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Re: I: Re: Porosity


Question: which value of friction angle do you use during the compaction phase? Should be the final one or should be lower than that? Would it be possible to run the analysis with a value equal to zero?
Anything between 0 and the final value. Higher than the final value would result in volumetric collapse at the beginning of the test.

I would expect that also at a small level of stress on the walls, this value of unbalanced force remains quite low.
unbF is non-dimensional, it is not affected by the level of stress. See it as a percentage of the loading.

I suppose that the reason you (if it were you) put the bool isARadiusControlIteration relays in the concept of maintaining a quasi-static equilibrium as much as possible during the analysis.
I see the problem now.
The point of cycling without expanding is just to speed up the simulation. Increasing sizes need an iteration on all bodies, and one on interactions. It is expensive. Increasing by 1e-5 at each step is more or less like increasing by 1e-4 each 10 steps, so...

Actually, unbF _should _be close to 1 during the begining of the growth, since most particles have 0 (unbF undefined) or 1 contact (unbF=1, since the resultant force IS the contact force in this situation). The only time when you really want it low is at the end of the compaction. I don't really care if the compaction is dynamic in between, and for sure the interval between growth is too small to let the sample really stabilize.
To make a summary I see that the unbalanced force reaches low values (say 0.07 or whatever) only after having compressed the packing. Am I escaping something?

That is correct and expected. Gaz particles can't be at static equilibrium under pressure, dense packings with many contacts can.