“GRANULAR” package - Lammps

Principles of DEM
In it‘s simplest form (linear spring-dashpot model), the force balance is
••
mp xp
= Fn
+ Ft
+
mg
The normal force tending to repulse the particles is
F = −k
δ + c ∆v
n
δ: spatial overlap, ∆v n: normal relative velocity at the contact point.
The tangential force F t is written as
F
t
n
t
n
t t
tc,
0
��� �
" δt
"
∆v t: relative tangential velocity, t: contact point tangential vector
tc,0: time when the contact between the particles started
Christian Doppler Laboratory on Particulate Flow Modelling www.particulate-flow.at
n
= k ∫ ∆v
( τ ) dτ
��� t + ct
∆vt
, max⎜
⎛ F
⎝
t
⎟
⎞
⎠
=
µ F
n
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