In-plane buckling of semi-cylindrical shells with elastic edge restraints under a central radial load

Abstract

The present study investigates the elasto-plastic buckling behaviour of semi-cylindrical shells with elastic edge restraints under the action of a central radial load, both numerically and experimentally. Several design parameters are expressed to characterize the influence of elastic edge restraints on load-bearing capacity. A reduction factor equation is developed as a multivariate function of the shell parameters, which evaluates the amount of decrease in load-bearing capacity of the structure caused by elastic edge restraints. Additionally, an equation to predict load-bearing capacity under clamped edge conditions is introduced, which is used as a reference value in the reduction factor equation. Conditions for the elasto-plastic buckling occurrence are identified with the help of normalized parameters. An exclusive validation process is applied to the proposed expressions using a large series of numerical, experimental data and statistical methods to ascertain the accuracy of the predictions at a wide range of design parameters. Furthermore, parametric studies are performed in which the influence of elastic edge restraints, material plasticity and radius-to-thickness ratio on the limit load as well as deformation patterns of the semi-cylinders, is investigated. The results show that elastic edge restraint stiffness has a significant effect on the limit load of semi-cylindrical shells under in-plane loading and, therefore, cannot be underestimated.