Loading-unloading of an elastic-plastic adhesive spherical microcontact

Area of Science:

• * Solid Mechanics
• * Materials Science
• * Tribology

Background:

• * Understanding adhesive contact is crucial for predicting material behavior under load.
• * Elastic-plastic deformation and unloading phenomena in adhesive contacts are complex.
• * Existing models often simplify material response, necessitating more detailed analysis.

Purpose of the Study:

• * To numerically simulate the load-unload cycle of an adhesive contact.
• * To investigate the influence of key dimensionless parameters on contact behavior.
• * To analyze plastic deformation and separation modes during unloading.

Main Methods:

• * A numerical solution approach was employed for the adhesive contact problem.
• * Nonlinear spring elements obeying Lennard-Jones potential simulated interacting forces.
• * Kinematic hardening was assumed for the elastic-plastic sphere material.

Main Results:

• * The Tabor parameter and a plasticity parameter were identified as critical governing factors.
• * Load-approach curves, deformed sphere profiles, and internal plastic strain fields were analyzed.
• * Distinct separation modes during the unloading phase were observed and characterized.

Conclusions:

• * The study provides a comprehensive numerical framework for adhesive contact analysis.
• * The identified dimensionless parameters effectively predict contact behavior.
• * The findings offer insights into material separation mechanisms in elastic-plastic contacts.