Molecular dynamics simulation of surface energy and ZDDP effects on friction in nano-scale lubricated contacts

Berro, Hassan; Fillot, Nicolas; Vergne, Philippe

doi:10.1016/j.triboint.2010.02.011

Cited by 100 publications

(129 citation statements)

References 20 publications

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“…The function of many lubricant additives depends on chemical reactions, which are generally not considered in classical MD simulations. Despite this, classical MD simulations have given unique insights into the behaviour of a range of lubricant additives including detergents [207,208], dispersants [209,210], viscosity modifiers [91,92,211], anti-wear additives [212][213][214][215], and corrosion inhibitors [216][217][218]. The most widely studied class of lubricant additives with MD are friction modifiers [219], which are a wellsuited application of confined NEMD simulations.…”

Section: Nemd Simulations Of Lubricant Additivesmentioning

confidence: 99%

Advances in nonequilibrium molecular dynamics simulations of lubricants and additives

2018

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Nonequilibrium molecular dynamics (NEMD) simulations have provided unique insights into the nanoscale behaviour of lubricants under shear. This review discusses the early history of NEMD and its progression from a tool to corroborate theories of the liquid state, to an instrument that can directly evaluate important fluid properties, towards a potential design tool in tribology. The key methodological advances which have allowed this evolution are also highlighted. This is followed by a summary of bulk and confined NEMD simulations of liquid lubricants and lubricant additives, as they have progressed from simple atomic fluids to ever more complex, realistic molecules. The future outlook of NEMD in tribology, including the inclusion of chemical reactivity for additives, and coupling to continuum methods for large systems, is also briefly discussed.

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Section: Nemd Simulations Of Lubricant Additivesmentioning

confidence: 99%

Advances in nonequilibrium molecular dynamics simulations of lubricants and additives

2018

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“…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%

“…19 Further, the branched alkanes remain more liquid-like in confinement as compared to linear ones and yield an increase in shear stresses. 20 With regards to the influence of the tribo-pair, the surface morphology 14,15 and the wall-fluid adhesion strength 9,20 have been shown to play the vital roles. High surface corrugation results in a reduction of inplane ordering of lubricant, interfacial slip, and consequently increases the friction of tribological systems.…”

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

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. (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)

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“…rigid layers shown in (a), so that the lubricant is sheared. This sliding velocity conduction has been widely used in MD simulations of thin film lubrication as it enables the simulation to obtain a required sliding distance within a reasonable calculation time [37,38,52,54]. In addition, the constant velocity mode makes it easy to record the friction forces.…”

Section: Molecular Model Of Lubricant Systemmentioning

confidence: 99%

“…A wide range of potentials have been adopted in MD simulations in tribology community. For example, the simple ideal springs [52,61] and sine-wave potentials are often used. Another potential function, the L-J potential [54,62], gives a realistic representation of typical inter-atomic interactions.…”

Section: Liquid-solid Interactions and Other Non-bonded Interactionsmentioning

confidence: 99%

Multiscale modeling and simulation of rolling contact fatigue

Gharehbagh

Ali

2018

International Journal of Fatigue

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iii ABSTRACT In this thesis, a hierarchical multiscale method was developed to predict rolling contact fatigue lives of mechanical systems. In the proposed multiscale method, the molecular modeling and simulation of lubricant was conducted to investigate the friction between rolling contact surfaces. The calculated friction coefficient was passed to the continuum model of rolling contact components to predict fatigue lives.Molecular dynamics modeling and simulation of thin film lubrication and lubricated contact surfaces were carried out to investigate mechanisms of hydrodynamic lubrication at nano-scale first. Although various lubricant alkane chains were considered in the molecular model, the chain length of eight united molecules were mainly employed in this thesis. In addition, the effects of temperature and nano-particles (debris) on the friction forces were discussed. It was found that the existing of nano-particles (debris) could increase the friction force between contact surfaces with hydrodynamic lubrication.In the continuum model of the developed multiscale method, finite element analysis was employed to predict rolling contact fatigue life of rolling contact components, including bearing and gear-tooth. Specifically, the fatigue crack initiation of bearing was studied, and then the fatigue crack initiation and propagation in gear-tooth. In addition, the enhancement of gear-tooth fatigue life by using composite patches was discussed as well. It should be noted that the friction coefficient used in the continuum model was calculated in the molecular model. It is one-way message passing in iv the developed multiscale method.Another continuum method was studied and developed in this thesis to provide alternate methods for the continuum model in the proposed multiscale framework.Peridynamics method has advantages in modeling and simulation of discontinuities, including cracks, over the conventional finite element methods. The applications of Peridynamics in predicting fatigue crack initiation and propagation lives were discussed in this thesis. v PUBLIC ABSTRACTThis research aims to develop a hierarchical multiscale method to predict rolling contact fatigue lives of mechanical systems. In the proposed multiscale method, the molecular modeling and simulation of lubricant was conducted to investigate the friction between rolling contact surfaces. The calculated friction coefficient was passed to the continuum model of rolling contact components to predict fatigue lives.Molecular dynamics modeling and simulation of thin film lubrication and lubricated contact surfaces were carried out to investigate mechanisms of hydrodynamic lubrication at nano-scale first. In addition, the effects of temperature and nano-particles (debris) on the friction forces were discussed. It was found that the existing of nanoparticles (debris) could increase the friction force between contact surfaces with hydrodynamic lubrication.In the continuum model of the developed multiscale method, finite element analysis was employed to pred...

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Molecular dynamics simulation of surface energy and ZDDP effects on friction in nano-scale lubricated contacts

Cited by 100 publications

References 20 publications

Advances in nonequilibrium molecular dynamics simulations of lubricants and additives

Advances in nonequilibrium molecular dynamics simulations of lubricants and additives

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

Multiscale modeling and simulation of rolling contact fatigue

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