Page 28 - The Combined Finite-Discrete Element Method

A TYPICAL PROBLEM OF COMPUTATIONAL MECHANICS OF DISCONTINUA 11

Figure 1.13 Gravity induced motion of the pack after 0.605 s and 0.830 s.

1

0.9
0.8
t = 0.000 s
0.7 t = 0.055 s
Density 0.6 t = 0.105 s
t = 0.205 s
t = 0.730 s
0.5 t = 0.305 s
0.4
0.3
0 50 100 150 200 250 300 350
Distance from the bottom (mm)
Figure 1.14 Averaged density over horizontal cross-section of the box as function of distance of
the cross-section from the bottom of the box.

Density profiles for this pack are shown in Figure 1.14. The density profiles shown
are normalised using the theoretical density. Initially (solid line), the particles are loosely
packed inside the box. The motion of the particles under gravity gradually increases
density at the bottom of the pack and decreases density at the top of the pack, finally
making the upper parts of the box empty. As the particles settle, the pack gets denser.
At the state of rest (top line), almost uniform density over most of the pack is achieved,