Particle fracture regimes from impact simulations

Area of Science:

• Computational mechanics
• Material science
• Geophysics

Background:

• Understanding particle breakage is crucial for various scientific and engineering fields.
• Existing models often simplify particle geometry and fracture mechanics.

Purpose of the Study:

• To develop and implement a discrete element model for simulating single particle breakage upon impact.
• To analyze the influence of impact energy on fracture dynamics and fragment characteristics.

Main Methods:

• Modeling particles as aggregates of polyhedral cells with surfaces governed by the Griffith fracture criterion.
• Implementing the model within a discrete element code.
• Simulating particle impact on a rigid plane under varying normalized impact energy (ω).

Main Results:

• Identified three distinct fracture regimes based on normalized impact energy: elastic rebound, crack propagation without breakup, and fragmentation.
• Observed that the restitution coefficient initially declines and then increases with impact energy beyond a fragmentation threshold.
• Demonstrated that particle damage, restitution coefficient, and fracture efficiency scale with dimensionless parameters.
• Found fragment mass distributions follow a power-law, and fragment shape characteristics align with experimental and lunar sample data at optimal fracture efficiency.

Conclusions:

• The developed model accurately captures particle breakage phenomena across different impact energy levels.
• The study provides insights into scaling laws for fragment size and shape distributions.
• Results offer valuable data for optimizing fracture processes and understanding granular material behavior.