Pre/Post-Processing

For more details on commands, refer to: https://docs.lammps.org/commands_list.html.

# 2d LJ crack simulation

dimension   2
boundary    s s p

atom_style  atomic
neighbor    0.3 bin
neigh_modify        delay 5

# create geometry

lattice             hex 0.93
region              box block 0 100 0 40 -0.25 0.25
create_box  5 box
create_atoms        1 box

mass                1 1.0
mass                2 1.0
mass                3 1.0
mass                4 1.0
mass                5 1.0

# LJ potentials

pair_style  lj/cut 2.5
pair_coeff  * * 1.0 1.0 2.5

# define groups

region              1 block INF INF INF 1.25 INF INF
group               lower region 1
region              2 block INF INF 38.75 INF INF INF
group               upper region 2
group               boundary union lower upper
group               mobile subtract all boundary

region              leftupper block INF 20 20 INF INF INF
region              leftlower block INF 20 INF 20 INF INF
group               leftupper region leftupper
group               leftlower region leftlower

set         group leftupper type 2
set         group leftlower type 3
set         group lower type 4
set         group upper type 5

# initial velocities

compute             new mobile temp
velocity    mobile create 0.01 887723 temp new
velocity    upper set 0.0 0.3 0.0
velocity    mobile ramp vy 0.0 0.3 y 1.25 38.75 sum yes

# fixes

fix         1 all nve
fix         2 boundary setforce NULL 0.0 0.0

# run

timestep    0.003
thermo              200
thermo_modify       temp new

neigh_modify        exclude type 2 3

dump                1 all atom 500 dump.crack

dump                2 all image 250 image.*.jpg type type zoom 1.6 adiam 1.5
dump_modify 2 pad 4

#dump               3 all movie 250 movie.mpg type type zoom 1.6 adiam 1.5
#dump_modify        3 pad 4

run         5000