General Mechanical

General Mechanical

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Solver Engine Error – unable to converge for non-linear analysis

    • Anand V

      I am using Ansys 2023 Student version. I am unable to analyse even simple non-linear problems. Even the one from Ansys innovation courses gave this 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."

      May I pleaseknow if this is due to the limitation of my system or is it sue to the limitation of the student version software or is it some other setting in my system?Non-linear problem from Ansys Innovation course

    • Sampat Kumar
      Ansys Employee

      Hi Anand ,
      Will you please check if the large deformation is on or not? 


    • Anand V

      Large Deformation is "on"

    • Nanda Veralla
      Ansys Employee

      Hello Anand,

      Well, it might be due to limitation of student version. How many nodes/elements are we dealing with here? Does the solve.out file contain any error, which can give more insights.



      • Anand V

        Hello Nanda,

        There are only 16951 nodes and 3444 elements whereas the Student license permits upto 100,000 nodes.

        Yes! the solver file shows several similar errors, one of which I have copied and pasted here below.

         *** ERROR ***                           CP =       7.438   TIME= 16:06:21
         Element 2980 (type = 2, SOLID186) (and maybe other elements) has become
         highly distorted.  Excessive distortion of elements is usually a       
         symptom indicating the need for corrective action elsewhere.  Try      
         incrementing the load more slowly (increase the number of substeps or  
         decrease the time step size).  You may need to improve your mesh to    
         obtain elements with better aspect ratios.  Also consider the behavior 
         of materials, contact pairs, and/or constraint equations.  Please rule 
         out other root causes of this failure before attempting rezoning or    
         nonlinear adaptive solutions.  If this message appears in the first    
         iteration of first substep, be sure to perform element shape checking. 
         *** LOAD STEP     1   SUBSTEP     1  NOT COMPLETED.  CUM ITER =      3
         *** BEGIN BISECTION NUMBER   1    NEW TIME INCREMENT=  0.17500E-01


    • Sampat Kumar
      Ansys Employee


      Hi Anand, 
      Would you kindly increase the substeps so that the load incrementing happens more gradually? I can see from your error message that it has one substep.






    • khesh.selvaganapathi


      what plasticity model are you using ?

      bi linear or multi linear ?

      are you loading by displacement or force ?

      i have simulated necking with a 2D axisymmetric model with multi linear plasticity and displacement control, displace it to a reasonable level, you should be able to calculate what this is, for say 30% strain.

      your high distortion elements warning is probably in the necking region.

      Track reaction force and if necking has occured, you will see a peak force that then drops.


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