Download or read book Minimum Weight Design of Stiffened Cylinders and Cylindrical Panels Under Combined Loads written by George J. Simitses and published by . This book was released on 1976 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is divided into two parts, Parts A and B. In Part A, a methodology is presented for the minimum weight design of stiffened cylinders under combined loads of torsion, uniform axial compression and pressure. A number of illustrative examples are included in order to demonstrate the methodology. In addition, the listing of the developed computer program is included and thus those interested in the program can easily use it. In Part B, a methodology is presented for the minimum weight design of stiffened curved plates under combined shear with uniaxial or biaxial compression. This methodology is illustrated through a number of examples. At the end of this second part a complete listing of the developed computer programs is included along with the associated flow charts for data preparation. The load cases considered in both parts are representative of the worst possible load cases of destabilizing loads that an aircraft fuselage is expected to encounter. The methods developed represent a fully automated design procedure for that portion of the fuselage which is designed primarily against general instability.
Download or read book Minimum Weight Design of Stiffened Fiber Composite Cylinders written by Tung-Lai Chao and published by . This book was released on 1969 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: A structural synthesis capability for stiffened fiber composite cylindrical shells has been developed. The design variables are the configuration and material parameters. The material parameters considered are the fiber volume content and the ply orientations in the skin. Both longitudinal and circumferential stiffeners are assumed to have hat cross-sections. The instability loads of the heterogeneous anisotropic cylinder under combined axial, radial, and torsional loading are calculated with smeared stiffener theory. In the synthesis scheme, multiple load conditions on the cylinder are permissible. The optimal design problem is cast into a model of a nonlinear mathematical programming problem which is solved with the penalty function technique of Fiacco-McCormick. Since weight is independent of the ply orientations there exist alternative optima. Special modifications on the iteration procedure are made, so that the ply angles tend to move in such a way that the overall strength of the cylinder is improved. Numerical examples are discussed. (Author-PL).
Download or read book Minimum Weight Design of Axially Compressed Ring and Stringer Stiffened Cylindrical Shells written by David L. Block and published by . This book was released on 1971 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report investigates the minimum weight design of axially compressed ring and stringer stiffened cylindrical shells.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1982 with total page 1282 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 Minimum Weight Design Aspects of Stiffened Cylinders Under Compression written by C. Lakshmikantham and published by . This book was released on 1967 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Criteria and Methods of Structural Optimization written by Andrzej M Brandt and published by Springer Science & Business Media. This book was released on 1987-06-30 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is intended to serve all those who are interested in structural opti mization, whether they work in this field or study it for other purposes. Rapid growth of interest in the cognitive aspects of optimization and the increas ing demands that the present day engineer has to meet in modern design have created the need of a monographic treatment of the subject. The vast number and wide range of structural optimization problems formulated and investigated in the last twenty years call for an attempt to sum up the pres ent state of knowledge in this domain and to outline the directions of its further development. The present authors undertook this task, hoping that the result would stimulate further work towards finding new methods and solutions and increasing the range of applications of the optimization methods to structural design. The immediate aim of the book is to present the basic criteria and methods of optimization and to provide a reference guide to the most important publications in the field. 'The book consists of fourteen chapters. Chapter 1 introduces the basic concepts, definitions and assumptions relating to structural optimization. Chapter 2 gives the foundations of optimization for minimum elastic strain potential or maximum rigidity, and sets a basis for optimization of bar, plate and lattice structures. Chapter 3 presents criteria of strength design and their applications to plane structures.
Download or read book General Instability of Orthotropically Stiffened Cylinders written by C. Lakshmikantham and published by . This book was released on 1965 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of a general program to determine the applicability of linear orthotropic theory to the design of cylindrical shells under various loading conditions, a theoretical and experimental investigation was performed on the general instability of orthotropic cylinders under bending and combined axial compression and bending loading. Based on a simple approximation for the asymmetric buckling pattern, theoretical results suitable for design use were obtained for the buckling of orthotropic cylinders for both bending and combined loading conditions. It was shown that the buckling stress for orthotropic cylinders under bending or axial compression loading are equal which agrees with previous results for isotropic cylinders. Theoretical results were evaluated by means of a series of careful experiments performed on orthotropically stiffened cylinders designed to fail in the elastic general instability mode. For both bending loading and the combined axial and bending loading condition, experimental results were in good agreement with the theory.
Download or read book Computerized buckling analysis of shells written by D. Bushnell and published by Springer Science & Business Media. This book was released on 1985-09-30 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Minimum Weight Design of Ring and Stringer Stiffeners for Axially Compressed Cylindrical Shells with and Without Internal Pressure written by David L. Block and published by . This book was released on 1972 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of analytical study to determine desirable ring and stringer stiffener parameters and proportions for axially compressed stiffened isotropic cylinders with and without internal pressure are presented. This investigation examines the panel and general instability buckling modes of a stiffened cylindrical shell and from this determines desirable stiffener parameters and proportions. Classical buckling equations are used which retain the important effects of the stiffeners. The results determined by using the simpler classical buckling equations are then spot checked and verified using buckling equations which considered discrete ring stiffeners and nonlinear prebuckling deformations. For both rings and stringers, T-shaped stiffeners are preferable and the effects to stiffener shape are much more pronounced at low or zero values of the internal pressure parameter. Simple analytical expressions are developed and presented which express the stiffener area parameter, the ratio of stiffener area and elastics to shell wall area and elastic modulus, in terms of the cylinder geometry and internal pressure parameter.
Download or read book Stability Analysis of Plates and Shells written by and published by . This book was released on 1998 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1972 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Buckling Experiments Experimental Methods in Buckling of Thin Walled Structures Volume 2 written by Josef Singer and published by John Wiley & Sons. This book was released on 2002-08-12 with total page 1140 pages. Available in PDF, EPUB and Kindle. Book excerpt: * Edited by Josef Singer, the world's foremost authority on structural buckling. * Time-saving and cost-effective design data for all structural, mechanical, and aerospace engineering researchers.
Download or read book Panel Optimization with Integrated Software POIS PANDA written by and published by . This book was released on 1981 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analysis and an interactive computer program are described through which minimum weight designs of composite, stiffened, cylindrical panels can be obtained subject to general and local buckling constraints and stress and strain constraints. The panels are subjected to arbitrary combinations of in-plane axial, circumferential, and shear resultants. Nonlinear material effects are included if the material is isotropic or has stiffness in only one direction (as does a discrete or a smeared stiffener). Several types of general and local buckling modes are included as constraints in the optimization process, including general instability, panel instability with either stringers or rings smeared out, local skin buckling, local crippling of stiffener segments, and general, panel, and local skin buckling including the effects of stiffener rolling. Certain stiffener rolling modes in which the panel skin does not deform but the cross section of the stiffener does deform are also accounted for. The interactive PANDA system consists of three independently executed modules that share the same data base. In the first module an initial design concept with rough (not necessarily feasible or accurate) dimensions are provided by the user in a conversational mode. In the second module the user decides which of the design parameters of the concept are to be treated by PANDA as decision variables in the optimization phase. In the third module the optimization calculations are carried out. Many examples are provided in which optimum designs obtained by PANDA are compared to those in the literature. (Author).
Download or read book Aeronautical Engineering written by and published by . This book was released on 1977 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).
Download or read book Mechanics of Composite Materials written by Zvi Hashin and published by Elsevier. This book was released on 2013-10-22 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanics of Composite Materials: Recent Advances covers the proceedings of the International Union of Theoretical and Applied Mechanics (IUTAM) Symposium on Mechanics of Composite Materials. The book reviews papers that emphasize fundamental mechanics, developments, and unresolved problems of the field. The text covers topics such as mechanical properties of composite materials; influence of microstructure on the thermoplastics and transport properties of particulate and short-fiber composites; and further applications of the systematic theory of materials with disordered constitution. The selection also explains the curved thermal crack growth in the interface of a unidirectional carbon-aluminum composite and energy release rates of various microcracks in short-fiber composites. The book will be of great interest to researchers and professionals whose line of work requires the understanding of the mechanics of composite materials.
Download or read book Journal of Hydronautics written by and published by . This book was released on 1977 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: A publication of the American Institute of Aeronautics and Astronautics devoted to marine science and technology.
Download or read book Optimal Structural Design under Stability Constraints written by Antoni Gajewski and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first optimal design problem for an elastic column subject to buckling was formulated by Lagrange over 200 years ago. However, rapid development of structural optimization under stability constraints occurred only in the last twenty years. In numerous optimal structural design problems the stability phenomenon becomes one of the most important factors, particularly for slender and thin-walled elements of aerospace structures, ships, precision machines, tall buildings etc. In engineering practice stability constraints appear more often than it might be expected; even when designing a simple beam of constant width and variable depth, the width - if regarded as a design variable - is finally determined by a stability constraint (lateral stability). Mathematically, optimal structural design under stability constraints usually leads to optimization with respect to eigenvalues, but some cases fall even beyond this type of problems. A total of over 70 books has been devoted to structural optimization as yet, but none of them has treated stability constraints in a sufficiently broad and comprehensive manner. The purpose of the present book is to fill this gap. The contents include a discussion of the basic structural stability and structural optimization problems and the pertinent solution methods, followed by a systematic review of solutions obtained for columns, arches, bar systems, plates, shells and thin-walled bars. A unified approach based on Pontryagin's maximum principle is employed inasmuch as possible, at least to problems of columns, arches and plates. Parametric optimization is discussed as well.
