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Sol 601. Initial penetration nodes.

Valued Contributor
Valued Contributor

Hello all.

 When calculating the flange connection problem with the emergence of the initial penetration of the flange plate  nodes. Flange plate thickness 2.5 cm "Measure Distance Between Nodes" gives the distance between nodes 2.500057 cm.

After starting sol 601 at node 39860 nodes initial penetration was 0.235 cm, Why?

 After removal from the calculation of the wall elements and restart  sol 601 node 39860 nodes initial penetration was reduced to 0.00123 cm. Why has it changed?

(view in My Videos)

 

The file part of the calculation model

4 REPLIES

Re: Sol 601. Initial penetration nodes.

Siemens Phenom Siemens Phenom
Siemens Phenom

FEMAP and NX Nastran by default work in the original Nastran's 8-character fields, since your model is way out in XYZ space 7000.0, 8000.0....units, there not a lot of significant digits when all you have is 8 characters to write out the nodal locations .....

 

GRID 39860 0-7031.398650.4135173.879 4
GRID 39861 0-7026.228657.7265175.301 4
GRID 39862 0-7021.478663.7885176.309 4

 

You can turn on wide field export for nodes and elements in the Analysis Case Manager, under NASTRAN Bulk Data Options, you can turn on "Large Field (Csys, Nodes) and you will get a lot more precision, I think this will help pick up some significant digits.

 

GRID* 39860 0 -7031.387 8650.4134
* 5173.879 4
GRID* 39861 0 -7026.2236 8657.7257
* 5175.3011 4
GRID* 39862 0 -7021.4703 8663.7882
* 5176.3086 4
GRID* 39863 0 -7015.5608 8670.5982

Re: Sol 601. Initial penetration nodes.

Valued Contributor
Valued Contributor

Thank you for the answer.

After applying the "Large Field (Csys, Nodes)" increased accuracy, but only in those nodes where the initial penetration of the flange nodes was small. In some nodes where the wall is attached to the flange, nothing has changed. If you remove the wall elements in all nodes of the flange decreases initial penetration  nodes.

Initial_penetrations.PNG

Re: Sol 601. Initial penetration nodes.

Siemens Phenom Siemens Phenom
Siemens Phenom

The NX Nastran team is looking at this issue right now.  I'll let you know as soon as I hear something.

Re: Sol 601. Initial penetration nodes.

Siemens Phenom Siemens Phenom
Siemens Phenom

It may not make a difference in this particular model, but when using shell elements in Contact Regions, I recommend that you turn on the option for Double-sided Contact for the NX Adv Nonlinear Connection Property.

Best Regards,
Chip Fricke
Principal Applications Engineer - Femap Product Development