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# Post processing - combining stress results in NX

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?

regards,

Georg

3 REPLIES

# Re: Post processing - combining stress results in NX

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

Experimenter

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
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