beaded shear webs - your thoughts

huangyhg

beaded shear webs - your thoughts
ladies and gents,
how do beaded webs help in shear buckling problems.
for example, assume that i have a large spanning web = 2l.  assume i have an actual stiffener riveted on at located at x=l.  and assume that the web, spanning length l (either side) buckles.  now finally assume that i place 1 bead (running upper chord to lower chord) at 1/2 l. how do you freebody that?
the only thing i can think of is that the bead actually offers (if sized correctly) a simple support.  how would one go about developing a free body diagram?  do you treat the bead like an attached stiffener?
your thoughts appreciated,
nert
  
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nert
sorry,
also, assume that the load is introduced at x=l, and that it can load the web in shear.
beam is simply supported at x=0 and x=2l
cheers,
nert
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nert
i for one have no idea what a beaded web is; a sketch or 2 would clarify.
these kinds of "stiffeners" are used in cold formed steel design, and do act as a mini-simply supported span as you have guessed.  they act at very low loads, relative to stiffness, and normally serve to restrain (read: postpone or offset) one of the failure modes (there are numerous in cfs design).  if you have a stiffener which is meant to be restraining the same failure mode as this "swag" you'll probably find that the swag will be doing nothing at all.
i would really like to help more, however i'm having a bit of trouble being sure of what your layout is.  i suggest you take apsix's advice and post a sketch.  there are a good number of tallented structurals around to potentially help you...
regards,
ys
b.eng (carleton)
working in new zealand, thinking of my snow covered home...
apsix,
sorry, i don't have a picture.
at least in my case, a beaded web is when a bead (like 1/2 a sine wave) is actually formed into a thin shear web of a beam. it's main purpose, as far as i can tell, is to help for out of plane stability.
cheers,
nert
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nert
yup:  that is very much the same as we see in cfs design... if you do not have a code which describes their design, i would suggest you look into obtaining a copy of one of the available codes.  the eurocode is purported to be quite comprehensive, although i have never worked with it myself.
also, if you would prefer a text to a code, i would recommend the text by handcock of the university of sydney.  he is a world expert in cfs and the text is quite a good starting point for many problems.
cheers,
ys
b.eng (carleton)
working in new zealand, thinking of my snow covered home...
thank you!
just an fyi,  this is more of just a mental exercise.  i work primarily w/ aluminum (read aircraft).  so, as you already know,  low weight and low part count are primary drivers.  typically on smaller aircraft beads will be used in very thin webs if buckling is a concern.  after giving it some thought over the weekend, i'm convinced that provided there is enough out of web plane inertia, it will stabilize the web such that my effective panel width (in regards to my original query) is reduced in half.   
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nert