Plastic instability of annular crystalline membrane in circular confinement

TL;DR

This paper studies the plastic deformation mechanisms in annular crystalline membranes under shrinking conditions, highlighting dislocation dynamics and vortex structures that influence material stability and morphology.

Contribution

It introduces a detailed analysis of dislocation behavior and vortex formation in crystalline membranes during plastic deformation under confinement.

Findings

Dislocations continuously generated at the inner boundary.

Dislocations migrate collectively to the outer boundary.

Vortex structures emerge from defect-displacement interactions.

Abstract

Understanding the mechanical instabilities of two-dimensional membranes has strong connection to the subjects of structure instabilities, morphology control and materials failures. In this work, we investigate the plastic mechanism developed in the annular crystalline membrane system for adapting to the shrinking space, which is caused by the controllable gradual expansion of the inner boundary. In the process of plastic deformation, we find the continuous generation of dislocations at the inner boundary, and their collective migration to the outer boundary; this neat dynamic scenario of dislocation current captures the complicated reorganization process of the particles. We also reveal the characteristic vortex structure arising from the interplay of topological defects and the displacement field. These results may find applications in the precise control of structural instabilities in packings of particulate matter and covalently bonded systems.