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Colloidal lattice shearing and rupturing with a driven line of particles
A Libál1, B M Csíki, C J Olson Reichhardt
1Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Summary
We simulated 2D colloidal systems to understand shear bands. A decoupling transition was observed, where driven particles separate from the bulk, forming shear bands in both monodisperse and bidisperse systems.
Area of Science:
- Soft Matter Physics
- Condensed Matter Physics
- Materials Science
Background:
- Colloidal systems are complex fluids with applications in materials science.
- Understanding shear-induced dynamics is crucial for controlling material properties.
- Previous studies have explored shear banding in various systems, but detailed dynamical regimes remain under investigation.
Purpose of the Study:
- To investigate the dynamics of two-dimensional colloidal systems under local shear.
- To identify and characterize shear banding phenomena in monodisperse and bidisperse colloidal assemblies.
- To explore the influence of bidispersity, pinning, and thermal noise on shear band formation and dynamics.
Main Methods:
- Numerical simulations of two-dimensional colloidal systems.
- Application of a localized drive to induce shear.
- Analysis of particle dynamics, velocity-force curves, and noise fluctuations.
Main Results:
- A decoupling transition was observed in monodisperse systems, separating elastic and plastic regimes with shear band formation.
- In bidisperse systems, shear band broadening coincided with bulk disordering.
- Decoupling force exhibited nonmonotonic behavior with bidispersity, influenced by noise and velocity profiles.
- Pinning localized shear bands, while thermal noise extended them.
Conclusions:
- Shear band dynamics in 2D colloidal systems are complex and depend on system composition and external conditions.
- The decoupling transition is a key feature governing the transition from elastic to plastic behavior.
- Bidispersity, pinning, and thermal noise significantly alter shear band characteristics and system response.
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