Particle strengthening simulation error

Hello,

I am trying to do a Particle hardening simulation where in a copper spot has been embedded in a Mo0.8075W0.0425Ta0.1Ti0.05Zr0.05 matrix. A sliced version of the triclinic simulation box is shown below (red circle is the copper spot). Eventually I plan to provide shear strain to this box to see if the dislocations “cut” or “bow through” the copper spot.

image.png

I am facing two problems in the program

  1. The number of atoms in group Mo (Molybdenum) is becoming zero despite using any value in the type/fraction command of group Mo (type 2).

  2. The pressure and other parameters are nan.

image.png

Also in the end I face this error

image.png

The code is here-

units metal
dimension 3
boundary p p p
atom_style atomic
variable latparam equal 2.895

----------------------- ATOM DEFINITION ----------------------------

lattice bcc ${latparam}

region whole prism 0 31.5 0 31.5 0 31.5 6 0 0
create_box 6 whole
lattice bcc ${latparam} orient x 1 0 0 orient y 0 1 0 orient z 0 0 1

region r2 sphere 15 15 15 6 side in
create_atoms 2 region r2
group r2 region r2
set group r2 type 1
group Cu type 1

region r3 sphere 5 5 5 3 side out
create_atoms 3 region r3
group r3 region r3

variable fa equal 14500
variable fb equal 12000
variable fc equal 5900
variable fd equal 2933
variable ft equal 62500

set type 2 type/fraction 3 (v_fa/v_ft) 1734536 set type 3 type/fraction 4 (v_fb/(14545)) 1734535
set type 4 type/fraction 5 (v_fc/(11955)) 1734534 set type 5 type/fraction 6 (v_fd/(5867)) 1734533

group Mo type 2
group W type 3
group Ta type 4
group Ti type 5
group Zr type 6

pair_style eam/alloy
pair_coeff * * MoTaTiWZrCu.set Mo Ta W Ti Zr Cu
dump 4 all custom 1000 dump.hea_equi id type x y z
run 10

print “-------Minimization SD------------------”
min_style sd
min_modify dmax 0.1
thermo 1000
thermo_style multi
minimize 1e-15 1e-15 100000 100000

reset_timestep 0

timestep 0.001
velocity all create 3000 123456 dist gaussian

fix 1 all npt temp 3000 3000 1 iso 0 0 1 drag 1
thermo 10000
thermo_style custom step temp press ke pe etotal vol density

0.09 nanosec run

run 90000
unfix 1

fix 2 all npt temp 3000 300 0.1 iso 0 0 1 drag 1
thermo 10000
thermo_style custom step temp press ke pe etotal vol density

0.09 nanosec run

run 1500000
unfix 2

fix 3 all npt temp 300 300 0.1 iso 0 0 1 drag 1
thermo 10000
thermo_style custom step temp press ke pe etotal vol density

0.09 nanosec run

run 90000
unfix 3

log log.quench_npt

fix 1 all npt temp 300 300 1 iso 0 0 1 drag 1
thermo 1000
thermo_style custom step temp press ke pe etotal vol density

2 nanosec run

run 10000
unfix 1

fix 2 all nvt temp 300 300 1
thermo 1000
thermo_style custom step temp press ke pe etotal vol density
run 20000
unfix 2

fix 3 all nve
thermo 1000
thermo_style custom step temp press ke pe etotal vol density
run 10000
unfix 3

log log.equi
dump 4 all custom 10000 dump.hea_equilibrate id type x y z

write_restart restart.tensile_equi
run 10000

as for the diverging forces/pressure: you seem to be creating atoms on top of each other. baaaaad idea.

as for the second issue. please study the documentation and build your input gradually. nobody here will provide you one-on-one training or even resolve for you what is essentially your job to do. if you need help with this, you should ask your adviser and/or your colleagues.

axel.