[lammps-users] lammps-users Digest, Vol 52, Issue 127

Dear users,
Struggling with a typical 3D crack propagation problem. Fortunately it is opening for the configuration below,

units metal
boundary s s s

atom_style atomic
lattice fcc 3.52
region box block 0 16.0 0 16.0 0 2.828427
create_box 3 box

lattice fcc 3.52 orient x 1 0 0 orient y 0 1 1 orient z 0 -1 1 origin 0.5 0 0
create_atoms 1 box

pair_style eam
pair_coeff * * Cu_u3.eam

neighbor 0.3 bin
neigh_modify delay 5

region lower block INF INF INF 0.9 INF INF
region upper block 0.0 INF 14.1 INF INF INF
group lower region lower
group upper region upper
group boundary union lower upper
group mobile subtract all boundary

set group lower type 2
set group upper type 3

#crack
region crack block -1 8 6.0 6.5 INF INF
delete_atoms region crack

temp controllers

fix 1 all nve
fix 2 boundary setforce 0.0 0.0 0.0
thermo 500

tension

#velocity mobile create 10 887723 temp new
#velocity upper set 0.0 0.0 25.0

velocity mobile ramp vy 0.0 2.0 y 1.4 14.6 sum yes

dump 1 all custom 1000 crack.dat.* id type x y z

timestep 0.001
run 3000

And is not opening if I extend the same for a bigger problem, tried lot of combinations and orientations of the structure. Would be glad to know some tips for a successful crack opening.

Thanks
Pattabhi

If you pull hard enough and long enough, how can it not crack or come
apart at some point?

Steve