Maximum width to thickness before a stiffened element of a section elastically buckles?
Maximum width to thickness before a stiffened element of a section elastically buckles?
(OP)
I'm getting a contradiction in this book: https://books.google.com/books/about/Cold_Formed_S...
When designing a section, say an I-beam, you'd determine the critical buckling stress from the buckling equation from Von Karman plate theory right?
Then the max width to thickness ratio to buckle in the elastic region would be found from the same equation, subbing in the stress for the yield stress, would boil down to (width/thickness)_critical=1.9*sqrt(E/sigma_yield)
However, after some empirical relations he shows for effective width, and setting effective width=1 (the condition it is at before critical width to thickness is reached) then solving for the width to thickness ratio, it boils down to (width/thickness)_critical=0.95*sqrt(E/sigma_yield) (eq. 3.34), or (width/thickness)_critical=1.28*sqrt(E/sigma_yield) if you worked through the math using the effective width formula from eq.3.44.
Can anybody clear up this confusion about what is the best way to compute maximum width to thickness ratio to buckle in the elastic region?
When designing a section, say an I-beam, you'd determine the critical buckling stress from the buckling equation from Von Karman plate theory right?
Then the max width to thickness ratio to buckle in the elastic region would be found from the same equation, subbing in the stress for the yield stress, would boil down to (width/thickness)_critical=1.9*sqrt(E/sigma_yield)
However, after some empirical relations he shows for effective width, and setting effective width=1 (the condition it is at before critical width to thickness is reached) then solving for the width to thickness ratio, it boils down to (width/thickness)_critical=0.95*sqrt(E/sigma_yield) (eq. 3.34), or (width/thickness)_critical=1.28*sqrt(E/sigma_yield) if you worked through the math using the effective width formula from eq.3.44.
Can anybody clear up this confusion about what is the best way to compute maximum width to thickness ratio to buckle in the elastic region?






RE: Maximum width to thickness before a stiffened element of a section elastically buckles?
don't quite get your 2nd paragraph ...
another day in paradise, or is paradise one day closer ?
RE: Maximum width to thickness before a stiffened element of a section elastically buckles?
Depending on the source I've seen the constant go from 0.95 to 1.9.
Having a rule of thumb isn't ideal since it's dependent upon yield stress and yield stress in steels has such a large range nowadays.
RE: Maximum width to thickness before a stiffened element of a section elastically buckles?
I'd probably take exception to "fully effective if it buckles elastically". Different industries have different rules ...
I note that 0.95 is 1/2 of 1.9 ... hummm
another day in paradise, or is paradise one day closer ?
RE: Maximum width to thickness before a stiffened element of a section elastically buckles?
RE: Maximum width to thickness before a stiffened element of a section elastically buckles?
another day in paradise, or is paradise one day closer ?