both drum and disc brakes. Many studies have evaluated the influence of material and operational parameters on brake instability to reduce squeal. However, the effect of temperature, a key factor in brake performance, is often overlooked. This study aims to fill this gap by analyzing a single rear-axle disc brake from an off-road single-seater vehicle using a parametric approach. Two branches were developed in ANSYS software. The first branch consisted of a finite element model of the brake with disc, pads, and backplates. A static structural analysis was performed to simulate a real braking pressure situation, and the resulting pre-stress state was used to conduct complex modal analysis, which extracted eigenvalues and values responsible for stability. The second branch involved a transient thermal simulation before the static analysis, also considering a real braking situation, to create a gradient of temperature and change component pre-stress reactions accordingly. A design of experiments process was used to explore geometric, thermal, and operational variables. The results showed that temperature and its parameters (convection and emissivity coefficient) increase brake squeal. Thus, considering the effect of temperature is crucial when evaluating brake instability, and optimizing temperature control can help reduce brake squeal, improving safety and comfort for drivers and passengers.

35

Pan, Gongyu, Xiaoman Zhang, Peng Liu e Lin Chen. "Impact analysis of contact symmetrical caliper structure on brake squeal". Journal of Vibration and Control, 10 settembre 2020, 107754632095951. http://dx.doi.org/10.1177/1077546320959517.

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Abstract (sommario):

The brake squeal of automobiles has become one of the most annoying issues for passengers. Hence, it is essential to suppress the noise from the design stage of the braking system. In this article, the method for reducing squeal noise is explored based on the finite element model of the brake system. Studies on this model show that the structural deficiency of the brake caliper may cause the instability of the braking system and then cause squeal noise. Thus, the brake caliper is optimized to achieve a symmetrical contact pressure distribution on the inner and outer sides of the disc surface. The effectiveness of this method is analyzed by ANSYS/workbench software and verified in bench tests and road tests. The results show that the symmetrical caliper structure can make the brake pressure distribution more reasonable and the brake system more stable. Finally, it has reduced the noise incidence from 19.27% to 3.63%, which provides an effective method of reducing brake squeal noise.

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Patil, Yatesh, Subim Khan, Shoaib Iqbal, Amol Bankar e Maheshwari Patil. "Brake Squeal Analysis using Finite Element Analysis Method". International Journal of Engineering Sciences 13, n. 3 (ottobre 2020). http://dx.doi.org/10.36224/ijes.130301.

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Abstract (sommario):

The Finite Element Analysis (FEA) is widely used for solving many Engineering problems. This paper focuses on use of FEA for Brake Squeal Analysis. Automobiles generates several kinds of noises like Groan, chatter, judder, moan, and squeal. Brake squeal can be defined as an unwanted noise that occurs due to dynamic instability of the system. It generally occurs in the frequency range of 1 KHz to 16 KHz.The aim of the project is to predict the squeal noise occurring at particular frequencies at an early stage of development using full corner brake model. The preprocessing of the full corner brake model is done using Hypermesh while the processing and post-processing is to be carried out by using Abaqus. Analysis uses non-linear static simulation which is followed by Complex Eigen Value (CEA) extraction for carrying out the squeal Simulation. It provides the relation between damping ratio and frequency (Real part of the complex Eigen value). If the damping ratio at any particular frequency is above one, it can be said that squeal will occur at that particular frequency.

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Maciel, Mateus Holanda Cardoso, Romulo do Nascimento Rodrigues, Camilo Augusto Santos Costa, Roberto de Araujo Bezerra, Vanessa Vieira Gonçalves e Thiago Victor Albuquerque de Freitas. "Brake squeal finite element performance comparison between commercial and coconut shell-reinforced material drum brake linings". Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 18 aprile 2024. http://dx.doi.org/10.1177/14644207241247741.

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Abstract (sommario):

Brakes play a vital role in vehicles, converting kinetic energy into heat and vibration. Brake squeal, an uncomfortable noise phenomenon, has been thoroughly researched in both drum and disc brakes. Many studies have explored how factors such as material, temperature, and operations impact brake instability and noise. Yet, commercial drum brake linings often contain hazardous asbestos. This poses health risks, exposing individuals to harmful airborne particles, particularly affecting lung health. Hence, current research aims to develop asbestos-free alternative linings, prioritizing reduced wear rates while maintaining effectiveness comparable to traditional ones. These alternatives primarily use organic materials for reinforcement. However, few studies have evaluated the performance of these biomaterial-based linings against commercial counterparts. This study aims to bridge this gap by analyzing a rear-axle drum brake from a heavy vehicle, comparing two linings: One commercially available and the other specially made with coconut shell reinforcement, in a finite element software. Five similar simulation stages were set for both linings in the ANSYS software. Each stage comprises transient thermal and static simulations. The input parameters were chosen to simulate a real braking situation, and the resulting pre-stress state was used to conduct complex modal analysis, which extracted the eigenvalues and values responsible for stability. The results proved that biomaterials such as coconut shells can be used for industrial purposes, such as the manufacture of a brake pad or lining, creating a cheaper, less polluting, and less brake squeal-inducing material.

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Hagedorn, Peter, Manuel Eckstein, Eduard Heffel e Andreas Wagner. "Self-Excited Vibrations and Damping in Circulatory Systems". Journal of Applied Mechanics 81, n. 10 (27 agosto 2014). http://dx.doi.org/10.1115/1.4028240.

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Abstract (sommario):

Self-excited vibrations in mechanical engineering systems are in general unwanted and sometimes dangerous. There are many systems exhibiting self-excited vibrations which up to this day cannot be completely avoided, such as brake squeal, the galloping vibrations of overhead transmission lines, the ground resonance in helicopters and others. These systems have in common that in the linearized equations of motion the self-excitation terms are given by nonconservative, circulatory forces. It has been well known for some time, that such systems are very sensitive to damping. Recently, several new theorems concerning the effect of damping on the stability and on the self-excited vibrations were proved by some of the authors. The present paper discusses these new mathematical results for practical mechanical engineering systems. It turns out that the structure of the damping matrix is of utmost importance, and the common assumption, namely, representing the damping matrix as a linear combination of the mass and the stiffness matrices, may give completely misleading results for the problem of instability and the onset of self-excited vibrations. The authors give some indications on improving the description of the damping matrix in the linearized problems, in order to enhance the modeling of the self-excited vibrations. The improved models should lead to a better understanding of these unwanted phenomena and possibly also to designs oriented toward their avoidance.

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