Torsional Warping and St Venant's warping constants 1

[EngDM]

Hey all,

I'm trying to find a general equation to calculate these constants to use in the compressive resistance (asymmetric shapes) equation from Clause 13.3.2 CSA S16. I've found this link as the reference

http://dir.cisc-icca.ca/files/technical/techdocs/updates/torsionprop.pdf

however it only gives equations for a general shape. I'm trying to figure out what the equation would be for for example a OWSJ web member getting reinforced on the one side. If there is no easy equation, are there any AutoCAD plugins that you know about that will calculate it when applying the MASSPROPS command perhaps, or something similar? Or another program that will calculate it for shapes you draw.

I'm at a loss here trying to source a general equation.

 

[driftLimiter]

Warping constants are difficult to determine for various shapes. I think typically FEA is employed to determine them for general shapes. I don't know about any AUTOCAD section analysis programs, but I am aware that there are structural packages available that can solve for these constants based on an Imported shapes.

Some examples:
-Robot Structural Analysis
-SAP2000 Section Designer
-RISASection
-IES Web

Many others can do it.

 

[Celt83]

There isn't really a simple general equation for the Torsion Properties, the general integral becomes very difficult if not impossible to solve for various section shapes so usually an FEM approach is used.

The best free option is this Python program created by Handofthelion: Link

I'm making a thing:

http://www.thestructuraltoolbox.com

(It's no Kootware and it will probably break but it's alive!)

 

[driftLimiter]

@Celt83 thanks for this, very cool and interesting. Out of curiosity, do you know why yield moment isn't included in this package?

 

[Celt83]

I'm not involved in the development at all, but my guess is they are working out how best to present the information since My could actually be multiple values for unsymmetric shapes.

I'm making a thing:

http://www.thestructuraltoolbox.com

(It's no Kootware and it will probably break but it's alive!)

 

[EngDM]

Hey @Celt83,

I'm not really versed in python at all but would love to look into it. Is that a program where you can draw your shapes in etc?

 

[Agent666]

You have to build up your shapes via code (but can easily view the geometry you've created), there are plenty of examples to get you started in the documents:-

https://sectionproperties.readthedocs.io/en/master/sphinx_gallery_examples/index.html

https://engineervsheep.com

 

[EngDM]

I've found a section on there where you can import a DXF file, hopefully I can get that running.

 

[handofthelion]

Out of curiosity, do you know why yield moment isn't included in this package?

Gday @driftLimiter, to be honest I never got around to it and no-one asked me to do it, so I forgot about it! I'll put it on the to-do list as it shouldn't be too hard to implement!