Hi,
My model is two blocks system. At the beginning, I minimize and relax the system by fixing both end. Then I need to apply loading on the top surface, so I unfix the top layers. Just relax with fixing bottom layers. And I find out that the top surface atoms will move up and down, like a dynamic equilibrium. I want to remove or decrease this kind of vibration. But I tried a lot of ways, they didn’t work. So any suggestions?
(Followed is the input file)
Joe
3d metal indenter simulation
units metal
boundary p p s
atom_style atomic
lattice fcc 4.08
region up block 0 52 0 15 30.4 44
region both block 0 212 0 61 -40 300 units box
create_box 2 both
create_atoms 1 region up
lattice fcc 4.08
region down block 0 52 0 15 0 30
create_atoms 2 region down
mass * 196.97
EAM potentials
pair_style eam
pair_coeff * * auu3
neighbor 0.3 bin
neigh_modify delay 5
lattice fcc 4.08
region 1 block INF INF INF INF INF 4
region 2 block INF INF INF INF 40 INF
group bottom region 1
group top region 2
group mobile subtract all bottom top
#delete_atoms region 2
region 3 block 24 27 INF INF 40 INF
group replace region 3
fix 1 top setforce 0.0 0.0 0.0
velocity top set 0.0 0.0 0.0
fix 2 bottom setforce 0.0 0.0 0.0
velocity bottom set 0.0 0.0 0.0
equilibrate
compute new3d mobile temp
compute new1 all centro/atom fcc
compute new2 all stress/atom
compute new3 all pressure new3d
compute new4 all displace/atom
timestep 0.001
dump output all custom 200 * id type x y z fz c_new1 c_new4[1] c_new4[2] c_new4[3]
minimize 1.0e-8 1.0e-8 1000 10000
fix 3 all npt temp 300.0 300.0 100.0 x 0.0 0.0 1000.0 y 0 0 1000.0
thermo 500
thermo_style custom step temp pxx pyy pzz
thermo_modify temp new3d
run 10000
unfix 1
run 3000
apply displacement loading
fix 6 replace indent 1 sphere 0.01 1.5 1.0 3.0 units box
run 3000
unfix 6
run 7000