scholarly journals Velocity dependence of kinetic friction in the Prandtl-Tomlinson model

2011 ◽  
Vol 84 (12) ◽  
Author(s):  
Martin H. Müser
Keyword(s):  
Kinetic Friction ◽  
Velocity Dependence ◽  
Tomlinson Model

Atomistic Origins of Friction

2019 ◽  
pp. 348-388
Author(s):  
C. Mathew Mate ◽  
Robert W. Carpick
Keyword(s):  
Atomic Structure ◽  
Real Life ◽  
Static Friction ◽  
Electronic Excitations ◽  
Kinetic Friction ◽  
Dynamic Simulations ◽  
Tomlinson Model ◽  
Current State ◽  
Friction Models ◽  
Kontorova Model

This chapter covers the current state of knowledge about how the shear strength (the force needed to slide one surface over another) originates at the atomic level. For adhesive friction, friction originates from the forces needed to move the atoms on one surface over the atomic structure of the opposing surface; the simplest model for adhesive friction is the cobblestone model. The Frenkel–Kontorova model, the Prandtl–Tomlinson model, and molecular dynamic simulations are typically used to show how the atomic structure of the surfaces leads to static friction. One exciting aspect of these friction models is the prediction of superlubricity or negligible friction for incommensurate sliding surfaces, which is now being realized in experiments. Also discussed is why superlubricity is not observed in real-life situations. As atoms and molecules slide over surfaces, kinetic friction originates from phonon and electronic excitations, which are typically studied using the quartz crystal microbalance (QCM).

Numerical Investigation of Atomic Scale Kinetic Friction in Ambient Condition With a Novel Extended Prandtl-Tomlinson Model

2014 ◽  
Author(s):  
Birahima Gueye ◽  
Chenfei Sun ◽  
Yan Zhang ◽  
Yujuan Wang ◽  
Yunfei Chen
Keyword(s):  
Relative Humidity ◽  
Adhesion Force ◽  
Normal Load ◽  
Analytical Data ◽  
Two Dimensions ◽  
Atomic Scale ◽  
Kinetic Friction ◽  
Capillary Bridge ◽  
Mode Operation ◽  
Tomlinson Model

A more adequate extended Prandtl-Tomlinson model in two dimensions (2D) analysis is proposed in the aim to thoroughly investigate the interplay between kinetic friction, relative humidity (RH), normal load, and temperature in both contact and tapping mode atomic force microscopic (AFM). In contact mode operation, results firstly show that for various applied normal loads highly wetted surface in contrast to partially wetted surface exhibits lower friction at finite temperature range. This phenomenon is attributed to the film layer acting as a lubricant. Secondly, two different regimes when varying the relative humidity were further observed with increasing temperature. The first one shows the thermolubricity’s effect at low RH (RH 20%) while the second regime remarkably confirms an increase of friction with temperature at higher RH (RH60%) which is inconsistent with common observation. The latter regime is characterized by the thermally activated capillary bridge formation leading to an increase of the total adhesion force. Thirdly we demonstrated that both regimes also hold in ac mode operation and regardless to the humidity level, either low or high RH, friction force decreases with increasing amplitude modulation. Good agreement was found with measurement and analytical data reported previously. In the model treatment, however, only effects of capillary force which dominate in AFM measurement were considered.

scholarly journals Atomic simulations of kinetic friction and its velocity dependence atAl∕Alandα−Al2O3∕α−Al2O3interfaces

2005 ◽  
Vol 72 (4) ◽  
Author(s):  
Qing Zhang ◽  
Yue Qi ◽  
Louis G. Hector ◽  
Tahir Çağın ◽  
William A. Goddard
Keyword(s):  
Kinetic Friction ◽  
Velocity Dependence ◽  
Atomic Simulations

scholarly journals The Non-Stationary Metal Vapour Arc

1973 ◽  
Vol 28 (3-4) ◽  
pp. 428-437
Author(s):  
G. Ecker
Keyword(s):  
Residence Time ◽  
Critical Currents ◽  
Theoretical Studies ◽  
Velocity Dependence ◽  
Metal Vapour ◽  
Energy Characteristics ◽  
Upper Limit ◽  
Physical Background ◽  
Experimental And Theoretical Studies ◽  
Spot Motion

AbstractThe motion is depicted as a sequence of steps of a finite residence time.The spot motion affects essentially only the energy characteristics Te which in comparison to the stationary characteristics Tes are shifted to smaller values. Hereby the critical currents I0, I1 are raised in comparison to the corresponding stationary limits I0s, I1s. Particularly attractive are the phenomena found in connection with the dependence of the spot velocity ʋ on the spot current I. If the spot velocity increases with the spot current stronger than ʋ ∞ I1/2 then the E-diagram reveals the existence of an upper limit lu for the spot current. This result can be used to explain qualitatively the experimentally observed phenomena of "spot multiplicity" and “spot extinction”.Quantitative conclusions are obstructed by the lack of knowledge about the velocity dependence on the spot current, ʋ(I). Experimental and theoretical studies to provide a better understanding of the physical background and the analytical laws describing the motion of the cathode spots are urgently needed.

scholarly journals Frictional properties of anorthite (feldspar): implications for the lower boundary of the seismogenic zone

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Koji Masuda
Keyword(s):  
Dominant Role ◽  
Lower Boundary ◽  
Earthquake Magnitude ◽  
Seismogenic Zone ◽  
Effective Pressure ◽  
Velocity Dependence ◽  
Brittle Deformation ◽  
Frictional Properties ◽  
Depth Extent ◽  
Mineral Constituents

Abstract Earthquake magnitude is closely related to the depth extent of the seismogenic zone, and higher magnitude earthquakes occur where the seismogenic zone is thicker. The frictional properties of the dominant mineral constituents of the crust, such as feldspar-group minerals, control the depth extent of the seismogenic zone. Here, the velocity dependence of the steady-state friction of anorthite, the calcic endmember of the feldspar mineral series, was measured at temperatures from 20 to 600 °C, pore pressures of 0 (“dry”) and 50 MPa (“wet”), and an effective pressure of 150 MPa. The results support previous findings that the frictional properties of feldspar play a dominant role in limiting the depth extent of the seismogenic zone. This evidence suggests that brittle deformation of anorthite may be responsible for brittle fault movements in the brittle–plastic transition zone.

Press velocity dependence in nanoimprint lithography

2004 ◽  
Author(s):  
T. Yoshikawa ◽  
N. Takagi ◽  
T. Kanakugi ◽  
H. Schulz ◽  
H.-C. Scheer ◽  
...  
Keyword(s):  
Nanoimprint Lithography ◽  
Velocity Dependence
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