[lammps-users] how to apply linear increased loading condition

Hi all

I need to apply a load on a group of atoms which is linearly increased from 0 to F during time interval t=(0,t), because this loading condition is in accordance with real linear loading condition in experiments.
I checked the ��fix setforce��, ��fix addforce��, ��fix aveforce�� commands in lammps command, but ��fix setforce�� can only apply a constant force on a group of atoms from the beginning of loading to end. Can I make a modification in lammps to implement it? How to make this modification?
Thank you~

Yang

Sure, add some input parameters to one of those commands
to specify the time dependence, then add the code to apply
it in the post_force() routine. Recompile and its done.

Steve

2008/7/7 YANG LU <[email protected]>:

Thanks Steve!!
Now I am gonna make a modification in some certain source codes. Which source codes should I add? I am not familiar with cpp programing. Can you give me some instructions.
Take ‘fix aveforce’ command for example, add force F=a*t, t=(0,T).
Can I add t denomination in fix_ave_atom.h, and add above formula to fix_ave_atom.cpp?
I can’t find ‘post_force() routine’ in the src directory.
Thank you.

Yang

Steve Plimpton [email protected] д����

See doc/Section_modify.html for details on how to modify
LAMMPS. I can't help you learn C++. The post_force() routine
is inside the fix. In this case, it is the one that applies the additional
force.

Steve

2008/7/8 YANG LU <[email protected]>: