Local–global mode interaction in stringer-stiffened plates

• Analytical study of elastic stringer-stiffened plates under axial compression.
• Nonlinear variational approach developed to model local–global mode interaction.
• Local buckling in the main plate and of the stringer is included.
• Comparisons with finite element models and published experiments are excellent.

A recently developed nonlinear analytical model for axially loaded thin-walled stringer-stiffened plates based on variational principles is extended to include local buckling of the main plate. Interaction between the weakly stable global buckling mode and the strongly stable local buckling mode is highlighted. Highly unstable post-buckling behaviour and a progressively changing wavelength in the local buckling mode profile are observed under increasing compressive deformation. The analytical model is compared against both physical experiments from the literature and finite element analysis conducted in the commercial code Abaqus; excellent agreement is found both in terms of the mechanical response and the predicted deflections.