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Applying Constraints is extremely slow

Valued Contributor
Valued Contributor

Hi all,

 

I'm trying to model an end of a shell boiler, see attached pic. I use ctria6 shell elements. All edges (i.e. all circles) shall be constrained by fixed constraints. After switching to the sim file I choose the fixed constraint as Constraint Type, use the rectangle tool in order select all polygon edges (using the selection filter "Polygon Edge" ) and klick oK. It takes one hour and more until the constraints appear in the model. Sometimes they don't appear at all. I have to kill NX via task manager then.

I'm using a 6 months old PC with a Core i7-4790 processor and 32 GB RAM. The operating system is Windows 8.1 64 bit. The NX version is 9.0.0.19. Several years ago I calculated the identical problem using I-DEAS. Applying the constraints took 1 minute using a slower computer.

 

Does anybody have an idea what the problem could be? Probably the problem is sitting in front of the display Smiley Wink

 

Thank you in advance

 

muppets

 

7 REPLIES

Re: Applying Constraints is extremely slow

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Hello!,

Is strange behaviour, post your model here (make a ZIP of all files) to investigate if the problem is local of your computer or comes from the NX software.

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Applying Constraints is extremely slow

Valued Contributor
Valued Contributor

Thank you very much !

 

Greetings

muppets

Re: Applying Constraints is extremely slow

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Hello!,

When I try to open the SIM file then NX V10 gets locked, then something is wrong with your file. I have opened with sucess the FEM & PRTs files. Saved in NX10 and now I am able to open the SIM file. But if I load the FEM and get back to SIM again NX10 is locked.

 

nxerror-bcs.png

 

Investigating I see the source of the error: you have selected in your FEM file two bodies, the 3-D solid and the midsurface created in the IDEALIZED file. This is dangerous mixing the two bodies, because later in the SIM file you can select wrong geometry to apply the FIXED BCs in the circular edges, the circle coming from the midsurface or the circle coming from the solid edge?.

 

two-bodies.png

 

Better in the FEM environment in the SIMULATION NAVIGATOR click in 3_15_fr_fem.fem and select EDIT command, next xclixk in EDIT BODIES TO USE > SELECT and make sure to select ONLY the MIDSURFACE body, this way all your geometry selections will be correct, OK?.

 

select-one-body.png

 

Next if in the FEM file I create a new SIM environment file I am able to prescribe FIXED BCs in the poligon faces instantabeolsuly, not any delay exist, OK?.

 

applied-BCs.png

 

If I apply an arbitrary pressure load and solve for displacements & stresses using NX NASTRAN (SOL101) I get the following results (by the way, improve your mesh, you have a low quality elements to capture curved edges. you need to refine your mesh):

 

results.png

 

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Applying Constraints is extremely slow

Valued Contributor
Valued Contributor

Hello,

 

again thank you so much. Unfortunately the model still doesn't work. I chose the midface body via Edit - Select. Making a new sim file, selecting all polygon edges leads to a locked NX. I tried to use NX 8 instead of NX 9. There applying of the constraints works well.

 

Do you have NX 9, too? If so, might I ask you to check the model using NX 9?

 

Many grretings

 

muppets

Re: Applying Constraints is extremely slow

Valued Contributor
Valued Contributor

Hello,

 

one of my colleagues found the solution. We have to switch the Display Mode of the Edge Boundary Conditions to Collapse. After having done so and restarted NX it takes 4 seconds to allpy the fixed constraints.

NX9-CustomerDefaults-BCDisplay.PNGThank you again.

 

Many greetings

muppets

Re: Applying Constraints is extremely slow

Siemens Phenom Siemens Phenom
Siemens Phenom

Thanks for reporting the solution to the edge constraint's graphics problem. The performance of your model was very bad for me as well until I changed the display of the edge constraints to collapsed. I will report this as a PR using your model. Development needs to fix this issue with the offset edge display.

 

Regards,

Mark

 

Mark Lamping

Simulation Product Management

Product Engineering Software

 

Siemens Industry Sector

Siemens Product Lifecycle Management Software Inc.

www.siemens.com/plm

Re: Applying Constraints is extremely slow

Siemens Phenom Siemens Phenom
Siemens Phenom

I have some good news related to this topic. The PR I submitted (on Monday) has been closed as fixed (on Tuesday). There was a problem related to LBC offset display on circular edges. The fix went into NX 11 since that is our current development release.

 

I do appreciate that you shared your model and experience here so that Siemens PLM could evaluate and fix the poor display performance. Here is a summary of the PR.

 

Regards,

Mark

 

Mark Lamping

Simulation Product Management

Product Engineering Software

 

Siemens Industry Sector

Siemens Product Lifecycle Management Software Inc.

 

mark.lamping@siemens.com

www.siemens.com/plm

 

PR 7516699

 

PR Text

I was running NX 11 CAE build 197.

This was reported by a user on the Siemens community site.

Files: FEM, SIM

The SIM contains a simple model with 200 circular edges. All of the edges are constrained and displayed using the offset method. The display takes FOREVER and leads one to believe that NX is hung. It is simply taking a long time to display the offset edge LBCs. If you use the collapsed display mode, all is fine (a few seconds compared to minutes).

Final Response Text

A fix is sumbitted to Analysis_nx11.215 for the poor performance problem of LBC display on circular edges using offset display.