[lammps-users] Can I specify boundary velocity to be constant? how can I do that

Dear All Developers/Users,

May I know, how to specify the displacement boundary conditions in lammps.
I need to conduct a uniaxial compression/tensile simulation, with the ends of the specimen moving with prescribed velocity in the uniaxial direction, and without constraining the lateral movement of the atoms.

I have tried the fix_deform but I am not satisfied because it uniformly rescales the atoms in the interior.

I found the documentation of fix_deform also is not clear and it is not given clearly about the boundary conditions.
In few of the questions in this form I found a command known as fix_uniaxial, but I don’t find it in the latest version nor in the documentation. Can I know how to use that command and whether that feature is still present in LAMMPS

Please help me.

Thank you,

M

You can set the velocity of those atoms with the velocity command.
Turn off force on them via fix setforce. Then they will move as
you wish when integrated.

Steve