Not inserting all sizes of spheres

Submitted by mschramm on Tue, 12/03/2019 - 06:07

Hello,
I am trying to fill a box with 3 different sized spheres but only the largest two spheres are being inserted.

I have called the template fix 3 times with 3 different sized spheres then I call the distribution fix and have
30% for the smallest sphere, 35% for the med, and 35% for the largest but I am not seeing the smallest sphere.

I attached a simple file that replicates my error. LIGGGHTS version is the public 3.8 release.
Any help/suggestions would be greatly appreciated.
Thank you.

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Daniel Queteschiner | Tue, 12/03/2019 - 10:43

Ah, this classic again.
a) insert/pack will never be able to reach a volume fraction of 0.6; the maximum with this insertion method is around 0.35
b) which brings us directly to the issue you see: there's simply not enough space to insert all the particles. The simple sequential inhibition (SSI) algorithm used in insert/pack starts inserting the largest particles and simply stops when there's no more space for insertion, hence you're missing the smaller particles ... LIGGGHTS should give you a warning about less particles inserted than request. As soon as you see this, your size distribution will be messed up.