Piling and avalanches of magnetized particles.

Area of Science:

• Computational physics
• Materials science
• Granular mechanics

Background:

• Granular materials exhibit complex behaviors influenced by interparticle forces.
• Magnetization introduces an additional force, potentially altering granular system dynamics.

Purpose of the Study:

• To investigate the influence of magnetic dipole interactions on the properties of granular systems.
• To quantify the effect of magnetization on the angle of repose, surface roughness, and avalanching behavior of magnetized spherical particles.

Main Methods:

• Two-dimensional distinct element method (DEM) computer simulations.
• Systematic variation of the interparticle force ratio (f), defined as magnetic dipole interaction to gravitational force.
• Measurement of angle of repose and surface roughness of particle piles.

Main Results:

• A linear relationship was observed between the interparticle force ratio (f) and both the angle of repose and surface roughness.
• Avalanche formation transitions from small vertical chains (granular regime, f < 7) to large particle clusters (correlated regime, f > 7).
• The transition in avalanche behavior is gradual, not abrupt.

Conclusions:

• Magnetization plays a crucial role in dictating the macroscopic properties and dynamic behaviors of granular systems.
• The interparticle force ratio (f) serves as a key parameter to predict the transition between different granular flow regimes.
• Stability criteria can provide estimates for the critical interparticle force ratio (f(c)) marking the transition.