A molecular dynamics study on water lubrication of amorphous cotton fiber sliding against chromium

Abstract

This study investigates the influence of sliding velocity and loading on the friction of chromium and amorphous cotton fibers using water molecules act as lubricants via molecular dynamics simulation. It is found that the movement of water molecules between the contact interfaces is mainly along the sliding-direction not than the loading-direction during the sliding process. The high sliding velocity or large loading will reduce the lubricating properties of water molecules and increase the average coefficient of friction in the stabilization. The sliding time before the stabilization increase with sliding velocity while decreases with loading. Moreover, the water-lubricants can reduce the damage to chromium, and the increase of sliding velocity is more easy to cause the damage than loading, so it is more important to choose a right sliding velocity.

Friction Properties of Crystalline Cellulose Sliding on Chromium under Water Lubrication Based on Molecular Dynamics Simulations

“…All of the simulations are performed by Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), which is an open-source code for MD simulation, and then the software OVITO is used for visualization . The interactions among different atoms are described by the reactive force field (ReaxFF) developed by Shin et al, which is in agreement with Yan et al , and Fan et al…”

“…Because of their structural characteristics, crystalline and amorphous cellulose have different properties and need to be studied separately. In this study, crystalline cellulose is used as the object because amorphous cellulose has been discussed …”

“…The environment of molecular dynamics (MD) simulations is more extensive, and it can compensate for experimental shortcomings and show the friction and wear mechanism at the atomic level. − Pan et al , and Hao et al investigated the friction properties between Fe and polytetrafluoroethylene (PTFE) by combining experimental and MD simulations and, more importantly, confirmed the correctness and reliability of MD simulations on friction and wear. At the same time, using MD simulations to study the properties of cellulose − and water acting as lubricants to reduce friction and wear − is still valid and feasible. Besides this, it is also effective for the simulation of surfaces and interfaces of metals and steel .…”

“…The study is to investigate the friction and wear of crystalline cellulose and Cr using water as a lubricant by MD simulations, considering the factors of loading ( F n ) and sliding velocity ( v x ). However, using a smooth surface ,, is imperfect because it is almost non-existent in the real world. A rough surface of Cr was used in this study, which can lead to more serious friction and wear of cellulose and Cr but is closer to the real friction compared to a smooth surface.…”

“…At the same time, using MD simulations to study the properties of cellulose 32−38 simulation of surfaces and interfaces of metals and steel. 42 Yan et al 7,8 studied the dry friction of crystalline and amorphous cellulose with chromium (Cr), and Fan et al 41 analyzed the friction of amorphous cellulose with Cr using water act as a lubricant, with the results showing that water as a lubricant can effectively reduce the friction between amorphous cellulose and Cr. It is not enough to study only amorphous cellulose to investigate the lubricating friction of cellulose and Cr; crystalline cellulose must also be studied.…”