Problem with convergence using Mohr-Coulomb

I am having problem with converging nonlinear analysis. I am using static structural anslysis for 3D model of wall made of rammed earth. Firstly, I have made linear model that has proved to be correct, based on comparison with results from literature. However, when I add Mohr-Coulomb properties to the model, I face problems with convergence, even in part of analysis that should be linear. I have also added plastic behaviour to the model using Bilinear Isotropic Plasticity.

Model is placed on fixed support along bottom side of the wall, and it is loaded with vertical pressure and horizontal displacement along top side. Displacement is ramped and it should cause neonlinear behaviour of the wall, while pressure is constant. 

I have read through the forum and tried inputs like changing boundary conditions and using NEQIT,100 (or even 1000), but solution haven't converged. I have also plotted Newton-Raphson residuals, but since I don't have any contact area in my model, I am not sure how to use that information to help solution converge.

I am attaching the archive of my model.

Comments

  • KING1998KING1998 Member
    edited July 3

     Hi, please have you got the solution to your problem, I have the same problem if you can help me! Please

  • annaperannaper Member
    edited July 3

    Hi,

    I have managed to solve my model using Drucker-Prager instead of Mohr-Coulomb. If you need to use Mohr-Coulomb, try constructing Mohr's circle, and you should see where the failure envelope is in regards to the circle.

  • KING1998KING1998 Member
    edited July 3

    Thanks a lot for your answer! 

    The problem is also how do we go about modeling this.  I don't have a lot of knowledge about ANSYS.  Your help will be very beneficial.  It's for a school project.

     Thank you for everything.

     

  • annaperannaper Member
    edited July 3

    I am also still learning, you should post your own post and someone with more experience will hopefuly answer you. In the meantime, you can watch tutorials on YouTube or look for some literature with examples similar to your's.

  • KING1998KING1998 Member
    edited July 3

    OK thanks for the advice!

     

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