Database units in NX Nastran 8.5

[amedish]

Hello Everyone,

I'm using NX Advanced 8.5 as pre/post and NX Nastran 8.5 as solver.
Sometimes I use to import FE models and results in FEMAP for some postprocessing wiht APIs so I need to be consistent with Units.

The problem I'm facing now is the following (composite material structure with several PCOMPs properties):

If I run the db in NX nastran with m/s/kg/N untis, the simulation runs well but I'm gonna have "not common" Stress units when imported in FEMAP.

If I run the same model with mm/s/t/N units, I have problem such as Excessive pivot ratio or the following FATAL

*** USER FATAL MESSAGE 4558 (ETR3D)
INAPPROPRIATE GEOMETRY OR INCORRECT MATERIAL DATA
SPECIFIED FOR ELEMENT WITH ID = 357772. SUBROUTINE REASON IS NUMBER 6.
*** USER FATAL MESSAGE 4558 (ETR3D)
INAPPROPRIATE GEOMETRY OR INCORRECT MATERIAL DATA
SPECIFIED FOR ELEMENT WITH ID = 357772. SUBROUTINE REASON IS NUMBER 6.
MID2 MATERIAL -G- 3X3 MATRIX INSUFFICIENT, MATERIAL ID = 200000079

How can the same model have problems only if exported with different units? Any suggestion?

Thank you.
Kind Regards
Amedeo

 

[Tuw]

Hi Amedeo,

From first glance, you will need to change the import unit setting in FEMAP to the same unit in order to read it right.
You can refer to the link below for unit comparison:

http://ftp.lstc.com/anonymous/outgoing/jday/faq/consistent_units

Each software will have difference default unit set, so I doubt you can directly get a right data without checking the default unit for each software.

Kind regards,
Tuw