2 edition of Frictionally induced, self excited vibrations in a disc brake system found in the catalog.
Frictionally induced, self excited vibrations in a disc brake system
M. R. North
Written in English
Thesis(Ph.D.) - LoughboroughUniversity of Technology 1972.
|Statement||by M.R. North.|
Finally, the stability of the system was lost, and a self-excited vibration was induced when the total damping of the system was negative. Figures 4, 5, 8, and 9 show the effect of the disc rotational speed on the system vibration for a given brake pressure. The stability of the vibration system was lost at a certain brake pressure with the Cited by: 2. It has become commonly accepted by scientists and engineers that brake squeal is generated by friction-induced self-excited vibrations of the brake system. The noise-free configuration of the brake system loses stability through a flutter-type instability and the system starts oscillating in a limit cycle. Usually, the stability analysis of disk brake models, both analytical as well as finite Cited by:
The instabilities and the self-excited vibrations are recognized as one of the most serious problems of the modern engineering industries. The addition of damping to one part of a brake system (such as the pads) is commonly taken into account to reduce the self-excited friction-induced vibrations and to eliminate the by: 2. Frictionally Excited Thermoelastic Instability in Automotive Disk Brakes Thermoelastic instability in automotive disk brake systems is investigated focusing on the effect of a finite disk thickness. A finite layer model with an antisymmetric mode of deformation can estimate the onset of instability observed in actual disk brake systems.
Most brake noise is caused by frictionally induced dynamic instabilities in the brake (‘source’), which create vibrations of brake components that then radiate the sound (‘response’). Experimental and analytical approaches to investigating the mechanisms and characteristics of brake noise and judder are discussed, and ‘best practice’ design rules to minimise brake noise and judder propensity are suggested. The measured vibrations indicated that the self-excited vibration, characterized by a single-mode vibration modulated by the shaft speed, emerged at a specific speed and grew stronger as the shaft speed decreased, but it would cease at a very low-speed. To explain the mechanism of instability, a dynamic model of the system was by: 4.
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Frictionally induced, self excited vibrations in a disc brake system This work describes an investigation into the frictionally induced, self excited vibrations which occur in braking systems and are generally known as by: 6. A Doctoral Thesis.
Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough work describes an investigation into the frictionally induced, self excited vibrations which occur in braking systems and are generally known as : M.R.
North. This work describes an investigation into the frictionally induced, self excited vibrations which occur in braking systems and are generally known as squeal. is largely theoretical, but measurements made on a rig are used to correlate the predictions of the theory with a practical brake by: 6.
From a system dynamics point of view, technical systems with friction are non-linear dissipative open systems. Even if it is possible for a system to be in a state of steady motion, it can only practically take place if it is stable relative to small disturbances.
Otherwise, the perturbations intensify, resulting in a periodic or self excited vibrations in a disc brake system book : Valentin L. Popov. From a system dynamics point of view, technical systems with friction are nonlinear dissipative open systems.
Even if it is possible for a system to be in a state of steady motion, it can only practically take place if it is stable relative to small disturbances. Otherwise, the perturbations intensify, resulting in a periodic or chaotic : Valentin L. Popov. Friction-induced vibration is a common phenomenon in nature and thus has attracted many researchers’ attention.
Many of the mathematical models that Cited by: 4. Friction vibrations and noises which are common in brakes, have attracted a great deal of attention lately. This paper analyses low frequency vibrations in disc brakes excited at high car speed. This vibration, called judder, has a frequency in the range 10 to Hz and usually comes in association with hum noises.
The dynamic phenomenon shows two principal components, one normal. Friction vibrations and noises which are common in brakes, have attracted a great deal of attention lately. This paper analyses low frequency vibrations in disc brakes excited at high car speed.
Friction-induced vibration for an aircraft brake system—Part 1: Experimental approach and stability analysis International Journal of Mechanical Sciences, Vol Issue 5, MayPages J.-J.
Sinou, O. Dereure, G.-B. Mazet, F. Thouverez and L. Jezequel FRICTION INDUCED VIBRATION FOR AN AIRCRAFT BRAKE SYSTEM. PART 1: EXPERIMENTAL. Numerical Study of Friction-induced Pad-mode Instability in Disc Brake Squeal S. Oberst*, J.C.S. Lai a simpliﬁed brake system in the form of a pin-on-disc is ﬁrstly approximated by a block sliding on a plate.
By it was found that the transverse disc vibrations couple with the. A simple spring-mass system is sufficient to understand and simulate the friction induced vibrations in the system.
The complex brake system can be reduced and idealised as the simple 1 degree of freedom model where the brake pad is represented by a mass resting on the conveyor belt which represents the brake disc.
INTRODUCTION Systems with frictional joints, where one surface slides on another with dry friction or with boundary lubrication, are often susceptible to friction-induced self-excited vibrations. Under certain conditions, the steady state sliding motion becomes unstable and Cited by: The experiment for investigation of self-excited vibrations of brake unit is carried out in two phases.
The first phase is conducted in a laboratory. The second phase is carried out in real-time conditions during train braking. In both cases, the same type of brake block is used (BCR-6”, manufactured in Wabtec MZT Hepos).Cited by: 1.
SUMMARY This work describes an investigation into the frictionally induced, self excited vibrations which occur in braking systems and are generally known as squeal. is lFile Size: 4MB. A new treatment for predicting the self-excited vibrations of nonlinear systems with frictional interfaces: The Constrained Harmonic Balance Method, with application to disc brake squeal Nicolas Coudeyras, Jean-Jacques Sinou, Samuel Nacivet To cite this version: Nicolas Coudeyras, Jean.
In order to create friction induced vibration of the drum brake squeal, the apparatus is set up as shown in Fig. The drum brake is installed on the lathe machine together with the brake shoes and back Cited by: 6. Brake squeal is an example of noise caused by vibrations induced by contact forces. During brake operation, the contact between the pad and the disc can induce a dynamic instability in the system.
This paper presents the analytical modeling and dynamic characteristics of disc brake systems under equal contact loads on both sides of the disc.
The friction force acting on the pad is assumed to be concentrated along its trailing edge due to the moment arising from the friction force, and thus results in a redistribution of normal by: A typical frictionally excited pin on disk system is modeled as a basis for vibration control.
The model is based on chosen experimental setup parameters. The stiffness of the shaft, the internal or material damping, and the aerial or external damping are referred to the disk center. In Fig. 1, the disk center is shown in a deflected position during whirling and the springs represent the equivalent bending stiffness of the rotor by:.
Numerical results show that there is a strong propensity of self-excited vibration of the pantograph-catenary system when the friction coefficient is greater than The dynamic transient analysis results show that the self-excited vibration of the pantograph-catenary system can affect the contact condition between the pantograph and by: 7.Brake noise and vibration has been classified according to its frequency as judder, groan, hum, squeal, squelch and wire brush .
The squeal noise that is particularly annoying usually falls into a frequency range from 1 to 16 by: It is known that nonlinearities in the friction-velocity curves of dry friction may lead to instability of the steady frictional sliding, namely, friction-induced vibration.