Welded angle bracket 3

[bugbus]

What is the failure mode for a bracket like this? I imagine it is more complicated than it appears, and probably involves some kind of twisting action.

I wonder if there are any design guides or if anyone has prior experience?

 

[ALK2415]

for the sake of science let see your simulations of the both case
[know that the twisting Moment resisted by both sides Top_&_Bot flange]
some References
-Link
-Link
-Link