[lammps-users] Applying constant force

Dear all,

I am going to apply a constant force to one end of a carbon nanotube while the other end is constant. I have used command “fix setforce”, but the results does not make any sense. While I expect after some time to have a constant extension (with some fluctuations), the extension is increasing until the carbon nanotube rupturs. I am using MD, and the “pairstyle” is “Airebo”. What is your idea?

All the best,

Hi Iman,

Try using "fix aveforce" at the moving end and use "fix setforce 0.0 0.0
0.0" at the constant end . This is the link to the doc files for fix


Maybe the force you are applying is too big. Have you tried
reducing it by large factors and seeing what happens?