scholarly journals The contribution of plastic sink-in to the static friction of single asperity microscopic contacts

2021 ◽  
Vol 477 (2256) ◽  
Author(s):  
Owen Brazil ◽  
John B. Pethica ◽  
George M. Pharr
Keyword(s):  
Sliding Friction ◽  
Dynamic Range ◽  
Surface Force ◽  
Static Friction ◽  
Fused Silica ◽  
Metallic Substrates ◽  
Interfacial Sliding ◽  
Friction Regime ◽  
Interface Sliding ◽  
Contact Pressures

We report microscale friction experiments for diamond/metal and diamond/silica contacts under gigapascal contact pressures. Using a new nanoprobe technique that has a sufficient dynamic range of force and stiffness, we demonstrate the processes involved in the transition from purely interface sliding at the nanoscale to the situation where at least one of the sliding bodies undergoes some plastic deformation. For sliding of micrometre-sized tips on metallic substrates, additional local plastic yielding of the substrate resulting from tangential tractions causes the tip to sink into the surface, increasing the contact area in the direction of loading and resulting in a static friction coefficient higher than the kinetic during ploughing. This sink-in is largely absent in fused silica, and no friction drop is observed, along with lower friction in general. The transition from sink-in within the static friction regime to ploughing in the sliding friction regime is mediated by failure of the contact interface, indicated by a sharp increase in energy dissipation. At lower contact pressures, the elastic interfacial sliding behaviour characteristic of scanning probe or surface force apparatus experiments is recovered, bridging the gap between the exotic realm of nanotribology and plasticity-dominated macroscale friction.

Shear-induced lamellar ordering and interfacial sliding in amorphous carbon films: A superlow friction regime

2011 ◽  
Vol 514 (4-6) ◽  
pp. 325-329 ◽  
Author(s):  
Tian-Bao Ma ◽  
Yuan-Zhong Hu ◽  
Liang Xu ◽  
Lin-Feng Wang ◽  
Hui Wang
Keyword(s):  
Amorphous Carbon ◽  
Carbon Films ◽  
Amorphous Carbon Films ◽  
Interfacial Sliding ◽  
Friction Regime

Adhesion Force Between High Energy Surfaces in Vapor Atmosphere

1994 ◽  
Vol 366 ◽  
Author(s):  
Jerome Crassous ◽  
Jean-Luc Loubet ◽  
Elisabeth Charlaix
Keyword(s):  
Liquid Bridge ◽  
Adhesion Force ◽  
Van Der Waals ◽  
Surface Force ◽  
High Energy ◽  
Attractive Force ◽  
Experimental Measurements ◽  
Metallic Substrates ◽  
Energy Surfaces ◽  
Good Agreement

ABSTRACTWe report experimental measurements of the adhesion force between metallic substrates in undersaturated heptane vapor atmosphere, with a surface force apparatus. The attractive force between the substrates is strongly dependant of the condensation of a liquid bridge connecting the surfaces. The results show the importance of wetting phenomena for the maximum attractive force: we find that this maximum attraction varies as the power two-third of the curvature of the meniscus connecting the surfaces, in good agreement with the theory of Van der Waals wetting.

scholarly journals Calculation and AFM Experimental Research on Slip Friction for Unlubricated Spherical Contact with Roughness Effect

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1428
Author(s):  
Shengguang Zhu ◽  
Liyong Ni
Keyword(s):  
Friction Force ◽  
Sliding Friction ◽  
Static Friction ◽  
Friction Model ◽  
Rigid Sphere ◽  
Roughness Effect ◽  
Force Microscopy ◽  
Comparison Results ◽  
Experimental Values ◽  
Calculation Models

Previous research on friction calculation models has mainly focused on static friction, whereas sliding friction calculation models are rarely reported. In this paper, a novel sliding friction model for realizing a dry spherical flat contact with a roughness effect at the micro/nano scale is proposed. This model yields the sliding friction by the change in the periodic substrate potential, adopts the basic assumptions of the Greenwood–Williamson random contact model about asperities, and assumes that the contact area between a rigid sphere and a nominal rough flat satisfies the condition of interfacial friction. It subsequently employs a statistical method to determine the total sliding friction force, and finally, the feasibility of this model presented is verified by atomic force microscopy friction experiments. The comparison results show that the deviations of the sliding friction force and coefficient between the theoretical calculated values and the experimental values are in a relatively acceptable range for the samples with a small plasticity index (Ψ ≤ 1).

Collision of two coins on a horizontal surface

2021 ◽  
Vol 57 (1) ◽  
pp. 015009
Author(s):  
Rod Cross
Keyword(s):  
Friction Force ◽  
Sliding Friction ◽  
Static Friction ◽  
Video Camera ◽  
Horizontal Surface ◽  
Collision Process ◽  
Oblique Angle ◽  
Billiard Ball ◽  
Air Table

Abstract Oblique angle collisions of two penny coins on a smooth, horizontal surface were filmed with a video camera to investigate the physics of the collision process. If one of the coins is initially at rest, then the two coins emerge approximately at right angles, as commonly observed in billiard ball collisions and in puck collisions on an air table. The coins actually emerged at an angle less than 90 degrees due to friction between the coins, which also resulted in both coins rotating after the collision. At glancing angles, the friction force was due to sliding friction. At other angles of incidence the coins gripped each other and the friction force was then due to static friction.

Influence of Water Absorption on Static Friction of Pure and Friction-Modified PA6 Polymers

2019 ◽  
Vol 799 ◽  
pp. 59-64
Author(s):  
Igor Velkavrh ◽  
Stefan Klien ◽  
Joel Voyer ◽  
Florian Ausserer ◽  
Alexander Diem
Keyword(s):  
Water Absorption ◽  
Static Friction ◽  
Polyamide 6 ◽  
Coated Steel ◽  
Friction Modifiers ◽  
Test Conditions ◽  
Influence Of Water ◽  
Steel Surfaces ◽  
Contact Pressures ◽  
Lubrication Conditions

In the present study, static coefficients of friction of pure and friction modified (FM) polyamide 6 (PA6) polymers against primer-coated steel surfaces were investigated under a series of nominal contact pressures and by considering the influences of water absorption by the polymer, temperature, counter-body surface roughness and lubrication conditions. Under the majority of the test conditions investigated, FM PA6 exhibited lower static friction than pure PA6. Under unlubricated conditions, this was due to the low adhesion of the FM PA6 provided by its friction modifying inclusions; while under lubricated conditions, a combination of softening due to water absorption and decreased adhesion provided by its friction modifiers enabled lower static friction, especially at medium and high contact pressures.

Interfacial Shear Behavior of Sapphire-Reinforced NiAi Composites

1990 ◽  
Vol 194 ◽  
Author(s):  
C. A. Moose ◽  
D. A. Koss ◽  
J. R. Hellmann
Keyword(s):  
Sliding Friction ◽  
Fiber Diameter ◽  
Friction Stress ◽  
Shear Behavior ◽  
Interfacial Shear ◽  
Interface Failure ◽  
Test Technique ◽  
Large Variability ◽  
Interfacial Sliding ◽  
Shear Process

AbstractThe interfacial shear behavior in near-equiatomic NiA1 reinforced by sapphire filaments has been examined at room temperature using a fiber pushout test technique. The loaddisplacement data indicate a large variability in the initial interface failure stress, although reverse push behavior indicates a comparatively constant interfacial sliding friction stress. The observed behavior suggests that the presence of asperities on the fiber surfaces and nonuniformities in fiber diameter require constrained plastic flow within the NiAl matrix in order for interfacial shear to occur. The location, shape, severity, and distribution of fiber asperities as well as the uniformity of fiber diameter are critical to the interfacial shear process.

Scale-dependent nanomechanical behavior and anisotropic friction of nanotextured silicon surfaces

2009 ◽  
Vol 24 (10) ◽  
pp. 3038-3043 ◽  
Author(s):  
Hanshen Zhang ◽  
Kyriakos Komvopoulos
Keyword(s):  
Sliding Friction ◽  
Adhesion Force ◽  
Normal Load ◽  
Ion Beam ◽  
Strong Dependence ◽  
Surface Texturing ◽  
Surface Force ◽  
Silicon Surfaces ◽  
Real Contact Area ◽  
Ripple Orientation

Nanoscale surface texturing of silicon was accomplished by oblique Ar+ ion beam irradiation. Atomic force microscope (AFM) imaging showed that nanotexturing produced an anisotropic morphology consisting of ordered nanometer-sized ripples. Surface force microscope (SFM) measurements showed that the nanotextured surface exhibited scale-dependent nanomechanical behavior during indentation loading/unloading and anisotropic sliding friction, significantly different from those of the original (untextured) surface. AFM and SFM results showed a strong dependence of the nanoindentation response and friction coefficient on the tip radius and sliding direction relative to the ripple orientation. The observed experimental trends are interpreted in terms of the applied normal load, real contact area, interfacial adhesion force, tip-ripple interaction scale, and ripple orientation.

scholarly journals Critical shoe contact area ratio for sliding on a tennis hard court

2017 ◽  
Vol 232 (2) ◽  
pp. 112-121 ◽  
Author(s):  
John Eric Goff ◽  
Luke Boswell ◽  
Daniel Ura ◽  
Mark Kozy ◽  
Matt J Carré
Keyword(s):  
Friction Coefficient ◽  
Contact Area ◽  
Sliding Friction ◽  
Static Friction ◽  
Area Ratio ◽  
Critical Ratio ◽  
Static Friction Coefficient ◽  
The Creation ◽  
Contact Area Ratio

Dimples have been used in the design of some modern tennis shoe outsoles to enhance sliding ability on hard courts. Experiments were performed with bespoke rubber samples possessing various numbers of holes, which served to simulate dimples in tennis shoe treads. The aim of the research was to assess the effect of contact area on sliding friction. As the ratio of holes to solid rubber increased, a critical ratio was reached whereby the static friction coefficient decreased by more than 11% for tread-to-court pressures comparable to real tennis play. Although this study analyzed bespoke rubber samples and not actual tennis shoe treads, shoe manufacturers should be interested in the existence of a critical dimple ratio that could aid them in the creation of tennis shoes suited for sliding on hard courts.

AFM Interaction Forces of Lubricity Materials Surface

2012 ◽  
Vol 528 ◽  
pp. 95-98
Author(s):  
Xue Feng Li ◽  
Chu Wu ◽  
Shao Xian Peng ◽  
Jian Li
Keyword(s):  
Atomic Force Microscopy ◽  
Friction Force ◽  
Sliding Friction ◽  
Static Friction ◽  
Adhesive Force ◽  
New Method ◽  
Interaction Forces ◽  
Scanning Angle ◽  
Force Microscopy ◽  
Atomic Force

Micro interaction forces of lubricity surface of silicon and mica were studied using atomic force microscopy (AFM). From different scanning angle and bisection distance of the AFM, a new method of measuring micro static friction of lubricity surface materials was investigated. Results show that the micro coefficients of static and sliding friction of mica are less than the silicon, but the adhesive force is bigger. The mechanism of friction force of the two lubricity materials was discussed.

scholarly journals Adequate Force Characteristics of a Friction System

2013 ◽  
Vol 13 ◽  
pp. 20-36
Author(s):  
Zdzisław Pluta ◽  
Tadeusz Hryniewicz
Keyword(s):  
Sliding Friction ◽  
Static Friction ◽  
The Body ◽  
Friction Process ◽  
New Knowledge ◽  
Mechanical Behaviours ◽  
Adequate Definition ◽  
Definition Of ◽  
Inertia Forces ◽  
Force Characteristics

In the paper, at first some remarks concerning friction are presented by the definition of the friction itself, as well as its essential force characteristics. An adequate definition of friction is introduced, and moreover a correct its characteristics. Next the statics, dynamics, and kinematics of the friction system is given, forming the force characteristics of this system for each of the mechanical behaviours, taking into account real inertia forces of the body under friction. Three types of coefficients of sliding friction have been separated, namely: coefficient of static friction, dynamic friction, and kinematic friction. Then the comparative analysis of existent and new knowledge on the force characteristics of friction process has been presented. The consideration on how to determine the coefficient of static friction has also been carried out. Reflections on the possibilities to form further force characteristics of the friction process are presented to develop this work with some final remarks directing the attention on the conditions of development of science on friction.

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