The local buckling and postbuckling behaviour of omega-stringer-stiffened composite panels is investigated using novel computational models developed explicitly for different load cases. A Lévy type solution is derived for the local buckling under uniaxial compression and successfully evaluated based on a developed dedicated algorithm. The Ritz method is used to develop a computational model for multiaxial load cases implementing the Lagrange multiplier method and different combinations of superposed trial functions. Based on the principle of the minimum of the total elastic potential several closed-form analytical models are introduced that consider the local buckling under uniaxial compression, local buckling under shear loading and, in a displacement-based analysis, the local buckling and postbuckling of omega-stringer-stiffened panels under uniaxial compression. The computationally highly efficient analysis models are intended for the preliminary design of lightweight structuresweiterlesen