Network of coarse-grained beads

Hello,

I was working on a network of a coarse-grained beads using LAMMPS 7Aug19 version. There are multiple beads (say 50) forming one chain and there are around 1000 chains in the system. When all the chains are linearly arranged, the job runs well.

But I cannot compress a network of beads to experimental density and wanted to ask the forum here if I am missing something. Since the coarse-grained model was developed using the atomistic crystalline structure, will this affect the simulation of the network in any case?

I am trying to create a large simulation box and then compressing it to reach the targeted density but the lateral stresses (pxx, pyy,…) are very high.

I wanted to ask for an opinion and try before sending the input fille here.

Best regards,

Without the details of your force field, it is impossible to say what the result should be. For sure, a general fact in polymer systems is that due to entanglement you may not be able to obtain the experimental density without inducing high strain on the chains (which seems to be what you are experiencing). Try looking at the literature of polymer simulations, in particular Monte Carlo based methods that generate low-strain configurations for the chains by iteratively building them. Here is an example of a code that is well integrated with LAMMPS: http://montecarlo.sourceforge.net/emc/Welcome.html

Giacomo