Compressibility of Thin Film Lubricants Characterized Using Atomistic Simulation

Martini, Ashlie; Vadakkepatt, Ajay

doi:10.1007/s11249-009-9568-6

Cited by 15 publications

(14 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2(a) indicates a linear correlation between the lubricant density and the applied load, as a higher pressure induces an increase in the density of confined hexadecane. This observation agrees with previous investigations by Martini et al [8,10]. The reduction in film thickness due to the applied pressure ( Fig.…”

Section: Influences Of the Applied Loadsupporting

confidence: 94%

See 1 more Smart Citation

Impact of chosen force fields and applied load on thin film lubrication

Tran

2021

Friction

View full text Add to dashboard Cite

The rapid development of molecular dynamics (MD) simulations, as well as classical and reactive atomic potentials, has enabled tribologists to gain new insights into lubrication performance at the fundamental level. However, the impact of adopted potentials on the rheological properties and tribological performance of hydrocarbons has not been researched adequately. This extensive study analyzed the effects of surface structure, applied load, and force field (FF) on the thin film lubrication of hexadecane. The lubricant film became more solid-like as the applied load increased. In particular, with increasing applied load, there was an increase in the velocity slip, shear viscosity, and friction. The degree of ordering structure also changed with the applied load but rather insignificantly. It was also significantly dependent on the surface structure. The chosen FFs significantly influenced the lubrication performance, rheological properties, and molecular structure. The adaptive intermolecular reactive empirical bond order (AIREBO) potential resulted in more significant liquid-like behaviors, and the smallest velocity slip, degree of ordering structure, and shear stress were compared using the optimized potential for liquid simulations of united atoms (OPLS-UAs), condensed-phase optimized molecular potential for atomic simulation studies (COMPASS), and ReaxFF. Generally, classical potentials, such as OPLS-UA and COMPASS, exhibit more solid-like behavior than reactive potentials do. Furthermore, owing to the solid-like behavior, the lubricant temperatures obtained from OPLS-UA and COMPASS were much lower than those obtained from AIREBO and ReaxFF. The increase in shear stress, as well as the decrease in velocity slip with an increase in the surface potential parameter ζ, remained conserved for all chosen FFs, thus indicating that the proposed surface potential parameter ζ for the COMPASS FF can be verified for a wide range of atomic models.

show abstract

Section: Influences Of the Applied Loadsupporting

confidence: 94%

“…Hexadecane lubricant, which is widely used in many tribological systems, has been analyzed in several theoretical studies over the last two decades, particularly in studies on steel surfaces [1][2][3][4][5][6][7][8][9][10]. Under confined conditions, thin hexadecane film behaves differently from its bulk form.…”

Section: Introductionmentioning

confidence: 99%

Impact of chosen force fields and applied load on thin film lubrication

Tran

2021

Friction

View full text Add to dashboard Cite

show abstract

“…Over the last two decades, there have been extensive studies of thin film lubrication of alkane between metal tribo-pairs using molecular dynamics (MD) method. [4][5][6][7] Attempts have been made to assess the role of Fe 2 O 3 (001) surfaces in thin film lubrication; [8][9][10] however, a thorough understanding of tribological and structural properties of hexadecane on different iron and iron oxides surfaces as well as their surface orientations is still missing. Additionally, previous investigations employed a simple model, in which each methyl or methylene group was described using a united-atom (UA) model and tribo-surfaces were modeled by harmonic spring without the consideration of electrostatic contribution.…”

Section: Introductionmentioning

confidence: 99%

Thin film lubrication of hexadecane confined by iron and iron oxide surfaces: A crucial role of surface structure

Zhu

Kosasih

2015

The Journal of Chemical Physics

View full text Add to dashboard Cite

. (2015). Thin film lubrication of hexadecane confined by iron and iron oxide surfaces: A crucial role of surface structure. Journal of Chemical Physics, 143 164702-1-164702-16. Thin film lubrication of hexadecane confined by iron and iron oxide surfaces: A crucial role of surface structure Abstract A comparative analysis of thin film lubrication of hexadecane between different iron and its oxide surfaces has been carried out using classical molecular dynamic simulation. An ab initio force-field, COMPASS, was applied for n-hexadecane using explicit atom model. An effective potential derived from density functional theory calculation was utilized for the interfacial interaction between hexadecane and the tribo-surfaces. A quantitative surface parameterization was introduced to investigate the influence of surface properties on the structure, rheological properties, and tribological performance of the lubricant. The results show that although the wall-fluid attraction of hexadecane on pure iron surfaces is significantly stronger than its oxides, there is a considerable reduction of shear stress of confined n-hexadecane film between Fe(100) and Fe(110) surfaces compared with FeO(110), FeO(111), Fe 2 O 3 (001), and Fe 2 O 3 (012). It was found that, in thin film lubrication of hexadecane between smooth iron and iron oxide surfaces, the surface corrugation plays a role more important than the wall-fluid adhesion strength. A comparative analysis of thin film lubrication of hexadecane between different iron and its oxide surfaces has been carried out using classical molecular dynamic simulation. An ab initio force-field, COMPASS, was applied for n-hexadecane using explicit atom model. An effective potential derived from density functional theory calculation was utilized for the interfacial interaction between hexadecane and the tribo-surfaces. A quantitative surface parameterization was introduced to investigate the influence of surface properties on the structure, rheological properties, and tribological performance of the lubricant. The results show that although the wall-fluid attraction of hexadecane on pure iron surfaces is significantly stronger than its oxides, there is a considerable reduction of shear stress of confined n-hexadecane film between Fe(100) and Fe (110)

show abstract

“…(5) Subscripts i, j, ij atomic index nonbond nonbonding interaction bond, angle, dihed, impro intramolecular interaction [19][20][21][22]. Examples of the few MD studies on liquid compressibility use simple hard-sphere fluid models [23], dissipative particle dynamics investigations [24], coarse-grained bead-spring models, and normal alkane models [2,[25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

“…This phenomenon occurs in thin films regardless of whether the structure of the lubricant molecule is a spherical LJ particle, a short linear chain, a long linear chain, a branched chain or a ring chain [3,26,[29][30][31]. Existing studies always consider the broadening of density profile peaks as their distance from the walls increased [3,29,32].…”

Section: Introductionmentioning

confidence: 99%