Stability Behavior Of Cylindrical Shells Research Articles

05.16: Stability behavior of graded dented cylindrical steel shells under the action of combined external and axial pressure

ABSTRACTThin‐walled cylindrical steel shells such as silos, tanks and other containers are used in various applications of engineering. For economic reasons, large fluid storage steel tanks are made with varying thickness in height. Cylindrical steel shells with stepwise variable wall thickness are the most prevalent structural components in petrochemical and oil industry. However, during the construction procedure and service life, these reservoirs may be exposed to some geometrical imperfections in the form of dents. These shells are subjected to peripheral pressure loading and when a large liquid storage is discharged, an internal suction will be applied to its wall and head, causing external pressure on the wall and axial compression on the head. These structures are prone to fail by buckling under external pressure and axial compression. Previous studies show that the stability behavior of cylindrical shells under pressure load is strongly dependent on the nature and magnitude of the imperfections. Despite many studies on the buckling behavior of thin‐walled cylindrical steel shells of constant thickness, so far only a few investigations have been undertaken to examine instability behavior of these structures with thickness variation under the action of combined external pressure and axial compression, considering the dent imperfections. In this study, the effects of vertical and horizontal dents on the buckling and post‐buckling behavior of dented graded cylindrical steel shells with two and three layers under the action of a combination of peripheral and axial pressure are investigated. The models are designed in practical dimensions, with some horizontal and vertical dents in different positions. In the present study, non‐linear buckling and post‐buckling solutions of thin‐walled cylindrical steel shell with varying thickness are obtained by using ABAQUS, which is a general‐purpose finite element program designed specifically for advanced structural analysis.

Nonlinear Stability Analysis of Laminated Composite Simply Supported Circular Cylindrical Shells Subjected to Partial Axial Loading

AbstractThe present investigation deals with the nonlinear stability behavior of cross-ply laminated composite circular cylindrical shells subjected to partial and complete edge loading along with uniform external pressure. The shell is modeled using Donnell’s shell theory including the first-order shear deformation theory (FSDT). The analysis uses the simply supported boundary condition (at x=0, L Nxx=N¯xx, w=Mxx=v=ϕθ=0). The equations governing the nonlinear stability behavior of cylindrical shells are derived in terms of displacements (u-v-w) and rotations (ϕx, ϕθ). The applied partial edge loading is expressed in terms of Fourier series, and stress distributions within the cylindrical shell are determined by prebuckling analysis. The study uses multiterm Galerkin’s method along with the Newton-Raphson method to solve the governing partial differential equations of the shell nonlinear stability. With the help of numerical investigations, the authors present the number of modes required for the postbuck...

The stability of compositionally graded ceramic–metal cylindrical shells under aperiodic axial impulsive loading

In this paper, an analytic solution is provided for the stability behavior of cylindrical shells made of compositionally (or functionally) graded ceramic–metal materials under the axial compressive loads varying as a power function of time. The material properties of the compositionally graded shells are assumed to vary continuously through the thickness of the shell according to arbitrary distribution of the volume fraction of the constituents. The fundamental equations for thin shells of compositionally graded ceramic–metal material are obtained using the Love’s shell theory and a solution for two initial conditions is obtained by applying Galerkin method and Lagrange–Hamilton type principle. The effects of the constituent volume fractions, the variations of loading parameters and the variations of power of time in the axial load expression on the critical parameters of the shell for two initial conditions are also elucidated. The results reveal that these effects play a major role in dictating the loss of the stability of the compositionally graded shells under the axial compressive loads. Comparing results with those in the literature validates the present analysis.