Computational Materials Modelling Using LAMMPS: Nickel sphere collision

Nickel sphere collision

In this blog, I have made a simulation on which two nickel spheres colloid each other. Through this simulation, I have introduces some new commands. Have a look at them.

Input script

#------------------ Setup the simulation -------------------------
log                   log.in
dimension       3
units                metal
atom_style      atomic
boundary         p p p



region box       block  -100 100 -100 100 -400 400 units lattice
create_box      1 box

lattice              fcc 3.52
region             1 sphere 0 0 350 50 units box
create_atoms  1 region 1
group              1 region 1

lattice              fcc 3.52
region             2 sphere 0 0 -350 50 units box
create_atoms  1 region 2
group              2 region 2


#-------------- Define Interatomic Potential -------------------

pair_style       eam
pair_coeff      1 1 Ni_u3.eam

compute 1     all pe/atom
compute 2     all stress/atom NULL virial

#------------- Run the simulation for equilibration -------------
velocity        all create 300.0 12345 dist gaussian
fix                1 all npt temp 298 298 .5 x 0.0 0.0 .5 y 0.0 0.0 .5

thermo         100
thermo_style custom step pe ke etotal temp lx ly lz press atoms

dump            eve all custom 25 dump.in id type x y z vx vy vz c_1 c_2[1] c_2[2] c_2[3]

timestep       0.001

fix                bal all balance 250 1 shift z 10 1
thermo_style custom step temp ke pe press vol

run               50


unfix            1


change_box all boundary p p s

#------------- Run the simulation for impact --------------

reset_timestep 0

velocity         1 set 0.0 0.0 -20.0 sum yes units box   #20 A/ps =7200 Km/hr
velocity         2 set 0.0 0.0 20.0 sum yes units box   #20 A/ps =7200 Km/hr

fix                 2 all nve
timestep        0.002
run                10000
#-----------------------end---------------------------------------
#------------------------------------------------------------------
Visit LAMMPS Manual for further explanation.

Simulation


If you see the nickel spheres disperses completely. The reason is the spheres move at very velocity. Each of the spheres moves at a speed of 7200 Km/hr!



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