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["Danny (Dingeman) van der Haven" <question700213@xxxxxxxxxxxxxxxxxxxxx>]

Question #700213 on Yade changed:
https://answers.launchpad.net/yade/+question/700213

    Status: Answered => Open

Danny (Dingeman) van der Haven is still having a problem:
Hi Jerome and Bruno,

Thank you for your replies.

I checked and the simulations always reach abs((sigma_ii - goal)/goal) <
PeriTriaxController.relStressTol for the z-axis. Because stressMask = 4,
only the z-axis stress should matter.

On another note, PeriTriaxController.relStressTol does not allow itself
to be plotted. However, I can print it and the value it has is as
specified in the setup script. I can also create a boolean to check if
abs((sigma_ii - goal)/goal) < PeriTriaxController.relStressTol, which
becomes true near the end of the defined compression stage.

If I do not fix the particles then the simulation reaches
unbalanedForce() < PeriTriaxController.maxUnbalanced. The simulation
advances to the next stage and completes successfully. However, this is
only the case if I set the target stress to -0.8e6 or smaller absolute
values. If I set the target stress to -1e6, the simulation stops the
compression around sigma_zz = -0.83e6 and does not continue to the next
stage but does keep iterating. (The unbalancedForce() is well below the
tolerance.) Why does YADE stop the compression and how can we reach
higher absolute stress values?

If I fix the particles then unbalancedForce() = NaN. The target stress
is reached but the simulation does not initiate the decompression stage.
Likely, PeriTriaxController cannot evaluate unbalancedForce() <
PeriTriaxController.maxUnbalanced due to the NaN value. Is there a way
to circumvent this? I would very much like to compare fixed normal
particles vs fixed level set particles.

I am sure the next stage is not reached in case of fixed particles,
because if I replace the next stage with

def compactionFinished():
           triax.maxUnbalanced = 10

the value of maxUnbalanced in PeriTriaxController (labelled 'triax')
has not changed.

@Bruno: If I set triax.maxStrainRate=(0,0,0) for any stage, that stage
stops progressing at all.

Kind regards,
Danny

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