Dear all,
I’m simulating boron nitride system with 5nm*5nm (960 atoms ) prepared with VMD. I had an error with preparation of lammps data file from vmd tk console. I got wrong boundary conditions. I changed it manually. But when applied strain to x direction (0.001 ), the sheet is not expanding but boundaries are expanding.
here is my input script
echo both
units metal
atom_style full
boundary p p p
newton on
dimension 3
read_data bn.layer
pair_style tersoff
pair_coeff * * BNC.tersoff B N
neighbor 0.2 bin
neigh_modify every 20 delay 100 check no
timestep 0.0005
fix 1 all npt temp 300.0 300.0 0.05 y 0 0 0.05
thermo 200
compute 1 all stress/atom NULL
compute 2 all pe/atom pair bond
compute 3 all reduce sum c_1[1] c_1[2] c_1[3]
thermo_style custom step temp pe ke etotal press lx ly lz pxx pyy pzz c_3[1] c_3[2] c_3[3]
run 60000
unfix 1
fix 1 all nvt temp 300 300 0.05
fix 2 all ave/atom 1 1000 1000 c_1[1] c_1[2] c_1[3] c_2 fx fy fz
fix 3 all ave/time 1 1000 1000 c_thermo_press[2] file stress.all
dump 1 all custom 1000 dump.new.* id type x y z vx vy vz c_1[1] c_1[2] c_1[3] c_2 f_2[1] f_2[2] f_2[3] f_2[4] f_2[5] f_2[6] f_2[7]
dump 2 all xyz 1000 dump.graphene.*.xyz
variable tmp equal “lx”
variable L0 equal {tmp}
print "Initial Length, L0: {L0}"
variable srate equal 1.0e9
variable srate1 equal “v_srate/1.0e12”
fix 4 all deform 1 x erate ${srate1} units box remap x
variable strain equal “(lx-v_L0)/v_L0”
variable p0 equal “v_strain”
variable p1 equal “-(pxx33)/10000"
variable p2 equal "-(pyy33)/10000”
fix 5 all print 1000 "{p0} {p1} ${p2} " file strain.txt screen no
thermo_style custom step temp v_strain v_p1 v_p2 press
run 600000
echo both
data file :
LAMMPS data file. CGCMM style. atom_style full generated by VMD/TopoTools v1.4 on Wed Jul 02 15:35:43 IST 2014
960 atoms
0 bonds
0 angles
0 dihedrals
0 impropers
2 atom types
0 bond types
0 angle types
0 dihedral types
0 improper types
-5 55 xlo xhi
-5 55 ylo yhi
-5.000000 5.000000 zlo zhi