Blockiness limits of superquadric particles in LIGGGHTS

Dear all,

I am trying to simulate cylindrical particles as superquadric shapes in LIGGGHTS using cylinder radius as shape parameters a and b and half of cylinder height as c. For the blockiness parameters I use n1 >> 2 and n2 equal to 2. In order to model the cylinder edges as accurately as possible I kept increasing n1 which seems to work fine to a certain value (45 in my case), but further increase results in apparently unphysical behaviour of the particles (in the resulting packing, the packing height becomes much lower and the particles seem to overlap drastically and/or the particles do not come to rest and keep jumping around, even after a long simulated time).

Has anyone else encountered a similar problem? Is there a solution to this issue?

Thanks,
Markus