Hi,
I am working on a nano-indentation problem using a berkovich indentor. Dimensional parameters are not exact yet. But I am trying towrite the script to obtain the force on the indentor with its displacement.
This is how my current input file looks like:
#3d indent simulation singlecrystal
dimension 3
boundary p p s
atom_style atomic
units metal
#Create Geometry
#Simulation box
lattice fcc 3.615
region box block -45.188 45.188 -45.188 45.188 -54.225 36.15 units box
create_box 2 box
#Sample
lattice fcc 3.615
region mybox block -45.188 45.188 -45.188 45.188 -54.225 -10.845 units box
create_atoms 1 region mybox
#Identify bottom layer and movable copper atoms
region bottom block INF INF INF INF INF -43.380 units box
group bottom region bottom #Bottom layer
group sample region mybox #Sample
group mobile subtract sample bottom
region thermoatoms block INF INF INF INF -43.380 -30.728 units box
group thermoatoms region thermoatoms
#Masses
mass 1 63.546
mass 2 12.011
Potentials
pair_style hybrid morse 4.5 eam
pair_coeff * * eam Cu_u6.eam
pair_coeff 1 2 morse 4.5 0.087 5.14 2.05
neighbor 2.0 bin
neigh_modify delay 5 exclude type 2 2
minimize 1.0e-4 1.0e-6 100 1000
fix 1 mobile nvt temp 300.0 300.0 0.01
compute samptemp sample temp
timestep 0.001
thermo 100
thermo_style custom step press c_samptemp
#run 1000
unfix 1
reset_timestep 0
#Diamond Indentor
variable x equal 1
lattice none
lattice diamond 3.3
region plane1 plane 0 0 0 4.996 2.88 -9.610 side out move NULL NULL v_x
region plane2 plane 0 0 0 0 -5.769 -4.8052 side out move NULL NULL v_x
region plane3 plane 0 0 0 -4.996 2.88 -9.610 side out move NULL NULL v_x
region plane4 plane 0 0 10.0 0 0 1 side out units box move NULL NULL v_x
region myindentor intersect 4 plane1 plane2 plane3 plane4
create_atoms 2 region myindentor
fix 3 mobile nve
fix 2 bottom setforce 0.0 0.0 0.0
fix 4 thermoatoms temp/rescale 10 300.0 300.0 0.01 1.0
fix 5 indentor wall/region myindentor harmonic 100.0 0.0 7.0
#fix 6 indentor move linear NULL NULL 1.0 units box
dump 1 all xyz 100 dump.indent.xyz
dump 2 sample xyz 100 dump.sample.xyz
#velocity indentor set 0 0 -1.0 sum no units box
thermo_style custom step f_5 press c_samptemp
run 22000
Now, on running, ERROR :lost atoms is coming. I have also tried fix rigid but it is also showing the same error. I think on moving the indentor it is crossing the defined region and thus the error lost atoms. Is it correct? Please correctme if I am wrong and how should i approach to get the correct force values.
Thanks in advance
Yours Sincerely
Ayush Suhane
Dept.of Metallurgical Engineering
IIT(BHU)