A Research Method for the Influence of Substrate Support Stiffness Gradient Variation on Friction Force

Abstract

The invention discloses a research method for the influence of the gradient change of the base support stiffness on the friction force. The method comprises the following steps: Step 1, establishment of molecular dynamics model. The model system includes a square graphene flake adsorbed by the probe tip of an atomic force microscope and a single-layer graphene substrate supported by a stiffness gradient; step 2, the influence of the stiffness gradient on the average friction of graphene. As the support stiffness increases, the friction energy consumption decreases, and when the stiffness exceeds a certain critical value, the friction force no longer decreases. Step 3. Effect of stiffness gradient on normal load. When the support stiffness is large, the normal deformation of the substrate is small, the distance between the sheet and the substrate is small, and the van der Waals force between layers is large. Step 4. Intrinsic mechanism of the influence of stiffness gradient on friction force. The friction force is jointly caused by the interface potential barrier and the potential gradient caused by the thermal vibration of supporting atoms with different stiffnesses, as well as the boundary barrier caused by the asymmetric deformation of the atoms on both sides of the boundary transition region and the sudden change of the degree of freedom constraint.

Description

Technical field [0001] The present invention belongs to the field of molecular dynamics, and it is related to the study of a substrate support rigidity gradient change on frictional effects. Background technique [0002] When the two contact objects occurs or have a relative motion trend, the force hindering its relative movement is referred to as friction, this phenomenon or characteristic between the contact surface is friction. The friction is essentially the irreversible energy dissipation under contact surface atoms, involving complex non-equilibrometric thermodynamics. From the atomic level analysis of the composition, the smooth contact becomes a numerous rough peak contact, and the continuous medium contact theory of macro applications is no longer suitable for micro discrete contact models. Graphie is a two-dimensional carbon material having atomic thickness, which is considered to be an ideal friction study material due to its unique large specific surface area structur...

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Problems solved by technology

However, the relative motion that combines the commensurate contact between graphene layers and the gradient change of substrate support stiffness has rarely been studied by scholars at home and abroad.

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