Semi-Analytical Buckling Analysis of Omega Stiffened Panels Under Multi-Axial Loads

This paper presents a semi-analytical method for the buckling analysis of composite panels reinforced with omega stiffeners and subjected to combined loading conditions of biaxial loads and shear. The approach is based on the representation of the panel as an assembly of plate elements, allowing to capture local buckling modes involving skin and stiffener deflections. The panel model includes also the possibility of accounting for the stiffener foot. Trigonometric shape functions are introduced to describe the buckling patterns, while the buckling equations are derived through the application of the minimum potential energy principle. The comparison with Abaqus finite element analyses is presented, demonstrating, for a wide variety of test cases, percent differences below 9% and a good accuracy of the computed buckling modes. The computational speed up is of the order of 100, suggesting the use of the formulation in the context of preliminary design loops, sensitivity analyses or design optimizations.