Collective nonaffine displacements in amorphous materials during large-amplitude oscillatory shear

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Materials Science

Background:

• Amorphous solids like glasses exhibit complex mechanical behaviors under stress.
• Understanding the response of these materials to cyclic loading is crucial for predicting their durability and failure modes.

Purpose of the Study:

• To investigate the transient response of a binary Lennard-Jones glass under periodic shear deformation.
• To elucidate the mechanisms of particle rearrangement and shear band initiation in amorphous solids.

Main Methods:

• Employing molecular dynamics simulations to model a three-dimensional Kob-Andersen binary mixture.
• Applying cyclic shear deformation to slowly annealed, quiescent glass samples at low temperatures.

Main Results:

• Observed irreversible particle rearrangements and stress-strain hysteresis at large strain amplitudes.
• Identified disconnected clusters of atoms with large nonaffine displacements near the critical strain amplitude.
• Documented a decrease in shear stress oscillation amplitude with cyclic loading, correlating with shear band initiation and growth.

Conclusions:

• Periodic shear deformation induces significant structural changes in binary glasses.
• Shear banding is a key mechanism governing the plastic response and eventual failure of these amorphous materials.