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Groundcheck KNN+AUTO (N+AUTOSPC-SET) issue

Phenom
Phenom

to all

 

i am doing some checking of a FEM using the groundcheck().

FEM is fully grouded

 

G-set, N-set all 6-dof passes

 

 *** USER INFORMATION MESSAGE 7570 (GPWG1S)
     RESULTS OF RIGID BODY CHECKS OF MATRIX KNN+AUTO (N+AUTOSPC-SET)  FOLLOW:
     PRINT RESULTS IN ALL SIX DIRECTIONS AGAINST THE LIMIT OF   7.784169E+03
           DIRECTION        STRAIN ENERGY        PASS/FAIL
           ---------        -------------        ---------
             1               1.330514E-06          PASS
             2               1.056021E+05          FAIL
             3               8.529908E-08          PASS
             4               3.243689E+09          FAIL
             5               1.978236E+10          FAIL
             6               1.222525E+10          FAIL

 

F-set  and A-set all 6-dof failed as expected as model is not free-free

 

Wha could be the cause of the (N+AUTOSPC-SET) failure in dof-2?

 

Thanks

Regards

Production: NX9.0.3.4, NX10.0.2.6
Development: VB.NET (amateur level !)
2 REPLIES

Re: Groundcheck KNN+AUTO (N+AUTOSPC-SET) issue

Siemens Phenom Siemens Phenom
Siemens Phenom

The n-set is the MPC and rigid element DOF's, so it seems all of those are OK. It is unusual for autospc to generate grounding espsecially in a translation direction, but it does happen to certain models. There a couple of ways to find out what is happening.  Assuming you did not turn off printing of the grid point singularity table, then inspect it and see which nodes were constrained by autospc(look for nodes constrained in Y translation) and see if it makes sense, or maybe there is a modeling error.

If that does not highlight the issue, then GROUNDCHECK has the option to request data recovery so you would actually gets stress results for the problem areas to investigate.

 


Regards,

 

Joe

Re: Groundcheck KNN+AUTO (N+AUTOSPC-SET) issue

Phenom
Phenom

Thanks. A mis-connection spotted so model was not quite right anyway. Looks a bit better now but no great

Production: NX9.0.3.4, NX10.0.2.6
Development: VB.NET (amateur level !)