About addforce problem

I want to move a dislocation by shear stress.
I used the following command.
But it didn’t seem to work.
Dislocation in my model didn’t move at all.
Would someone tell me where the problem is?

# ---------- BOUNDARY ---------------------
variable THICKNESS equal 3.0 
variable LOWER_END equal (bound(all,zmin))
variable UPPER_END equal (bound(all,zmax))
variable LBOUND equal ${LOWER_END}+${THICKNESS}
variable UBOUND equal ${UPPER_END}-${THICKNESS}

# ---------- GROPUS ---------------------
region lowerBlock block INF INF INF INF INF ${LBOUND}
region upperBlock block INF INF INF INF ${UBOUND} INF 
group top region upperBlock
group bot region lowerBlock
group bounds union top bot
group body subtract all bounds

compute peatom all pe/atom

# ---------- RIGID BOUNDARY ---------------------
fix 2 top setforce 0.0 0.0 0.0 
fix 3 bot setforce 0.0 0.0 0.0

# ---------- Initial_System ---------------------
reset_timestep 0
write_dump all cfg initial*.cfg mass type xs ys zs modify sort id element Al

# ---------- Apply_Shear_Strain ---------------------

variable i loop 20
        label loop1
        #displace_atoms top move  0.01 0.0 0.0 units box
        #displace_atoms bot move -0.01 0.0 0.0 units box
        fix shear1 top addforce 2e-04 0 0 
        fix shear2 bot addforce -2e-04 0 0 
        minimize 0.0 0.001 50000 50000 

        print "@ ${i}"

        reset_timestep ${i}
        write_dump all cfg shear*.cfg mass type xs ys zs modify sort id element 
        next i
jump shear_static.in loop1

print "All done."

You are running a minimization of your system 20 times with the same external force.
Why should there be a change once the system is minimized?

Thank you.
I’ll do so.