Non-reflective boundary condition

Dear all,
I am trying to develop ultrafast laser shock on pure Cu metals by using ATC package. I need to build nonreflective boundary condition at the bottom of my simulation cell. But I don’t know how LAMMPS can create nonflective boundary condition. Can anyone please help me out? Any suggestion will be highly appreciated.
Thanks
Karim
graduate student
UTD

What is a non-reflective BC?

Steve

Dear all,
I am trying to develop ultrafast laser shock on pure Cu metals by using ATC
package. I need to build nonreflective boundary condition at the bottom of
my simulation cell. But I don't know how LAMMPS can create nonflective
boundary condition. Can anyone please help me out? Any suggestion will be
highly appreciated.

check out the boundary command in the LAMMPS documentation.

axel.

​Dear Steve,

In non-reflective boundary condition, wave will not reflect. Rather, wave is absorbed at the boundary layer.

Thanks

Karim

graduate student

UTD

If you mean a collection of atoms at a boundary that can absorb a shock wave

or dislocations that enter it, then no, LAMMPS does not have any special

commands for that. I’ve heard of those kinds of boundary conditions,

and I presume they could be implemented as a new fix in LAMMPS, but

I don’t know the details of how they work.

Steve

Dear steve,

I found a command “fix viscous”. In manual, it says that it helps to drain out energy at boundary. I tries to implement it on my case. But it is not working perfectly.

Another problem: I am using AtC package for laser shock peening. Initially electrons are heated up and absorb energy. After coupling between electron and lattice, both electrons and lattice supposed to have an equal equilibrium temperature. But I am not getting it. I am attaching the figure and script file. The figure is for 40 Ps. I tried for longer timesteps also. But got the same result.

Thanks

Karim

laserpart.txt (2.16 KB)

temperature profile.docx (95 KB)

The AtC folks can comment.

Steve