Molecular dynamics simulations of mixed lubrication with smooth particle post-processing

Area of Science:

• Tribology
• Computational Materials Science
• Nanotechnology

Background:

• Understanding nanotribological phenomena is crucial for designing advanced materials and devices.
• Existing molecular dynamics (MD) simulation methods face challenges in accurately capturing solid-solid contact and friction under lubrication.

Purpose of the Study:

• To propose and validate a novel post-processing method for MD simulations of friction.
• To introduce and evaluate the solid-solid contact area in nanotribological systems.
• To investigate the relationship between friction force and load in lubricated systems.

Main Methods:

• Developed a post-processing method based on the smooth particle approach for MD simulations.
• Performed numerous MD calculations on lubricated nanotribological systems with varying asperity geometries.
• Systematically varied the number of lubricant molecules in the simulations.

Main Results:

• The proposed method successfully introduces and evaluates the solid-solid contact area due to asperity interaction.
• Friction force as a function of load closely follows a three-parameter friction law.
• The observed friction law includes adhesion-controlled, load-controlled, and load-independent offset terms.

Conclusions:

• The developed post-processing method is feasible and effective for simulating nanotribological friction.
• The findings provide a more comprehensive understanding of friction mechanisms at the nanoscale.
• The three-parameter friction law offers a robust model for predicting friction behavior in lubricated systems.