Pressure Calculation

Hello everyone,
I am running glassy polymer simulation in lammps. I choose a box that is 1/3rd volume filled with glassy polymer chains(1000 chains). then I equilibrate this box and maintained zero pressure inside the box. Now I am filling 1/3rd volume by another 1000 chains.
now we get some positive pressure in our system.
can anyone explain why we are getting some positive pressure? while chains are in a glassy (solid) state.

This should be posted in the lammps category not under Materials Project.

This isn’t really LAMMPS question but a physics question.
You get a positive pressure when the system “wants to expand”.
There can be many reasons for that. It is impossible to say which in general.

1 Like