Titel: Computerized buckling analysis of shells
Autor/en: D. Bushnell
HC runder Rücken kaschiert.
30. September 1985 - gebunden - 448 Seiten
This report describes the work performed by Lockheed Palo Alto Research Labora tory, Palo Alto, California 94304. The work was sponsored by Air Force Office of Scientific Research, Bolling AFB, Washington, D. C. under Grant F49620-77-C-0l22 and by the Flight Dynamics Laboratory, Air Force Wright Aeronautical Laboratories, Wright-Patterson AFB, Ohio under Contract F3361S-76-C-31OS. The work was completed under Task 2307Nl, "Basic Research in Behavior of Metallic and Composite Components of Airframe Structures". The work was admini stered by Lt. Col. J. D. Morgan (AFOSR) and Dr. N. S. Khot (AFWAL/FIBRA). The contract work was performed between October 1977 and December 1980. The technical report was released by the Author in December 1981. Preface Many structures are assembled from parts which are thin. For example, a stiffened plate or cylindrical panel is composed of a sheet the thickness of which is small com pared to its length, breadth, and stiffener- spacing, and stiffeners the thickness of which is small compared to their _ heights and lengths. These assembled structures, loaded in compression, can buckle overall, that is sheet and stiffeners can collapse together in a general instability mode; the sheet can buckle locally between stiffeners; the stiffeners can cripple; and a variety of complex buckling interactions can occur involving local and overall deformations of both sheet and stiffeners. More complex, built-up structures can buckle in more complex and subtle ways.
1. Descriptions of types of instability and classical buckling problems.- Summary of the volume.- Purpose.- Why do shells buckle?.- What is buckling?.- Various types of bifurcation buckling.- Capsule of recent progress in buckling analysis.- Asymptotic analysis.- General nonlinear analysis.- Axisymmetric structures.- Simple examples to illustrate various types of buckling.- Column buckling.- Prebuckling solution or fundamental equilibrium path.- Bifurcation buckling.- Post-bifurcation stability.- Loss of stability and imperfections.- Buckling of plates.- "Classical" buckling of cylindrical and spherical shells.- Cylindrical shells under axial compression.- A caution for novice users of computer programs for buckling.- Stiffened cylinders under axial compression.- Cylinders under uniform external pressure or torsion.- Spherical shells under uniform external pressure.- Spherical caps.- 2. Nonlinear collapse.- Summary.- Elastic-plastic-creep collapse of axially compressed monocoque cylinders.- No-creep.- Creep included.- Creep collapse of ring-stiffened cylinder under external hydrostatic pressure.- Snap-through of very shallow spherical caps.- Straight and curved tubes under bending and external pressure.- Long tubes and elbows: A survey of work done.- Elastic models.- Bending tests on long elastic-plastic straight pipes and elbows.- Elastic-plastic piping analysis.- Axisymmetric model of long pipe or elbow-bending problem.- Simulation of the pipe-bending problem by thermal loading of a torus.- Collapse and bifurcation buckling moment of a long straight pipe.- Collapse of a 90° elastic plastic elbow 45 Collapse and bifurcation buckling due to bending of straight elastic pipes of finite length.- Collapse of cylindrical panels and shells with concentrated loads and cutouts.- Cylindrical panels and shells with concentrated normal loads.- Panels.- Complete cylindrical shells.- Collapse of axially compressed cylindrical shells with cutouts.- Rectangular cutouts.- Circular cutouts.- Collapse of axially compressed noncircular cylinders.- Axially compressed elliptical cylinder.- Axially compressed "Pear-shaped" cylinder.- Axially compressed cylindrical shell with local load path eccentricity.- 3. Bifurcation buckling in which nonuniformity or nonlinearity of the prebuckling state is important.- Summary.- Bifurcation buckling due to edge effects and localized circumferential compression.- Bifurcation buckling due to edge effects.- Cylindrical shell under axial compression.- Externally pressurized spherical caps with edge rings.- Buckling of shallow and deep spherical caps.- Buckling due to localized hoop compression.- Thermal buckling of cylindrical shells.- Buckling of cylinder heated halfway along length.- Buckling of axisymmetrically heated clamped cylinder.- Buckling of an internally pressurized rocket fuel tank.- Local buckling at a field joint in a large rocket payload shroud 84 Bifurcation buckling of spherical shells under meridional tension combined with hoop compression.- Axial load applied uniformly over latitude with finite radius r1.- Axial load applied at a point.- Buckling of internally pressurized vessel heads.- Cause and characteristics of nonsymmetric bifurcation buckling.- Difference in elastic behavior of ellipsoidal and torispherical heads.- Elastic bifurcation buckling.- Elastic-plastic bifurcation buckling.- Conclusions about bifurcation buckling of internally pressurized heads.- Bifurcation buckling near the axisymmetric collapse load.- A summary of examples already described.- Failure of a water tank.- An attempt to predict elastic-plastic buckling of the large steel water tower including fabrication effects.- Tank configuration and discretized model.- Welding.- Mismatch.- Cold bending.- Conclusions.- 4. Effect of boundary conditions and eccentric loading.- Summary.- Effect of boundary conditions on buckling of monocoque shells.- Cylinders subjected to uniform external hydrostatic pressure.- Cylinders subject
`The book is a valuable contribution for engineers in government, industry, and universities who have complex shell buckling problems to solve and who have available to them computer programs for the buckling analysis of shells.'
Applied Mechanics Review, 38:8 (1986)
`What makes this book unique is that the author has succeeded in providing a `feel' for shell buckling based on careful mixture of theoretical, analytical, and numerical procedures. Many of the richly illustrated examples are written in a tutorial form, a guide-by-example for the modeling and solving of complex of nonlinear problems. It shows convincingly that the modern structural engineer must have a very thorough understanding of how structures behave if he is to use the advanced computational tools successfully. This book is a must for all those who work in the field of shell stability.'
Journal of Applied Mechanics, 53 (1986)