Subroutine of SANISAND model

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16 Comments
  1. David Mašín
    David Mašín 8 years ago

    Dear Pooja, thanks for your comment. Please check the Download section. I have uploaded updated version of SANISAND umat, including Plaxis interface. Thanks to my colleagues from Zhejiang University for releasing the implementation.

  2. Arun C
    Arun C 8 years ago

    Sir,
    is the sanisand umat is available for abaqus implementation?

  3. Arun C
    Arun C 8 years ago

    Thankyu sir..i got mymod_sas.for…stvarlini.for….umat.for…usr_add.for and usrmod.for
    Which one i should use

  4. Arun C
    Arun C 8 years ago

    I am using it for a pile group model sir 🙂 thankyu somuch for ur time

    • David Mašín
      David Mašín 8 years ago

      Arun, as you will see if you open the package, there is directly the umat.for file, which is the Abaqus implementation. Note however that there is no detailed documentation of this package, it is provided on SoilModels on as-is basis for experienced users. If you need some more documented constitutive model implementation, you may also want to check sand hypoplasticity.

      • Arun C
        Arun C 8 years ago

        Thank you sir for your time ..i am working on it..surely i ll let u know the progress

  5. Hossein Alimohammadi
    Hossein Alimohammadi 8 years ago

    I am using this model to simulate soil triaxial compression test by Abaqus (Axisymmetric model) but unfortunately it doesn’t give me the post peak softening results. I tried for Monotonic and cyclic loading and also with different soil model parameters but it is the same situation for post peak. Does it need any change in Umat code for softening or is there any solution (or suggestion) for this problem?

    • David Mašín
      David Mašín 8 years ago

      Hi Hossein, I contacted Yannis Dafalias, who contacted Majid Manzari and they have the following suggestion:

      David

      After I forwarded the site with the problem to Professor Manzari, I received the following response:

      Professor Dafalias,

      The student should use the parameters reported in the paper to simulate one of the drained triaxial compression tests shown in the paper. If he cannot get a stress-strain curve similar to what is shown in the paper, then the issue is with the numerical implementation of the model.

      Thanks,
      Majid

      It is a good idea for the user to use first exactly the input from the paper to check if he can get the same response. The issue of softening is quite tricky if not handled correctly.

      Best

      yfd

      • Alexandros Petalas
        Alexandros Petalas 8 years ago

        Hello Hossein

        If you write down the model input parameters you are using, the initial stress state and the maximum strain level you reach during your monotonic triaxial test I might be able to help you.

      • Hossein Alimohammadi
        Hossein Alimohammadi 8 years ago

        Dear David and Alexandros
        Thank you for your replies, Fortunately I could calibrate the UMAT code parameters with my Triaxial Test experiment results in Abaqus and it works well now.
        Best regards,
        Hossein

  6. MOHD SAQIB
    MOHD SAQIB 5 years ago

    Hello to all,
    I have been trying to simulate the cyclic triaxial test using the SANISAND04 umat provided here When I plotting the stress path (p-q plot), I am getting only the positive value of q. Maybe because the definition of q i.e; sqrt(J2) always gives a positive value. How to get the negative values of q?. Am I missing something in modeling in Abaqus?. Please help me to figure things out.

    Thanking you
    SAQIB

  7. Sudipta Bhowmick
    Sudipta Bhowmick 5 years ago

    Hi,
    How can I determine the model parameter ‘m’? I am using ABAQUS Explicit interface to simulate the simple shear behavior of sand.

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