These proceedings contain lectures presented at the NATO-NSF-ARO sponsored Advanced Study I~stitute on "Computer Aided Analysis and Optimization of Mechanical System Dynamics" held in Iowa City, Iowa, 1-12 August, 1983. Lectures were presented by free world leaders in the field of machine dynamics and optimization. Participants in the Institute were specialists from throughout NATO, many of whom presented contributed papers during the Institute and all of whom participated actively in discussions on technical aspects of the subject. The proceedings are organized into five parts, each addressing a technical aspect of the field of computational methods in dynamic analysis and design of mechanical systems. The introductory paper presented first in the text outlines some of the numerous technical considerations that must be given to organizing effective and efficient computational methods and computer codes to serve engineers in dynamic analysis and design of mechanical systems. Two substantially different approaches to the field are identified in this introduction and are given attention throughout the text. The first and most classical approach uses a minimal set of Lagrangian generalized coordinates to formulate equations of motion with a small number of constraints. The second method uses a maximal set of cartesian coordinates and leads to a large number of differential and algebraic constraint equations of rather simple form. These fundamentally different approaches and associated methods of symbolic computation, numerical integration, and use of computer graphics are addressed throughout the proceedings.

Multibody systems are used extensively in the investigation of mechanical systems including structural and non-structural applications. It can be argued that among all the areas in solid mechanics the methodologies and applications associated to multibody dynamics are those that provide an ideal framework to aggregate d- ferent disciplines. This idea is clearly reflected, e. g. , in the multidisciplinary applications in biomechanics that use multibody dynamics to describe the motion of the biological entities, in finite elements where multibody dynamics provides - werful tools to describe large motion and kinematic restrictions between system components, in system control where the methodologies used in multibody dynamics are the prime form of describing the systems under analysis, or even in many - plications that involve fluid-structure interaction or aero elasticity. The development of industrial products or the development of analysis tools, using multibody dynamics methodologies, requires that the final result of the devel- ments are the best possible within some limitations, i. e. , they must be optimal. Furthermore, the performance of the developed systems must either be relatively insensitive to some of their design parameters or be sensitive in a controlled manner to other variables. Therefore, the sensitivity analysis of such systems is fundamental to support the decision making process. This book presents a broad range of tools for designing mechanical systems ranging from the kinematic and dynamic analysis of rigid and flexible multibody systems to their advanced optimization.

The International Union of Theoretical and Applied Mechanics (IUTAM) initiated and sponsored an International Symposium on Optimization of Mechanical Systems held in 1995 in Stuttgart, Germany. The Symposium was intended to bring together scientists working in different fields of optimization to exchange ideas and to discuss new trends with special emphasis on multi body systems. A Scientific Committee was appointed by the Bureau of IUTAM with the following members: S. Arimoto (Japan) EL. Chernousko (Russia) M. Geradin (Belgium) E.J. Haug (U.S.A.) C.A.M. Soares (Portugal) N. Olhoff (Denmark) W.O. Schiehlen (Germany, Chairman) K. Schittkowski (Germany) R.S. Sharp (U.K.) W. Stadler (U.S.A.) H.-B. Zhao (China) This committee selected the participants to be invited and the papers to be presented at the Symposium. As a result of this procedure, 90 active scientific participants from 20 countries followed the invitation, and 49 papers were presented in lecture and poster sessions.

This book contains the edited version of the lectures presented at the NATO ADVANCED STUDY INSTITUTE on "COMPUTER AIDED ANALYSIS OF RIGID AND FLEXIBLE MECHANICAL SYSTEMS". held in Troia. Portugal. from the 27 June to 9 July. 1993. and organized by the Instituto de Engenharia Mecanica. Instituto Superior Tecnico. This ASI addressed the state-of-art in the field of multibody dynamics. which is now a well developed subject with a great variety of formalisms. methods and principles. Ninety five participants. from twenty countries. representing academia. industry. government and research institutions attended this Institute. This contributed greatly to the success of the Institute since it encouraged the interchange of experiences between leading scientists and young scholars and promoted discussions that helped to generate new ideas and to defme directions of research and future developments. The full program of the Institute included also contributed presentations made by participants where different topics have been explored. Such topics include: formulations and numerical aspects in rigid and flexible mechanical systems; object-oriented paradigms; optimal design and synthesis; robotics; kinematics; path planning; control; impact dynamics; and several application oriented developments in weapon systems. vehicles and crash worthiness. These papers have been revised and will be published by Kluwer in a special issue of the Journal of Nonlinear Dynamics and in a forthcoming companion book. This book brings together. in a tutorial and review manner. a comprehensive summary of current work and is therefore suitable for a wide range of interests.

This book contains the edited version of lectures and selected papers presented at the NATO ADVANCED STUDY INSTITUTE ON COMPUTER AIDED OPTIMAL DESIGN: Structural and Mechanical Systems, held in Tr6ia, Portugal, 29th June to 11th July 1986, and organized by CEMUL -Center of Mechanics and Materials of the Technical University of Lisbon. The Institute was attended by 120 participants from 21 countries, including leading scientists and engineers from universities, research institutions and industry, and Ph.D. students. Some participants presented invited and contributed papers during the Institute and almost all participated actively in discussions on scientific aspects during the Institute. The Advanced Study Institute provided a forum for interaction among eminent scientists and engineers from different schools of thought and young reseachers. The Institute addressed the foundations and current state of the art of essential techniques related to computer aided optimal design of structural and mechanical systems, namely: Vari ational and Finite Element Methods in Optimal Design, Numerical Optimization Techniques, Design Sensitivity Analysis, Shape Optimal Design, Adaptive Finite Element Methods in Shape Optimization, CAD Technology, Software Development Techniques, Integrated Computer Aided Design and Knowledge Based Systems. Special topics of growing importance were also pre sented.

Numerical methods and related computer based algorithms form the logical solution for. many complex problems encountered in science and engineering. Although numerical techniques are now well established, they have continued to expand and diversify, particularly in the fields of engineering analysis and design. Various engineering departments in the University College of Swansea, in particular, Civil, Chemical, Electrical and Computer Science, have groups working in these areas. It is from this mutual interest that the NUMETA conference series was conceived with the main objective of providing a link between engineers developing new numerical techniques and those applying them in practice. Encouraged by the success of NUMETA '85, the second conference, NUMETA '87, was held at Swansea, 6-10 July 1987. Over two hundred and twenty abstracts were submitted for consideration together with a number of invited papers from experts in the field of numerical methods. The final selection of contributed and invited papers were of a high quality and have culminated in the two volumes which form these proceedings. This volume contains papers on the themes of 'Numerical Techniques for Engineering Analysis and Design' and 'Developments in Engineering Software'. Many new developments on a wide variety of topics have been reported and these proceedings contain a wealth of information and references which we believe will be of great interest to theoreticians and practising engineers alike.