Extracting maximum Hill's failure criteria

[L D]

Hello everyone,

In addition to extracting the Von Mises stresses, I have to extract the maximum Hill's criteria for all elements.
The only documentation I could find on it was applying :
ft = 'HILL' 
With the failure theory being {HILL, HOFF, TSAI, STRN, None}
In the class pyNastran.bdf.cards.properties.shell.PCOMB

Is there a way to extract from an OP2 file the maximum Hill's criteria for a number of elements?

Thank you in advance for your help.

Best,

Laurène 

[Steven Doyle]

Yes, the stats you listed in your other email has them.   That tells you how to access them, e.g.,

model = read_op2(op2_filename)

  ctria3_composite_force_failure_indices =  model. op2_results.failure_indices.ctria3_composite_force[1]  

op2_results.failure_indices.ctria3_composite_force[1]

  type=FailureIndicesArray nelements=1895; table_name='OEFIT'

  data: [1, nelements, 3] where 3=[failure_index_for_ply (direct stress/strain), failure_index_for_bonding (interlaminar stresss), max_value]

  data.shape = (1, 1895, 3)

  element type: TRIA3LC-composite

  sort1

  loadIDs = [1]

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[L D]

Perfect, thank you very much for your help!

Best,

Laurène

[ashwin prabhu]

Hi  Laurène or Steve,

Can you guys let me know if you guys were able to get the maximum failure index(maximum Hill's criteria) for a number of elements.

op2_results.failure_indices.ctria3_composite_force[1]

  type=FailureIndicesArray nelements=1895; table_name='OEFIT'

  data: [1, nelements, 3] where 3=[failure_index_for_ply (direct stress/strain), failure_index_for_bonding (interlaminar stresss), max_value]

  data.shape = (1, 1895, 3)

  element type: TRIA3LC-composite

  sort1

  loadIDs = [1]

Do let me know how we can print this data out to a frame i.e. like failure_index_for_ply or failure_index_for_bonding  and max_value.

Thanks,
Ashwin

[Steven Doyle]

I don’t really remember that issue, but based on the previous thread, my guess is you’re not using the main branch directly from github.  You’re probably using 1.3.

Steve

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[ashwin prabhu]

Appreciate you getting back, i do understand the thread is a year old, but what i am trying to do is similar to what Laurène was trying.

I have checked the version steve that i have its 1.3.3 which i have pip installed as suggested.

What i am trying is to print the elements related to a particular composite material and extracting maximum Hill's failure index for all those elements.

what i am getting from the above code is as below

failureInd   type=FailureIndicesArray nelements=3684; table_name='OEFIT'

  data: [1, nelements, 3] where 3=[failure_index_for_ply (direct stress/strain), failure_index_for_bonding (interlaminar stresss), max_value]

  data.shape = (1, 3684, 3)
  element type: TRIA3LC-composite
  sort1
  loadIDs = [11001]

Do let me know how i can proceed here.

I am looking into test_op2 to check if any other tables can help or something.

Again appreciate you getting back.

[Steven Doyle]

Ashwin, 

 Try the main branch on github.  I believe the 1.3.3 doesn't support failure indices properly.

Steve

To view this discussion on the web visit https://groups.google.com/d/msgid/pynastran-discuss/bcef2871-271b-47a1-b20e-d17f5ad1600dn%40googlegroups.com.

[ashwin prabhu]

Hi Steve,

Have taken the main branch as suggested.

I am trying to get the data something like attached.

Can you please help me out if its possible to do so.

[Steven Doyle]

I'm not sure exactly how it's stored, but you can see if you run the following on the command line:

>>> test_op2 your_file.op2

You'll see a summary of the data in the file.  If you're familiar with say extracting pcomp stress, it should be similar to that.  An IDE helps as well.

To view this discussion on the web visit https://groups.google.com/d/msgid/pynastran-discuss/ffde1979-2ed4-41ac-8743-bc712ebb71f4n%40googlegroups.com.