periodic boundary conditions for polymers

Dear LAMMPS users,

I am modeling a polymeric system. I am going to stretch the polymeric system. To do so, I am going to produce two walls in both side of my system an subject it to displacement. Here are the questions.
1-How can I produce the walls?

2-How can I measure the produced load in the walls due to displacement.

Thank you in advance for you help.



Your message subject says PBC. If you want PBC, then
do not use walls. Just use fix deform to stretch the periodic
box over time.

It you do not use PBC, then you can use walls. In which
case there are several fix wall options. They all store the
force with which the system atoms interact with the wall,
so you can output that.