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The paper is devoted to a sandwich cylindrical pressure vessel with hemispherical and superellipsoidal dished heads loaded with external uniformly distributed pressure. The distinguishing feature of this sandwich structure is an individual functionally graded core. The strength and buckling problems are numerically FEM studied in the linear range. The calculations are carried out for vessels with aluminium faces and aluminium foam core. As a result stress distributions along the meridian and through the thickness of the shell have been generated as well as the buckling modes and buckling loads. Based on the obtained plots it is seen that the stress distribution is more favourable for the tank with superellipsoidal head especially when the shear stress in the core is considered. Moreover, the distribution of shear stress through the thickness of the tank changes considerably depending on the part of the tank in which it is measured. • Functionally graded mechanical properties of the core are introduced. • Dished head in the form of superellipsodial shell is proposed. • Shear stress through the thickness vary considerably depending on the point measured. • The edge effect can be diminished by application of superellipsoidal dished head. [ABSTRACT FROM AUTHOR]

The paper is devoted to a sandwich cylindrical pressure vessel closed with a dished head at both ends and loaded with external uniformly distributed pressure. Non-standard construction of the vessel is presented characterised by an asymmetric cross-section and superellipsoidal dished heads. The strength and buckling of such structure is numerically studied with the use of the finite element method limited to the linear range. The calculations are carried out for models with aluminium faces and aluminium foam core. The obtained results revealed the advantage of the superellipsoidal dished head compared to the hemispherical one in terms of stress distribution — the edge effect being a typical problem in such structures is diminished. This opens potential applications of such solution in actual structures. It is pointed out that the application of a superellipsoidal head assure a more favourable shear stress distribution in the core. • Alternative closure of the cylindrical tank is proposed. • The edge effect can be diminished by application of superellipsoidal dished head. • The edge effect influence the most the light core of a sandwich shell. • Symmetrical sandwich shell is characterised with the highest buckling load. [ABSTRACT FROM AUTHOR]

The paper is devoted to the static stress analysis of a cylindrical tank closed with two non-classical dished heads. The description of the geometry of the dished head in the form of super-ellipsoid is provided containing two dimensionless parameters to control the depth and curvature of the ellipsoid. The equivalent stress distribution along the meridian of the head is calculated analytically and numerically with the use of the finite element method. Based on the analysis of the stress in the whole tank it can be concluded that the replacement of the classical ellipsoidal head with the super-ellipsoidal one may decrease the edge effect at the junction of the two shells. This positive effect increases with the increase of the depth of the head. • Geometrical description of the super-ellipsoidal shell is provided. • Application of the super-ellipsoidal shell as a dished head of the cylindrical tank is discussed. • Super-ellipsoidal head allows to control the stress distribution in the cylindrical tank. • The use of super-ellipsoidal head diminishes the edge effect in cylindrical tank. [ABSTRACT FROM AUTHOR]

The subject of the work is a typical ground-based horizontal cylindrical tank. Two load cases are assumed: total internal pressure and total special pressure. A critical state of such a tank is described. An optimization criterion is formulated as the minimum of the tank mass, moreover the space of allowable solutions is defined. Optimal ratios of basic dimensions for an assumed family of tanks of given capacities are determined. The solutions are restrained by the strength and stability conditions. Results of numerical analysis were approximated with mathematical formulae convenient in the practice of tank design. [Copyright &y& Elsevier]

The subject of this paper is the supporting saddle of a horizontal cylindrical pressure vessel filled with liquid. A parametric model of the saddle support has been developed; the effect of the geometrical parameters on the stress values arising in the structure has been examined by means of the Finite Element Method. The shape and location of the supporting saddle have been determined with a view to minimizing the concentration of stresses. Results of numerical analysis allow determination of the effective proportions of the geometrical parameters of the vessel. [Copyright &y& Elsevier]

The paper presents the problem of stress concentration in a cylindrical pressure vessel with ellipsoidal heads subject to internal pressure. At the line, where the ellipsoidal head is adjacent to the circular cylindrical shell, a shear force and bending moment occur, disturbing the membrane stress state in the vessel. The degree of stress concentration depends on the ratio of thicknesses of both the adjacent parts of the shells and on the relative convexity of the ellipsoidal head, with the range for radius-to-thickness ratio between 75 and 125. The stress concentration was analytically described and, afterwards, the effect of these values on the stress concentration ratio was numerically examined. Results of the analysis are shown on charts. [Copyright &y& Elsevier]