Learning Forum

[Fetusboy]

Hello
I'm presently having a study on a pipe. The ain was to get the stress analysis; after the inclusion of the BCs and Operation load. I could not fine the stress pane on right clicking the solution tab.
However, I found direct stress and combined stress under the Beam tool selection.

How do I maintain my pipe as a pipe and not a beam and still get the required stress such as the Principal stress, max. Principal stress etc.?
Also, is direct stress same as combined stress?

Thank you all

[peteroznewman]

 Go to the ANSYS Help, and under the Mechanical Application category, search for Beam Tool. You will find this information:

Presented below are definitions of the beam stress results that are available:

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  Direct Stress: The stress component due to the axial load encountered in a beam element.

  
  


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  Minimum Bending Stress: From any bending loads a bending moment in both the local Y and Z directions will arise. This leads to the following four bending stresses: Y bending stress on top/bottom and Z bending stress on top/bottom. Minimum Bending Stress is the minimum of these four bending stresses.

  
  


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  Maximum Bending Stress: The maximum of the four bending stresses described under Minimum Bending Stress.

  
  


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  Minimum Combined Stress: The linear combination of the Direct Stress and the Minimum Bending Stress.

  
  


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  Maximum Combined Stress: The linear combination of the Direct Stress and the Maximum Bending Stress.

  
  

Beam Results

Beam results can be applied only to line body edges and are defined as follows in reference to the solution coordinate system of each beam or pipe element:

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  Axial Force: the force along a beam element axis (X component).

  
  


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  Bending Moment: the moment in the plane perpendicular to the beam element axis (Y and Z components).

  
  


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  Torsional Moment: the moment about the beam element axis (X component).

  
  


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  Shear Force: the force perpendicular to the beam element axis (Y and Z components).

  
  

Shear-Moment Diagram : simultaneously illustrates the distribution of shear forces, bending moments and displacements, as a function of arc length along a path consisting of line bodies.

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You have to take this information and the known cross-sectional area properties to compute the components of stress and combine those to compute a Principal Stress.  If you don't want to do that, then instead of a beam model, build a shell or solid model.

[Fetusboy]

Thank you for the assistance but won't the functions change from pipe if I should build it in shell or solid model.

[peteroznewman]

What functions?

[Fetusboy]

For an instance, with the pipe model adopted I could specify my internal and external pressure and also internal temp.
Can I indicate internal pressure in a beam model too?

[peteroznewman]

A pipe element is just a specialized beam element, it has the ability to have pressure on top of the beam bending.

[Bibek Kafle]

Should I compare Direct stress or maximum combined stress with yielding stress for fracture ?

[Wenhan Li]

Hi,

Considering the definition Maximum Combined Stress: The linear combination of the Direct Stress and the Maximum Bending Stress.

Does it mean that Maximum Combined Stress is just simply Direct Stress plus Maximum Bending Stress?