How do notches and beads increase stiffness of supporting brackets (sheet metal) theoretically?

[ninjaz]

How do notches , beads and flanges at appropriate positions increase stiffness of supporting brackets (sheet metal) theoretically..

Comments would be really appreciated

Thanks

 

[btrueblood]

Beads and flanges increase the area moment of inertia of the sheet, i.e. its resistance to bending out of the plane of the sheet. Take a look at a basic Mechanics of Materials textbook. Notches (removed material) decrease the stiffness, obviously.