Constant rate shearing on two-dimensional cohesive discs

Area of Science:

• Physics
• Materials Science
• Computational Science

Background:

• Understanding granular material behavior under shear is crucial.
• Simulating cohesive forces, like capillary forces, in granular systems is complex.
• Existing models often focus on disc-wall interactions rather than disc-disc shearing.

Purpose of the Study:

• To investigate the occurrence of stick-slip phenomena in cohesive discs under shear.
• To model capillary forces using spring interactions between neighboring discs.
• To analyze disc-disc shearing dynamics distinct from disc-wall interactions.

Main Methods:

• Two-dimensional molecular dynamics simulations were employed.
• Cohesion was modeled using springs between adjacent discs.
• Simulations focused on disc-disc shearing within a specialized cell geometry.

Main Results:

• A stick-slip phenomenon was observed for shearing rates exceeding a specific threshold.
• Measured forces on the upper cover exhibited periodic behavior over time.
• Collective disc displacements (forward and backward) correlated with the upper cover's constant velocity.

Conclusions:

• The simulations demonstrate that cohesive discs can exhibit stick-slip dynamics.
• The observed periodic force variations are indicative of a stick-slip phenomenon.
• The study highlights the importance of disc-disc interactions in shear-induced phenomena.