To all:
I am having trouble while performing an indentation simulation into Au with the included EAM potential. However, I am trying to move the indenter, and then minimize the energy, and repeat. I noticed that on 8/3/2006 another user wrote to the list with a similar question ([lammps-users] energy minimization question updated). However, I am working in 3D.
I changed the sample file from 2D to 3D using the l-j potential, and the simulation ran just fine. However, when I tried to use the eam potential (after changing all units to the 'metal' format) I found that the indenter did not appear to interact with the sample. Otherwise, I have implemented the suggestions in the 8/3/2006 email using the eam potential without success. As with the case reported in the email, a dynamic simulation using eam works as it should.
Any ideas would be appreciated. The input file is attached.
# 3d indenter simulation with minimization instead of dynamics
dimension 3
boundary p p s
atom_style atomic
units metal
neigh_modify delay 5
# create geometry
lattice fcc 4.08
#lattice fcc 4.08 orient z 1 1 1 orient x 1 1 -2 orient y -2 2 0 origin 0 0 0
region mainblock block 0 102.0 0 102.0 0 65.28 units box
create_box 2 mainblock
create_atoms 1 box
# EAM potentials
pair_style eam
pair_coeff * * Au_u3.eam
# define groups
region bottomface block INF INF INF INF INF 4.08 units box
group lower region bottomface
group mobile subtract all lower
set group lower type 2
# initial velocities
fix 2 lower setforce 0.0 0.0 0.0
# minimize with indenter
thermo 10
dump dumpxyz all custom 10 dump.xyz tag type x y z z
minimize 1.0e-6 1000 1000
#INDENT DISTANCE, 0.00
fix 4 all indent 10000.0 sphere 51.0 51.0 80.28 20.0
fix_modify 4 energy yes
minimize 1.0e-6 1000 1000
#INDENT DISTANCE, 0.10
fix 4 all indent 10000.0 sphere 51.0 51.0 80.18 20.0
fix_modify 4 energy yes
minimize 1.0e-6 1000 1000
#INDENT DISTANCE, 0.20
fix 4 all indent 10000.0 sphere 51.0 51.0 80.08 20.0
fix_modify 4 energy yes
minimize 1.0e-6 1000 1000
#more steps...