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

Abstract

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.