Buckling load reduction for stiffened panels due to cutouts in ribs

In aerospace structures it is common to find stiffened panels with transverse supporting structures, e.g. wing ribs or fuselage frames. Incorporating cutouts into these supporting structures to allow the stringers to pass through freely considerably reduces the buckling load of the panels. It is shown that a minor modification in the fabrication of the stiffened panel gives most of the advantages of cutouts while still giving a buckling load close to that of a panel with no cutouts.