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.

中文翻译：

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环形晶膜在圆形约束中的塑性不稳定性

了解二维膜的机械不稳定性与结构不稳定性、形态控制和材料失效等主题密切相关。在这项工作中，我们研究了环形结晶膜系统中为适应由内边界可控逐渐膨胀引起的空间收缩而发展的塑性机制。在塑性变形过程中，我们发现内边界位错不断产生，并集体迁移到外边界；位错电流的这种简洁的动态场景捕捉到了粒子复杂的重组过程。我们还揭示了拓扑缺陷和位移场相互作用产生的特征涡流结构。这些结果可能会应用于精确控制颗粒物质和共价键合系统的结构不稳定性。