[deprecated list] About the easiest method to obtain the contact force of each particle?

[Chen, Feng]

Hi, all:

I need to write a small routine so that the contact force of each particle can be checked from which I would like to accurately judge its value, if the contact force of one particle is (or close) zero, I should mark it as "quick" condition, suppose all particles are in the fluid. Which list should I look into? The ElasticContactLaw seems to loop over the contact but not for each particle.

Thanks in advance!

Feng Chen
Graduate Student
Department of Civil and Environmental Engineering
223 Perkins Hall
University of Tennessee, Knoxville, 37996
http://fchen3.googlepages.com/home

[Janek Kozicki]

Chen, Feng said: (by the date of Sat, 31 Jan 2009 01:23:17 -0500)

Post by Chen, Feng
The ElasticContactLaw seems to loop over the contact but not for each particle.

the sum of all forces acting on each body is stored in physical actions / bex
size of this container == number of bodies

[Chen, Feng]

Thanks Janek, is this similar to :ncb->physicalActions->find(idUnbal,actionForce->getClassIndex()).get())->force ??
However this gives the total force (unbalanced force), what I need is only the contact force, is there any way to extract that?
Thanks again for your help.

Feng Chen


-----Original Message-----
From: yade-users-bounces+fchen3=utk.edu-oU9gvf+***@public.gmane.org on behalf of Janek Kozicki
Sent: Sat 1/31/2009 2:07 AM
To: yade-users-oU9gvf+***@public.gmane.org
Subject: Re: [Yade-users] [deprecated list] About the easiest method to obtain the contact force of each particle?

Chen, Feng said: (by the date of Sat, 31 Jan 2009 01:23:17 -0500)

Post by Chen, Feng
The ElasticContactLaw seems to loop over the contact but not for each particle.

the sum of all forces acting on each body is stored in physical actions / bex
size of this container == number of bodies

[Chen, Feng]

Hi, Janek

I looked at the paper:

J. Kozicki, F.V. Donzé „YADE-OPEN DEM: an open-source software using a discrete element method to simulate granular material”. Engineering Computations, (accepted for publication) 2008

I think Figure 12 (b), or Figure 11 (b)- "distribution of forces" is enough to solve my problem, must I upgrade to the latest SVN to plot that? Sorry I am still using yade.0.11.1 :-P

Feng

-----Original Message-----
From: yade-users-bounces+fchen3=utk.edu-oU9gvf+***@public.gmane.org on behalf of Janek Kozicki
Sent: Sat 1/31/2009 2:07 AM
To: yade-users-oU9gvf+***@public.gmane.org
Subject: Re: [Yade-users] [deprecated list] About the easiest method to obtain the contact force of each particle?

Chen, Feng said: (by the date of Sat, 31 Jan 2009 01:23:17 -0500)

Post by Chen, Feng
The ElasticContactLaw seems to loop over the contact but not for each particle.

the sum of all forces acting on each body is stored in physical actions / bex
size of this container == number of bodies

[Janek Kozicki]

oh, that's just forces for each interaction. You can look on
interactions to get a contact force.

I thought that you need total force on each grain.

[Bruno Chareyre]

If I understand correctly, you need the same loop as for computing
unbalancedForce, don't you?
You can check the code, it's something like :

loop on bodies
{
...
f += Forces[body]
...
}

Bruno

Post by Chen, Feng
I need to write a small routine so that the contact force of each
particle can be checked from which I would like to accurately judge
its value, if the contact force of one particle is (or close) zero, I
should mark it as "quick" condition, suppose all particles are in the
fluid. Which list should I look into? The ElasticContactLaw seems to
loop over the contact but not for each particle.
Thanks in advance!
Feng Chen
Graduate Student
Department of Civil and Environmental Engineering
223 Perkins Hall
University of Tennessee, Knoxville, 37996
http://fchen3.googlepages.com/home
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