Yade

Calibration and/or verification of yade outputs?

Asked by Sebastian Pucilowski

Hello,

I'm hoping to use YADE to explore quasistatic loading of biaxial and triaxial systems. However, before I can investigate more elaborate conditions and packings, I need to verify the setup of my DEM simulations against external results.

The results I generate for simple systems with simple boundaries and materials --- e.g. 2000 particles, 100kPa isotropic compression, constant confining pressure loading, simple FrictMat materials --- appear qualitatively sensible. For example, biaxial and triaxial loading for varying friction angles at:
[1] https://db.tt/xOatmayU [pdf]
[2] https://db.tt/CqwUsfXH [pdf]

However, I've come across difficulties trying to recreate simulations used in the YADE published papers list.

For example, in the paper "Numerical simulations of triaxial test with sand using DEM" Widuliński, Kozicki and Tejchman, 2009[3], trying to recreate their Figure 9[4] without rolling moments shows my deviatoric stress overshooting their reported value by 100kPa[5], and a very different volumetric strain response[6].
[4] https://db.tt/cdG8CdKz [png]
[5] https://db.tt/IxXF2c6o [pdf]
[6] https://db.tt/XjT7AYSi [pdf]

In the paper "Failure mechanisms in granular media: a discrete element analysis" Nicot, Hadda, Bourrier, Sibille, Darve[7], the authors used 150k particles, starting from loose initial packings, making verification and recreation of results difficult.

Other papers on the YADE published list are much more involved and difficult to replicate.

My question is: are there any specific or recommended published results to compare, recreate and/or verify that the output of my YADE simulations are sensible?

Sebastian

[3] http://www.ibwpan.gda.pl/docs/ahem/ahem56str149.pdf

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Bruno Chareyre (bruno-chareyre) said : 		#1

On 09/10/14 03:07, Sebastian Pucilowski wrote:
> shows my deviatoric stress overshooting their reported value by 100kPa[5],
 Do you have the same initial porosity and the same particle size
distribution?
Yours looks dense, theirs looks loose.

> My question is: are there any specific or recommended published results to compare, recreate and/or verify that the output of my YADE simulations are sensible?
I don't know better comparisons that what you already found.
Something that you should always check is if the evolution is nearly
quasistatic (e.g. unbalancedForce()<0.01) and/or if changing the strain
rate a little gives similar results.
In this case the chances that you are doing something wrong are small.

Bruno

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