The following is the very concise explanation of the problem.
I modified LAMMPS in.friction example.
The upper rigid wall is expected to:
1-be rigid (implemented by “fix rigid”)
2- be applied a constant load in “z” direction (by “addforce …” command) and it has to move by time integration in “z”
3- have a constant velocity in “x” (by “velocity set …”)
But, the upper part doesn’t move in “x” direction. (velocity set command doesn’t work!!!)
What is wrong here?!
boundary p s p
neighbor 0.3 bin
neigh_modify delay 5
########## create geometry
lattice hex 0.9
region box block 0 50 0 22 -0.25 0.25
create_box 4 box
region lo-fixed block INF INF INF 1.1 INF INF
region lo-slab block INF INF INF 7 INF INF
region above-lo block INF INF INF 7 INF INF side out
region hi-fixed block INF INF 20.9 INF INF INF
region hi-slab block INF INF 15 INF INF INF
region below-hi block INF INF 15 INF INF INF side out
create_atoms 1 region lo-slab
create_atoms 1 region hi-slab