[lammps-users] Applying constant force

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1

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,
Iman.

2

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
aveforce:
http://lammps.sandia.gov/doc/fix_aveforce.html

Jan-Michael

3

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

Steve