Effect Of Fiber Orientation On Initial Postbuckling Behavior And Imperfection Sensitivity Of Composite Cylindrical Shells

Koiter's approach is used to formulate the influence of fiber orientation on the behavior of the cylindrical shell in the initial postbuckling region. Results are presented for three-layer composite cylindrical shells of either glass-epoxy or boron-epoxy subjected to uniform axial compressive load. The results show that the initial postbuckling coefficient that characterizes the extent of imperfection sensitivity of a structure is greater for the glass-epoxy shells than for the boron- epoxy shells. For the glass-epoxy cylinders the slope of the load vs. end-shortening curve in the initial postbuckling region is found to have high negative value, which is not significantly affected by the change in fiber orientation. This suggests that the buckling of a nearly perfect glass-epoxy cylinder under prescribed end-shortening will be catastrophic, regardless of fiber orientation. However, for the boron-epoxy cylinders the negative slope varies with the change in fiber orientation, and whether the failure will be catastrophic or not will depend on the fiber orientation.

As an expert in structure and stress analysis, the author has written extensively on functionally graded materials (FGMs), nonlinear vibration and dynamic response of functionally graded material plates in thermal environments, buckling and postbuckling analysis of single-walled carbon nanotubes in thermal environments. This book provides a comprehensive overview of the author's works which include significant contributions to the postbuckling behavior of plates and shells under different loading and environmental conditions. This book comprises eight chapters. Each chapter contains adequate introductory material so that an engineering graduate who is familiar with basic understanding of plates and shells will be able to follow it. Chapter 1 introduces higher order shear deformation plate theory and the derivation of the nonlinear equations of shear deformable plates in the von Kármán sense.Chapter 2, covers the postbuckling behavior of thin plates due to in-plane compressive loads or temperature variation.Chapter 3 presents analytical solutions of moderately thick isotropic plates without or resting on elastic foundations.Chapter 4 furnishes a detailed treatment of the postbuckling problems of shear deformable laminated plates subjected to thermal, electrical, and mechanical loads.Chapter 5 put forward a concepts of boundary layer theory for shell buckling and isotropic cylindrical shells.Chapter 6 extends this novel theory to the cases of anisotropic laminated cylindrical thin shells.Chapter 7 presents postbuckling analysis of shear deformable laminated cylindrical shells under the framework of boundary layer theory.Chapter 8 deals with postbuckling behavior of laminated cylindrical panels under various loading conditions.

This report contains documentation for four computer programs used in the imperfection sensitivity analysis of cylindrical shells. The four programs are based upon Donnell's equation for cylindrical shells. The formulation of each program is worked in detail so others may make modification. Input and output instructions, together with the program listings, are provided. This report is in two volumes. Volume I discusses the development and applications of the programs, and Volume II is the user's manual.

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.

Stability of structures is one of the most important and interesting fields in mechanics. This book is dedicated to fundamental concepts, problems and methods of structural stability along with qualitative understanding of instability phenomena. The methods presented are constructive and easy to implement in computer programs. Recent exciting experiments on dynamic stability of non-conservative systems are described and shown by many photographs.

* 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.

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.

The capability to predict the nonlinear response of beams, plates and shells when subjected to thermal and mechanical loads is of prime interest to structural analysis. In fact, many structures are subjected to high load levels that may result in nonlinear load-deflection relationships due to large deformations. One of the important problems deserving special attention is the study of their nonlinear response to large deflection, postbuckling and nonlinear vibration. A two-step perturbation method is firstly proposed by Shen and Zhang (1988) for postbuckling analysis of isotropic plates. This approach gives parametrical analytical expressions of the variables in the postbuckling range and has been generalized to other plate postbuckling situations. This approach is then successfully used in solving many nonlinear bending, postbuckling, and nonlinear vibration problems of composite laminated plates and shells, in particular for some difficult tasks, for example, shear deformable plates with four free edges resting on elastic foundations, contact postbuckling of laminated plates and shells, nonlinear vibration of anisotropic cylindrical shells. This approach may be found its more extensive applications in nonlinear analysis of nano-scale structures. Concentrates on three types of nonlinear analyses: vibration, bending and postbuckling Presents not only the theoretical aspect of the techniques, but also engineering applications of the method A Two-Step Perturbation Method in Nonlinear Analysis of Beams, Plates and Shells is an original and unique technique devoted entirely to solve geometrically nonlinear problems of beams, plates and shells. It is ideal for academics, researchers and postgraduates in mechanical engineering, civil engineering and aeronautical engineering.