Learning Forum

[matthew fig]

I am simulating the crushing of an aluminum cylinder using Mechanical and a multilinear model. I got to the point where needed to try adaptive meshing due to large deformation, so I activated the nonlinear remeshing model. The first time that Mechanical remeshes, I get an "Unknown error" message. Here is the relevant section of the solver output. I searched online for anywhere that the message found in the output has been seen before, and I had no luck.  Can anyone tell me what happened and how to fix it? I am using tetrahedral elements.

 

Thanks

 

 **** REGENERATE MESH AT SUBSTEP  1430 OF LOAD STEP      1 BECAUSE OF
      NONLINEAR ADAPTIVE CRITERIA

      PREPARING DATA TO REMESH......

      REMESHING REGIONS ARE CREATED; GENERATING NEW MESH......


 AmsMesher(ANSYS Mechanical Solver Mesher),Graph based ANSYS Meshing EXtension,v
 1.35.06f
 (c)ANSYS,Inc. v241-20230804
   Platform           :  Windows 10.0.22621 AmsMesher
 
 - 12:0:12 2024-4-20 AmsMesher started...
 
   ===================================================================
   == Mesh quality metrics comparison [ EType 285 ]
   ===================================================================
   Element Average    : ------Source/32894-----+------Target/44436----
   ..Skewness(Vol)    :    0.4666                   0.2436             
   ..Aspect Ratio     :    2.4440                   1.8848             
   Domain Volume      :  1.0562e-07               1.0548e-07           
 
   Worst Element      :  --------Source--------+--------Target--------
   ..Skewness(Vol)    :    0.9666  (e4495    )      0.8494  (e81110   )   
   ..Aspect Ratio     :   20.7607  (e13696   )     12.6873  (e91729   )   
   ===================================================================
   == Remeshing result statistics                                    
   ===================================================================
   Domain(s)          :   1      
   Region(s)          :   1      
   Patch(es)          :   9      
   nNod[New]          :   11729       
   nElm[New/Ef/Sd/Sr] :   44436 / 32894 / 7248 / 33152      
 
   Peak memory        :   132 MB AmsMesher
 
 - 12:0:17 2024-4-20 AmsMesher finished..
 - AmsMesher run completed in 4.115 seconds
 
   ========================= End Run =================================
   ===================================================================
 
 

 *** ERROR ***                           CP =    3173.672   TIME= 12:00:24
 New nodal normal was not correctly computed for node 16213 of face     
 16729 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3173.672   TIME= 12:00:24
 New nodal normal was not correctly computed for node 16213 of face     
 16730 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3173.672   TIME= 12:00:24
 New nodal normal was not correctly computed for node 16213 of face     
 16729 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3173.672   TIME= 12:00:24
 New nodal normal was not correctly computed for node 16213 of face     
 16730 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3173.703   TIME= 12:00:24
 New nodal normal was not correctly computed for node 16213 of face     
 16729 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3173.703   TIME= 12:00:24
 New nodal normal was not correctly computed for node 16213 of face     
 16730 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3173.703   TIME= 12:00:24
 New nodal normal was not correctly computed for node 16213 of face     
 16729 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3173.703   TIME= 12:00:24
 New nodal normal was not correctly computed for node 16213 of face     
 16730 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3175.109   TIME= 12:00:29
 New nodal normal was not correctly computed for node 16213 of face     
 16729 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3175.109   TIME= 12:00:29
 New nodal normal was not correctly computed for node 16213 of face     
 16730 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3175.109   TIME= 12:00:29
 New nodal normal was not correctly computed for node 16213 of face     
 16729 while doing Nonlinear Adaptivity.                                

 *** ERROR ***                           CP =    3175.109   TIME= 12:00:29
 New nodal normal was not correctly computed for node 16213 of face     
 16730 while doing Nonlinear Adaptivity.                                

 **** FAILED IN NEW MESH GENERATION! PLEASE CHECK THE ERROR FILE FOR DETAILS.


 *** ERROR ***                           CP =    3176.094   TIME= 12:00:31
 Unexpected error was encountered in NlAdptStartRun.F.  Please send the 
 data leading to this operation to your technical support provider, as  
 this will allow ANSYS, Inc to improve the program.                     


 NUMBER OF WARNING MESSAGES ENCOUNTERED=       1359
 NUMBER OF ERROR   MESSAGES ENCOUNTERED=         13

[Aurojyoti Prusty]

Hello,

The large deformation problems tend to distort the element which leads to convergence issues and that might be the reason why it is showing the error. Does the model involve alluminium with any type of rubber? You can try with hex elements if the geometry is not too complicated and go for tet element for little complex geometry parts. You can refer the below video to know how to handle Element Distortion Errors in Hyperelastic Material.

https://www.youtube.com/watch?v=fI2a_xP0veI&t=33s

Similar discussion below on why NLAD does not resolve issue if it involves plasticity.

Q. Why does nonlinear adaptive remeshing (NLAD) not resolve a metal plasticity application failing to convergence with element distortion error? - Ansys Knowledge

Please let us know.

Thanks,

Aurojyoti