General Mechanical

General Mechanical

USERMAT linear elastic code

    • janot.lubritz
      Subscriber

      Hey guys!

      I'm struggling with my first USERMAT code and thereby want to ask if somebody has a working .f code for a basic linear elastic material behaviour? The default USERMAT code (BISO material) works fine but when I tried to modify it into an elastic model (just for practice) the code compiles correctly but the APDL calculation does not give me any results (no displacement at all).

      A working code would give me the ability to check where my mistakes are or maybe somebody knows right away what could be my problem?

       

      Thanks a lot in advance!

       

    • David Weed
      Ansys Employee

      Hi Janot,

      You might want to instead use user_tbelastic.F. This can be found in the path C:\Program Files\ANSYS Inc\v2XX\ansys\customize\user. 

      • janot.lubritz
        Subscriber

        Hi David,

         

        thank you for your reply but I think that's not exactly what I'm looking for. The user_tbelastic.F does not look like a complete user material rather than definition of the elasticity parameters. My problem is that I did some changes to the usermat.f code to check out how the coding works but ansys does not give me any results when I work with the compiled usermat.f code. That's why I'm asking for an easier example than the BISO material law that is written in the usermat.f example.

        Later on I'd like to write a completely new usermat for my project but until then I need to figure out how usermat is actually working. Would be great if somebody has some more advice or tips on how to proceed with the first changes in an usermat code and make sure that everything is working correctly.

         

        Thank you so much!

        • David Weed
          Ansys Employee

          You can consider using Fortran write statements in the code so that when the MAPDL solver is running, you will get feedback in the solver output file. Also, if you want the model to behave in a linear elastic fashion, you can consider setting the yield stress to a very high value, then it will not enter the portion of the code where plastic strain is calculated. I would also suggest running a one element problem so that you can easily track the output.

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