Download or read book Influence of Imperfections on Mechanism of Buckling of Shallow Spherical Shells written by R. M. Evan-Iwanowski and published by . This book was released on 19?? with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report contains the results of a theoretical and experimental investigation of the influence of initial geometrical imperfections, imperfect boundary conditions and imperfections in loading on stability of shallow spherical shells subjected to uniform pressure, concentrated loads and a combination of uniform pressure and concentrated loads. The initial geometrical imperfections were considered to be axisymmetric having a form of damped waves. The initial boundaries imperfections were considered to be relaxed constraints of the radial forces at the instant of buckling. The imperfections in loadings were considered to be the eccentricities in concentrated loads. Correctly argued theory of the influence of initial imperfections on stability of shells has been verified theoretically and experimentally. Moreover, a complete agreement was obtained between the theory and experimentation within the investigated class of geometrical imperfections. (Author).

Download or read book Effect of Geometrical Imperfection on the Elastic Buckling of Thin Shallow Spherical Shells written by Wen Liang Chen and published by . This book was released on 1959 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Influence of Residual Stresses and Thermal Gradients on Mechanism of Buckling of Shallow Spherical Shells written by Megumi Sunakawa and published by . This book was released on 1967 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains results of a theoretical and experimental investigation of the influence of residual stresses and thermal gradients on stability of shallow spherical shells. Basic equations, thermoelastic problems for spherical shells, taking a large deformation into consideration, are derived. Assuming 'damped' axisymmetrical deformation pattern, solution for the stability of spherical shell subjected to external pressure is presented. Good agreement between the theoretical and previous experimental results is obtained. The effects of residual stresses and thermal gradients on stability of spherical shells subjected to external pressure are determined. These effects are of considerable significance, and should be taken into account in application. Experiments indicating the effects of residual stresses have been performed for 'inverted' shells subjected to symmetrical and eccentric concentrated loads.

Download or read book Asymptotic Methods in the Buckling Theory of Elastic Shells written by P. E. Tovstik and published by World Scientific. This book was released on 2001 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book The Axisymmetric Buckling of Initially Imperfect Complete Spherical Shells written by Tatsuzo Koga and published by . This book was released on 1968 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: A theoretical investigation of the axisymmetric buckling of complete thin-walled spherical shells under uniform external pressure is undertaken to determine the effect of axisymmetric initial imperfections. In the analysis, the complete spherical shell is divided into two parts; the shallow cap in which the initial imperfection exists, and the remaining portion of the shell most of which deforms in simple contraction. The rotation of the meridian of the cap is assumed in the form of a polynomial function. Four matching conditions are enforced at the juncture of the cap and remainder. The total potential energy of the complete spherical shell is minimized in accordance with the Rayleigh-Ritz approximation method. Two types of initial imperfections are studied; one is an axisymmetric dimple, and the other is a spherical region whose radius of curvature is greater than that of the perfect spherical shell. The maximal values of the pressure parameter rho in the equilibrium state before snap-through were calculated for various values of the geometric parameter lambda, which is proportional to the angular extent of the imperfection for a given radius-to-thickness ratio, and the imperfection amplitude parameter delta, which is the ratio of the initial deviation of the shell mid-surface at the axis of rotation to the wall-thickness. The results of numerical computations show that for all values of delta the lowest buckling pressure is reached when lambda is about 4. (Author).

Download or read book Elastic Stability of Circular Cylindrical Shells written by N. Yamaki and published by Elsevier. This book was released on 1984-02-01 with total page 573 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Some Recent Studies of the Buckling of Thin Shells written by Stanford University. Department of Aeronautics and Astronautics and published by . This book was released on 1969 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: After a brief summary of the development of present knowledge of the buckling process of thin shells, the results of recent investigations are discussed in some detail. In particular, information is given on analyses of the maximum stress a circular cylindrical shell of infinite or finite length can carry in axial compression in the presence of an initial deviation of the shell wall from the perfect cylindrical shape, and on the number of circumferential waves into which finite cylindrical shells buckle. The maximum external pressure is calculated that can be supported by a complete spherical shell in the presence of known deviations of its wall from the perfect spherical shape. The results of recent experiments on cylindrical and complete spherical shells are also presented. Recommendations are made for the practical calculation of the buckling stresses of circular cylindrical shells and spherical shells. (Author).

Download or read book Analytical Investigation of the Effect of Material and Geometric Imperfections on Buckling Strength of Spherical Shells written by Rama Krishna Challa and published by . This book was released on 1995 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Buckling of Shallow Spherical Shells Under External Pressure Classic Reprint written by Edward L. Reiss and published by Forgotten Books. This book was released on 2018-02-07 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Buckling of Shallow Spherical Shells Under External Pressure The pressure to which the shell jumps is called the final buckling load. The purpose of this paper is to determine the values of por for various shell configurations. A series of experiments have been conducted by Kaplan and Fung (1) on clamped, shallow, Spherical shells under uniform external pressure. Not only were the initial and final buckling loads determined, but measurements were made of the vertical deflections at various points of the shell for several different values of the pressure. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Download or read book Collected Papers on Instability of Shell Structure 1962 written by and published by . This book was released on 1962 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1978 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book The Effect of Imperfections on the Buckling of Cylindrical Shells written by Jean Francois Imbert and published by . This book was released on 1971 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Buckling of Spherical Shells with Large Axisymmetric Imperfection and Application in Soft Robotics written by Chuan Qiao and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Spherical shells are ubiquitous in nature and engineering for their simple geometry and excellent load-bearing capacity. A long-standing topic of spherical shells subject to uniform external pressure is their highly unstable post-buckling response that leads to a catastrophic collapse. This type of failure fully exhausts the load-bearing capacity of the shell, and it is thus detrimental for traditional engineering applications. On the other hand, recent advances in soft robotics and metamaterials demonstrate that geometric nonlinearities and elastic instabilities can be harnessed to generate distinctive functions, such as shape morphing, fast motion, and logic operation.This thesis proposes the use of a large axisymmetric imperfection to control the buckling mode of spherical shells, and demonstrates its application when integrated into a soft bi-shell valve for the fast actuation of soft robots. On the first front, the proposed imperfection can escape the classical bifurcation of perfect spherical shells, and induce snap-through buckling followed by a stable post-buckling; this response provides increasing pressure resistance over a large change in volume. The buckling of the imperfect shell is investigated through a theoretical study that employs exact expressions of the middle surface strains, curvature changes, and live pressure loading along with validating experiments and numerical simulations. The post-buckling characteristics and transition between four buckling modes can be programmed by tuning the defect geometry and shell radius to thickness ratio. On the second front, a new concept for soft valves is proposed: a bi-shell valve consisting of an imperfect shell and a shallow spherical cap. The bi-shell valve harnesses the snap-through interaction of the constituent shells to convert a slowly imparted volume into a fast volume output. Upper bounds and performance metrics are presented to guide the design of the bi-shell valve, and its performance is illustrated through an application that demonstrates the fast actuation of a soft striker.Overall, the work in this thesis contributes to unveil original aspects of shell buckling with results that are promising for diverse applications. Geometric imperfections can be programmed into spherical shells to trigger new buckling modes that can be exploited for the design of soft robots, mechanical metamaterials, and soft matter. Furthermore, the bi-shell valve concept here introduced can inspire the design of future soft valves with unique actuation modes for soft pneumatic robots"--

Download or read book Influence of Periodic Axisymmetric Imperfections of Various Wavelengths on the Buckling Load of a Cylindrical Shell in Axial Compression written by Stanford University. Department of Aeronautics and Astronautics and published by . This book was released on 1971 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: Koiter's well-known buckling analysis of cylindrical shells with periodic axisymmetric imperfections yields a solution which is valid for imperfection of different wavelengths and amplitudes. Numerical calculations were carried out to evaluate several of these cases. Of particular interest are imperfections of the wavelength which are larger than the one considered in Koiter's original analysis. In such cases, the validity of the solution may be extended to imperfection amplitudes of a much larger order of magnitude hitherto considered. The numerical results are plotted and tabulated. A rederivation of Koiter's analysis is added in an appendix together with a brief description of the computational method that was used. (Author).

Download or read book Influence of Asymmetric Imperfections on the Vibrations of Axially Compressed Cylindrical Shells written by Aviv Rosen and published by . This book was released on 1975 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of two types of asymmetric initial geometrical imperfections on the vibrations and buckling of axially loaded isotropic cylindrical shells is studied. The analysis is based on a solution of the Karman-Donnell nonlinear shell equations by the Galerkin method. The results indicate that the influence of the initial geometrical imperfections depends strongly on the mode of the initial imperfection and its relation to the mode of vibration. The imperfections may lower or raise the frequency. The buckling loads also depend strongly on the relation between the corresponding modes. In general, a reduction in buckling load is predicted, but in some cases the solution predicts an increase in buckling loads due to imperfections and in certain cases even large bending deformation without buckling.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1971 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt: