Tensile test using fix deform - effect of system size?


I am running simulations to apply tensile tests on sheet materials. In fact, I am using this to measure the shear stress between the sheets.
I’m using periodic boundary conditions, as there is coul long range interactions.

I am noticing that the stress along the deforming direction (pxx) depends on the size of the system.

Has any one encountered such situation when using fix deform? Do you have any idea how stress should be normalized?


Don’t know how (in LAMMPS) you are computing “stress”, but

it is normally an intensive variable, i.e. independent of system

size. So if you monitor the equilibrium pressure (press or pxx, pyy, etc)

as a function of system size for a simple liquid or solid, it will

not be a function of size.