displace_atoms command

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

it produce these errors that the force of indenter isn't steady and the basement is broken when indentation is begin .

I don't know what this means. You need to ask a more specific
question and indicate that there is a some issue with LAMMPS
rather than an issue with your understanding of how the system
should respond. Why should the force be "steady"?

Steve

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.

if your system breaks into pieces, then you have a bad choice
of model. the choice of hybrid potential in the way how you have
set it up is definitely not good.

please keep in mind that, if people could see what a simulation
it doing (including what it is doing wrong) simply by looking at
an input file, we wouldn't need simulation programs anymore.

so, as has been said many, many times on this list. you
have to *build* your setup in pieces and you have to
*understand* and validate each step and piece that you
add. just slapping stuff together and hoping to get it to
work somehow is almost a guarantee for failure. in MD
there are too many ways to get it wrong in order to be
able to get it right by chance.

axel.