Hello,
I am using the UMAT code for sand hypoplasticity provided by Prof. Masin — https://soilmodels.com/download/plaxis-umat-hypoplas-zip/. I am simulating Axisymmetric condition in Abaqus. To check the results given by the hypoplastic model for sand. I started with a simple model as shown here. I have two steps: Geostatic step and pressure step. The parameters used as shown in the figures. I added permeability for the soil (as shown below) because I need it.

The problem is when I run the model using the UMAT code, it completes without showing/implementing any step calculation (photo attached) and no results will be found. When I use one of the materials models built in Abaqus, the model runs correctly. What is the issue. could you Please help !!.

Thanks in advance.
Isam

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16 Comments
  1. Kassem Dib
    Kassem Dib 1 year ago

    Dear Isma..
    I don’t know if it is possible to use permeability beside mechanical constant of the user defined material in Abaqus..
    Why you are using permeability?

    • Isma Khabis Author
      Isma Khabis 1 year ago

      I think you are correct. I think I have done two mistakes here. The first one is the solver; I am using soil solver that defines consolidation. This should be changed to static. The second is the permeability. I will change them and see.

  2. Isma Khabis Author
    Isma Khabis 1 year ago

    It is still not working Mr Kassem. Can I send you the model and the UMAT to check please.

  3. Kassem Dib
    Kassem Dib 1 year ago

    Hello Isma..
    Sorry for replying late..
    This is my email:
    kassem.dib@net.usj.edu.lb

  4. Tom Scheeper
    Tom Scheeper 12 months ago

    I am also running into the same issue. If you managed to resolve it, please leave a message here for the rest of the world 🙂

    • Tom Scheeper
      Tom Scheeper 12 months ago

      I have managed to resolve this after 4-5 hours of debugging. In the *.log file in the working directory I got the error “can’t find the specified path”. After some research it seems this referred to the fact I had not installed any compiler for the Fortran subroutines. So, the solution: install compatible versions of Intel Fortran (or similar) and Visual Code. In my case, still using Abaqus 6.12, I used this tutorial: https://www.researchgate.net/post/What_is_the_Specification_for_Linking_Abaqus_614with_Fortran_Compiler

    • Isma Khabis Author
      Isma Khabis 12 months ago

      I could not solve it till now. There is no such message in the .log file. Could you please tell me what are you simulating? Is it axisymmetric model or 3D model?

      • Tom Scheeper
        Tom Scheeper 12 months ago

        Hello,

        Yes I can tell you what I am simulating. I am simulating a seabed-spudcan interaction. The model is in 3D and I have modelled the seabed with Coupled Eulerian Lagrangian (CEL) to allow sand to physically displace. The spudcan has a rigid body constraint to not allow deformations. The model is a dynamics/explicit model (required for CEL) and I used the vumat to umat interface provided by Bienen on this website in order to use the hypoplastic model in dynamics/explicit (you can’t use .umat in explicit anlysis).

        Regarding your post, the only difference between my and your user material is that I have 16 rows defined in the User Material tab. The 16th material property is the initial void ratio (https://web.natur.cuni.cz/uhigug/masin/plaxumat/node5.html). For this I assumed a value between the minimum and critical void ratio (parameters 5 and 6).

      • Tom Scheeper
        Tom Scheeper 12 months ago

        In order to rule out whether the problem is in your material definition or with the installation of programs required to use subroutines, please do the following. Open Abaqus Command, if you setup everything correctly you see two messages about the Intel Fortran compiler and Visual Code. Then run “abaqus verify -user_std” without quotation marks and it will look for Visual Code and Intel Fortran Compiler: https://i.imgur.com/ZPhOHG2.png. In my case you can see, it successfully found these. When I was debugging, once I got the ‘pass’ here, the model worked.

  5. Mohammad Khalil
    Mohammad Khalil 12 months ago

    Hey Tom and Isam,
    It seems that I am running into similar issue,
    Actually, I am trying the Hypoplasticity Umat provided by prof. Masin for a simple single element model.
    and I am using the same material parameters depicted in the figure above (in Isam’s explanation).
    but the analysis is not running and I am getting the message “abaqus exited with an error” without any details.
    I tried Abaqus with the Fortran compiler for many Umat subroutine.
    but when it comes to the Hypoplasticity subroutine, it doesn’t work.
    any suggestion please? I am in desperate need to solve this issue.
    many thanks,

    • Tom Scheeper
      Tom Scheeper 12 months ago

      Check my comment of five days ago. Please check in the command windows of Abaqus whether it installation of Fortran compiler has succeeded.

      • Mohammad Khalil
        Mohammad Khalil 12 months ago

        Hiu Tom,
        Thank you for your reply,
        I have done this verification and I checked the compatibility between Abacus and the Fortran compiler using different Umat subroutines and it works,
        however, when it comes to the hypoplasticity, Abaqus doesn’t even start analysis.

  6. Isma Khabis Author
    Isma Khabis 11 months ago

    Hi Mohammad,

    The Hypoplastic model just works for Coupled Eulerian Lagrangian (CEL) in 3D simulation or dynamic/explicit or implicit in Axisymmetric simulation. It does not work for pore pressure elements. Also, I tried the static, it did not work.

    Let us discuss it further, here is my email: ikhasi1@lsu.edu

  7. Giada Orlando
    Giada Orlando 11 months ago

    Hi everyone, I have the same problem as Mohammad Khalil, I am trying to use the Hypoplastic model on a simple 1-element model to simulate a drained triaxial test, it doesn’t run, exits with a error without giving further information. Can someone Help?

  8. Zhenyu Liu
    Zhenyu Liu 7 months ago

    The comment given by Giada Orlando should be helpful.

    When we are using those “old” UMAT codes, always pay attention to some “outdated” commands.

    It seems that the “STOP” command used in those files will make your simulations abort immediately, if you are using a quite new version of Abaqus. WITHOUT any error notifications.

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