[lammps-users] A little question about 'fix_addforce'

Hi, all,

As described in the LAMMPS manual, command ’ fix_addforce ’ could add fx, fy, fz to the corresponding component of force of each atom in the group, however, does this mean a constant increment will be added for every time step? For example, if command ’ fix kick flow addforce 1.0 0.0 0.0’ was used and for a 1000 timesteps running, will the final fx of the atoms in the group be 1000(suppose fx at the start is 0)?

By the way, there are many examples of deforming a nanowire(with free surface along the axial direction) through displacement control, are there some ways to deform such nanowire by load control?



You're asking as if force is a cummulative quantity, maintained
across timesteps. It isn't. It is zeroed every timestep. Fix addforce
simple adds in the delta force every timestep to whatever the
current force is on that timestep. If you want to add a force
that increases over time, then use the variable input to fix addforce.


Thanks, Steve.

2011/2/8 Steve Plimpton <[email protected]>