Investigation on Snap-Through Buckling Behavior of Dished Shells Under Uniform External Pressure

Previously, the buckling behavior of several conical and spherical shells have been studied with great rigor. In this paper, snap-through buckling behavior for metallic dished shells under uniform external pressure is investigated. These shells are geometrically complex since they consist of a shallow conical frustum with a flat closed top. Such shells find many engineering applications, for instance as actuator elements in control components in cryogenic engines. Currently, no clear guidelines exist for design performance evaluation of such peculiar shells. This paper aims to establish a valid FE methodology for snap-through buckling and post-buckling analysis of such shells using abaqus in tandem with experiments. A parametric study is carried out to understand the effect of geometrical parameters and imperfection sensitivity of these shells to snap-through buckling. Moreover, experiments were carried out using 3D Digital Image Correlation (3D-DIC) for measuring whole-field deflection and strains. Numerical analysis was carried out, using generalized Eigen value analysis and non-linear analysis using a modified-Riks technique with various material models to correlate with the experimental observations. Non-linear elasto-plastic analysis with a perfectly elastic-plastic material model agrees well with the experimental observations. A comparison of experimental results with that of the numerical study indicates that material plasticity has a major effect on critical buckling pressure.

Buckling of Corrugated Ring under Uniform External Pressure

Stability analysis of a corrugated ring subjected to uniform external pressure is under consideration. Two main approaches to solving this problem are analyzed. The equivalent bending stiffness approach is often used in engineering practice. It is based on some plausible assumptions about the behavior of a structure. Its advantage is the simplicity of the obtained relations; the disadvantage is the difficulty in estimating the area of applicability. In this paper, we developed an asymptotic homogenization method for calculating the critical pressure for a corrugated ring, which made it possible to mathematically substantiate and refine the equivalent bending stiffness approach. To evaluate the results obtained using the equivalent stiffness approach and asymptotic homogenization method, the imperfection method is used. The influence of the corrugation parameters on buckling pressure is analyzed.