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Post processing - combining stress results in NX

Valued Contributor
Valued Contributor

Hello everyone,

 

I have one question. I know the function in NX to make an envelope operation over the stress results of several different load cases of a calculation.

My problem is, that using this procedure the final result is a scalar representing one stress component.

I am searching now for a possibility to use the envelope function, but based on the whole stress tensor of each single load case.

 

Does anybody has an idea or some experience how to realize this?

 

Many thanks in advance,

regards,

Georg

9 REPLIES

Re: Post processing - combining stress results in NX

Siemens Phenom Siemens Phenom
Siemens Phenom

Georg,

 

NX currently doesn't support enveloping of vector or tensor data. If I understand correctly, you want to:

 

1. Input stress (or other) tensor data to an enveloping process

2. Envelope across each tensor component to get an enveloped component

3. Output a tensor of enveloped components

 

One problem I see with this is that it may not represent a realistic load condition. That is, for a given element's tensor, the enveloped tensor component max/min values could come from different load sets. It may be an overly conservative representation of the stress tensor. Regardless, is this the type of operation you want to perform?

 

We have an NX Open program that automates the enveloping of results by performing multiple scalar enveloping operations. NX OOTB does one envelope calculation at a time. For displacements, the NX Open program envelopes X, Y, Z, and magnitude displacements independently, and produces 4 scalar outputs. One might be able to extend this approach to reconstruct an enveloped displacement vector from the scalar outputs for X, Y, and Z.

 

A less conservative approach would be to do a scalar enveloping of a particular quantity, but then retrieve/store the vector/tensor data of each extreme value instead of the extreme value. For example, if I envelope for maximum von Mises stress, rather than store the scalar von Mises stress, one could store the stress tensor data from the load set that produces the maximum von Mises stress. This would be an extension to the OOTB enveloping supported by NX.

 

Regards,

Mark

 

Mark Lamping

Simulation Product Management

Product Engineering Software

 

Siemens Industry Sector

Siemens Product Lifecycle Management Software Inc.

mark.lamping@siemens.com

Re: Post processing - combining stress results in NX

Creator
Creator

I only want to point out that request of GStricker could be interesting for calculation of Pressure Vessels according to ASME Code (or similar codes) where is the Standard that requires combination of stresses based on tensor component basis.

So I hope in the future this would be an implementation.

 

Regards

Re: Post processing - combining stress results in NX

Valued Contributor
Valued Contributor
Hello Mark,

thank you for your answer. After thinking some time about the possibilities I came to the point, that for my actual purpose the envelope function is not possible to use. So it looks like that I am forced to deal with the different load cases separately in future.

Nevertheless I need to say that it would be really helpful to include the two options you described above in NX as applications. It would make work easier for the users at a lots of points.

Regards,

Georg

Re: Post processing - combining stress results in NX

Gears Phenom Gears Phenom
Gears Phenom

@MarkLamping,

 

you wrote in your message that there is as NX Open script to envelop more than on result component at one go.

 

We have an NX Open program that automates the enveloping of results by performing multiple scalar enveloping operations. NX OOTB does one envelope calculation at a time. For displacements, the NX Open program envelopes X, Y, Z, and magnitude displacements independently, and produces 4 scalar outputs. One might be able to extend this approach to reconstruct an enveloped displacement vector from the scalar outputs for X, Y, and Z.

 

Is it possible to get this script. It would be good for instance to to have a collection stress components of all displacement components together. I assume that script might achieve this, right? Maybe the combination to one vector or so is also done already by yours over the last years.

 

Best wishes, Michael

 

I assume the script is from former NX version, at the moment we use NX 10.0.3, bat maybe that is no problem, isn't it?

| Production: NX10; Development: VB, TCL/TK, FORTRAN; Testing: NX11 | engelke engineering art GmbH, Germany
| Kudos for good posts! And if my post answers your question, please mark it as an "Accepted Solution".

Re: Post processing - combining stress results in NX

Siemens Phenom Siemens Phenom
Siemens Phenom

Michael,

 

You and I are in luck. You can have the NX Open applications I referred to, and I don't have to send them directly to you. This year we uploaded our previously internal library of NX Open applications to the Simcenter 3D Knowledge Base. Under the Knowledge Bases menu, go to Downloadables. There you will find a slew of NX Open applications we chose to share with the general public. The two that you should try for the enveloping are:

 

Simcenter 3D API: Envelope Results Loadcase

Simcenter 3D API: Envelope Results

 

Selecting the links will send you to a summary page and a download for the application. Both of these applications were created based upon NX 8.5 and 9. They "should" work in newer versions, but there's no guarantee. I'd be interested in knowing if they don't work, so that we can request to have them updated.

 

Regards,

Mark

Re: Post processing - combining stress results in NX

Gears Phenom Gears Phenom
Gears Phenom

Hello Mark, thank you. We will test it. Michael

| Production: NX10; Development: VB, TCL/TK, FORTRAN; Testing: NX11 | engelke engineering art GmbH, Germany
| Kudos for good posts! And if my post answers your question, please mark it as an "Accepted Solution".

Re: Post processing - combining stress results in NX

Gears Phenom Gears Phenom
Gears Phenom

Hello @MarkLamping,

 

sorry, but I couldn't bring the NXOpen DLLs  into operation with NX 10 or NX11. As example see my comment

Simcenter-3D-API-Envelope-Results => Comment

What is my failure? Both DLLs don't work.

The second one I did test in NX8.5.2 because in description is written (... for NX8 or 9)2018-08-30_102129.png

Please, are you able to help me?

Best wishes, Michael

 

| Production: NX10; Development: VB, TCL/TK, FORTRAN; Testing: NX11 | engelke engineering art GmbH, Germany
| Kudos for good posts! And if my post answers your question, please mark it as an "Accepted Solution".

Re: Post processing - combining stress results in NX

Siemens Phenom Siemens Phenom
Siemens Phenom

Michael,

 

It works for me in version 12, so it seems to be a problem on your side with respect to the DLL not knowing where the DLX is. The attached document gives an overview of how you can set up your environment for custom applications. Basically, if you place all of your custom application files in directory UGII_USER_DIR\application, then the DLLs should find their DLXs. There are a number of other ways to do this, but that is the simplest. I hope that solves the issue for you.

 

Regards,

Mark

Re: Post processing - combining stress results in NX

Gears Phenom Gears Phenom
Gears Phenom

Hello Mark, thank you for your contribution. After defining the system variable UGII_USER_DIR and after copying the files into APPLICATION sub directory as you declared it the scripts did work. 2018-09-24_145348.png

 

 

 

But I guess there is a failure. Where is the selection of shell section or beam section in dialog above? See the dialog manually selected for "Results Envelope" >>>>

2018-09-24_145622.png

<<<

 

Best wishes, Michael

| Production: NX10; Development: VB, TCL/TK, FORTRAN; Testing: NX11 | engelke engineering art GmbH, Germany
| Kudos for good posts! And if my post answers your question, please mark it as an "Accepted Solution".