Learning Forum

[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?

[Sampat Kumar]

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

Regards, 
Sampat

[Anand V]

Large Deformation is "on"

[Nanda Veralla]

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.

Thanks,

Nanda

[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

"REASON FOR TERMINATION. . . . . . . . . .ERROR IN ELEMENT FORMULATION           
 RESTART BY RE-RUNNING THE ANALYSIS

[Sampat Kumar]

 

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.

Regards, 
Sampat

 

 

 

 

[khesh.selvaganapathi]

Anand,

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.