Equivalent area of Z-shape beam
Equivalent area of Z-shape beam
(OP)
Hello everyone, I am doin a structural analysis of a Z-shape beam bolted to a flat panel. I want to find the equivalent area of the Z-shape beam. I have constrained one end of the aluminum beam in the x-direction and i am pulling the other end of the composite beam in the x-direction. So now i have displacement of the aluminum beam at the unconstrained end and the reaction force and hence i can calculate the area. But there is local deformation in the bottom flange of the aluminum due to the presence of the fasteners. So how do i calculate the equivalent area of the aluminum beam? any ideas. Thanks.
Kota
Kota






RE: Equivalent area of Z-shape beam
One approach is to take an arbitrary width of the flat panel and assume it acts with the structural section. Typically, I'll use 16t on either side.
Another approach is shown in the appendices of AISC-ASD, where they give an equivalent width to use for an analysis. But as I recall, you calculate the stress, use it to calculate the width, then recalculate the width, etc. In my cases, these widths always come up greater than the 16t mentioned above. AISC ASD mentions the source of this method- von Karman, if I remember it right.
I have seen, but do not have current copies of, aluminum design manuals published by the aluminum associate. These seem fairly exhaustive, and may cover this case. And it occurs to me that aluminum sheets riveted to a stiffener describes a lot of airplane construction, so I would expect the question has been studied exhaustively by someone.
RE: Equivalent area of Z-shape beam
RE: Equivalent area of Z-shape beam
Additionally, if the thin plate is wide enough, it will not all deflect two-dimensionally like a beam- parts near the beam will deflect with the beam, while parts farther out will not. IE, it will not maintain the theoretical cross section in bending.
With a stiffener welded to a cylindrical shell, you can use shell theory to figure the effective parts of the cylinder.
RE: Equivalent area of Z-shape beam