The buckling and postbuckling behavior of some thin-walled structures made of laminated composite materials are studied by finite element analyses and by experimental investigations. The predicted buckling loads and modes agree reasonably well with experiments. The failure loads however cannot be estimated from the present post-buckling solutions which are based on the classical lamination theory.
The buckling and postbuckling behavior of laminated non-coplanar thin-walled structures have been investigated in the present study. A 32 degree-of-freedom assumed stress hybrid semiLoof finite element has been developed and utilized as the analytical tool. Based on the new balanced stress and displacement fields technique, an optimal stress pattern for the element model has been obtained. The programs for the buckling and postbuckling analysis have been separately made by using the new element model. For some standard problems and for the prediction of the buckling and postbuckling behavior of channels and square tubes, the analysis gives good results. The experimental program consisted of the testing of four kinds of specimens: channels, tubes, stiffened plates and stiffened sections. The results show that the postbuckling behavior of those specimens is not sensitive to slight initial imperfections but the prebuckling region is greatly affected. The square tubes with unsymmetric layups showed no initial deflection before the buckling load, which indicated that the square tube arrangement overcomes the unsymmetric elastic coupling effects in each individual side, i.e., the B matrix effects can be neglected effectively for the square tube arrangement. From the results of tube specimens it has been identified that the ratio of D11 /D22 plays a significant role in the determination of the deflection mode shapes, while the value of the buckling load is dominated by the parameters D22 and D66. The channels and square tubes failed by pii delamination at the corners due to stress concentrations and large out-of-plane deflection, while the failure of the stiffened plates and the stiffened sections were first caused by delamination of the base-plate from the square tube core of the stiffeners and covering face-sheet, and finally completed by ply delamination at the stiffener corners.
This volume contains the papers presented at the Fourth International Conference of Thin-Walled Structures (ICTWS4), and contains 110 papers which, collectively, provide a comprehensive state-of-the-art review of the progress made in research, development and manufacture in recent years in thin-walled structures.The presentations at the conference had representation form 35 different countries and their topical areas of interest included aeroelastic response, structural-acoustic coupling, aerospace structures, analysis, design, manufacture, cold-formed structures, cyclic loading, dynamic loading, crushing, energy absorption, fatigue, fracture, damage tolerance, plates, stiffened panels, plated structures, polymer matrix composite members, sandwich structures, shell structures, thin-walled beams, columns and vibrational response. The range of applications of thin-walled structures has become increasingly diverse with a considerable deployment of thin-walled structural elements and systems being found in a wide range of areas within Aeronautical, Automotive, Civil, Mechanical, Chemical and Offshore Engineering fields. This volume is an extremely useful reference volume for researchers and designers working within a wide range of engineering disciplines towards the design, development and manufacture of efficient thin-walled structural systems.
* 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.
This book provides an in-depth treatment of the study of the stability of engineering structures. Contributions from internationally recognized leaders in the field ensure a wide coverage of engineering disciplines in which structural stability is of importance, in particular the analytical and numerical modelling of structural stability applied to aeronautical, civil, marine and offshore structures. The results from a number of comprehensive experimental test programs are also presented, thus enhancing our understanding of stability phenomena as well as validating the analytical and computational solution schemes presented. A variety of structural materials are investigated with special emphasis on carbon-fibre composites, which are being increasingly utilized in weight-critical structures. Instabilities at the meso- and micro-scales are also discussed. This book will be particularly relevant to professional engineers, graduate students and researchers interested in structural stability./a
* 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.
Written by eminent researchers and renown authors of numerous publications in the buckling structures field. Deals with experimental investigation in the industry. Covers the conventional and more unconventional methods for testing for a wide variety of structures. Various parameters which may influence the test results are systemically highlighted including, imperfections, boundary conditions, loading conditions as well as the effects of holes and cut-outs.
Stability and Vibrations of Thin-Walled Composite Structures presents engineering and academic knowledge on the stability (buckling and post buckling) and vibrations of thin walled composite structures like columns, plates, and stringer stiffened plates and shells, which form the basic structures of the aeronautical and space sectors. Currently, this knowledge is dispersed in several books and manuscripts, covering all aspects of composite materials. The book enables both engineers and academics to locate valuable, up-to-date knowledge on buckling and vibrations, be it analytical or experimental, and use it for calculations or comparisons. The book is also useful as a textbook for advanced-level graduate courses. Presents a unified, systematic, detailed and comprehensive overview of the topic Contains contributions from leading experts in the field Includes a dedicated section on testing and experimental results
This collection of papers, written by friends and colleagues of Josef Singer, presents a comprehensive and timely review of the theoretical mechanics of thin shell-structures. Topics of great current interest such as the buckling of composite plates and shells, the plastic buckling of thin-walled structures and the optimum design of buckling sensitive curved composite panels are examined by experts, using a great diversity of approaches, whereby theoretical predictions are compared with experimental results whenever possible.Other topics reviewed include the buckling and post-buckling behaviour of imperfect shells under different external static or dynamic loads and a variety of boundary conditions. Papers dealing with the vibration and the dynamic response of thin elastic bodies are also presented.A strong emphasis is made on the practical applications aspect in the theories presented. Thus engineers, research workers and students who are involved with the design and analysis of shell structures made of different materials, and subjected to various static and dynamic loads will find this volume an invaluable source of reference.
