Buckling analysis of stiffened thin-walled sections under general loading conditions using the compound strip method

This paper presents buckling analysis of stiffened thin-walled sections due to arbitrary loading. One variation of the well-established finite strip method, namely the compound strip method, is used for the analysis. This method is a semi-analytical procedure which enables modelling of longitudinal and transverse stiffeners, as well as columns, within the flat shell finite strip. Influence of stiffeners is introduced through their interface lines using appropriately calculated rigidities. The main contribution of this method is its elegant and efficient approach for modelling of transverse stiffener within the harmonic finite strip method. In order to address the problem of buckling an arbitrary loading strip is longitudinally divided into cells, where the three stress components obtained from linear static analysis are recorded. Next the integration over these sub-domains is performed, results are summed and the geometric stiffness matrix is formed. Extensive numerical analysis is carried out with three examples. The results obtained are in excellent agreement with the ones from the finite element method. For prismatic structures, the procedure presented can provide better insight into the problems analysed than other purely numerical methods.