Dear Steve,
Thanks for your response. I figured that out in the weekend I forgot to take down the question.
But now I have another problem, which I really appreciate if you can help me figure that out. I’m modeling a lubricant on top of an Al block, and I’m applying two forces:
1- velocity applied to the block
2- gravity
I observed two behavior which are not correct, so I was wondering if you can help me out understand those:
1- When I apply velocity to the lower layers of the block, just that region moves and the rest of the block is not moving. The only thing that I can think of is the velocity that I apply causes much higher forces than available lj potential forces which overcome the lj force, so I’m trying to lower the velocity but so far, I didnt see any change.
2- The gravity force also makes the Al block gets more packed, I think it causes by the same reason, high forces.
Sorry this questions are not directly related to the LAMMPS but since I’m a newbie in LAMMPS I would really appreciate your help.
Here is my code by far:
------------------------------- Initialization Section --------------------
units real
atom_style full
bond_style hybrid harmonic
angle_style hybrid harmonic
dihedral_style hybrid fourier
improper_style hybrid cvff
pair_style hybrid eam/alloy lj/cut 10.0
------------------------------- Atom Definition Section -------------------
read_data system.data
------------------------------- Settings Section --------------------------
pair_coeff * * eam/alloy Al99.eam.alloy Al Al NULL
pair_coeff 3 3 lj/cut 0.0150 2.59964245953
pair_coeff 2 2 lj/cut 0.0860 3.39966950842
pair_coeff 1 3 lj/cut 0.0150 2.59964245953
pair_coeff 1 2 lj/cut 0.0860 3.39966950842
bond_coeff 1 harmonic 478.4 1.3870
bond_coeff 2 harmonic 344.3 1.0870
angle_coeff 1 harmonic 67.18 119.97
angle_coeff 2 harmonic 48.46 120.01
dihedral_coeff 1 fourier 1 3.625 2 180.0
improper_coeff 1 cvff 1.1 -1 2
region lo-fixed block INF INF INF INF INF 8.1
region lo-slab block INF INF INF INF INF 24.3
region above-lo block INF INF INF INF INF 24.3 side out
region hi-fixed block INF INF INF INF 46.2 INF
region hi-slab block INF INF INF INF 30 INF
region below-hi block INF INF INF INF 30 INF side out
group lo-slab region lo-slab
group above-lo region above-lo
group hi region hi-slab
group lo-fixed region lo-fixed
group hi-fixed region hi-fixed
group boundary union lo-fixed hi-fixed
group mobile subtract all boundary
------------------------------- Run Section -------------------------------