Stiffener attachment concepts for graphite-epoxy panels designed for postbuckling strength
Stiffener attachment concepts for suppressing or delaying the onset of the skin-stiffener separation failure mode in graphite-epoxy compression panels designed for postbuckling strength were experimentally studied. The effectiveness of these concepts was evaluated using panels with 16-ply skins and a single centrally-located I-shaped stiffener with both static and cyclic compressive loadings. Analytical results suggest that tailoring the relative thicknesses of the panel skin, stiffener attachment flange, and the stiffener web rotational stiffness can minimize the adverse effects of high interface shear and normal stresses. Interface stress levels may be reduced by tapering the thickness of the stiffener attachment flange and properly selecting the stacking sequences of the skin and stiffener attachment flange laminates.