Two-dimensional squishy glass: yielding under oscillatory shear

Area of Science:

• Polymer physics
• Soft matter science
• Materials science

Background:

• Dense glassy systems exhibit complex mechanical responses under stress.
• Deformable polymer rings present a unique model for studying yielding phenomena.
• Ring stiffness is a critical parameter influencing the dynamics of these systems.

Purpose of the Study:

• To investigate the yielding behavior of a two-dimensional dense glass model composed of deformable polymer rings.
• To understand the role of ring stiffness as a control parameter in yielding.
• To explore the relationship between shape fluctuations, shape changes, and translational rearrangements under shear.

Main Methods:

• Simulating a model two-dimensional dense glass of bidisperse, deformable polymer rings.
• Applying oscillatory shear to probe the yielding response.
• Analyzing the effect of varying ring stiffness on system dynamics and structure.

Main Results:

• Increasing ring stiffness constrains shape fluctuations in the quiescent state.
• Yielding occurs when the thermal assembly loses rigidity, with a threshold yield strain that increases as ring stiffness decreases.
• Sheared rings exhibit significant shape deviations compared to their unsheared states.

Conclusions:

• Ring stiffness critically influences the yielding transition in dense polymer systems.
• Shape changes and translational rearrangements are coupled during shear-induced yielding.
• This research provides insights into the fundamental mechanisms governing yielding in soft, deformable materials.