DRUCKER PRAGER Material Model

disladisla
I think this deserves its own post. It follows the discussion:

https://mecway.com/forum/discussion/479/ccx-mfront

I would like to help to the best of my ability, but the simplest DRUCKERPRAGER don’t seem too much documented in the TEFL website.

*Material, name=@CALCULIXBEHAVIOUR_DRUCKERPRAGER
…, , ,

I can’t relate constant with any reference from ABAQUS.
The simplest Druker Prager I can find in Abaqus is the lineal one but it has three constants. , , .
If anyone knows what does that means I could prepare an indirect verification test.

I think the most plausible one could @CALCULIXBEHAVIOUR_DRUCKERPRAGERCAP.
Constants are provided, It is documented and the final Linear+Cup Curve is provided for comparison.
I will be trying if anyone else is interested to finally compare.
Ccx 2.21 + lasts Portable MFRONT generated by Rafal.

Attached Parameters and Expected result.
https://thelfer.github.io/tfel/web/drucker-prager-cap.html

Comments

  • disladisla
    edited February 27
    Seems like the forum do not accept the symbols Bigger than and lower than and removes it's content.



    What I can't relate is constant MFRONT Tau with Abaqus beta, K , sigmac.

    NOTE: First post can't be edited. Damn it. Units are obviously wrong. Copy paste. My fault.
    These are the right parameters with their units:



  • disladisla
    edited March 2
    I have finished the testing and the agreement with the expected result is very good.
    DRUCKER PRAGER CAP material behavior needs custom cards as shown above and the portable MFRONT drivers recently published by Rafal.brzegowy in the Calculix forum.

    https://calculix.discourse.group/t/calculix-mfront/205/57?u=disla










  • FERNANDOFERNANDO
    I have tried the example and it does not converge
  • FERNANDOFERNANDO

  • disladisla
    edited March 2
    It must fail but not at the time step its shown on your monitor.(9.766E-6s ?¿?)

    Have you change material parameters or loading conditions.?
  • FERNANDOFERNANDO
    I have not changed anything
  • disladisla
    edited March 2
    Is there someone else that the convergence fails at that time step.?

    Is it for all s1 s2=s3 combinations or just some of them.

    Just for reference: Could you try this two time steps.



    EDITED: Loading conditions are not easy to constrain in such a way that the system is not over constrained and at the same time allows up to a certain level of asymmetry in the loading.
    The main goal is to obtain two of the principal stresses with the same value and a pure uniform stress State that triggers the Failure at the right spot.

    Let me know if that works now for you. If not, there are other more sophisticated options to constrain the model.
  • FERNANDOFERNANDO
    They all fail at the same time 9.766e-6s
  • FERNANDOFERNANDO

  • disladisla
    I would say you have something not properly linked to the .dll?

    This is how my working directory looks like. I'm using the dynamic version of ccx 2.21 from official webpage and very last MFRONT portable sent by Rafal v2.8.
    By sure the working directory is added to the path into the windows overall variable settings.



    Does it work for someone?.
  • FERNANDOFERNANDO
    I have tried with a directory like yours and I am missing the file mkl_rt.2.dll
  • FERNANDOFERNANDO
    I work with a ccx mkl pardiso 2.21 build included in mecway.
  • FERNANDOFERNANDO
    I did the compilation in Msys2 according to the instructions in the compressed file
  • disladisla
    I think that dll is related with the Pardiso solver. It should work also with the default PAstix solver.
    Suppress my entry on the ccx three to run with the default Pastix solver. It should work too.



  • FERNANDOFERNANDO
    It doesn't work either. It seems that the mkl library is related to the possibility of adding external libraries in calculix
  • disladisla
    edited March 3
    Yep. thats your problem. I have just try and it fails with the compiled version. Rafal portable links with the official version only.




    You must use the official ccx 2.21 downloaded from the webpage of the autor.

    http://www.dhondt.de/calculix_2.21_4win.zip
  • FERNANDOFERNANDO
    O.K. But it seems that with the official version I need the file mkl_rt.2.dll
  • FERNANDOFERNANDO
    I have downloaded the DLL but it doesn't work either
  • FERNANDOFERNANDO
    It is a pity. I am not able to run the official version
  • disladisla
    And if you order with Pastix neither. ¿?¿?.
  • FERNANDOFERNANDO
    I have tried it on another computer with W10 instead of W11 and it works perfectly.
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