Hello,i ran an simulation of nanoindentation.I used the command of displace_atoms for indentaion while it ran indentation and relaxation in cycle, but it produce these errors that the force of indenter isn’t steady and the basement is broken when indentation is begin . Can you give some advices for the problem ,thanks.

Lammps Graphene Test

boundary s s s

units metal

atom_style atomic

neighbor 2.0 bin

neigh_modify delay 1

########################### create geometry ############################

read_data data.DiaGra

lattice diamond 3.56

region 3 cylinder x 98 12 8 -5 200 side in units box

create_atoms 2 region 3 units box

group upper region 3

region 4 block INF 12 INF INF INF INF units box

group right region 4

region 5 block 161 INF INF INF INF INF units box

group left region 5

group boundary union left right

group mobile subtract all boundary upper

group plus union mobile boundary

#potentials

pair_style hybrid tersoff lj/cut 2.5

pair_coeff * * tersoff SiC.tersoff C C

pair_coeff 1 2 lj/cut 1.0 2.5

compute 1 upper displace/atom

compute 2 upper reduce ave c_1[3]

variable avedisplace equal c_2

compute 3 all property/atom fz

compute 5 upper reduce sum c_3

variable zforce equal c_5

thermo_style custom step temp press v_avedisplace v_zforce etotal pe ke vol lx ly pxx pyy pzz

thermo 100

timestep 0.001

min_style sd

minimize 1.0e-12 1.0e-12 1000 1000

velocity all create 0.01 24804 dist gaussian units box

fix init all nvt temp 0.1 0.1 0.1

fix upper set force 0.0 0.0 0.0

dump 1 all atom 100 dump.init.lammpstrj

run 30000

undump 1

fix 4 boundary setforce 0 0 0

variable i loop 60

label loop

displace_atoms upper move 0 0 -1 units box

dump 2 all atom 100 dump.down$i.lammpstrj

run 5000

fix init all nvt temp 0.1 0.1 0.1

run 5000

undump 2

next i

jump in.graphene loop