Experimental Investigation on the Stick-Slip Phenomenon in Granular Collision Lubrication

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Karim N. Elkholy ◽  
M. M. Khonsari
Keyword(s):  
Experimental Investigation ◽  
Friction Coefficient ◽  
Granular Materials ◽  
Applied Load ◽  
Stick Slip ◽  
Shear Cell ◽  
Parallel Disks ◽  
Sliding Motion ◽  
Annular Shear Cell ◽  
Slip Phenomenon

An investigation on the nature of stick-slip associated with granular materials sheared between two parallel disks within the context of granular lubrication is presented. Experiments are carried out in an annular shear cell apparatus to demonstrate the effect of the stick-slip on the friction coefficient. Results are presented for the friction coefficient and the displacement as a function of the rotational speed and the applied load. The results reveal the occurrence of stick-slip at low speed and provided further evidence for the formation of granular lift between two disks undergoing sliding motion.

Granular Collision Lubrication: Experimental Investigation and Comparison to Theory

2007 ◽  
Vol 129 (4) ◽  
pp. 923-932 ◽  
Author(s):  
Karim N. Elkholy ◽  
M. M. Khonsari
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Friction Coefficient ◽  
Kinetic Theory ◽  
Rotational Speed ◽  
Applied Load ◽  
Vertical Displacement ◽  
Shear Cell ◽  
Sliding Motion ◽  
Annular Shear Cell

An experimental investigation of the friction and lift characteristics of granular lubrication is presented. Experiments are carried out to demonstrate the vertical displacement (lift) observed in an annular shear cell apparatus. Results are presented for the friction coefficient as a function of the rotational speed and the applied load for several surface roughness combinations. Simulations of the kinetic theory for the granular material are performed and compared to the experimental results. The experiments provide an evidence for the formation of granular lift between two disks undergoing sliding motion.

scholarly journals Tribological functionalization of titanium alloys by Micro-Arc Oxidation for marine applications

2020 ◽  
Vol 321 ◽  
pp. 09001
Author(s):  
Aude MATHIS ◽  
Thierry MILLOT ◽  
Vincent BRANGER ◽  
Remy MULLER ◽  
Jean-Yves GUENEHEUX
Keyword(s):  
Friction Coefficient ◽  
Titanium Alloys ◽  
Pure Titanium ◽  
Dynamic Contact ◽  
Electrochemical Process ◽  
Commercially Pure Titanium ◽  
Tribological Behaviour ◽  
Stick Slip ◽  
Micro Arc Oxidation ◽  
Slip Phenomenon

Micro-arc Oxidation (MAO) process is a plasma assisted electrochemical process, which allows formation of ceramic-like dry oxides on top of light alloys surfaces. The good corrosion resistance as well as the low density of titanium alloys are recognized and so required for conception of structural parts in marine environment. However, their tribological behaviour reveals an important tendency to stick-slip phenomenon, which makes use of these alloys for dynamic contact mechanisms difficult. Through the MAO project from IRT M2P, formation of a MAO coating composed of aluminium titanate has been investigated to improve tribological behaviour of a commercially pure titanium (Grade 2) and an α+β alloy (TA6V, Grade 5). Pin-on-disc testing has been carried out to evaluate friction coefficient and the presence or not of stick-slip phenomenon in various contact configurations (involving non-treated titanium surfaces, MAO treated surfaces, with steel or titanium balls …) in dry or artificial seawater media. Those test campaigns are completed by evaluation of fatigue behaviour, and tribological testing on a demonstrator. Finally, this study highlights influence of MAO coating on diminishing (to removed) stick-slip phenomenon, accompanied by a reduction of friction coefficient, whatever the kind of contact (single treated surface or both ones) and the medium.

Mixed Lubrication of “Parallel” Plane Sliders

1972 ◽  
Vol 39 (1) ◽  
pp. 36-40
Author(s):  
D. S. Bedi ◽  
M. J. Hillier
Keyword(s):  
Theoretical Model ◽  
Friction Coefficient ◽  
Critical Speed ◽  
Mixed Lubrication ◽  
Parallel Plane ◽  
Stick Slip ◽  
Lubrication Conditions ◽  
Film Lubrication ◽  
Slip Phenomenon ◽  
Fluid Film Lubrication

A theoretical model for the friction coefficient indicates two critical speeds of sliding. The lower critical speed corresponds to a change-over from boundary to mixed lubrication conditions, the higher critical speed a transition to full fluid-film lubrication at angles of inclination less than 0.01 deg. The first critical speed appears to be associated with the “stick-slip” phenomenon.

scholarly journals The effect of laser surface texturing to inhibit stick-slip phenomenon in sliding contact

2019 ◽  
Vol 11 (9) ◽  
pp. 168781401987463
Author(s):  
Hao Wang ◽  
Xuan Xie ◽  
Xijun Hua ◽  
Bifeng Yin ◽  
Hang Du ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Friction Coefficient ◽  
Machine Tools ◽  
Laser Surface Texturing ◽  
Lubricating Oil ◽  
Textured Surface ◽  
Slip Effect ◽  
Stick Slip ◽  
Adequate Amount ◽  
Slip Phenomenon

Stick-slip phenomenon in some mechanical structures, especially in machine tools, should be eliminated or inhibited, otherwise the vibration will occur and the position error will inevitably be obtained. In this study, different kinds of surface textures were carried out on the lower samples of the pin-on-disk contact. The starting process of the machine tools was simulated on an Rtec-Multi-Function Tribometer. The stick-slip phenomenon was observed in each kind of samples. However, the stick-slip phenomenon of smooth sample is larger than that of the textured samples. The bulge-textured surface shows excellent anti-stick-slip effect, and the critical stick-slip speed of bulge-textured surface is 95.9% lower than that of the smooth surface. Simultaneously, the anti-stick-slip effect of bulge-textured surface is superior to that of the dent-shaped texturing surface. What’s more, when the amount of lubricating oil is 15 mL, the standard deviation values of friction coefficient and critical speed of stick-slip phenomena (rotational speed when the standard deviation of friction coefficient is abrupt) are the lowest at different rotational speeds. It can be predicted that the bulge textures and adequate amount of lubricating oil (15 mL) can eliminate stick-slip phenomenon when processed in the surface of the machine tool because the bulge textures and adequate amount of lubricating oil can improve frictional state effectively and avoid the slip of the contact surface.

scholarly journals THEORETICAL AND EXPERIMENTAL STUDIES ON SLIDING AT LOW SPEEDS WITH INTERMITTENCIES

2020 ◽  
Vol 20 (3) ◽  
pp. 767-774
Author(s):  
IVONA CAMELIA PETRE ◽  
ELENA VALENTINA STOIAN ◽  
MARIA CRISTIANA ENESCU ◽  
VERONICA DESPA
Keyword(s):  
Theoretical Model ◽  
Experimental Studies ◽  
Machine Building ◽  
Kinetic Friction ◽  
Stick Slip ◽  
Flat Surfaces ◽  
Sliding Motion ◽  
Steel Material ◽  
Slip Phenomenon

The guides of the machine tools, brakes, clutches there is the possibility of the intermittent movement of stick-slip. This opens in the case of frictional couples with sliding motion, due to the low sliding speeds. Intermittent slip introduces vibrational phenomena and influences the uniformity of movement and the state of the surface of the couples due to their use. In this respect, the concerns related to the study of this phenomenon represent an interest in the machine building industry. The paper aims to achieve an original theoretical model for calculating the static and kinetic friction coefficients and its experimental verification on a stick-slip stand. The proposed theoretical model establishes the calculation relations of the static and kinetic friction coefficient and the connection between them taking into account the surface processing method. The originality of the approach is that the model is considered friction between the conical penetrator (steel material) and a polymer material. In the literature, the stick-slip phenomenon is approached only in terms of the analysis of flat surfaces. The torques of said materials is frequently used on the parts of sliding machines where this phenomenon is possible. The paper highlights the influence of exploitation factors (load, speed), the processing of surfaces, and the quality of the lubricating liquid on the stick-slip phenomenon, for a friction coupling of polymeric material / metallic material.

scholarly journals Slow and intermittent stress relaxation of biomass granular media

2021 ◽  
Vol 249 ◽  
pp. 08010
Author(s):  
Florent Thevenon ◽  
Bharath Devulapalli ◽  
Muriel Marchand ◽  
Thierry Melkior ◽  
Alain de Ryck
Keyword(s):  
Particle Size ◽  
Stress Relaxation ◽  
Granular Materials ◽  
Granular Media ◽  
Stress History ◽  
Shear Cell ◽  
Powder Bed ◽  
Fast Relaxation ◽  
Annular Shear Cell

In the present work, the relaxation of several wood powders has been investigated in an annular shear cell. It is found that the slow logarithmic relaxation commonly observed for various materials including granular materials is interrupted by large events. Their frequency and amplitude are investigated with respect to particle size and stress-history by measuring stresses and strain. These large events during the relaxation appear to be controlled by the deformation. The coarser the particles are, the bigger is the deformation of the powder bed between two fast relaxation events and during the event.

An annular shear cell for granular materials

1968 ◽  
Vol 1 (6) ◽  
pp. 369-373 ◽  
Author(s):  
J.F. Carr ◽  
D.M. Walker
Keyword(s):  
Granular Materials ◽  
Shear Cell ◽  
Annular Shear Cell
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