Yade

Hertz-Mindlin model energy dissipation

Asked by rox212

Hi, I have a simple question:

From which part of the Hertz-Mindlin model is the energy dissipation coming if there is no dissipative force in the model? Can you please refer me to the publication from where this dissipative force appears or from where it comes the "normDampDissip" in this model?

I am using:

    [Ip2_FrictMat_FrictMat_MindlinPhys()],
    [Law2_ScGeom_MindlinPhys_Mindlin()]
    GravityEngine(gravity=(0,0,g))
    TranslationEngine(translationAxis=[0,0,1],velocity=damp,ids=(all),dead=False,)

For plotting the energy dissipation of the model I am using: "Hertz-Mindlin.normDampDissip"

If the system is energy conservative how it happens that we have energy dissipation?

Thank you in advance!

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Jan Stránský (honzik) said : 		#1

Hello,

> I am using:

please read [1] and provide a MWE.

> GravityEngine(gravity=(0,0,g))

GravityEngine is deprecated [2]

> For plotting the energy dissipation of the model I am using: "Hertz-Mindlin.normDampDissip"

surely you are using something else.
Here it is clear what you mean, but please try to use exactly the same code if referring it.

> From which part of the Hertz-Mindlin model is the energy dissipation coming if there is no dissipative force in the model? Can you please refer me to the publication from where this dissipative force appears or from where it comes the "normDampDissip" in this model?
> If the system is energy conservative how it happens that we have energy dissipation?

Documentation [3]:
"Moreover, it is also possible to include the effect of linear viscous damping through the definition of the parameters βn and βs."
Damping is the source. Of course, with damping, the system is "not energy conservative".

Have a look at Yade material models [4] and Modenese2012b [5]
Also source code is the option [6].

Cheers
Jan

[1] https://www.yade-dem.org/wiki/Howtoask
[2] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.GravityEngine
[3] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Law2_ScGeom_MindlinPhys_Mindlin
[4] https://yade-dem.org/wiki/ConstitutiveLaws
[5] https://www.yade-dem.org/doc/publications.html
[6] https://gitlab.com/yade-dev/trunk/-/blob/master/pkg/dem/HertzMindlin.cpp#L416

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