Page 25 - The Combined Finite-Discrete Element Method

8 INTRODUCTION

1
0.9

0.8
In-pack
t = 0.000 s
Density 0.7 t = 0.055 s
t = 0.105 s
0.6
t = 0.180 s
t = 0.830 s
0.5
0.4

0.3
0 50 100 150 200 250 300 350
Distance from the bottom (mm)
Figure 1.7 Averaged density over horizontal cross-section of the box as function of distance of
the cross-section from the bottom of the box.

Figure 1.8 Initial disturbance (left) and spatial distribution of spheres at the start of gravity
induced deposition, i.e. time 0.0 s (right).

The final packing density achieved is smaller than the theoretical density. The reasons
behind this can be investigated if the same volume of solid is deposited using iden-
tical spheres of a larger diameter. Thus, in Figures 1.8–1.13, numerical simulation of
gravitational deposition of 139,968 spheres all of the same diameter (d = 4.998 mm) is
performed. The total solid volume of the spheres is the same as in the previous example,
3
i.e. V = 9.150e−03 m .