Energy dissipation of atomic-scale friction based on one-dimensional Prandtl-Tomlinson model

Abstract

Abstract:The energy transition and dissipation of atomic-scale friction are investigated using the one-dimensional Prandtl-Tomlinson model. A systematic study of the factors influencing the energy dissipation is conducted, indicating that the energy that accumulated during the stick stage does not always dissipate completely during stick-slip motion. We adopt the energy-dissipation ratio (EDR) to describe the relationship between the energy dissipated permanently in the system and the conservative reversible energy that can be reintroduced to the driving system after the slip process. The EDR can change continuously from 100% to 0, covering the stick-slip, intermediate, and smooth-sliding regimes, depending on various factors such as the stiffness, potential-energy corrugation, damping coefficient, sliding velocity, and the temperature of the system. Among these, the parameter η, which depends on both the surface potential and the lateral stiffness, is proven in this paper to have the most significant impact on the EDR. According to η-T phase diagrams of the EDR, the smooth-sliding superlubricity and thermolubricity are found to be unified with regard to the energy dissipation and transition. An analytical formulation for the EDR that can be used to quantitatively predict the amount of energy dissipation is derived from a lateral-force curve.

Thermodynamic aspects of nanoscale friction

“…This led to the discovery of thermolubricity at high temperatures 4-7 , understanding the effect of humidity and oxidation in metals 8 , or revealing positive 4,5, [9][10][11][12][13][14][15][16] or negative 4,5 logarithmic velocity dependence of friction in a selected temperature range. A thermodynamic description of the nanoscale stick-slip motion has been considered recently using the Langevin dynamics-based description of friction 17,18 . The principle inherently relies on the fact that information about the heat and work is naturally contained in the fluctuating trajectory followed by the FFM tip during its sliding motion along the material surface, and could be extracted from it through appropriate thermodynamically consistent mathematical framework applicable to fluctuating systems.…”

Atomic-Scale Friction on Monovacancy-Defective Graphene and Single-Layer Molybdenum-Disulfide by Numerical Analysis

“…The schematic diagrams of the atomic-scale friction of monovacancy-defective graphene and SLMoS2 are shown in Figure 1a,b, respectively. In the atomic-scale friction process, stick-slip behaviors can be explained by the classical PT model, which simplifies the single-asperity friction into one point-mass (tip) pulled along a corrugated potential by a driving support (spring) [16]. The classical PT model is shown as follows:…”

“…This observation can be theoretically reproduced within classical mechanics by using the Prandtl-Tomlinson (PT) model, which describes the movement of a point-like tip connected to a support by a harmonic spring in constant-force mode of an idealized LFM. As the support moves at a constant speed, the tip is dragged by the spring to slide over a whole surface, while at the same time, feeling the force from a corrugated tip-surface interaction potential featuring atomic periodicity [13][14][15][16]. The stick-slip instability occurs when the tip moves through the regions where the curvature of the tip-surface interaction potential exceeds the elastic constant of the pulling spring.…”

Multiscale analysis of friction behavior at fretting interfaces

“…Moreover, friction contact intervals exist as the counter-part of the friction contacts. This is because the friction heat dissipation needs a relaxation period [15][16][17]. Friction contact interval refers to the time period when a certain asperity does not directly contact with or becomes severely deformed by the countersurface asperities and when the force response shows less surface-interactive features.…”