Analysis of High Frequency Squeal in a Disc-Brake System Using a Stick-Slip Friction Model

2003 ◽  
Author(s):  
Manish Paliwal ◽  
Ajay Mahajan ◽  
Peter Filip
Keyword(s):  
High Frequency ◽  
Contact Stiffness ◽  
Friction Model ◽  
System Stability ◽  
Disc Brake ◽  
Brake Pad ◽  
Stick Slip ◽  
Parametric Studies ◽  
The Stability ◽  
Two Degree Of Freedom

This paper presents a two degree of freedom (2-DOF) stick-slip friction model for studying the effect of contact stiffness on the stability of the system. It is shown that the stability is not only a function of non-linear variation in the friction force provide by stick-slip but also depends on the variation in stiffness of contact due to the formation of friction layers on the surface of the rotor and the brake pad. Parametric studies have been presented to show the effect of variation in coefficient of friction and contact stiffness on the system stability.

scholarly journals Squeal Frequency of a Railway Disc Brake Evaluation by FE Analyses

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
F. Cascetta ◽  
F. Caputo ◽  
A. De Luca
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Experimental Tests ◽  
Numerical Approach ◽  
System Stability ◽  
Brake System ◽  
Physical Parameters ◽  
Disc Brake ◽  
Complex Eigenvalues ◽  
The Stability

This paper deals with the development of a numerical model, based on the Finite Element (FE) theory for the prediction of the squeal frequency of a railway disc brake. The analytical background has been discussed and presented, as well as the most efficient methods for evaluating the system stability; the attention has been paid particularly to the complex eigenvalues method, which has been adopted within this paper to investigate the railway disc brake system. Numerical results have been compared with measurements from experimental tests in order to validate the proposed numerical approach. At the end of this work, a sensitivity analysis, aimed at understanding the effects of some physical parameters influencing the stability of the brake system and the squeal propensity, has been carried out.

Dynamics and Stability of a Nonlinear Brake Model

2001 ◽  
Author(s):  
Jörg Wauer ◽  
Jürgen Heilig
Keyword(s):  
Stability Analysis ◽  
Lyapunov Exponent ◽  
Nonlinear Model ◽  
Numerical Evaluation ◽  
Critical Speed ◽  
Initial Conditions ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Pad ◽  
The Stability

Abstract The dynamics of a nonlinear car disc brake model is investigated and compared with a simplified linear model. The rotating brake disc is approximated by a rotating ring. The brake pad is modeled as a point mass which is in contact with the rotating ring and visco-elastically suspended in axial and circumferential direction. The stability analysis for the nonlinear model is performed by a numerical evaluation of the top Lyapunov-exponent. Several parameter studies for the nonlinear model are discussed. It is shown that dynamic instabilities of the nonlinear model are estimated at subcritical rotating speeds lower than 10% of the critical speed. Further, the sensitivity of the nonlinear model to the initial conditions and the stiffness ratios is demonstrated.

Investigation of High-Frequency Squeal in a Disc Brake System Using a Friction Layer-Based Coupling Stiffness

2005 ◽  
Vol 219 (6) ◽  
pp. 513-522 ◽  
Author(s):  
M Paliwal ◽  
A Mahajan ◽  
J Don ◽  
T Chu ◽  
P Filip
Keyword(s):  
High Frequency ◽  
Elastic Stiffness ◽  
Brake Pad ◽  
Friction Layer ◽  
Disk Brake ◽  
Electron Microscopy Analysis ◽  
Coupling Stiffness ◽  
Microscopy Analysis ◽  
Two Degree Of Freedom ◽  
Automotive Brake

This paper presents a two degree of freedom model for disk brake systems that makes use of the concept of a friction layer-based coupling stiffness. This model is then used to investigate noise and vibration, especially high-frequency squeal. It is shown that for automotive brake systems, the friction layer plays a significant role in the performance characteristics. Hence, the coupling stiffness between the brake pad and the rotor is modelled as a combination of the elastic stiffness of the friction layer superimposed on the coupling modal stiffness of the brake-pad combination. The elastic properties of the friction layer are obtained from nano-indentor tests and the contact area is approximated using light microscopy and scanning electron microscopy analysis. The coupling modal stiffnesses are obtained from impact tests and finite element studies. Preliminary results from the model are consistent with the actual high squeal data collected from the field. The main objective of this work is to introduce a new way of modelling the coupling stiffness based on the properties of the friction layer, which has not been extensively studied till now.

A Novel Closed-Loop Time-Delayed Filter for Unstable System

2013 ◽  
Vol 684 ◽  
pp. 465-468
Author(s):  
Fen Liu ◽  
Ji Sheng Yang
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Dynamic Performance ◽  
Optimization Theory ◽  
Simulation Software ◽  
System Stability ◽  
Frequency Noise ◽  
Unstable System ◽  
Simulink Simulation ◽  
The Stability

Aiming to improve the stability dynamic performance of the oscillating system, an internal closed-loop time-delayed filter with negative pulse is designed. To make the unstable system into stable, a reasonable time delay is introduced within the feedback control system, based on optimization theory to design the delay filter parameters. Matlab/SIMULINK simulation software is used on system performance analysis. Simulation results show that the designed internal closed-loop time-delayed filter can effectively improve the system stability, but also inhibit the high-frequency noise, with a strong anti-interference ability.

A New Tube/Support Impact Model for Heat Exchanger Tubes in Loose Supports

2003 ◽  
Author(s):  
M. A. Hassan ◽  
D. S. Weaver ◽  
M. A. Dokainish
Keyword(s):  
Heat Exchanger ◽  
Contact Stiffness ◽  
Single Point ◽  
Friction Model ◽  
Fretting Wear ◽  
Analytical Models ◽  
Stick Slip ◽  
Proposed Model ◽  
Flow Induced Vibrations ◽  
Wear Damage

Heat exchanger tubes are usually loosely supported at intermediate points by plates or flat bars. Flow-induced vibrations result in fretting wear tube damage due to impacting and rubbing of tubes against their supports. Prediction of tube response relies on modelling the nonlinear tube/support interaction. The evaluated response is used to predict the resultant wear damage using experimentally measured wear coefficients. An accurate of prediction of impact forces and the work rate is therefore paramount. The analytical models available assume tube/support contact occurs over a single point. In this paper, a computational algorithm is proposed to describe the tube/support impact considering a finite support width. The new model provides a means of representing tube/support contact as a combination of edge and segmental contact. The proposed model utilizes a distributed contact stiffness to describe the segmental contact. The formulation also incorporates a stick/slip friction model. The model developed is utilized to simulate the dynamics of loosely-supported tubes.

Noise and vibration analysis of a disc–brake system using a stick–slip friction model involving coupling stiffness

2005 ◽  
Vol 282 (3-5) ◽  
pp. 1273-1284 ◽  
Author(s):  
Manish Paliwal ◽  
Ajay Mahajan ◽  
Jarlen Don ◽  
Tsuchin Chu ◽  
Peter Filip
Keyword(s):  
Vibration Analysis ◽  
Friction Model ◽  
Brake System ◽  
Disc Brake ◽  
Stick Slip ◽  
Noise And Vibration ◽  
Coupling Stiffness

scholarly journals Compressional of LLCL Filter and LCL Filter using Single-Phase Multi-Cell AC-DC Converter

2019 ◽  
Vol 8 (6S4) ◽  
pp. 516-521
Keyword(s):  
High Frequency ◽  
Single Phase ◽  
System Stability ◽  
Power Electronic ◽  
Optimization Scheme ◽  
Pulse Modulation ◽  
Passive Components ◽  
Filter Structure ◽  
The Stability ◽  
Electronic Switches

This paper elucidates a multi cell rectifier for AC to DC for single-phase energy transformation which is obtained by exclusive converter circuits to generate high frequency using the passive components for alternating to direct current. The anticipated method hires an easy structure based on concept of pulse modulation. An effective optimization scheme is exploited to enhance the filter constraints. A converter using power electronic switches will generate the harmonics. Harmonics will reduce the system stability. The harmonics reduced by using LLCL filter structure will enhance the stability of the power system network. The comparsion of LCL and LLCL filter is made with the help of THD analysis.

Mitigation of Stick-Slip Vibrations in Drilling Systems with Tuned Top Boundary Parameters

2020 ◽  
pp. 1-28
Author(s):  
Xianbo Liu ◽  
Zhao Zhang ◽  
Xie Zheng ◽  
Xinhua Long ◽  
Guang Meng
Keyword(s):  
Oil And Gas ◽  
Drill String ◽  
System Stability ◽  
Stick Slip ◽  
Alternative Approach ◽  
String Structure ◽  
Drilling Operations ◽  
Negative Damping ◽  
The Stability ◽  
Drilling Rigs

Abstract Aiming at preventing stick-slip oscillations in drilling systems for oil and gas explorations, a reduced-order model is proposed to capture the nonlinear torsional dynamics of drilling operations. In this model, the drill-string structure is simplified as a single-DOF system suffering from dry frictions at the drill bit, while the electromechanical boundary generated by the top-drive system is modeled as another tunable DOF used for stick-slip suppression. To simplify and parameterize the problems, a normalized 2-DOF system with negative damping and tunable parameters is deduced via nondimensionalization and linearization. Based on this system, stability criteria are obtained analytically in the 5-dimensional parametric space. Stable regions as well as the optimized boundary parameters are found analytically. The results suggest that the system can be stabilized by an optimally tuned boundary when and only when the magnitude of the negative damping is no greater than 2. It also reveals that the stability deteriorates if the inertia on the top is huge and non-adjustable, which is the commonest scenario for commercial drilling rigs nowadays. Finally, applications of the tuned boundary in a typical drilling system for stick-slip mitigation are conducted and verified numerically. The results indicate that the control performance can be potentially enhanced by three to five times, via an additional virtual negative inertia generated by the top-drive motor. This research provides an alternative approach to fully optimize the top boundary for curing stick-slip vibrations in drilling systems.

Analysis of out-of-plane motion of a disc brake system using a two-degree-of-freedom model with contact stiffness

2005 ◽  
Vol 219 (7) ◽  
pp. 869-879 ◽  
Author(s):  
J-E Oh ◽  
Y-G Joe ◽  
K Shin
Keyword(s):  
Friction Coefficient ◽  
Relative Velocity ◽  
Normal Force ◽  
Contact Stiffness ◽  
Plane Motion ◽  
Degree Of Freedom ◽  
Brake System ◽  
Disc Brake ◽  
Out Of Plane ◽  
Two Degree Of Freedom

A two-degree-of-freedom out-of-plane model with contact stiffness is presented to describe dynamic interaction between the pad and disc of a disc brake system. It is assumed that the out-of-plane motion of the system depends on the friction force acting along the in-plane direction. The dynamic friction coefficient is modelled as a function of both in-plane relative velocity and out-of-plane normal force. When the friction coefficient depends only on the relative velocity, the contact stiffness has the role of negative stiffness. The results of stability analysis show that the stiffnesses of the pad and disc are equally important. Complex eigenvalue analysis is conducted for the case where the friction coefficient is also dependent on the normal force. The results further verify the importance of the stiffness. It has also been found that increasing the gradient of the friction coefficient with respect to the normal force makes the system more unstable. Non-linear analysis is also performed to demonstrate various responses. Comparing the responses with experimental data has shown that the proposed model may qualitatively well represent a certain type of brake noise.

DISC BRAKE SQUEAL ANALYSIS USING NONLINEAR MATHEMATICAL MODEL

2021 ◽  
Vol 263 (2) ◽  
pp. 4773-4778
Author(s):  
Akif Yavuz ◽  
Osman Taha Sen
Keyword(s):  
Mathematical Model ◽  
Sliding Friction ◽  
Nonlinear Behavior ◽  
Friction Model ◽  
Degree Of Freedom ◽  
Computational Techniques ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Squeal ◽  
The Stability

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.

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