DETERMINING SECTION MODULUS FOR AN ODD SHAPE 2

[JP20]

I am analyzing a side bottom rail beam on an intermodal shipping container.

Does anyone know the "S" value on this in in3? Or have a software to quickly calculate? I know I had do by hand but don't really want to unless no resource is out there lol..

Attached is the section view.

 

[canwesteng]

If you use smath or mathcad, the hand calc probably takes less than 10 minutes, it's either just a bunch of rectangles, or break it into an unequal length angle and channel and combine with parallel axis theorem.

 

[jayrod12]

It's likely a custom shape, so I doubt anyone will just have this handy. I'd love to be proven wrong. In this instance, I think you need to go back to old fashioned solid mechanics to determine what you need. Set it up in a spreadsheet and you'd be done fairly quickly.

RISASection would do the calculations for you, but you'd need to build the shape in the program first. By the time you figured that out, if you don't already use it regularly which I assume you don't since you didn't do it already, you'd be done your spreadsheet and onto the next problem.

 

[JStephen]

If you're using AutoCAD, you can get section properties from there.
Otherwise, spreadsheet is good for that. Break it up into rectangles (quick and easy that way) or rectangles and segments of disk areas (more involved then).

 

[Celt83]

This tool if you don't mind some python programming: Link
user IDS has a spreadsheet that can interface with the above: Link

 

[DoubleStud]

Use autocad:

Draw the section
Use "region" command and select the section
Use "massprop" command and select that section.
Look at your dialog box, it should give you I and center of gravity. You should be able to figure out S from that info.

 

[JoelTXCive]

30 day free trial..........

Shapebuilder Software from IES. (They really should pay me for how often I recommend their products....)

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[GregLocock]

Just bear in mind the principal axes will not be paper X and Y

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[dik]

There's even formulae that accommodate the area, centroid, and moment of inertia of the 'curved' corners. I'll see if I can dig them up... came across them about a year back regarding calculating HSS properties.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Scuka]

These days, pretty much any CAD software will give you the section properties. Probably including the one you drew this in.

Out of curiosity, 4.5 mm thick metal sheets? Seems like an odd number. I've never seen that.

 

[Stress_Eng]

Just to add to the many ways of obtaining section properties. I’ve used MathCAD before, where I had an irregular shape. Used functions to model the top and bottom profiles and just used the inbuilt integration capabilities to get A, Ixx, Iyy and Ixy.

 

[EngDM]

Use autocad:

Draw the section
Use "region" command and select the section
Use "massprop" command and select that section.
Look at your dialog box, it should give you I and center of gravity. You should be able to figure out S from that info.

If you go with this method, you have to align the centroid of the shape with model space 0,0. Massprops calculates the properties based on where 0,0 is.

Another alternative is to use the sectionproperties library with Python. It's free, and has some awesome utility if you care to learn.