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

Młynarczyk, Przemysław; Kolusz, Adam; Gallina, Alberto

doi:10.2478/arsa-2023-0022

Figures & Tables

Geometrical setup for the DEM repose angle test in three views

Subsequent steps of the repose angle test

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

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

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 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
Tangential 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 (δ_adh)	0.0005	0.0015
p3	Force fraction (f_adh)	0.1	0.4
p4	Restitution coefficient (ɛ)	0.1	0.4
p5	Rolling resistance (f_r)	0.2	0.8
p6	Tangential stiffness ratio (r_K)	0.2	1.0

Computation time for different DEM contact models

Tangential forces models	Normal forces models
Tangential 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

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

Figures & Tables

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Particles’ material parameters

AR for different DEM contact models

Sensitivity analysis results

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

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

Computation time for different DEM contact models

Paradigm

My account