Stiffened panel- crippling stress under Uniaxial compresion vs Bending
Stiffened panel- crippling stress under Uniaxial compresion vs Bending
(OP)
Hi all, I am looking into buckling of unflanged stiffened flat panels under BENDING.
There are many reference for the above problem under UNIAXIAL COMPRESSION but NOT due to BENDING. How does the buckling stress and crippling stress defers from UNIAXIAL COMPRESSION to BENDING?.
Is the compression stress to cause crippling nearly the same for both UNIAXIAL COMPRESSION loading and BENDING?
Thank you.
There are many reference for the above problem under UNIAXIAL COMPRESSION but NOT due to BENDING. How does the buckling stress and crippling stress defers from UNIAXIAL COMPRESSION to BENDING?.
Is the compression stress to cause crippling nearly the same for both UNIAXIAL COMPRESSION loading and BENDING?
Thank you.





RE: Stiffened panel- crippling stress under Uniaxial compresion vs Bending
stiffener crippling, or panel buckling ?
"unflanged stiffener" = simple angle stiffener, or integrally machined panel ?
in-plane bending, or out-of-plane ?
RE: Stiffened panel- crippling stress under Uniaxial compresion vs Bending
Also would like to know in-plane bending of the panel too.
I am looking for unflanged integral stiffeners but would also like to know how it differs with simple angle stiffener.
Thanks.
RE: Stiffened panel- crippling stress under Uniaxial compresion vs Bending
if it's a simple angle stiffener (ie without a stiffening flange on the free edge) then i think you're looking at a panel (being the stiffener web) in compression rather than a true crippling failure. i'd plot the variation of stress across the web (ie through the bending stress field), and see if a "rational" value less than the maximum leaps out ... it'll either be mostly axially loaded or mostly bending.
RE: Stiffened panel- crippling stress under Uniaxial compresion vs Bending
But if one wants to calculate the crippling stress of the unflanged-stiffener due to BENDING will the results agree closely with crippling stress of the unflanged-stiffener due to UNIAXIAL COMPRESSION. Or will they both differ by considerable amount.
RE: Stiffened panel- crippling stress under Uniaxial compresion vs Bending
RE: Stiffened panel- crippling stress under Uniaxial compresion vs Bending
I can work out the crippling stress of the unflanged stiffened panel under uniaxial loading using ESDU 70003. However what would the results be for bending of the panel. Will both (uniaxial loading and bending) results agree closely with each other or differ greatly.
RE: Stiffened panel- crippling stress under Uniaxial compresion vs Bending
In the axial compression case, the stress on the stiffener is uniform.
In the bending case, the stress on the stiffener is not uniform (essentially a moment in the plane of the stiffener. The crippling (failure) of the panel will depend on whether the skin or stiffener side is in compression. If the skin side is in compression, then you can work out the crippling stress for the skin and from there the bending moment required to reach that stress. If the stiffener side is in compression, then you will need to figure out the portion of the stiffener that is in compression, then the affective area for crippling, and from that the bending moment to reach crippling of the stiffener.. There might be something in Bruhn for this case (I'm too lazy too look it up now).
SW
RE: Stiffened panel- crippling stress under Uniaxial compresion vs Bending
if you don't have an angle in compression, and only have a standing leg, then that looks like a long, narrow panel loaded in varying compression, with a panel allowable like kc*pi^2*E/(1-v^2)*(t/b)^2
RE: Stiffened panel- crippling stress under Uniaxial compresion vs Bending