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NX non linear material FEM/Sim Problem

NX non linear material FEM/Sim Problem

NX non linear material FEM/Sim Problem

(OP)
thread825-202613: NX Nastran Contact analysis

I used the above thread as initial information because I am doing a non linear material FEM.

Currently we are investigating the ability to model organics and thus are using Ogden and Mooney-Rivlin Materials.

My problem is exactly the same as the one referenced above.  I can apply a Fixed Constraint to one face of a 2x2x2 inch cube.  The cube is meshed using Tet(10) elements and therefore is a 3D solid body.  I apply a pressure to the opposite face and get the error as follows.
"NASTRAN Msg:      ***WARNING: No element connection for node 1 directions 4, 5, 6
                  ***WARNING: Similar warning suppressed for 313 other nodes.
NASTRAN Msg:      ***WARNING: Nodal degrees of freedom without element
                              connection have been fixed for data input file.


This is a very confusing error message to me. When I mesh the box as a solid body, how are the elements not connected in some way ?  The simulation will work if I apply two Enforced Displacement Constraints(the only displacements are in the X and -X directions with all others zero'ed) to the opposite faces but gives me an error when i attempt to Fix on face and load the other.


Any help is appreciated !  

RE: NX non linear material FEM/Sim Problem

Hello!,
Make sure to include PARAM,AUTOSPC,YES in the Bulk data section, this way NASTRAN will remove all rotation DOF on solids.
Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director
 
IBERISA
48011 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog de FEMAP & NX Nastran: http://iberisa.wordpress.com/

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