Defining a very low cohesive soil using Mohr-Coulomb

- September 19, 2022 at 4:28 pm
  
  ali.ismail
  Subscriber
  
  Hello,
  I'm using a student version of Ansys Workbench and I have the problem of "The solver engine was unable to converge on a solution" while using Mohr-Coulomb to define a 2-D soil with very low cohesion. I will be very grateful if anyone tells me what to do asap.
  
  The pic is for the boundary conditions where B and C are fixed on the X direction and A is fixed on Y. There is only gravity as an applied force.
- September 19, 2022 at 11:59 pm
  
  peteroznewman
  Subscriber
  
  Please check that you have the following 2D Plane Strain setting under the Geometry branch of Mechanical.
  If it shows you have a 3D model, follow the instructions in this thread: /forum/forums/topic/problem-with-flex-sheet/
  - September 20, 2022 at 5:07 am
    
    ali.ismail
    Subscriber
    
    Thank you for your reply.
    The model is 2D and the analysis is already plane strain.
    Actually, everything works well when the friction angle is 30 degrees and the cohesion is 0,01 Mpa. But when I reduce them to 15 for the friction angle and 0,001 Mpa for the cohesion I get in addition to the error also 2 warnings, which are:
    The error:
    ”The solver engine was unable to converge on a solution for the nonlinear problem as constrained. Please see the Troubleshooting section of the Help System for more information.”
    The warnings:
    ”The unconverged solution (identified as Substep 999999) is output for analysis debug purposes. Results at this time should not be used for any other purpose.”
    ”One or more objects may have lost some scoping attachments during the geometry update. You tun identify these tree objects by filtering the tree using the Scoping option set to Partial.”
    
    The last one I also get when the angle is 30 and the cohesion is 0,01 Mpa.
    
    I would like to know if there are other possibilities for the cause of the error ?