In the smeared stiffener approach, the stiffened panel is converted mathematically to an unstiffened uniform thickness panel with equivalent orthotropic stiffnesses. These equivalent or smeared stiffnesses can be used in a Rayleigh-Ritz method to solve for buckling loads of the stiffened panel. The smeared stiffener approach is computationally efficient to execute and can easily account for stiffeners in any direction. The smeared stiffener approach is applicable in general to stiffened panels where the local buckling load is equal to or greater than the global buckling load. This approach for preliminary design is consistent with the aeronautical design philosophy where a buckling-resistant design is the design goal. - http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1995002... - page 4

Chyba najblizej.
smeared stiffener model (SSM) is developed to obtain equivalent stiffness ...