Shear-buckling of omega-stringer-stiffened panels

Abstract

The local shear-buckling behaviour of omega-stringer-stiffened composite panels is analysed introducing a novel approximate analytical computational model. This type of stability analysis is critical for thin-walled structures like the proposed panel, which is applied, among other things, mainly in aerospace structures and marine vessels. In this context, computationally efficient methods are especially necessary for preliminary design phases that often involve optimization and extensive parameter studies. In the present work, a simple analytical model for the critical shear-buckling load is developed and evaluated taking bending-twisting coupling and different load directions into account. The modelling approach is based on energy methods and employs the principle of the stationary value of the total elastic potential. Hereby, the buckling shape functions are based on a combination of a polynomial term and a trigonometric Timoshenko-type term, where the latter is commonly used for closed-form analytical shear-buckling analysis. The approximate computational model is evaluated for four different laminate configurations and a wide range of different panel dimensions in comparison to finite element analyses. The parameter studies yield promising results with errors very acceptable in the context of preliminary design.