could any one help me to find whats wrong i am doing in the input script!!!

Dear lammps user,

i am trying to simulate the indentation of copper with spherical indenter by explicitly modeling the indenter as a rigid body.
could any help me to find what is wrong with the following input script.

yes i know that the spherical indenter option is their in the lammps command list
but for different shape of indenter it has to modelled explicitly,

so as a first step i tried to simulate the spherical indenter!!!
the interaction of indenter atoms and the Cu is defined by an LJ potential.

The input file is attached with the mail.
please help me.

thank you & with regards

initial_relaxation.in (3.85 KB)

Dear lammps user,

i am trying to simulate the indentation of copper with spherical indenter by
explicitly modeling the indenter as a rigid body.
could any help me to find what is wrong with the following input script.

this input is far to complex and the resulting system far
too large for anybody to have a serious look at it.

also, you don't say what your problem with this input is.

i suggest you first scale down the input to a very small fraction
of the size and build it step by step, adding component by component
to identify the what addition is creating the problem. once you have
that, you can try to create an input that has the minimum about
of commands (and the smallest possible system) that shows the
same problematic behavior. *then* and only then will you have a
good chance to get somebody to eagerly help you.

yes i know that the spherical indenter option is their in the lammps command
list
but for different shape of indenter it has to modelled explicitly,

so as a first step i tried to simulate the spherical indenter!!!!!
the interaction of indenter atoms and the Cu is defined by an LJ potential.

The input file is attached with the mail.
please help me.

please make it easier to help you.

thanks,
    axel.

Dear Axel,

first thanks for the suggestions. Please find the simplified/small size file attached with this mail.

the problem is after first run it is showing “nan” for thermodynamic variables out put.

thanking you
naveen

initial_relaxation.in (1.9 KB)

Dear Axel,

first thanks for the suggestions. Please find the simplified/small size file
attached with this mail.

the problem is after first run it is showing "nan" for thermodynamic
variables out put.

i don't get this. i get:

      0 6.4167792e-05 -53952.349 0 -53952.349
198.75447 931164
ERROR: Fix npt/nph has tilted box too far in one step - periodic cell
is too far from equilibrium state (fix_nh.cpp:1101)

are you using the current version of the code?

so that indicates that your dynamics are bad. after a short look
at the input, i wonder if a 25 fs time step is a bit too aggressive,
especially for an non-equlibrated system?

have you visualized the results with writing out coordinates
at every time step. should be informative as to why the system
goes "beserk".

axel.