Elastic Stability Of Circular Cylindrical Shells

The object of this book is to clarify the whole aspect of the basic problems concerning the elastic stability of of circular cylindrical shells under typical loading conditions. The book deals with buckling, postbuckling and initial postbuckling problems under one of the three fundamental loads, that is, torsion, pressure and compression. The emphases are placed on the accurate analysis and comprehensive numeral results for the buckling problem, experimental verification of the theoretical analysis for the postbuckling problem and clarification of the range of applicability of the perturbation method for the analysis of initial postbuckling behaviors and imperfection sensitivity. The problems under typical combined loads as well as the influence of the contained liquid are also clarified.

This book gives a unified presentation of the field of stability. Buckling and post-buckling states are studied on the basis of total potential energy of structural systems. Emphasis is placed throughout the text on post-buckling analysis and behaviour. The sensitivity of buckling and post-buckling states to changes in design parameters is also discussed as well as changes due to imperfections and damage.

1. Equations of thin elastic shell theory. 1.1. Elements of surface theory. 1.2. Equilibrium equations and boundary conditions. 1.3. Errors of 2D shell theory of Kirchhoff-Love type. 1.4. Membrane stress state. 1.5. Technical shell theory equations. 1.6. Technical theory equations in the other cases. 1.7. Shallow shells. 1.8. Initial imperfections. 1.9. Cylindrical shells. 1.10. The potential energy of shell deformation. 1.11. Problems and exercises -- 2. Basic equations of shell buckling. 2.1. Types of elastic shell buckling. 2.2. The buckling equations. 2.3. The buckling equations for a membrane state. 2.4. buckling equations of the general stress state. 2.5. Problems and exercises -- 3. Simple buckling problems. 3.1. Buckling of a shallow convex shell. 3.2. Shallow shell buckling modes. 3.3. The non-uniqueness of buckling modes. 3.4. A circular cylindrical shell under axial compression. 3.5. A circular cylindrical shell under external pressure. 3.6. Estimates of critical load. 3.7. Problems and examples -- 4. Buckling modes localized near parallels. 4.1. Local shell buckling modes. 4.2. Construction algorithm of buckling modes. 4.3. Buckling modes of convex shells of revolution. 4.4. Buckling of shells of revolution without torsion. 4.5. Buckling of shells of revolution under torsion. 4.6. Problems and exercises -- 5. Non-homogeneous axial compression of cylindrical shells. 5.1. Buckling modes localized near generatrix. 5.2. Reconstruction of the asymptotic expansions. 5.3. Axial compression and bending of cylindrical shell. 5.4. The influence of internal pressure. 5.5. Buckling of a non-circular cylindrical shell. 5.6. Cylindrical shell with curvature of variable sign. 5.7. Problems and exercises -- 6. Buckling modes localized at a point. 6.1. Local buckling of convex shells. 6.2. Construction of the buckling mode. 6.3. Ellipsoid of revolution under combined load. 6.4. Cylindrical shell under axial compression. 6.5. Construction of the buckling modes. 6.6. Problems and exercises -- 7. Semi-momentless buckling modes. 7.1. Basic equations and boundary conditions. 7.2. Buckling modes for a conic shell. 7.3. Effect of initial membrane stress resultants. 7.4 Semi-momentless buckling modes of cylindrical shells. 7.5. Problems and exercises -- 8. Effect of boundary conditions on semi-momentless modes. 8.1. Construction algorithm for semi-momentless solutions. 8.2. Semi-momentless solutions. 8.3. Edge effect solutions. 8.4. Separation of boundary conditions. 8.5. The effect of boundary conditions on the critical load. 8.6. Boundary conditions and buckling of a cylindrical shell. 8.7. Conic shells under external pressure. 8.8. Problems and exercises -- 9. Torsion and bending of cylindrical and conic shells. 9.1. Torsion of cylindrical shells. 9.2. Cylindrical shell under combined loading. 9.3. A shell with non-constant parameters under torsion. 9.4. Bending of a cylindrical shell. 9.5. The torsion and bending of a conic shell. 9.6. Problems and exercises -- 10. Nearly cylindrical and conic shells. 10.1. Basic relations. 10.2. Boundary problem in the zeroth approximation. 10.3. Buckling of a nearly cylindrical shell. 10.4. Torsion of a nearly cylindrical shell. 10.5. Problems and exercises -- 11. Shells of revolution of negative Gaussian curvature. 11.1. Initial equations and their solutions. 11.2. Separation of the boundary conditions. 11.3. Boundary problem in the zeroth approximation. 11.4. Buckling modes without torsion. 11.5. The case of the neutral surface bending. 11.6. The buckling of a torus sector. 11.7. Shell with Gaussian curvature of variable sign. 11.8. Problems and exercises -- 12. Surface bending and shell buckling. 12.1. The transformation of potential energy. 12.2. Pure bending buckling mode of shells of revolution. 12.3. The buckling of a weakly supported shell of revolution. 12.4. Weakly supported cylindrical and conical shells. 12.5. Weakly supported shells of negative Gaussian curvature. 12.6. Problems and exercises -- 13. Buckling modes localized at an edge. 13.1. Rectangular plates under compression. 13.2. Cylindrical shells and panels under axial compression. 13.3. Cylindrical panel with a weakly supported edge. 13.4. Shallow shell with a weak edge support. 13.5. Modes of shells of revolution localized near an edge. 13.6. Buckling modes with turning points. 13.7. Modes localized near the weakest point on an edge. 13.8. Problems and exercises -- 14. Shells of revolution under general stress state. 14.1. The basic equations and edge effect solutions. 14.2. Buckling with pseudo-bending modes. 14.3. The cases of significant effect of pre-buckling strains. 14.4. The weakest parallel coinciding with an edge. 14.5. Problems and exercises.

There have been stability theories developed for beams, plates and shells — the most significant elements in mechanical, aerospace, ocean and marine engineering. For beams and plates, the theoretical and experimental values of buckling loads are in close vicinity. However for thin shells, the experimental predictions do not conform with the theory, due to presence of small geometric imperfections that are deviations from the ideal shape.This fact has been referred to in the literature as ‘embarrassing’, ‘paradoxical’ and ‘perplexing’. Indeed, the popular adage, “In theory there is no difference between theory and practice. In practice there is”, very much applies to thin shells whose experimental buckling loads may constitute a small fraction of the theoretical prediction based on classical linear theory; because in practice, engineers use knockdown factors that are not theoretically substantiated.This book presents a uniform approach that tames this prima-donna-like and capricious behavior of structures that has been dubbed the ‘imperfection sensitivity’ — thus resolving the conundrum that has occupied the best minds of elastic stability throughout the twentieth century.

The effect of axial elastic restrain on the instability of a circular cylindrical shell under uniform axial compression is analysed by a Rayleigh Ritz approach within the bounds of linear theory. The effect is calculated for a wide range of parameters and design curves are presented for the percentage increase in critical load. The analysis is carried out for restraints which are active from the beginning of loading and for such which come into action only at the onset of buckling. (Author).

When a structure is put under an increasing compressive load, it becomes unstable and buckling occurs. Buckling is a particularly significant concern in designing shell structures such as aircraft, automobiles, ships, or bridges. This book discusses stability analysis and buckling problems and offers practical tools for dealing with uncertainties that exist in real systems. The techniques are based on two complementary theories which are developed in the text. First, the probabilistic theory of stability is presented, with particular emphasis on reliability. Both theoretical and computational issues are discussed. Secondly, the authors present the alternative to probability based on the notion of 'anti-optimization', a theory that is valid when the necessary information for probabilistic analysis is absent, that is, when only scant data are available. Design engineers, researchers, and graduate students in aerospace, mechanical, marine, and civil engineering who are concerned with issues of structural integrity will find this book a useful reference source.

Thin-walled metal shell structures are highly efficient in their use of material, but they are particularly sensitive to failure by buckiling. Many different forms of buckling can occur for different geometries and different loading conditions. Because this field of knowledge is both complex and industrially important, it is of great interest and concern in a wide range of industries. This book presents a compilation and synthesis of a wealth of research, experience and knowledge of the subject. Information that was previously widely scattered throughout the literature is assembled in a concise and convenient form that is easy to understand, and state-of-the-art research findings are thoroughly examined. This book is useful for those involved in the structural design of silos, tanks, pipelines, biodigestors, chimneys, towers, offshore platforms, aircraft and spacecraft. Buckling of Thin Metal Shells is essential reading for designers, researchers and code writers involved with thin-walled metal shell structures.