Problem in tensile test

Hi all,
I was just trying to do some uniaxial tension test by using fix_deform and as a specimen sample I took single crystal Al. I use the available lamps script at

But, surprisingly I do not see any fracture even after the strain value of over 200%. The sample is stretched unusually at that high strain. I have seen a recent post about this type of behaviour but do not see any comments over it.

Could anybody please make some suggestion what I’m missing.

Thanks for your help in advance.


you are now posting the exact same question to this list for the 3rd time within 24 hours.
what is the point for that?

if you do not get an answer immediately that can have one or more of the following reasons:

  • nobody knows the answer
  • nobody cares
  • people that could help you are busy
  • people think that you should figure out the answer yourself for maximum learning effect
  • people don’t understand what you are asking

I suggest you ask the owners/authors of the script.
In general, asking a Q like “this script doesn’t do
what I expect, can you tell me why?” isn’t easy to answer.

You gave no indication LAMMPS is doing something wrong,
or that the script isn’t correct. Maybe the behavior you
see is normal. Maybe there is no fracture b/c the potential
is soft, or the system is small and there is no initial defect,
the strain rate is too large, etc, etc. No one else is likely
to dig into a random script and figure that our for you.

You could start with the examples/in.crack script which
does show fracture if you run it long enough, and see
what is different compared to your script.