Modification of Doublet Modes in a Circular Disc Constrained by Cyclic Symmetric Features

2015 ◽  
Author(s):  
Sung-Han Tsai ◽  
Jen-Yuan (James) Chang
Keyword(s):  
Engineering Application ◽  
Circular Disc ◽  
Brake System ◽  
Brake Disc ◽  
Geometry Design ◽  
Cyclic Symmetric ◽  
Parametric Studies ◽  
Design Perspective ◽  
Squeal Noise ◽  
New Criterion

From design perspective, structural modification including material modification and geometry modification in a brake system is the most common approach in reducing the brake squeal. Research of this paper will focus on the modification of the largest noise-generating part in motorcycle’s brake system-the circular disc rotor, based on an existing product available in Taiwan. To reach the best geometry design of a circular disc rotor for specific vibration reduction criteria, parametric studies will be carried out in understanding effects of two evenly distributed modifications in the disc — the bolts and ribs. This paper aims to find a criterion in dealing with the design of a pattern on a disk through finite element analyses and experimental modal analyses. From which results, a new criterion for frequency splitting is developed and a mode-veering phenomenon is observed. The outcome has engineering application in reducing specific squeal noise caused by split doublet modes and shifting natural frequencies of a brake disc without creating a new one.

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.

Tribological behavior of laser textured nodular cast iron surface

2019 ◽  
Vol 71 (7) ◽  
pp. 949-955
Author(s):  
Yongmei Zhu ◽  
Junjie Chen ◽  
Jiajun Du ◽  
Yujie Fan ◽  
Jifei Zheng
Keyword(s):  
Cast Iron ◽  
Tribological Behavior ◽  
Surface Texturing ◽  
Nodular Cast Iron ◽  
Area Ratio ◽  
Brake System ◽  
Resin Matrix ◽  
Dry Sliding ◽  
Brake Disc ◽  
Content Type

Purpose Previous publications were mainly focused on the effect of textures under lubrication. Under dry sliding, area ratio of surface texturing (pit area ratio) and diameter of pit affect the tribological behavior. This paper aims to investigate the effect of laser surface texturing on tribological behavior of nodular cast iron under dry sliding. Design/methodology/approach Pit-like textures with different diameters and spaces were fabricated by laser on nodular cast iron (QT600-3). Using nodular cast iron (QT600-3) as the disc specimen and resin matrix composites (UCV018) as the pad specimen, the tribological test was performed with pin-on-disk reciprocating tribo-tester. Findings The coefficient of friction (COF) of the non-textured specimen was larger than that of the textured one. For the same pit diameter, a larger pit area ratio induced a slight decrease of COF, while wear volume decreased significantly. The pit diameter induced a slight decrease of COF as the pit area ratio, but its effect was weaker. Practical implications The experimental studies will help to improve the brake system such as structure modeling of brake disc. Predicting the performance and life of the brake disc in vehicle based on tribological behavior checked in test, it was proved that pit-like texture had application value in vehicle brake system. Originality/value This paper showed that the effect of pit area ratio on friction and wear was greater than that of pit diameter. The experimental results will be useful to the design on safety brake disc.

scholarly journals Influence of Physical Parameters and Operating Conditions for Structural Integrity of Mechanical System Subjected to Squeal Noise

2013 ◽  
Vol 569-570 ◽  
pp. 1076-1084 ◽  
Author(s):  
Kevin Soobbarayen ◽  
Sébastien Besset ◽  
Jean Jacques Sinou
Keyword(s):  
Friction Coefficient ◽  
Static Loading ◽  
Structural Integrity ◽  
Operating Conditions ◽  
Brake System ◽  
Physical Parameters ◽  
Loading Conditions ◽  
Fundamental Frequencies ◽  
Loading Case ◽  
Squeal Noise

This work proposes to study the effects of physical parameters and loading conditions on both dynamic and acoustic responses of a brake system subjected to squeal. A simplified brake system model composed of a disc and a pad is investigated. The friction interface is modeled by introducing linear and non-linear stiffnesses at several local nodes to model contact. The classical Coulomb law is applied to model friction and the friction coefficient is assumed to be constant. A stability analysis of this system is performed with respect to the friction coefficient and the hydraulic brake pressure. Then self-excited vibrations are investigated for two cases of loading conditions: static loading and ramp loading. Time responses for these cases are significantly different: the case with ramp loading presents higher amplitude of velocity than the static loading case. For the case with ramp loading, the spectrum analysis performed by the Continuous Wavelet Transform, shows the appearance of the fundamental frequencies of unstable modes but also their harmonics and combinations frequencies. Sound pressures radiated during squeal event present different peculiar patterns of directivity for both cases and for a progressive load, the levels are significantly higher.

Coupling Analysis of Frictional Heat under Control of Disc Brake Anti-Skid Brake System

2011 ◽  
Vol 199-200 ◽  
pp. 721-728
Author(s):  
Yi Bing Zhang ◽  
Ying Ying Zhang
Keyword(s):  
Thermal Stress ◽  
Friction Pair ◽  
Brake System ◽  
Frictional Heat ◽  
Brake Disc ◽  
Analysis Model ◽  
Element Analysis ◽  
Study Results ◽  
Friction Temperature ◽  
Braking Force

The nonlinearity of material properties at different temperatures and the manner of braking force applying on a brake system are two key factors to affect the coupling of temperature and thermal stress. Considering these two factors, a finite element analysis model of automobile brake disc and pad is established. By using the model, the dynamic frictional heat and thermal stress of braking friction pair could be simulated and the coupling characters of temperature and thermal stress on friction surfaces could be studied, where the braking force is constant or controlled by an anti-skid brake system(ABS). The study results shown that the friction temperature of brake disk rises in periodic and fluctuant tendency. The fluctuant increase of temperature will influence the character of braking. The increase of friction temperature between a brake disc and pad can decrease under the control of ABS, so the effect of thermo-mechanical coupling could be reduced.

scholarly journals Research on squeal noise of tread brake system in rail freight vehicle

2017 ◽  
Vol 220 ◽  
pp. 012040 ◽  
Author(s):  
Jun Zhang ◽  
Yong-hua Li ◽  
Ji Fang ◽  
Wen-zhong Zhao
Keyword(s):  
Brake System ◽  
Rail Freight ◽  
Squeal Noise

scholarly journals Microstrip-Fed Circular Disc Monopole Antenna with Defected Waveguide Structure

2018 ◽  
Vol 8 (1) ◽  
pp. 189 ◽  
Author(s):  
S. J. Chin ◽  
M. Z. A. Abd. Aziz ◽  
M. R. Ahmad
Keyword(s):  
Return Loss ◽  
Waveguide Structure ◽  
Monopole Antenna ◽  
Circular Disc ◽  
Inner Surface ◽  
Parametric Studies ◽  
Low Efficiency ◽  
Cst Microwave Studio

This paper presented the microstrip-fed circular disc monopole antenna with defected waveguide structure. First, the microstrip-fed circular disc monopole antenna was designed. Next, the monopole antenna was designed with waveguide and lastly followed by the defected waveguide structure where the uniplanar compact (UC) structure was used. CST Microwave studio software was used for simulation and parametric studies process. Initially, the microstrip-fed circular disc monopole antenna was designed to achieve return loss less than -10dB for wideband frequencies. Then, the gain and directivity was improved with the integration of waveguide. The highest directivity of 11.38dBi found at 13.5GHz. However, low efficiency and narrower bandwidth were obtained. Next, uniplanar compact defected waveguide structure (UC DWS) was designed at inner surface of waveguide. The bandwidth achieved 3.09GHz where it covered from 10.91GHz to 14GHz. Meanwhile, the directivity maintained higher than the monopole antenna with highest directivity of 8.84dBi at 10GHz. The gain was also improved from 11GHz to 14GHz with highest gain of 6.38dB occurred at 13.5GHz.

scholarly journals Rectangular Ring Antenna Excited by Circular Disc Monopole for WiMAX System

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Souphanna Vongsack ◽  
Chuwong Phongcharoenpanich ◽  
Sompol Kosulvit ◽  
Kazuhiko Hamamoto ◽  
Toshio Wakabayashi
Keyword(s):  
Radiation Pattern ◽  
Circular Disc ◽  
Impedance Bandwidth ◽  
Frequency Range ◽  
Compact Size ◽  
Ring Antenna ◽  
Parametric Studies ◽  
Simulation Results ◽  
Wimax System ◽  
Good Agreement

This research presents a rectangular ring antenna excited by a circular disc monopole (CDM) mounted in front of a square reflector. The proposed antenna is designed to cover a frequency range of 2.300–5.825 GHz and thereby is suitable for WiMAX applications. Multiple parametric studies were carried out using the CST Microwave Studio simulation program. A prototype antenna was fabricated and experimented. The measurements were taken and compared with the simulation results, which indicates good agreement between both results. The prototype antenna produces an impedance bandwidth (|S11|< −10 dB) that covers the WiMAX frequency range and a constant unidirectional radiation pattern (θ=0°and∅=90°). The minimum and maximum gains are 3.7 and 8.7 dBi, respectively. The proposed antenna is of compact size and has good unidirectional radiation performance. Thus, it is very suitable for a multitude of WiMAX applications.

Brake squeal noise due to disc run-out

2007 ◽  
Vol 221 (7) ◽  
pp. 811-821 ◽  
Author(s):  
J-P Park ◽  
Y-S Choi
Keyword(s):  
Stability Analysis ◽  
Degrees Of Freedom ◽  
Experimental Results ◽  
Brake System ◽  
Brake Squeal ◽  
Friction Characteristic ◽  
Linear Friction ◽  
Brake Dynamometer ◽  
Squeal Noise ◽  
Three Degrees Of Freedom

To understand brake squeal noise, the sound and vibration of an automobile brake system were measured using a brake dynamometer. The experimental results show that an important factor in squeal generation is the run-out due to disc misalignment. A three-degrees-of-freedom model is developed for the brake system, where the run-out effect and non-linear friction characteristic are included. A stability analysis of the model was also performed to predict the generation of squeal with the modification of the brake system. The results show that squeal generation is dependent on the run-out rather than the friction characteristic between the pad and disc.

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.

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