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[Justin <question702743@xxxxxxxxxxxxxxxxxxxxx>]

Question #702743 on Yade changed:
https://answers.launchpad.net/yade/+question/702743

    Status: Answered => Open

Justin is still having a problem:
Jan,

Does a DEM simulation ever converge relative to the time step? I.e., at
a small enough time-step, any reduction in time step would produce the
same results?

I ask, because I read in literature a good time-step is 20-40% of
rayleigh's wave. However, when I go well below that, the model still
produces slightly different results for different time steps.

To see example plots, go back to the shared link:
https://drive.google.com/drive/folders/1ygHckMnSksTSuMzfdsxSRS5pFaQP4-mC?usp=sharing

The full torque path:
Sensitivity_Testing_time_step.png

The zoomed in start to the torque path:
time_step_zoomed.png

Legend: 
 - Original: the original model with a time-step of 20% of rayleigh's wave
 - ts_1_wave_vtk: time step is 1% of rayleigh's wave and the model outputted VTK files
 - The other ones follow the same naming convention as ts_1_wave_vtk

This just goes back to trying to get my model to start from 0, at least
as close as possible. Note, these models are the same as above. Except I
reduced the sphere size even smaller to a radius of 1 mm. Note, the real
rubber particles this simulation is trying to mimic range from 0.2125 to
0.84 mm radius.

Thanks,
Justin

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