Abstract
Background: In the space environment, microgravity and vacuum influence the mechanical behaviors of the devices. In the microgravity environment, the mechanical components vibrate with a small amplitude once there is a disturbance. The vibration can be seen as a reciprocating sliding contact with a small amplitude. In addition to the vibration, adhesion effects are predominant in a vacuum, which will induce a high friction force.
Objective: To reduce the friction force, textured surfaces are widely used in mechanical engineering on the earth, and nanoscale textures are also verified to be used to improve the frictional behaviors of components in the size of nanometers.
Methods: In this paper, the adhesion effects are considered by using molecular dynamics (MD) simulation, and the microgravity induced vibration is simplified as a reciprocating sliding contact. Coupling MD simulation and the finite element method which is a multiscale method are used to investigate the frictional properties of nanoscale reciprocating sliding contact between rigid multiasperity tips and an isosceles trapezoid textured surface.
Results: Average friction forces for the different tips are presented, and the friction processes are analyzed. A stable friction process is discovered for a specific case, and the average friction force is kept at two stable values corresponding to two sliding directions.
Conclusion: Compared with the total average friction forces of a smooth surface, the textured surface can reduce the friction forces greatly. This work could contribute to the textured surface design to improve frictional properties in the space environment.
Keywords: Frictional property, multi-asperity, reciprocating sliding contact, space environment, textured surface, vibration
Graphical Abstract
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