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# Advanced Post - Beam Cross Section (Bug?)

Creator

I'm having some issues with looking at the stresses in the cross section of a beam.  I have the beam elements as follows

As you can see, it's made up of beams of various cross-sections, including to beam elements that are tapered beams.

The issue I'm having is with the tapered beams, more specifically, extracting the cross-section stresses in the tapered beams.  When I use the View-->Advanced Post--> Beam Cross Section tool and select Element 124, I get the following results (notice that I'm looking at axial stress, and only using the axial force in the calculation):

As would be expected, the stress is constant throughout the cross-section.  As I wouldn't expect, however, is that the stress is constant through the length of the tapered beam.  The axial stress should follow this relationship:

σA = FA / AA

σB = FB / AB

For this output set,

FA = FB = 46.536

A= 5.067E-6

AB = 6.207E-5

This should give the following stresses

σA = 46.536 / 5.067E-6 = 9.184e6

σB = 46.536 / 6.207E-5 = 7.497e6

As you can see in the image above, the axial stress is the same at end A and end B (9.184e6, which is what it should be at end A).

Am I doing something wrong, or is this a bug in the beam cross-section tool?  To me it seems like it's not using the correct area at End B.  Perhaps this tool doesn't work for tapered beams.

Below is the property card for the beam element in question.  Any feedback would be appreciated.

EDIT to add: This issue has been seen on Femap Version 11.4.0.  I'm not aware if this problem existed on previous versions.

5 REPLIES

# Re: Advanced Post - Beam Cross Section (Bug?)

Experimenter

To piggyback on ajostler's question: does the beam cross section stress tool not account for beam offsets?

# Re: Advanced Post - Beam Cross Section (Bug?)

Genius

Issue confirmed in v11.3.1

End A = high f (small A)

End B = high f (small A):

# Re: Advanced Post - Beam Cross Section (Bug?)

Solution Partner Creator

I have the same.
Femap 11.4.0

# Re: Advanced Post - Beam Cross Section (Bug?)

Siemens Legend

@ajostler

The FEMAP development team is looking into this.

# Re: Advanced Post - Beam Cross Section (Bug?)

Siemens Legend

@APezz

Beam Cross Section Stress Control does account for beam offsets. If you have a specific case that you think isn't accounting for it, please let us know and provide the model.