Glamorous Beams

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Inquisitor
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Beiträge: 39
Registriert: Fr 7. Sep 2012, 00:14
Wohnort: Atlanta, Georgia, USA

Glamorous Beams

Beitrag von Inquisitor »

As a former engineer that used FE on a daily basis, I have always felt it the responsibility of the engineer to evaluate the tools used. Even though, I’m no longer doing FE work professionally and this is merely a hobby, old habits die hard. I’m evaluating Z88 for its suitability toward my current hobby. I know most of your effort is probably around using exotic solids and non-linear materials for some future version, but I’m hoping you can help me understand something I’m finding with Beams(2). I’m hoping, I just don’t understand the output.

I have a VERY simple test case… 2 nodes, 1 element, 1 boundary condition, 1 force. Here are the details and a zipped file of the project. http://z88.garmf.com/GlamorousBeam.zip

• Cantilever beam
• Length = 100 mm (in the X direction)
• Section: B = 1mm, H = 1mm
• Material: 1
• Node 0 constraint: x,y,z,rx,ry,rz = 0.
• Node 1 constraint: Fy = 1N

After running the analysis, these results check out as I would expect.
• Node 2 y deflection = 19.048
• Node 2 z rotation = 0.2857
• Node 1 Force y direction = -1.0
• Node 2 Force y direction = 1.0
• Max axial stress at x: My/I = Sigma xx = 600.0

The one thing that seems wrong… I’m expecting a shear stress (TauXX in the z88o3.txt file) of 1.0 and I find 0.0

What am I miss understanding?
Thanks for your help.

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Inquisitor
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Beiträge: 39
Registriert: Fr 7. Sep 2012, 00:14
Wohnort: Atlanta, Georgia, USA

Re: Glamorous Beams

Beitrag von Inquisitor »

Sorry. False alarm. I've figured it out.

I was looking for Tau xy due to the shear and its not available.

I just tested using a torque and found that Tauxx is the stress associated with torque.

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wehmann
Alumni
Beiträge: 60
Registriert: Fr 20. Nov 2009, 07:28

Re: Glamorous Beams

Beitrag von wehmann »

Dear Inquisitor,

you are right, we are not calculating shear stresses due to transverse forces, because they are mostly negligible compared to shear stresses due to torque. So the shear stresses in z88o3.txt are due to torque.

Best regards,

Christoph Wehmann

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