3037 Dynamic Friction Characteristics of Paper-Based Wet Friction Material Subjected to Vibratory Loading

2007 ◽  
Vol 2007.4 (0) ◽  
pp. 147-148
Author(s):  
Yasuhisa HATTORI
Keyword(s):  
Friction Material ◽  
Dynamic Friction ◽  
Friction Characteristics ◽  
Wet Friction

Paper 16: Friction in Wet Clutches

1967 ◽  
Vol 182 (14) ◽  
pp. 132-138 ◽  
Author(s):  
E. M. Evans ◽  
J. Whittle
Keyword(s):  
Coefficient Of Friction ◽  
Power Transmission ◽  
Sliding Speed ◽  
Friction Materials ◽  
Friction Characteristics ◽  
Sliding Surfaces ◽  
Base Oils ◽  
Wet Friction ◽  
Friction Clutch ◽  
The Coefficient Of Friction

This paper is intended to demonstrate that designers of wet clutches for power transmission can obtain the optimum friction characteristics for specific applications by considering the interaction between friction materials and lubricants. A friction clutch plate rig is described and the friction results obtained are presented. It is shown that a wide variation of coefficients of friction and frictional characteristics in wet friction clutches can be obtained by changing the oils and friction materials. In particular the coefficient of friction is dependent upon (1) the oil, (2) the materials of the sliding surfaces, (3) sliding speed, and (4) temperature. It is also shown that the coefficient of friction is affected by ( a) refining treatment given to the oil, ( b) different base oils, and ( c) additives.

scholarly journals TRANSMITTED POWER AND ENERGY FLOW BEHAVIOR OF DEGRADING WET FRICTION CLUTCHES

2012 ◽  
pp. 286-291
Author(s):  
SHOAIB IQBAL ◽  
THIERRY JANSSENS ◽  
WIM DESMET ◽  
FARID AL- BENDER
Keyword(s):  
Energy Flow ◽  
Relative Velocity ◽  
Normal Load ◽  
Flow Behavior ◽  
Friction Material ◽  
Friction Model ◽  
Friction Torque ◽  
Phase Changes ◽  
Transmitted Power ◽  
Wet Friction

Experiments and simulations performed in the framework of accelerated-life tests of wet friction clutches reveal that with the progression of degradation of clutches, the transmitted power decreases together with a change in the energy flow behavior, mainly in the pre-lockup phase. In addition, the engagement duration increases and the relative velocity fluctuation in post-lockup phase changes. These degradation effects are due to the reduction in friction torque and the change in the relative velocity profile caused by the changing friction characteristics of the clutch friction material with degradation. Simulations are performed in a bond graph methodology incorporating an adapted form of the Generalized Maxwell Slip (GMS) friction model, which calculates the friction torque taking into account the dynamic variation in relative velocity and the normal load.

Dynamic Friction Characteristics of Bulk Seeds Against Flat Vertical Surfaces

1992 ◽  
Vol 35 (2) ◽  
pp. 665-669 ◽  
Author(s):  
D. A. Irvine ◽  
D. S. Jayas ◽  
M. G. Britton ◽  
N. D. G. White
Keyword(s):  
Dynamic Friction ◽  
Friction Characteristics

The dynamic friction characteristics of a rapidly sheared granular material applied to the motion of snow avalanches

1993 ◽  
Vol 18 ◽  
pp. 215-220 ◽  
Author(s):  
J.D. Dent
Keyword(s):  
Shear Layer ◽  
Slip Plane ◽  
Flat Surface ◽  
Dynamic Friction ◽  
Friction Characteristics ◽  
Dynamic Friction Coefficient ◽  
Dispersed Particles ◽  
Number Of Layers ◽  
Shear Speed ◽  
Shearing Motion

A numerical simulation of simple two-dimensional shear of round uniform grains is used to investigate the dynamic friction characteristics of the layer of snow at the base of an avalanche. For steady, uniform flow on a uniform flat surface, the dynamic friction coefficient transmitted through the shear array is found as it varies with the shear speed and normal force applied to the top of the shear layer, and the properties of the particles in the shear layer.For this simple model, the flow in the shear layer is found to be independent of the total number of layers in the shear flow. A slip plane is formed along which most of the shearing motion takes places, so that the shear is confined to just two layers of particles which slide over one another. In the absence of gravity this slip plane jumps up and down randomly within the shear layer, which is otherwise composed of agitated semi-dispersed particles.

Model-Based Investigation of Friction During Start-Up of Hydrodynamic Journal Bearings

1995 ◽  
Vol 117 (4) ◽  
pp. 667-673 ◽  
Author(s):  
A. Harnoy
Keyword(s):  
Friction Model ◽  
Journal Bearings ◽  
Time Variable ◽  
Stribeck Curve ◽  
Dynamic Friction ◽  
Stick Slip ◽  
Friction Characteristics ◽  
Start Up ◽  
Variable Friction ◽  
Steady Velocity

An analysis is developed for the time-variable friction during the start-up of a rotor system. The analysis is based on a dynamic friction model that has been developed from the theory of unsteady lubrication and can describe the observed friction characteristics. The model reduces to the Stribeck curve of friction versus steady velocity, and shows hysteresis curves in oscillating velocity. The “Dahl effect” of a presliding displacement before the breakaway is also included. The results indicate that the friction characteristics and energy friction losses, during the start-up, depend on a set of dimensionless parameters that represent the bearing as well as the dynamic system. The study shows that appropriate design and operation can prevent stick-slip friction and minimize wear during start-up.

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