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Sensitivity Analysis of the DEM Model Numerical Parameters on the Value of the Angle of Repose of Lunar Regolith Analogs


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Figure 1.

Geometrical setup for the DEM repose angle test in three views
Geometrical setup for the DEM repose angle test in three views

Figure 2.

Subsequent steps of the repose angle test
Subsequent steps of the repose angle test

Figure 3.

Example of the 3D DEM obtained pile (A), averaged particles pile (B), and the result of the angle of repose evaluation (C)
Example of the 3D DEM obtained pile (A), averaged particles pile (B), and the result of the angle of repose evaluation (C)

Figure 4.

Angle of repose versus particle size (left) and computational time versus particle size (right) diagrams from the simulation results
Angle of repose versus particle size (left) and computational time versus particle size (right) diagrams from the simulation results

Figure 5.

Morris plot of the repose angle. The diagram shows that the rolling resistance is the most important factor with a significant linear correlation with the repose angle.
Morris plot of the repose angle. The diagram shows that the rolling resistance is the most important factor with a significant linear correlation with the repose angle.

Figure 6.

Morris plot of the simulation time. The diagram shows that the adhesive distance is the predominant factor on the simulation time.
Morris plot of the simulation time. The diagram shows that the adhesive distance is the predominant factor on the simulation time.

Particles’ material parameters

Parameter Value
Density (bulk density) (kg/m3) 2900 (1740)
Young's modulus (MPa) 45
Poisson's ratio (-) 0.5

AR for different DEM contact models

Tangential forces models Normal forces models
Hertzian spring dashpot Linear spring dashpot Hysteretic linear spring
Mindlin–Deresiewicz 42.58 - -
Linear spring Coulomb limit 43.00 45.03 41.40

Sensitivity analysis results

Friction coefficient Adhesive distance (m) Force fraction Restitution coefficient Rolling resistance Tangential stiffness ratio Angle of repose (deg)
0.2 0.0011 0.16 0.34 0.32 0.52 33.84
0.2 0.0011 0.16 0.34 0.32 1 34.45
0.8 0.0005 0.16 0.22 0.2 0.2 35.88
0.2 0.0005 0.4 0.16 0.68 0.68 36.42
0.2 0.0009 0.28 0.28 0.68 0.36 37.40
0.2 0.0005 0.22 0.34 0.68 0.68 37.40
0.2 0.0011 0.16 0.34 0.68 0.52 37.87
0.2 0.0005 0.4 0.34 0.68 0.68 38.47
0.2 0.0015 0.1 0.1 0.68 0.84 38.47
0.8 0.0011 0.16 0.22 0.2 0.2 38.69
0.44 0.0005 0.22 0.22 0.32 0.52 39.97
0.8 0.0011 0.16 0.22 0.2 0.68 40.73
0.44 0.0005 0.22 0.22 0.32 1 41.63
0.56 0.0009 0.28 0.28 0.32 0.36 41.63
0.32 0.0011 0.4 0.22 0.2 0.68 41.86
0.2 0.0011 0.4 0.16 0.68 0.68 42.43
0.32 0.0011 0.4 0.22 0.2 0.2 42.55
0.32 0.0011 0.4 0.4 0.2 0.68 42.99
0.44 0.0005 0.4 0.22 0.32 1 43.69
0.8 0.0005 0.4 0.22 0.32 1 44.26
0.44 0.0011 0.22 0.22 0.32 0.52 45.72
0.2 0.0015 0.28 0.1 0.68 0.84 46.94
0.8 0.0005 0.34 0.4 0.56 0.2 47.00
0.2 0.0015 0.28 0.28 0.68 0.84 47.20
0.2 0.0015 0.28 0.28 0.68 0.36 47.54
0.68 0.0011 0.4 0.4 0.56 0.68 47.95
0.44 0.0005 0.34 0.4 0.56 0.2 48.32
0.32 0.0011 0.4 0.4 0.56 0.68 48.56
0.56 0.0011 0.16 0.34 0.68 0.52 48.68
0.2 0.0015 0.4 0.34 0.44 0.36 49.37
0.68 0.0005 0.22 0.4 0.56 0.68 49.69
0.8 0.0005 0.16 0.22 0.56 0.2 49.86
0.56 0.0011 0.4 0.16 0.32 0.2 50.49
0.56 0.0009 0.4 0.16 0.44 0.84 51.93
0.56 0.0005 0.34 0.16 0.68 0.52 52.16
0.56 0.0015 0.4 0.34 0.44 0.84 52.42
0.56 0.0009 0.28 0.28 0.68 0.36 52.70
0.56 0.0009 0.22 0.16 0.8 0.84 53.48
0.8 0.0005 0.34 0.22 0.56 0.2 53.65
0.56 0.0009 0.4 0.34 0.44 0.84 54.97
0.8 0.0005 0.4 0.22 0.68 1 55.15
0.56 0.0009 0.4 0.16 0.8 0.84 57.67
0.56 0.0015 0.4 0.34 0.44 0.36 58.06
0.56 0.0011 0.16 0.16 0.68 0.52 59.11
0.68 0.0011 0.22 0.4 0.56 0.68 59.65
0.8 0.0005 0.4 0.4 0.68 1 61.26
0.56 0.0011 0.4 0.16 0.68 0.2 61.70
0.56 0.0011 0.4 0.16 0.68 0.68 63.71
0.56 0.0011 0.34 0.16 0.68 0.52 64.06

Materials’ interaction parameters used in the grain size and contact model analyses

Parameter Particle–particle Particle–boundary
Static friction (−) 0.7 0.7
Dynamic friction (−) 0.7 0.7
Tangential stiffness ratio (−) 1 1
Adhesive distance (m) 0.0001 0.0001
Force fraction (−) 0.2 0
Restitution coefficient (−) 0.2 0.3

Ranges of variability of the contact model parameters used in the sensitivity analysis

Parameter Lower limit Upper limit
p1 Friction coefficient (f) 0.2 0.5
p2 Adhesive distance (δadh) 0.0005 0.0015
p3 Force fraction (fadh) 0.1 0.4
p4 Restitution coefficient (ɛ) 0.1 0.4
p5 Rolling resistance (fr) 0.2 0.8
p6 Tangential stiffness ratio (rK) 0.2 1.0

Computation time for different DEM contact models

Tangential forces models Normal forces models
Hertzian spring dashpot Linear spring dashpot Hysteretic linear spring
Mindlin–Deresiewicz 117.73 - -
Linear spring Coulomb limit 122.93 181.41 237.09
eISSN:
2083-6104
Język:
Angielski
Częstotliwość wydawania:
4 razy w roku
Dziedziny czasopisma:
Geosciences, other