How to record the breakage of the cohesion?

Hello,

it depends on what you mean by "track the breakage of the cohesion"
(overall breakage, breakage of one specific interaction, of all
interactions...).

but it is definitely possible :-) so please be more specific and we should
find a solution
cheers
Jan

2014-12-22 4:21 GMT+01:00 whr <email address hidden>:

> New question #259419 on Yade:
> https://answers.launchpad.net/yade/+question/259419
>
> Dear all,
>
> I am a new yade user. I'm trying to use the cohesion friction model to
> simulate the behavior of sand stone.
>
> The material type is 'CohFrictMat'.
> I choose the following three to form the Interaction loop:
> Ig2_Sphere_Sphere_ScGeom6D()
> Ip2_CohFrictMat_CohFrictMat_CohFrictPhys
> Law2_ScGeom6D_CohFrictPhys_CohesionMoment
>
> I'd like to know if there is a way to track the breakage of the cohesion.
> Or should I write in the script to record the events that satisfy breakage
> condition myself.
>
> Thanks in advance.
>
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Dear Jan,

Thanks for your reply.

Actually, I'm trying to count the number of the cohesion-breakage during compression to compare with data on acoustic emission (AE) activity.

I tried the following code to count the interactions with broken cohesion every 100 steps.

   num = 0
   for i in O.interactions:
      if i.phys.cohesionBroken:
         num+=1

However, when I used that code, I found the number decrease sometimes. The amount of interactions (len(O.interactions)) also varies. FYI, I use periodic boundary.
So, any suggestions?

Cheers
Huanran

Hi Jan,

Thanks for your answer. I followed your suggestion and try that code. Then I got following error information:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "test_load.py", line 25, in saveAddData
    if i.phys.cohesionBroken:
AttributeError: 'NoneType' object has no attribute 'cohesionBroken'

I added following code and got results that seems right.

  except AttributeError:
      ret +=1

Am I right? Where did this AttributeError come from? It seems the interaction remains but no physical information.

Ah, sorry, I forgot the isReal check. Your solution is correct, but more
clean way is to put

if not i.isReal: continue

line:

def numBroken():
   ret = 0
   for id1,id2 in intrsOrigIds:
      try:
         i = O.interactions[id1,id2]
         if not i.isReal:
            continue
         if i.phys.cohesionBroken:
            ret += 1
      except IndexError: # the interaction does not exist any more
         ret += 1

cheers
Jan

Dear Jan,

Thanks for your answer. This way is better.

However, the interaction is not real should be counted into the broken one, right?
So I think the code should be:

if not i.isReal:
   ret +=1
   continue

Am I right?
In this way, the result is same as my previous method.

Cheers
Huanran

Thanks Jan Stránský, that solved my question.

sorry again, you are absolutely right :-)
cheers
Jan

2014-12-28 17:26 GMT+01:00 whr <email address hidden>:

> Question #259419 on Yade changed:
> https://answers.launchpad.net/yade/+question/259419
>
> Status: Answered => Solved
>
> whr confirmed that the question is solved:
> Dear Jan,
>
> Thanks for your answer. This way is better.
>
> However, the interaction is not real should be counted into the broken
> one, right?
> So I think the code should be:
>
> if not i.isReal:
> ret +=1
> continue
>
> Am I right?
> In this way, the result is same as my previous method.
>
> Cheers
> Huanran
>
> --
> You received this question notification because you are a member of
> yade-users, which is an answer contact for Yade.
>
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