A kinematics-based model for the settling of gravity-driven arbitrary-shaped particles on a surface.

Area of Science:

• Physics
• Computational Science
• Materials Science

Background:

• Conventional discrete element methods (DEM) struggle with accurate particle-wall interactions, often resulting in unrealistic overlaps and equilibrium states.
• Simulating particle settling requires robust models that handle complex geometries and contact physics effectively.

Purpose of the Study:

• To develop a discrete model for simulating the settling of arbitrary-shaped particles onto a flat surface under gravity.
• To ensure accurate particle dynamics, preventing overlap and achieving realistic equilibrium states, which are limitations in traditional DEM.
• To validate the model's capability in predicting stable equilibrium positions for diverse particle shapes.

Main Methods:

• A discrete particle dynamics model is proposed, modifying kinematics upon collision detection based on contact type (point, line, surface).
• The contact point/line is treated as the instantaneous center/line of rotation for rigid body dynamics calculations.
• Two stability conditions are implemented, comparing the center of mass projection with contact points to determine equilibrium states for multi-contact scenarios.

Main Results:

• The model successfully prevents particle-wall overlap during settling simulations.
• It accurately predicts realistic equilibrium states for particles settling on a flat surface.
• Simulations encompassing smooth (ellipsoids), regular (cylinders, pyramids), and irregular particles demonstrate the method's effectiveness in achieving known analytical equilibrium states.

Conclusions:

• The proposed discrete model offers a significant improvement over conventional DEM for particle settling simulations.
• It provides a reliable method for determining stable equilibrium positions of various particle shapes under gravitational influence.
• This approach enhances the accuracy and realism of simulating granular material behavior and particle-surface interactions.