The structural configuration essentially determines the complexity of the residual strength analysis.  Typical structural parameters which must be considered for skin-stiffened structure are:

·        Type of Construction

-        Monolithic (unreinforced/forgings)

-        Skin (longerons, stringer)

-        Integrally stiffened

-        Planked

-        Layered (honeycomb/laminated)

·        Panel Geometry

-        Planform

-        Curvature

-        Stiffener spacing and orientation

-        Attachments (spar caps, webs, frames, etc.)

·        Details of Construction

-        Stiffener geometry (hat, Z-channel, etc.)

-        Attachment details (bolted, riveted, welded, etc.)

-        Fastener flexibility

-        Eccentricity

Ideally, the residual strength analysis will take all these parameters into consideration.  In practice, many are treated empirically and others are not considered except in extremely detailed analyses.  This section provides details of the analysis methods used for built-up skin stringer structure and the effects of many of the structural parameters listed above.  In the order of their presentation, the subsections provide: overviews of the analysis for edge stiffened and for centrally stiffened skin structure, the analysis methods used to determine the stress-intensity factor in the skin structure and the loading transferred to the stringers, the analysis of stiffener failure, the analysis of fastener failure, the analysis methodology and an example.