Integrated Computational Materials Engineering (ICME)

LAMMPS Input Deck for MD Fatigue Crack Growth

# Mg Single Crystals LAMMPS input file
# Tian Tang, 2010
# Description: This input file for LAMMPS runs 15 cycles of a fatigue crack growth simulation
# with the EAM Magnesium potential for a single crystal.
 
units            metal
boundary         p m p
atom_style       atomic
read_data        datafile1
pair_style       eam/fs
pair_coeff       * * Mg_mm.eam.fs Mg
neighbor         0.3 bin
neigh_modify     delay 1
 
# define groups
 
region  upper block INF INF   290.000000   INF INF INF units box
region  lower block INF INF INF  -290.000000   INF INF units box
region  center block -180 180 -70 70 INF INF units box
group   center region center
group   upper region upper
group   lower region lower
group   mobile subtract all lower upper
 
# fixs
 
fix 1 all nve
fix 2 upper setforce 0.0 0.0 0.0
fix 3 lower setforce 0.0 0.0 0.0
 
# equilibrate
 
velocity mobile create 100.0 4928459 rot yes dist gaussian
fix 4 mobile temp/rescale 100 100.0 100.0 0.1 1.0
 
run 2000
 
# compute centrosymmetric number and stress components
compute 1 all centro/atom
compute 2 all ackland/atom
compute 3 all stress/atom
compute myTemp mobile temp/partial 1 0 1
compute mypress all pressure myTemp
 
thermo    1
thermo_style custom step c_myTemp etotal c_mypress f_2[2] f_3[2]
thermo_modify format 1 %5d
thermo_modify format 2 %22.12f
thermo_modify format 3 %22.12f
thermo_modify format 4 %22.12f
thermo_modify format 5 %22.12f
thermo_modify format 6 %22.12f
 
# unfixs
 
unfix 1
unfix 4
 
# new fixs
 
fix 1 all nvt 100.0 100.0 10.0 drag 100.0
fix_modify 1 temp myTemp
 
reset_timestep 0
 
dump 1 all custom 1000 Ensight1/dump.custom.* id type x y z c_1 c_2 c_3[2]
dump_modify 1 format "%d %d %10.5f %10.5f %10.5f %7.2f %7.2f %10.5f"
dump_modify 1 thresh c_1 > 11.5
dump 2 center custom 1000 Ensight1A/dump.custom.* id type x y z c_1 c_2 c_3[2]
dump_modify 2 format "%d %d %10.5f %10.5f %10.5f %7.2f %10.5f %10.5f %10.5f %10.5f %10.5f %10.5f"
dump 3 all custom 1000 Ensight1B/dump.eampost id x y z c_1
dump_modify 3 format "%d %10.5f %10.5f %10.5f %10.5f"
 
# Apply cyclic loading
 
# ------------------------------------------------------------
#CYCLE  1-LOADING
velocity all ramp vy  -0.4350    0.4350   y    -290.000     290.000 sum yes units box
uncompute myTemp
compute myTemp mobile temp/ramp vy  -0.4350    0.4350   y   -290.00    290.00   units box
run 30000
 
#CYCLE  1-UNLOADING
velocity all ramp vy   0.8700   -0.8700   y    -290.000     290.000 sum yes units box
uncompute myTemp
compute myTemp mobile temp/ramp vy   0.8700   -0.8700   y   -290.00    290.00   units box
run  6000
# ------------------------------------------------------------

print "All done"