Effective breadth/web concept for elastic coupled buckling analysis in flat-bar stiffened plates

• To study interaction of torsional-web-plate buckling in flat bar stiffened plates.
• To propose a method for coupled web-plate-torsional buckling analysis.
• To check the accuracy of rule-based expressions for buckling analysis of stiffened plates.

Stiffened plate buckles in different modes, including web/flange buckling, torsional buckling, plate buckling and interaction of these. Design codes ignore interaction of different buckling modes and each mode is treated separately. By introducing an effective breadth/web concept, coupled plate-torsional-web buckling in flat-bar stiffened plates is simply analyzed by torsional buckling analysis of equivalent cross section. The model provides a tool that is more accurate than existing design codes, and more efficient than finite element method. An expression for effective breadth/web of flat-bar stiffened plate has been derived and Euler stress for coupled buckling mode in flat-bar stiffened plate are calculated and compared with finite element method and rule-base equation. It is found that this method has better agreement irrespective of dominant mode of buckling.