yade-users team mailing list archive

["Feng, Chen" <fchen3@xxxxxxx>]

I am currently trying to implement the CC in YADE according to the previous 
discussion, I wonder if I can get some help for the following issues:
(1)
the first step is to get sum(|SFi|), which is sum of the norms of resutant 
forces on bodies, and I am debuging a two ball example that is easy to trace 
the results, for example, if we have a sphere that has 3 contacts, how can I 
get the contace force (I think can be represented by cf_x[i], cf_y[i], 
cf_z[i])? I wonder it should be obtained through the pointer:

ParticleParameters* pp = 
dynamic_cast<ParticleParameters*>(body->physicalParameters.get()); //How can I 
find the detailed implementation of the ParticleParameters?

or

MetaBody::shared_ptr<PhysicalActionContainer> //I am wondering how I can use 
it

Therefore my first problem is how to get all the contact forces on a single 
sphere through that variable?

(2) When I have summed all the forces on a body(sphere), and if the 
calculation has reached a boundary value which the calculation should be 
stopped, how can I terminate the calculation in the program, e.g. in the 
ForceRecorder.cpp?

BTW, I have downloaded the YADE manual in the svn, I compiled the 
YadeUserManual.tex with WINEDT in WinXP, have you put figures in the manual:)?

I am not sure if I have made my questions clear, thanks a lot!

>===== Original Message From Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx> =====
>I think there is no file to look into currently. A separate engine
>should be created for iterating over all bodies and summing the
>resultant forces.
>You should re-post your question on the mailing-list however, Janek's
>ideas are surely more precise as mine.
>
>Bruno
>
>Feng, Chen a écrit :
>
>>Can you tell that which file should I look into for detailed implementation
>>for the convergence criterion (CC)?
>>
>>Thanks a lot!
>>
>>
>>
>>>===== Original Message From Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx> 
=====
>>>I must correct my previous definition of CC.
>>>
>>>It is better to define :
>>>
>>>           sum(|SFi|)  (sum of the norms of resutant forces on bodies)
>>>CC =    ___________
>>>            **sum(|Fi|)**    (sum of the norms of contact forces)
>>>
>>>In my previous definition, CC was proportional to the number of bodies
>>>because the denominator was mean(|Fi|).
>>>
>>>Sorry...
>>>
>>>Bruno
>>>
>>>
>>>
>>>Simply compute the sum of all forces on a body. At equilibrium, sum of all
>>>
>>>
>>Fi on body Bk is 0. If you sum now on all bodies, you still have
>>
>>
>>>sum of F over all i and k equal to 0 (SFik = 0).
>>>If SFik != 0, you are not at equilibrium.
>>>If you normalize SFik dividing it by the mean value of F, you have the
>>>
>>>
>>classical definition of CC.
>>
>>
>>>Bruno
>>>
>>>
>>>_______________
>>>Chareyre Bruno
>>>     Maître de conférence
>>>     Institut National Polytechnique de Grenoble
>>>     Tél : 04.56.52.86.21
>>>     ________________________________________
>>>     bureau I 08
>>>     Laboratoire 3S (Soils Solids Structures)
>>>     BP 53 - 38041, Grenoble cedex 9 - France
>>>_______________
>>>
>>>
>>>
>>>
>>>--
>>>_______________
>>>Chareyre Bruno
>>>     Maître de conférence
>>>     Institut National Polytechnique de Grenoble
>>>     Tél : 04.56.52.86.21
>>>     ________________________________________
>>>     bureau I 08
>>>     Laboratoire 3S (Soils Solids Structures)
>>>     BP 53 - 38041, Grenoble cedex 9 - France
>>>_______________
>>>
>>>
>>
>>/////////////////////////////////////////////////////////////////////
>>Chen Feng
>>
>>Graduate Student
>>Department of Civil and Environmental Engineering
>>University of Tennessee, Knoxville
>>(865) 974-4835 (Office)
>>//////////////////////////////////////////////////////////////////////
>>
>>
>>
>
>
>--
>_______________
>Chareyre Bruno
>      Maître de conférence
>      Institut National Polytechnique de Grenoble
>      Tél : 04.56.52.86.21
>      ________________________________________
>      bureau I 08
>      Laboratoire 3S (Soils Solids Structures)
>      BP 53 - 38041, Grenoble cedex 9 - France
>_______________

/////////////////////////////////////////////////////////////////////
Chen Feng

Graduate Student
Department of Civil and Environmental Engineering
University of Tennessee, Knoxville
(865) 974-4835 (Office)
//////////////////////////////////////////////////////////////////////

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