Bending of doubler plates

[Cactus_]

Hi all,

Looking for some guidance on an query I have around plate bending. I am checking that we can attach a lug to some steelwork on a machine. The lug will be used for lifting perpendicular to the steelwork. The existing steelwork is not sufficient under bending. I have checked a doubler plate using plate theory assuming the plate is welded along all four sides. I am wondering how I can check that the new plate is large enough such that the bending stresses are spread out enough such that the existing plate is now compliant.

Cheers

 

[SWComposites]

A figure of the configuration would help.
A simple shell element FEM might be sufficient to get the moment distribution in the existing plate, along with some conservative factors.

 

[KootK]

Generically, something like the Yield Line Method might work as an evaluation technique.

If at all possible, I'd ditch the doubler and move the load around using plates loaded in plane rather than out of plane. A new stiffener welded to the steel work that attaches to some flanges or something. This usually winds up more efficient, and more predictable, than trying to mobilize plate bending.