[lammps-users] Can the fix deform command use another value as L0?

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1

Dear LAMMPS users,

I am performing a tensile simulation using the "fix deform" command with the "erate" keyword, in order to strain my system at a fixed "engineering strain rate". The "fix deform" command uses an initial value L0, the initial box length, in order to calculate the change in the current box length L.

The documentation says that this L0 is the value from a create_box, read data, or read_restart command. My question is: can I specify another value as L0? In my case, I set up my system and then let it relax for a while. During the relaxation the box length usually changes a bit, and I would like to use this "new" L0 as the L0 in the "fix deform" command. Is this possible, and if so, how?

Thanks for your answers and suggestions.

Sincerely,
Christer H. Ersland.

2

The fix deform doc page says:

The size and shape of the simulation box at the beginning of the
simulation run were either specified by the create_box or read_data or
read_restart command used to setup the simulation initially if it is
the first run, or they are the values from the end of the previous
run.

So I think you are fine. If you invoke the fix deform command after
your relaxation
run, then it will use a L0 which is whatever the box size is when fix deform
is invoked.

Steve