I am trying to reproduce a TX monotonic, compressive test on a sand by using a 1-element, axisymmetric ABAQUS FE model, assigned to a SANISAND material. For this purpose, I am using a umat subroutine that is made available at soilmodels.com

In the ABAQUS model, I have set a material with 36 “depvar” state variables and 19 “user material – mechanical” parameters, as suggested by the documentation of the package. The only additional feature I set to the material is the density, set = 1 (ton/m^3). The adopted element type is axisymmetric stress, hybrid formulation (CAX4H). Two steps of analysis are set, static general. A confinement load of 100 (kPa) is applied to the two boundaries of the soil element throughout a “confinement” and a “shear” static steps of analysis. During the “shear” step, I applied a vertical (axial) displacement of the upper boundary of the sample, producing a deviatoric stress.
I properly linked the subroutine to the job in the “General” option of the job menu.
When I run the job, an error occurs before the analysis is run reporting “Abaqus/Standard Analysis exited with an error – Please see the message file for possible error messages if the file exists.”

What could the problem be? Thanks to anyone who could help in troubleshooting.

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8 Comments
  1. Srinivas Vivek Bokkisa
    Srinivas Vivek Bokkisa 7 months ago

    Hello Ricardo,
    I face the same issue. Did you find a solution?
    Thanks.

  2. Srinivas Vivek Bokkisa
    Srinivas Vivek Bokkisa 7 months ago

    Hello Riccardo,
    I face the same issue. Did you find a solution?
    Thanks.

  3. MOHD SAQIB
    MOHD SAQIB 7 months ago

    There are a few suggestions!.
    1- Check the Msg file or Dat file to find the error.
    2-Please, check all the constants (i.e-19) in your case are properly calibrated with units. If you aren`t incorporating all parameters, reduce constants.
    3- Check your drainage conditions, Put value of bulk_w according to the drainage conditions.

  4. Srinivas Vivek Bokkisa
    Srinivas Vivek Bokkisa 7 months ago

    Dear MOHD SAQIB,

    Thank you for the suggestions.

    Can you guide me how to initialize the state variables?
    The manual says, “state variables should all be initialised to 0 using sdvini.f”. But I don’t see a “sdvini.f” file in the downloaded package.
    I tried adding SDVINI subroutine of abaqus to the UMAT code but that didn’t help. I am unsure if it is the right thing do. Any help is much appreciated.

    Thank you

  5. MOHD SAQIB
    MOHD SAQIB 7 months ago

    SDVINI is a must. If it is not in UMAT, then you have to include it and initialize it according to your requirements.

  6. Srinivas Vivek Bokkisa
    Srinivas Vivek Bokkisa 7 months ago

    Thank you MOHD SAQIB for your insights.

    Commenting out all the “stop” commands in the umat code solved my issue.

    • Sanchari Mondal
      Sanchari Mondal 4 months ago

      Hi Srinivas,

      Did you use all the 19 parameters? I am trying to run a drained TXC 3D model, but I face convergence issue.

    • Riccardo Zabatta Author
      Riccardo Zabatta 3 months ago

      Hi Srinivas,

      thanks to your suggestion, I was able to run the Subroutine. Thank you so much! Hope this can be useful for other users.

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