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?
Solved! Go to Solution.
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.
Thanks. A mis-connection spotted so model was not quite right anyway. Looks a bit better now but no great