Computerized buckling analysis of shells


Book Description

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.










An Assessment of Current Capability for Computer Analysis of Shell Structures


Book Description

The report contains an assessment of current shell analysis capability. The assessment is based on work conducted at the Lockheed Palo Alto Research Laboratory under contract to the Air Force Flight Dynamics Laboratory. In addition to surveying the open literature, information for the study was gathered during a series of visits made to organizations throughout the United States at which there is an active shell analysis research effort. More than 40 industrial concerns, government agencies and universities have been visited to date. During each visit, technical personnel working in the area of shell analysis were interviewed to determine the scope of their present analysis capability, to learn of current research activities and to discuss computer methods of shell analysis in general. Information so obtained is summarized in a series of briefs which appear in the Appendix of this report.







Shell and Spatial Structures: Computational Aspects


Book Description

In recent years powerful engineering workstations for a reasonable price become a valuable tool for the design of complicated constructions such as shell and spatial structures. This availability causes an increasing use of advanced numerical techniques for the static and dynamic analysis of these structures, also in the non-linear range. The I.A.S.S. Working Group nO 13 concerned with "Numerical Methods in Shell and Spatial Structures" and the Department of Civil Engineering of the Katholieke Universiteit Leuven have taken the initiative to organise an International Symposium, providing a forum for discussion and exchange of views between researchers, specialists in numerical analysis on one hand and designers, practising engineer ings on the other hand. These Proceedings contain the papers presented at the Symposium, held in Leuven, July 14-16 1986. The papers are organised in five sections 1. Shell structures 2. Spatial structures 3. Dynamic analysis 4. Non-linear analysis 5. Presentation and interpretation of results The papers covering more than one domain are classified following the main subject. We hope that researchers as well as practising engineers will find a lot of useful information in the book.




NASA Scientific and Technical Reports


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Scientific and Technical Aerospace Reports


Book Description

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.




Flexible Shells


Book Description

Euromech-Colloquium Nr. 165 The shell-theory development has changed its emphasis during the last two decades. Nonlinear problems have become its main motive. But the analysis was until recently predominantly devoted to shells designed for strength and stiffness. Nonlinearity is here relevant to buckling, to intensively vary able stress states. These are (with exception of some limit cases) covered by the quasi-shallow shell theory. The emphasis of the nonlinear analysis begins to shift further - to shells which are designed for and actually capable of large elastic displacements. These shells, used in industry for over a century, have been recently termedj1exible shells. The European Mechanics Colloquium 165. was concerned with the theory of elastic shells in connection with its applications to these shells. The Colloquium was intended to discuss: 1. The formulations of the nonlinear shell theory, different in the generality of kine matic hypothesis, and in the choice of dependent variables. 2. The specialization of the shell theory for the class of shells and the respective elastic stress states assuring flexibility. 3. Possibilities to deal with the complications of the buckling analysis of flexible shells, caused by the precritial perturbations of their shape and stress state. 4. Methods of solution appropriate for the nonlinear flexible-shell problems. 5. Applications of the theory. There were 71 participants the sessions were presided over (in that order) by E. Reissner, J. G. Simmonds, W. T. Koiter, R. C. Tennyson, F. A. Emmerling, E. Rarnm, E. L. Axelrad.