I made a Lammps script for the case shock propagation using diaphragm breaking method.
I made a 3d input script with negligible thickness in z dimension (5 Angstrom), compared to x (5000 Angstrom) and y dimension (800 Angstrom). Periodic boundary in y and z, whereas fixed boundary in x direction.
Initially i run with argon gas as driver gas and driven gas, with same argon as diaphragm material by setting force and velocity equals zero on diaphragm material. I used LJ potential with cut-off distance. After that, I am trying to place a solid material in the downstream of shock propagation. I used Aluminum as solid material, with EAM potential. I used hybrid pair style, with EAM for aluminum and LJ/cut for all other interactions.
During the initial equilibration to keep the system at 300 K, aluminum shows a shrinking behavior, (unexpected trajectory) which is not good for my simulation. I would appreciate any help.
I used LAMMPS 2 August-2023 version.
I attached both my input script and trajectory output along with this. input.lammps (5.2 KB)
Have you tested your aluminum potential on its own? Can you reproduce the properties documented in the publication describing the potential?
Generally speaking, a simulation does what the input data tells it to do and it follows the rules of physics. So you have to ask yourself whether the settings and parameters are suitable for the conditions that you want to simulate. If you manipulate the settings or parameters so that you get what you desire, then you are replacing a simulation with a computer animation. We are all scientists here and prefer simulations.
Thank you very much for your thoughtful feedback.
I checked aluminum potential with EAM by using piston method for shock generation. Shock was generated. I didn’t reproduce any properties. Later I moved to diaphragm method, and tried to validate analytically. I produced some results with argon gas.
I will check the aluminum potential and made some validated results.
