Dear lammps users,
I was trying to find out hardy stress in carbon nanotube undergoing tension. I used atc package in lammps. ( Lammps version 7 Aug 2019 ). I am getting an error saying stress field not possible using selected pair. I have given my code below and attached my data file.
Lammps code for cnt tension
using atc package
5 feb 2020
Abhiram B R
INITIALIZATION
units metal
dimension 3
boundary s s s
atom_style atomic
neighbor 0.3 bin
neigh_modify delay 5
READ DATA
read_data data.cnt
GROUPING OF ATOMS
group upper id 401 402 405 406 409 410 413 414 417 418 403 404 407 408 411 412 415 416 419 420
group lower id 1 2 5 6 9 10 13 14 17 18 3 4 7 8 11 12 15 16 19 20
group internal id 203 204 207 208 211 212 215 216 219 220 221 222 225 226 229 230 233 234 237 238 223 224 227 228 231 232 235 236 239 240
group boundary union upper lower
INTERATOMIC POTENTIAL
pair_style airebo 2.5 1 1
pair_coeff * * CH.airebo C
COMPUTE
compute cnt_temp all temp
compute cnt_pe all pe/atom
compute cnt_stress all stress/atom cnt_temp pair bond
compute cnt_str all reduce sum c_cnt_stress[3]
variable tmp equal “lz”
variable L0 equal {tmp}
print "Initial Length :{L0}"
EQUILIBRIATE
reset_timestep 0
velocity all create 300 12342 mom yes rot no
fix 1 all nvt temp 300 300 0.005
fix 2 boundary setforce 0.0 0.0 0.0
thermo_style custom step temp press pe ke etotal lx ly lz
thermo 100
DEFORMATION
velocity upper set 0 0 1 units box
velocity lower set 0 0 -1 units box
USING ATC
fix AtC internal atc hardy
fix_modify AtC kernel quartic_cylinder 9.0375
fix_modify AtC fields none
fix_modify AtC fields add mass_density displacement stress internal_energy
fix_modify AtC gradients add displacement
#fix_modify AtC mesh create 5 1 1 feregion p p p
variable strain equal “(lz-v_L0)/v_L0”
variable p1 equal “v_strain”
variable p2 equal “c_cnt_str”
variable strain equal “(lx - v_L0)/v_L0”
fix 3 all print 100 “{p1} {p2}” file atc_cnt.txt screen no
fix_modify AtC output cnt_strain 1 text
run 5000
END
THIS IS THE ERROR MESSAGE I AM GETTING
ATC: constructing kernel field estimate
ATC: version 2.0
ATC: peratom PE compute created with ID: 8
ATC: ERROR: Calculation of stress field not possible with selected pair type.
terminate called after throwing an instance of ‘ATC::ATC_Error’
CAN ANYONE HELP ME PLEASE
data.cnt (13 KB)
in.atc_cnt (1.77 KB)