Numerical investigation on angle of repose and force network from granular pile in variable gravitational environments

• Forming of granular pile under variable gravity conditions is simulated.
• Effect of gravity on the angle of repose of the pile is negligible.
• Distribution of the contact force in the pile scales linearly with gravity.
• Distribution of the tangential to normal force ratio is independent of gravity.
• Particle's properties do not affect the relation of angle of repose and gravity.

This paper presents a numerical investigation on the relationship between the angle of repose and gravity by a three dimensional discrete element method. Taking particle shape, particle size and surface roughness of particle into account, the forming of granular pile was simulated under four different gravitational conditions: the Moon gravity, Martian gravity, Earth gravity and super-gravity. The angle of repose at macro level and the contact forces between particles of the pile were analyzed. Results show that the contact forces are lognormal distributed with about 65% smaller than the mean, and the ratio of tangential to normal force is uniformly distributed except for a small peak where the friction force is fully mobilized. The probability distribution of contact forces normalized by particle's weight under all gravity conditions shows to be in mutual coincidence, and the distribution of the ratio of tangential to normal force is independent of gravity. Although the microstructure of pile varies randomly, the angle of repose will not be affected by the magnitude of gravity.

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