Beam Web Buckling
Beam Web Buckling
(OP)
I am wondering if it is possible in bending to have the web of beam deform (buckle) without the flanges showing any signs of deformation. If the web is slender, and the flanges are really stiff, can this occur?
Supposively if this beam is being operated correctly, there will be no concentrated shear loads, and large distributed loads will cause large bending moments. The web is buckled almost the entire height, but i don't see how this could be from bending. I think this kind of failure is due to shear, but all the shear checks from ASD involve concentrated forces (crippling, yielding, compression buckling, etc).
Supposively if this beam is being operated correctly, there will be no concentrated shear loads, and large distributed loads will cause large bending moments. The web is buckled almost the entire height, but i don't see how this could be from bending. I think this kind of failure is due to shear, but all the shear checks from ASD involve concentrated forces (crippling, yielding, compression buckling, etc).






RE: Beam Web Buckling
RE: Beam Web Buckling
I've even worked on a wing spar that buckles at limit load.
RE: Beam Web Buckling
What you're describing almost sounds like sidesway web buckling. Are the two flanges moving transversely relative to each other?
Unless it's mainly buckling at the high shear areas only, I wouldn't suspect shear buckling, but it's hard to know from your description.
RE: Beam Web Buckling
None of the stiffeners are buckled, none of the longitudinal bulkheads are buckled. Since the top and bottom flanges are essentially continuously supported, i did not think sidesway buckling could be an issue. The buckle looks as if the web has bowed out with the largest part being at its center.
Another reason i thought it must due to shear, is because of where the web is buckled. It is buckled in the tension zone.
I am just not very familiar with the slenderness aspect, and maybe something may be occuring that i am not thinking about. I've looked into the local buckling affects in ASD such as web crippling, web yielding, and compression buckling of the web. However, these all involve concentrated loads, and the buckles are occuring in areas where there should be none.
Thanks for your replies
RE: Beam Web Buckling
Don Phillips
http://worthingtonengineering.com
RE: Beam Web Buckling
Could your transverse bulkheads be acting as compression struts to brace the sides of the ship? Are the buckles forming locally between the stiffeners or globally across the ship? When you say the web is buckled in the tension zone, how did you come to that conclusion?
The shape of the bottom of the ship may have something to do with the bulkhead buckling. As the shape changes due to different loading conditions, it may be distorting the thin bulkheads.
RE: Beam Web Buckling
Read the introduction of NASA TN-2661 to understand the concept of "pure shear resistant webs" and "diagonal tension" web design. It sounds as though your case may be "intermediate diagonal tension" web design.
http://nt
Regards
RE: Beam Web Buckling
RE: Beam Web Buckling