Creep Buckling of a Complete Spherical Shell

1976 ◽  
Vol 43 (3) ◽  
pp. 450-454 ◽  
Author(s):  
Norman Jones
Keyword(s):  
Spherical Shell ◽  
External Pressure ◽  
Elastic Instability ◽  
Spherical Shells ◽  
Critical Mode ◽  
Linear Elastic ◽  
Buckling Behavior ◽  
Creep Buckling ◽  
Imperfect Shape ◽  
Long Cylindrical Shell

The creep buckling behavior of a complete spherical shell which is subjected to a uniform external pressure is investigated using a perturbation method of analysis. The spherical shell has an arbitrary initial imperfect shape and is made from a material which creeps according to the generalized Norton’s law. It turns out that the critical mode number of the deformed profile is identical to that obtained previously by various authors for the linear elastic instability of complete spherical shells. It also appears that the resistance to creep buckling of complete spherical shells is greater than the resistance of a long cylindrical shell having the same R/h ratio and material properties.

Nonlinear Stability Analysis of the Vaulted Roofs With Corrosion Defects of Oil Storage Tank

2009 ◽  
Author(s):  
Baosheng Dong ◽  
Xinwei Zhao ◽  
Hongda Chen ◽  
Jinheng Luo ◽  
Zhixin Chen ◽  
...  
Keyword(s):  
Spherical Shell ◽  
Nonlinear Stability ◽  
Storage Tank ◽  
Critical Pressure ◽  
External Pressure ◽  
Shallow Spherical Shell ◽  
Nonlinear Stability Analysis ◽  
Spherical Shells ◽  
Oil Storage ◽  
Oil Storage Tank

The vaulted roofs of oil storage tank are usually designed as the shallow spherical shells subjecting to a uniform external pressure, which have been widely observed that these shallow spherical shells undergo various levels of corrosion in their employing conditions. It is important to assess the stability of these local weaken shallow spherical roofs due to corrosion for preventing them from occurring unexpected buckling failure. In this paper, the uniform eroded part of a shallow spherical oil tank vaulted roof is simplified as a shallow spherical shell with elastic supports. Based on the simplification, a general pathway to calculate the critical pressure of eroded shallow spherical shell is proposed. The modified iteration method considering large deflection of the shell is applied to solve the problem of nonlinear stability of the shallow spherical shells, and then the second-order approximate analytical solution is obtained. The critical pressure calculated by this method is consistent with the classical numerical results and nonlinear finite element method, and the calculation errors are less than 10%. It shows that it is feasible to apply the method proposed here.

The Elastic Instability of a Complete Spherical Shell

1962 ◽  
Vol 13 (2) ◽  
pp. 189-201 ◽  
Author(s):  
J.M.T. Thompson
Keyword(s):  
Spherical Shell ◽  
High Speed ◽  
Large Deflection ◽  
Elastic Shell ◽  
External Pressure ◽  
Maximum Pressure ◽  
Elastic Instability ◽  
Rotationally Symmetric ◽  
Post Buckling ◽  
Good Agreement

SummaryThe elastic instability of a complete spherical shell under uniform external pressure is studied experimentally and theoretically. The premature snapping of a thin elastic shell, made of polyvinyl chloride, is seen to be classical in nature. The experimental maximum pressure and pre-snapping bending deformation are correlated with the theoretical behaviour of an initially imperfect shell. The large deflection behaviour of a perfect shell is assessed experimentally, and the stable post-buckling states are observed to be rotationally symmetric. A fairly precise theoretical analysis of these states is performed, the use of a high-speed digital computer allowing a considerable advance over previous treatments. The experimental and theoretical post-buckling curves are in good agreement, yielding the first detailed correlation of post-snapping equilibrium states in the field of shell instability.

Creep Buckling Under Varying Loads

1991 ◽  
Vol 113 (1) ◽  
pp. 41-45 ◽  
Author(s):  
N. Miyazaki ◽  
S. Hagihara ◽  
T. Munakata
Keyword(s):  
Cylindrical Shell ◽  
Spherical Shell ◽  
Circular Cylindrical Shell ◽  
Critical Time ◽  
Initial Imperfection ◽  
External Pressure ◽  
Deformation Analysis ◽  
The Finite Element Method ◽  
Creep Buckling ◽  
Damage Rule

Creep buckling analyses under stepwise varying loads are performed on a circular cylindrical shell with initial imperfection subjected to axial compression and a partial spherical shell under uniform external pressure. The finite element method is applied to a creep deformation analysis to obtain the critical time when creep buckling occurs. The results show that a linear cumulative damage rule for creep buckling can be well applied to the creep buckling of the circular cylindrical shell, but cannot to that of the partial spherical shell.

Lower-Bound Assessment of Creep Buckling Strength

1983 ◽  
Vol 105 (3) ◽  
pp. 216-221
Author(s):  
D. L. Marriot
Keyword(s):  
Experimental Data ◽  
Lower Bound ◽  
Reasonable Accuracy ◽  
Short Term ◽  
Spherical Shells ◽  
Buckling Strength ◽  
Buckling Behavior ◽  
Creep Buckling ◽  
Accuracy Of Prediction ◽  
Made In

A method is developed for predicting the creep buckling behavior of complex pressurized components from the results of ambient, short-term buckling tests on geometrically similar components. The method has been tested against experimental data on boss-loaded spherical shells and shows reasonable accuracy of prediction of the buckling load after a given period of time. Application to the design analysis of a component for a boiler is described. An analysis of the approximations made in developing the method is included. It is shown that a lower bound on buckling strength at a given time is obtained.

On Establishing Buckling Knockdowns for Imperfection-Sensitive Shell Structures

2018 ◽  
Vol 85 (9) ◽  
Author(s):  
S. Gerasimidis ◽  
E. Virot ◽  
J. W. Hutchinson ◽  
S. M. Rubinstein
Keyword(s):  
Cylindrical Shells ◽  
Strong Dependence ◽  
Elastic Shell ◽  
External Pressure ◽  
Buckling Load ◽  
Spherical Shells ◽  
Nonlinear Buckling ◽  
Buckling Loads ◽  
Buckling Behavior ◽  
Global Buckling

This paper investigates issues that have arisen in recent efforts to revise long-standing knockdown factors for elastic shell buckling, which are widely regarded as being overly conservative for well-constructed shells. In particular, this paper focuses on cylindrical shells under axial compression with emphasis on the role of local geometric dimple imperfections and the use of lateral force probes as surrogate imperfections. Local and global buckling loads are identified and related for the two kinds of imperfections. Buckling loads are computed for four sets of relevant boundary conditions revealing a strong dependence of the global buckling load on overall end-rotation constraint when local buckling precedes global buckling. A reasonably complete picture emerges, which should be useful for informing decisions on establishing knockdown factors. Experiments are performed using a lateral probe to study the stability landscape for a cylindrical shell with overall end rotation constrained in the first set of tests and then unconstrained in the second set of tests. The nonlinear buckling behavior of spherical shells under external pressure is also examined for both types of imperfections. The buckling behavior of spherical shells is different in a number of important respects from that of the cylindrical shells, particularly regarding the interplay between local and global buckling and the post-buckling load-carrying capacity. These behavioral differences have bearing on efforts to revise buckling design rules. The present study raises questions about the perspicacity of using probe force imperfections as surrogates for geometric dimple imperfections.

A Comparison of Theoretical and Experimental Results From Spherical Shells With a Single Radially Attached Nozzle

1967 ◽  
Vol 89 (3) ◽  
pp. 333-338 ◽  
Author(s):  
F. J. Witt ◽  
R. C. Gwaltney ◽  
R. L. Maxwell ◽  
R. W. Holland
Keyword(s):  
Spherical Shell ◽  
Internal Pressure ◽  
Experimental Results ◽  
Strain Gages ◽  
Spherical Shells ◽  
Axial Thrust ◽  
Outside Diameter ◽  
Theoretical Results

A series of steel models having single nozzles radially and nonradially attached to a spherical shell is presently being examined by means of strain gages. Parameters being studied are nozzle dimensions, length of internal nozzle protrusions, and angles of attachment. The loads are internal pressure and axial thrust and moment loadings on the nozzle. This paper presents both experimental and theoretical results from six of the configurations having radially attached nozzles for which the sphere dimensions are equal and the outside diameter of the attached nozzle is constant. In some instances the nozzle protrudes through the vessel.

A fast approach for acoustic source localization on a thin spherical shell

2021 ◽  
pp. 147592172110419
Author(s):  
Zixian Zhou ◽  
Zhiwen Cui ◽  
Tribikram Kundu
Keyword(s):  
Velocity Profile ◽  
Spherical Shell ◽  
Source Localization ◽  
Pressure Vessels ◽  
Solution Technique ◽  
Acoustic Source ◽  
Spherical Shells ◽  
Fast Approach ◽  
Acoustic Source Localization ◽  
Thin Spherical Shell

Thin spherical shell structures are wildly used as pressure vessels in the industry because of their property of having equal in-plane normal stresses in all directions. Since very large pressure difference between the inside and outside of the wall exists, any formation of defects in the pressure vessel wall has a huge safety risk. Therefore, it is necessary to quickly locate the area where the defect maybe located in the early stage of defect formation and make repair on time. The conventional acoustic source localization techniques for spherical shells require either direction-dependent velocity profile knowledge or a large number of sensors to form an array. In this study, we propose a fast approach for acoustic source localization on thin isotropic and anisotropic spherical shells. A solution technique based on the time difference of arrival on a thin spherical shell without the prior knowledge of direction-dependent velocity profile is provided. With the help of “L”-shaped sensor clusters, only 6 sensors are required to quickly predict the acoustic source location for anisotropic spherical shells. For isotropic spherical shells, only 4 sensors are required. Simulation and experimental results show that this technique works well for both isotropic and anisotropic spherical shells.

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