access friction and inelastic collision contributions in the total loss of energy of the system

Asked by rox212

Dear all,

Is there a way to access the friction energy dissipation contribution? and the impact energy dissipation? Or to put in other words, the energy that is loss by friction and the energy that is loss by inelastic collisions?

I am using yade 2018b. And I am using the following engines with integrators/laws:

O.engines = [
  ForceResetter(),
  InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb()],label='collider'),
  InteractionLoop(
    [Ig2_Sphere_Sphere_ScGeom(),Ig2_Facet_Sphere_ScGeom()],
    [Ip2_FrictMat_FrictMat_FrictPhys(label='frict')],
    [Law2_ScGeom_FrictPhys_CundallStrack(traceEnergy=True,label='cundall')],
  ),
    GravityEngine(gravity=(0,0,-9.8)),
    NewtonIntegrator(damping=dampingCoeffCundall,label='newtonInt'),
    TranslationEngine(translationAxis=[0,0,1],velocity=velocityDamp,ids=idTop,dead=False,label='translat'),
    TranslationEngine(translationAxis=[0,0,1],velocity=velocityDamp,ids=idWalls,dead=False,label='translatbottom'),
    TranslationEngine(translationAxis=[0,0,1],velocity=velocityDamp,ids=idBottom,dead=False,label='translatBottom'),
    HarmonicMotionEngine(A=amplitude, f=frequency , fi = initialPhase, ids = idTop, label='combEngine',dead=True),
    HarmonicMotionEngine(A=amplitude, f=frequency , fi = initialPhase, ids = idWalls, label='combEngine1',dead=True),
    HarmonicMotionEngine(A=amplitude, f=frequency , fi = initialPhase, ids = idBottom, label='combEngine2',dead=True),
]

Thank you in advance!

Question information

Language:
English Edit question
Status:
Answered
For:
Yade Edit question
Assignee:
No assignee Edit question
Last query:
Last reply:
Revision history for this message
Jan Stránský (honzik) said :
#1

Hello,

> Is there a way to access the friction energy dissipation contribution?

see [1,2]

> and the impact energy dissipation?

You have (possibly constant) total energy Etot.
You can compute kinetic energy Ekin [3], elastic energy Eel [4], energy dissipated by friction [1,2]
The rest is other dissipation Eother.
Etot = Eel + Ekin + Efrict + Eother

Or you can use O.energy [5,6,7], where you can get other values if Law2 implements it.
O.energy also stores artificial dissipation of newton integrator numerical damping.

You can compare both approaches :-)

> loss by inelastic collisions

Note that for your case (only Law2_ScGeom_FrictPhys_CundallStrack), theoretically the only dissipation is only by friction and the numerical damping of newton integrator (there are no true "inelastic collisions")

Cheers
Jan

[1] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Law2_ScGeom_FrictPhys_CundallStrack.plasticDissipation
[2] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Law2_ScGeom_FrictPhys_CundallStrack.traceEnergy
[3] https://yade-dem.org/doc/yade.utils.html#yade._utils.kineticEnergy
[4] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Law2_ScGeom_FrictPhys_CundallStrack.elasticEnergy
[5] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Omega.energy
[6] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Omega.trackEnergy
[7] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.EnergyTracker

Revision history for this message
Bret Ritchie (ritchie141) said :
#2

Because kinetic energy is also conserved, we simultaneously have another constraint:
https://www.thirtyonetoday.me/

Revision history for this message
rox212 (rox212) said :
#3

Thank you for your answer. I am still confused, the energy dissipation in Cundall-Strack is only through friction and contact damping.
In Yade, which energy tags (tag example: "nonViscDamp") correspond to contact energy dissipation contribution? and which explicitly corresponds to friction contribution?

> Etot = Eel + Ekin + Efrict + Eother
Which tag corresponds to "Efrict"?

Thank you for your time and help!

Revision history for this message
Bruno Chareyre (bruno-chareyre) said :
#4

As pointed out by Jan, there is no contact damping in Yade's CundallStrack.
If Newton.damping =0 (which I recommend in quastistatic simulations) then the only dissipation is frictional.
And the collisions conserve kinetic energy (at least if they do not lead to plastic slip).
Bruno

Revision history for this message
Jan Stránský (honzik) said :
#5

> the energy dissipation in Cundall-Strack is only through friction and contact damping.

no, only through friction.

> "nonViscDamp"

it is numerical dissipation made in NewtonIntegrator for damping > 0

> and which explicitly corresponds to friction contribution?
> Which tag corresponds to "Efrict"?

It seems that none from O.energy.. You will have to use
cundall.plasticDissipation() # [1]

Cheers
Jan

Can you help with this problem?

Provide an answer of your own, or ask rox212 for more information if necessary.

To post a message you must log in.