Thin-Walled Structures with Structural ImperfectionsBy
- L.A. Godoy, University of Puerto Rico at Mayaguez, Puerto Rico, USA
Thin-walled structures are designed with advanced numerical analysis techniques and constructed using sophisticated fabrication processes. There are, however, a number of factors that may result in a structure that is not exactly coincident with what was considered during the design calculations. These features may be associated with changes in the properties of the structure, in the geometry, and many others. But even small changes in the structure may sometimes produce significant changes in the response.
The present work is intended to introduce professionals and researchers to the effects of imperfections on the stresses in thin-walled structures. The main idea behind the presentation is that small imperfections may introduce changes in the stresses that are nearly equal to the stresses due to the loads.
The book is organized into two main parts. The first part (Chapters 1 to 6) covers the techniques for analyzing imperfections. In the second part the emphasis is on applications, which at present may be found scattered throughout many scientific and professional journals. More practical aspects of imperfections may be found in Chapter 12.It is assumed that the reader is familiar with finite element techniques, and with the basics of shell structures.
For professionals and researchers in civil and mechanical engineering; and applied and computational mechanics.
Published: May 1996
...With the current trend of large structures of complex shapes, this book will be helpful in covering all aspects of imperfection analysis in a single source. The book, which is possibly the first in the topic, will be an asset to practising design engineers, research scientists as a reference book and as a text book for post-graduate studies....The publishers deserve appreciation for the quality printing and illustrations and alos bringing out the book on this useful practical topic.
R. Narayanan, Journal of Structural Engineering, January 1997
- Chapter headings and selected section headings: Introduction.Thin-Walled Structures and Imperfections. Classification of Imperfections in Thin-Walled Structures. Some Shell Structures in which Imperfections may be Important. A Few Situations in which Imperfections are Considered. Outline of the Book. Single Degree-of-Freedom Systems with Imperfections. Imperfections in Geometric Parameters. Imperfections in Intrinsic Parameters. Imperfections in Both Geometric and Intrinsic Parameters. Maximum Values of the Response. Imperfections in Intrinsic Parameters. Basic Equations. Direct Analysis. Equivalent Load Analysis. Explicit Form of the Equivalent Load. Perturbation Analysis. Two Degree-of-Freedom System with Intrinsic Imperfections. Systems with Geometrical Imperfections. Models of Geometric Imperfections. Direct Analysis. Initial Strain Model of Geometric Imperfections. Equivalent Load Analysis. Explicit Equivalent Load. Perturbation Analysis. Two Degree-of-Freedom System with Geometric Imperfection. Imperfections Defined in Terms of Two Parameters. Systems with Interacting Imperfections. Direct Analysis. Perturbation Analysis. Non-linear Analysis of Imperfect Structures. Direct Analysis. Perturbation Analysis of Geometric Imperfections. Perturbation Analysis of Intrinsic Imperfections. Example of Non-linear Analysis. Plates and Plate Assemblies with Imperfections. Finite Strips for Plate Bending. Plates with Thickness Changes. Plate Assemblies with Thickness Changes. Plates with Imperfections in the Modulus. Imperfect Shallow Shells. Equivalent Load in Geometric Imperfections. Elliptical Paraboloidal Shell. Imperfect Spherical Shells. Tools of Analysis. Axisymmetric Geometrical Imperfections. Local Geometrical Imperfections. Non Linear Behavior of Geometrically Imperfect Spheres. Thickness Variations in Spheres. Cylindrical Shells with Imperfections. Influence of Meridional Imperfections. Influence of Local Damage. Local Imperfections in Large Vertical Cylinders. Interaction Between Geometrical and Material Imperfections. Interaction Between Geometrical Imperfections and Cracks. Experimental Studies. Influence of Changes in Thickness. Imperfect Hyperboloids of Revolution. Stresses in a Perfect Cooling Tower. Influence of Meridional Imperfections. Influence of Circumferential Imperfections. Influence of Local Imperfections. Interaction Between Geometric Imperfections and Cracks. Creep of Imperfect Cooling Towers. Imperfections in Practice. Surveying Geometrical Imperfections. Detection of Imperfections in the Material. Some Records of Structural Imperfections. Collapse of Structures with Imperfections. Possible Explanations for Collapses. Geometric Tolerance Limits. Closure. Plato on the Imperfect World, and Other Contributions. Other Approaches. Basics of Perturbation Techniques. Taylor Expansions. Explicit and Implicit Perturbation Techniques. Degenerate and Non-Degenerate Problems. Regular and Singular Perturbations. Shell Equations. Summary of Shell Theory. Applications.