Stability analysis of a cylindrical shell with axially symmetric defects under axial compression based on the reduction stiffness method

Initial imperfections can greatly reduce critical buckling load of axially compressed thin-walled cylindrical shells. During the buckling process of a cylindrical shell, the total potential energy of cylindrical shell can be divided into a constant linear component and a square nonlinear component. In this study, based on deriving the buckling load of a perfect cylindrical shell under axial compression, the role of different stiffness reductions in the evaluation of stable load carrying capacity was assessed with reference to the Reduction Stiffness Method (RSM). Then the influence of initial axisymmetric defects on stiffness of each part of compressed cylindrical shell was discussed. The mechanism by which axially symmetric initial imperfections affected the stability of axially compressed cylindrical shells was analyzed. The results show that (1) Initial axisymmetric defects affected the membrane stiffness of cylindrical shell. (2) The stability carrying capacity of axially compressed cylindrical shell was reduced. (3) The initial defect was amplified by the square of instability wavenumber of cylindrical shell. Hence, a small defect could have a significant influence on stability carrying capacity of axially compressed cylindrical shell. The results presented in this paper provide a useful reference for the design of axially compressed cylindrical shell structures.