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Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

(OP)
This is me being hyper picky, but assume I have a group of nodes that are sequential: "1001,2000,1"

It is evident that FEMAP is able to detect that they are sequential because when I select them, it shows exactly what I have above in the selection dialogue (i.e. 1001,2000,1) when I go to create a single point constraint (SPC).

But when I go to my .BDF file, it is written as one thousand individual SPC1 cards. Is there anyway to force FEMAP to write it as:

CODE -->

SPC1    1       456     1001    THRU    2000 

instead of:

CODE -->

SPC1    1       456     1001
SPC1    1       456     1002
SPC1    1       456     1003
.
.
.
SPC1    1       456     2000 
???

________________________
FEMAP v11.1.0
MSC Nastran v2013

RE: Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

if you're looking at a .bdf file, then your question refers to Nastran rather than FeMap ...

or maybe to how FeMap writes a .bdf IF Nastran allows that format, which would surprise me.

another day in paradise, or is paradise one day closer ?

RE: Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

(OP)
Hi rb1957. My question, as stated, is how to get FEMAP to write the NASTRAN file as shown (if possible). So it is a FEMAP question. The THRU syntax is certainly allowed by NASTRAN. My guess is that this is wishful thinking. ;)

________________________
FEMAP v11.1.0
MSC Nastran v2013

RE: Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

could you fake it by making an RBS to join your 1000 points to 1 ?

another day in paradise, or is paradise one day closer ?

RE: Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

(OP)
Hi rb1957 - I don't see any RBS's in the NASTRAN QRG, but I am assuming that it's some sort of MPC. Again, I was just being a little obsessive compulsive about my input file. But now that we're talking about it, I am really going to show my ignorance here.

You may wonder why I would have thousands and thousands of SPCs in my bdf. Here is what I have been doing. If I have solid elements in my model, which do not generally support DOF 456, as well has other elements (or MPC) in my model, which do support rotational DOF, I manually SPC out ALL of the nodes that belong to solid elements. Why the heck do I do this? Because I like to do it manually and keep AUTOSPC = YES so that I can use the grid point singularity table as a "bucket" to catch anything that I may have missed. This is me being hyper-aware of my constraints so that I can track down improper model grounding.

Now to be honest, I am relatively new to FEM/FEA (maybe 2 years of industry experience) and even newer to FEMAP/NASTRAN (about 3 months .. prior experience with ANSYS) ... so this could just be me being obsessive compulsive without any good reasoning. I welcome any feedback or thoughts people have on this. This is how I learn.

________________________
FEMAP v11.1.0
MSC Nastran v2013

RE: Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

"RBS" should've been "RBE".

I like your non-use of auto-SPC ! of course you can use auto-SPC then check that all the created restraints don't generate large reactions.

another day in paradise, or is paradise one day closer ?

RE: Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?


Hi,

You can include this line in your analysis setting / Nastran BUlk Data Options / Start Text (Off):

SPC1 1 456 1001 THRU 2000

Give it a try without defining the constraints in Femap.

Hope this helps !

Seif Eddine Naffoussi, Stress Engineer
www.Innovamech.com
33650 Martillac û France

RE: Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

Dear Samurai,
You can remove rotational DOF from solid elements automatically in FEMAP without writing any SPC1 card, neither using PARAM,AUTOMPC,YES: the key is to use commnd "MODIFY > UPDATE OTHER > PERMANENT CONSTRAINTS" > select all nodes from solid elements and next select the DOF you want to remove:



If you PREVIEW your analysis you will see that not any SPC/CPC1 card exist, the DOF removed are part of the GRID card !!.



Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

IBERISA
48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog de FEMAP & NX Nastran: http://iberisa.wordpress.com/

RE: Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

(OP)
@rb1957 - Thanks for your feedback! Good to know that I am not just an insane person ... well, that might not be a valid conclusion ;) Also, it may just be that I haven't had my coffee yet, but how do check the reactions of these DOF? What should I be inspecting in my output?

@compositecurves - That's actually what I have been doing and what spawned my question. I know that sooner or later, we all have to manually edit our input decks. But for now, my line of thinking was that if I have to re-run a model with some adjustments, than I have to remember to update the model in FEMAP AND in the input deck. Giving myself 2 opportunities to make errors gives me great consternation ... but I guess I just have to get used to the idea and start being extra, EXTRA careful. Thanks for your input!

@Blas - Wow! I'll have to give this a try; it looks like it's exactly what I am looking for. I like the idea of doing the extra research to figure out to get FEMAP to generate a deck exactly the way I want to; this helps to eliminate extra opportunities for errors as I mentioned above.

________________________
FEMAP v11.1.0
MSC Nastran v2013

RE: Force FEMAP to write a single SPC1 card using "THRU" instead of one for each node?

@blas ... are the freedoms removed from the stiffness matrix, or effectively autoSPC'd ? I suspect the latter, as I've always understood that NASTRAN assigns 6 dofs to each grid by default.

another day in paradise, or is paradise one day closer ?

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