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Message #01953
R: Re: R: Re: Contact detection
Hi Luc,
I will deal with a dynamic problem and the global geometry is expected
to change a lot during the simulation.
Could you suggest me some papers where
I can find an example in which the SPA was used? Or a reference where it is
said that this contact detection method is fast or that it is fast according to
a specific kind of problem? Do you know other DEM softwares that are using the
SAP?
Many thanks,
Chiara
>----Messaggio originale----
>Da: luc.sibille@univ-
nantes.fr
>Data: 16/11/2009 17.58
>A: <yade-users@xxxxxxxxxxxxxxxxxxx>
>Ogg:
Re: [Yade-users] R: Re: Contact detection
>
>Hi!
>
> I coming back again
about the contact detection, actually in SDEC
>there was the choice between a
contact detection by grid and the
>simplest method were "every particles was
checked with every particles"
>because detection by grid is not always the
fastest method, that depends
>on what you are simulating:
>
>1/ When the
global geometry of your problem is more or less constant
>during the whole
simulation (for instance: simulation of a triaxial
>compression on a dense
granular assembly) the detection by grid is quite
>good, because you build the
grid once at the beginning of the simulation
>and you use the same grid during
the whole simulation. In addition you
>don't have to update the list of the
neighbouring particles too often.
>
>2/ When the global geometry of your
problem is not really fixed (for
>instance an avalanche of particles in a very
open space: you don't know
>a priori were the avalanche will propagate) it is
not sure if the
>detection by grid will be good, because you will have to
update often
>the grid to follow the particles or you will have to make an
inital very
>large grid, whereas only few cells of the grid will be used at a
given
>time step for the detection.
>
>Chiara, I read your mails quite quickly
so I don't remember if you have
>specified the kind of simulation you want to
do, but in my opinion
>contact detection is good, but not always ;-)
>
>Best,
>
> Luc
>
>Janek Kozicki a écrit :
>> Václav Šmilauer said: (by the date
of Mon, 16 Nov 2009 09:46:52 +0100)
>>
>>>>>> In another words, Olivier (and
you) didn't bother to google out articles
>>>>>> on that and thought he was the
smartest guy.
>>>>> yeah. That time there was a LOT of other stuff to bother
about, than
>>>>> colliders :) Paint me ashamed ;>
>>> I am not saying you are
to be blamed, but Frederic, as supervisor of the
>>> project, should have
managed that.
>>
>> I recall his point of view: SDEC has a lot slower collider
(IIRC:
>> it was "check everything with everything"?. Some SDEC user could tell
>> us). And so Frederic was very happy to see how much faster SAP is :)
>>
>
>--
>Luc Sibille
>
>Université de Nantes - Laboratoire GeM UMR CNRS
>
>IUT de
Saint Nazaire
>58, rue Michel-Ange - BP 420
>44606 Saint-Nazaire Cedex, France
>
>Tel: +33 (0)2 40 17 81 78
>
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