Vibrations induced by dry friction

Jarvis, Roger P.; Mills, B

doi:10.1243/pime_proc_1963_178_058_02

Cited by 40 publications

(14 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These oscillations are caused by stick-slipping at the clutch friction lining interfaces with the flywheel and/or the pressure plate. 2 Jarvis and Mills 3 presented clutch judder as a vibration, primarily induced by friction in dry clutches. However, this phenomenon is not only confined to dry clutches as shown by Berglund et al.…”

Section: Introductionmentioning

confidence: 99%

Effect of clutch lining frictional characteristics on take-up judder

Gkinis

Rahmani

Rahnejat

2017

Proceedings of the Institution of Mechanical Engineers, Part K:

View full text Add to dashboard Cite

Take-up judder is the first rigid body torsional mode of the clutch system, which occurs during clutch engagement. This phenomenon is induced by stick-slip oscillations at the friction lining interfaces between the clutch disc and flywheel, and the pressure plate. The phenomenon is influenced by the clutch lining friction characteristics, the topography of the mating-sliding surfaces and the operational conditions during the engagement process. Therefore, the interfacial characteristics are affected by contact pressure, interfacial slip speed and surface temperature. Take-up judder causes driver and vehicle occupant discomfort, as well as gradual wear of contacting surfaces. The response frequency of the system is reported to be in the range 5-20Hz, depending on the clutch system and vehicle inertia.In this paper the measured interfacial friction characteristics together with clamp load variation (contact pressure) under different surface temperatures are included in a multidegree of freedom dynamic analysis to obtain torsional vibrations of the system, pertaining to take-up judder conditions. Such an in-depth investigation has not hitherto been reported in literature. The paper shows that take-up judder is omnipresent under all clutch engagement conditions, but its poignancy is most evident at cold surface temperatures. It is also shown that the transient judder response has a broader spectral content that is generally acknowledged. Keywords Resistive torque Greek symbols Stiffness proportionality coefficient Damping ratioNon-dimensional time parameter

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of clutch lining frictional characteristics on take-up judder

Gkinis

Rahmani

Rahnejat

2017

Proceedings of the Institution of Mechanical Engineers, Part K:

View full text Add to dashboard Cite

show abstract

“…Squeal was only generated when this contact strip is sufficiently close to the leading edge of the pad, while it was ameliorated when it was moved towards the trailing edge. This phenomenon was subsequently correlated in ‘cantilever-on-disc’ systems by Jarvis and Mills 4 and by Earles 5 in ‘pin-on-disc’ system. The common conclusions of these models are that brake squeal can be caused by geometrically induced instabilities that do not require variations in the coefficient of friction.…”

Section: Introductionmentioning

confidence: 79%

Methodology for predicting brake squeal propensity using complex eigenvalue analysis, including thermo-mechanical effects

Tirovic

Vianello

Bannister

2018

Proceedings of the Institution of Mechanical Engineers, Part D:

View full text Add to dashboard Cite

With brake squeal being most prevalent Noise Vibration and Harshness (NVH) issue in modern vehicles, this paper presents an improved methodology for brake squeal propensity prediction at the design stage. The research established four clearly defined "Stages" in conducting Finite Element (FE) squeal analyses, describing crucial input data, modelling procedures, outputs and results validations. Stage 1 deals with freefree modal characteristics of individual brake components and their material characteristics. Stage 2 combines individual parts, conducting Brake Assembly Mechanical FE Analyses. Stage 3 concentrates on fully Coupled Thermo-mechanical FE Analyses, and the concluding Stage 4 focuses on Brake Assembly Stability Analyses. Validations proved that very accurate predictions are possible, but the geometries, material characteristics and established modelling procedures must be strictly followed. Material characteristics were most prone to introduce discrepancies with measured values. 'Generic' values are found to be unacceptable and conducting own measurements was necessary, in particular for the friction material, whose anisotropic properties have been measured in detail, leading to high accuracy in predicting pad natural modes and frequencies. In Stage 4 the stability analyses of the full brake assembly were based on the Complex Eigenvalue Analysis (which included thermal aspects), with the sign of the real part giving an indication of stability and the imaginary part defining the frequency of the unstable mode. Instabilities and frequencies predicted match well with the values measured in dynamometer tests, clearly demonstrating the influence of thermal effects. The final output of the procedures described in this Paper is a validated 3D thermo-mechanical FE NVH brake assembly model in which natural frequencies and modes, instabilities and contributing factors can be predicted at any time during a brake application.

show abstract

“…Earles and Lee [44] used modal analysis to analyse the behaviour of disc brake systems, most notably the generation of squeal noise. It was Jarvis and Mills [69] who first attempted to determine experimentally the generation of squeal noise. However, there were limitations with their model.…”

Section: Simulation and Modellingmentioning

confidence: 99%

“…The model was focused on the stick-slip oscillation of disc brake systems and a time-transient analysis was performed. The main difference between this model and the model developed by Jarvis and Mills is that this model uses non-linearized equations of motions whereas the one by Jarvis and Mills [69] used the linear equations of motions. This model is therefore more comprehensive than other models because linear models fail to account for the squeal generation far from the steady-state equilibrium.…”

Section: Simulation and Modellingmentioning

confidence: 99%

Interdependence of friction, wear, and noise: A review

Lontin

Khan

2021

Friction

View full text Add to dashboard Cite

Phenomena of friction, wear, and noise in mechanical contacts are particularly important in the field of tribomechanics but equally complex if one wants to represent their exact relationship with mathematical models. Efforts have been made to describe these phenomena with different approaches in past. These efforts have been compiled in different reviews but most of them treated friction, wear mechanics, and acoustic noise separately. However, an in-depth review that provides a critical analysis on their interdependencies is still missing. In this review paper, the interdependencies of friction, wear, and noise are analysed in the mechanical contacts at asperitical level. The origin of frictional noise, its dependencies on contact’s mechanical properties, and its performance under different wear conditions are critically reviewed. A discussion on the existing mathematical models of friction and wear is also provided in the last section that leads to uncover the gap in the existing literature. This review concludes that still a comprehensive analytical modelling approach is required to relate the interdependencies of friction, noise, and wear with mathematical expressions.

show abstract

Vibrations induced by dry friction

Cited by 40 publications

References 0 publications

Effect of clutch lining frictional characteristics on take-up judder

Effect of clutch lining frictional characteristics on take-up judder

Methodology for predicting brake squeal propensity using complex eigenvalue analysis, including thermo-mechanical effects

Interdependence of friction, wear, and noise: A review

Contact Info

Product

Resources

About