[lammps-users] fix_uniaxial in 2d

Hi all.

The fix_uniaxial fix is nice since it does shear at constant volume. My question is whether there is some easy way to get it to do 2d systems. I have a square system in 2d (which in LAMMPS reality has a small z width) and would like to perform area conserving pure shear. fix_uniaxial dilates my z-direction in order to keep the volume fixed... while shrinking *both* the in-plane axes.

My 2 options appear to be:
1) use fix_volume/rescale in many small steps to approximate volume preservation
2) hack fix_uniaxial

Any suggestions for something easier?


I suggest you make a new fix uniaxial/2d which does precisely
what you want. Unless you can add a few simple checks to fix
uniaxial to do the right thing in 2d vs 3d.