I-beam in torsion

[NS4U]

I am looking for equations/examples for shear stress distribution of an I-beam subjected to a torsion load.

I have derived the equations for normal and shears stresses due to warping of a I-beam subjected to a torsion load. So I have Jeffective, Gamma, angle of twist... etc...

I know what the torsion shear stress distribution of an I-beam should look like, but I can't find any equations or examples so I can try to solve for this stress.

Any suggestions?

 

[271828]

Do you have the AISC Torsion Design Guide? I'm trying to think of what you need that's not in there.

 

[NS4U]

I do not have that.

And all the strength of materials books I have don't really cover open section torsion well.

 

[prost]

My strength of materials book has some thin rectangular section approximations, would that work? J=bh^3/3,
tau(max)=TR*h/J, TR is the torsion.
tau(max) is located at midpoint of the long side of the rectangle. "J" is simply the addition of the Js of each rectangular leg. If you have 'thin legs' comprising your open section, you might want to consider looking at aircraft structural design books, as then make the 'thin' approximation all the time (though the primary aircraft structures ref. I use has only closed section torsion problems).

 

[271828]

Mike, download the AISC Torsion DG. It will help a lot and is free for AISC members.

I wouldn't even try to use the stuff in my Mech. of Matls and Adv. Mech. of Matls book on something like that. Life's too short, LOL.

 

[SE008]

try

http://www.webcivil.com/thintorsion.aspx

 

[dbuzz]

Also see Bradford M, Pi Y-L (2000), Design of steel I-beams curved in plan to AS4100, Australian Journal of Structural Engineering, Vol 3, No 1-2, pp 85-98.

 

[SHBH]

Have a look at section 2.10 of "Design of welded Structure" by W.Blodgett.
Torsional stresses and it's calculation for all the probable shapes have been explained very well.

 

[NS4U]

Great all thanks for the replies!!

I will be picking up those books/periodicals tomorrow

I would download AISC's torsion design guide... but of course I never bothered renewing my AISC membership

 

[271828]

Mike, you could still buy it. They want $60 for it, though. Even so, you might find it handy enough to be worth it.

http://www.aisc.org/Template.cfm?Se...gory=123&ShowFormats=N&FormatID=0&StartNum=21

 

[walterbrennan]

Mike,

Another alternative is the old Bethlehem Steel "Torsion Analysis of Rolled Steel Sections" guide, which is probably tabulated well enough to handle most of what you are doing with open shapes. It's the reference upon which the AISC design guide is founded, in the first place. Also, I believe US Steel had a similar publication, as well.

Anyway, until you scrape together the sixty bucks plus shipping for the AISC version (which really is actually worth having), you can probably procure an old Bethlehem for four or five bucks from a used book site.

Good luck.

walterbrennan

 

[NS4U]

Thanks Walter... I am definitely going to look into that.

I have put an email into some people in my office who are AISC members and might be able to get the PDF for me.