Simulating the effects of geometric imperfections on the buckling of axially compressed cylindrical shells through reducing localized stiffness

Thin-walled cylindrical shells are prone to buckling under axial compression. The load-carrying capacity of the shells can thus be significantly reduced. It's well known that the buckling loads of axially compressed cylindrical shells are quite sensitive to the initial geometric imperfections. Even though the magnitudes of these imperfections are relatively small, the corresponding buckling loads can be significantly reduced compared to the perfect shells. In this paper, the effects of geometric imperfections on the buckling loads are equivalently simulated by reducing localized stiffness of the cylindrical shells. Firstly, the method for simulating the effects of geometric imperfections on the buckling loads of cylindrical shells is introduced in detail. Then, the proposed method is used to simulate the effects of single dimple imperfection and multiple dimple imperfections on the buckling loads of cylindrical shells. Results show that the buckling loads and load-displacement curves of the shells with single and multiple dimple imperfections can both be well simulated by the localized stiffness reduction method. Furthermore, the measured geometric imperfections from manufactured cylindrical shells are investigated. The numerical results simulated by the proposed method are also verified by the shell models with real measured geometric imperfections and the experimental results from the literature. The applicability and reliability of the proposed equivalent method in dealing with complex imperfection configurations can thus be validated. Results show that the proposed equivalent method is suitable for simulating various geometric imperfections of the cylindrical shells. It is promising to be applied as an efficient tool to quantify the imperfection sensitivity of buckling loads and provide a new solution for buckling analysis of cylindrical shells.