This report presents the results of an investigation into the formulation and application of assumed-stress hybrid finite-elements for bending of multilayer laminated plates and shells. Two families of hybrid-stress-based multilayer plate elements are considered; these elements are denoted as thick plate and moderately-thick plate elements. In the development of the thick plate elements, transverse shear deformation effects are included by allowing lines normal to the plate midsurface in the undeformed state to be piecewise linear from layer to layer in the deformed state. Transverse shear deformation effects are included in an average sense in the moderately-thick plate element family by assuming that straight lines normal to the plate midsurface prior to deformation remain straight but not necessarily normal to the plate midsurface after deformation. Comparison of the results obtained by using the thick plate and moderately-thick plate elements with independent analytical results shows that the moderately-thick plate elements are more efficient and practical for the analysis of multilayer structures having a large number of elastically dissimilar layers.

Over the past decade or so much has been written on the various attempts to produce efficient, accurate and reliable Mindlin plate finite elements. In the late sixties, a degenerated, Mindlin-type, curved shell element was developed and subsequently many improvements in such elements have been made. Reliability and efficiency in use has always been a major objective. Degenerated shell elements have enjoyed widespread popularity despite certain potential defects, including shear and membrane lock ing behaviour and spurious mechanisms. After introducing the basic foundations of Mindlin-type elements, this book describes these defects and also gives the reasons for their occurrence. Furthermore, the author proposes an approach to overcome these defects. A series of linear benchmark tests are proposed to illustrate the performance of the assumed strain element formulations. The formula tions and applications for material non-linearity are also presented. Both isotropic and anisotropic material models are included together with the results for both static and transient dynamic analyses. Two associated programs are fully documented and provided on floppy discs with test examples. Source codes for the two associated programs are provided: one is for static analysis and the other for dynamic analysis, and the programs can be compiled and run on either a mini or mainframe coniputer via a terminal. The author hopes that this book may provide further impetus in the important research area of plate and shell element technology.

Structural Analysis Systems: Software—Hardware Capability—Compatibility—Applications, Volume 2 is a practical guidebook on structural analysis systems and their applications. It provides detailed information about a specific software, its postprocessor capabilities and limitations, computer-aided design connection, and compatibility with the most common computers. Several practical examples from industry with computer and user cost are given. This volume consists of 17 chapters and begins with a description of AFAG, a dual finite element analysis program based on the flexibility method. The discussion then turns to the AQUADYN system, designed primarily to reduce the hydrodynamics problem to a linear integral equation for large floating or immersed structures. The following chapters focus on other structural analysis computer programs such as BOSOR4 and BOSOR5, INFESA, MEF/MOSAIC, RCAFAG, and STRUGEN. Some general purpose and special purpose finite element programs used for stress analysis of composite materials are also considered. This book will be a useful resource for practitioners in scientific and industrial disciplines such as mechanical or civil engineering, informatics, applied mathematics, and computer science.

This book has one single purpose: to present the development of the partial hybrid finite element method for the stress analysis of laminated composite structures. The reason for this presentation is because the authors believe that partial hybrid finite element method is more efficient that the displacement based finite element method for the stress analysis oflaminated composites. In fact, the examples in chapter 5 of this book show that the partial hybrid finite element method is about 5 times more efficient than the displacement based finite element method. Since there is a great need for accurate and efficient calculation of interlaminar stresses for the design using composites, the partial hybrid finite method does provide one possible solution. Hybrid finite method has been in existence since 1964 and a significant amount of work has been done on the topic. However, the authors are not aware of any systematic piece of literature that gives a detailed presentation of the method. Chapters of the displacement finite element method and the evolution 1 and 2 present a sununary of the hybrid finite element method. Hopefully, these two chapters can provide the readers with an appreciation for the difference between the displacement finite element method and the hybrid finite element. It also should prepare the readers for the introduction of partial hybrid finite element method presented in chapter 3.