Iutam Symposium On Nonlinearity And Stochastic Structural Dynamics

Nonlinearity and stochastic structural dynamics is of common interest to engineers and applied scientists belonging to many disciplines. Recent research in this area has been concentrated on the response and stability of nonlinear mechanical and structural systems subjected to random escitation. Simultaneously the focus of research has also been directed towards understanding intrinsic nonlinear phenomena like bifurcation and chaos in deterministic systems. These problems demand a high degree of sophistication in the analytical and numerical approaches. At the same time they arise from considerations of nonlinear system response to turbulence, earthquacke, wind, wave and guidancy excitations. The topic thus attracts votaries of both analytical rigour and practical applications. This books gives important and latest developments in the field presenting in a coherent fashion the research findings of leading international groups working in the area of nonlinear random vibration and chaos.

This symposium, held at Innsbruck/lgls on June 21-26, 1987, is the fifth in a series of IUTAM-Symposia on the application of stochastic methods in mechanics. The flrst two meetings in Warwick (1972) and Southhampton (1976) concentrated on the stability of stochastic dynamical systems and stochastic methods in dynamics, respectively. The third meeting in Frankfurt/Oder (1982) added aspects of reliability, while the fourth symposium in Stockholm (1984) dealt mainly with fatigue and fracture problems. The general theme of the present symposium is devoted to nonlinear stochastic dynamics of engineering systems which is believed of great importance for providing the tools for basic development and progress in various fields of mechanical-, structural- and aeronautical engineering, particularly in the areas of vehicle dynamics, multi-storey structural dynamics, systems identiflcation, offshore structural dynamics, nuclear structures under various stochastic loading conditions (i. e. wind-, earthquake-, parametric excitations, etc. ). The contributions collected in this volume cover a wide spectrum of topics ranging from more theoretical, analytical and numerical treatment to practical application in various flelds. The truly international character of the meeting is accomplished by 42 contributions and 86 participants from as many as 19 countries and hence, contributed to the original idea of IUTAM, which is to foster international cooperation. It should be recalled, that, for getting this cooperation started again after the First World War, Theodore von Kanmm and Tullio Levi-Civita called the world's flrst international (IUTAM) conference on hydro- and aerornechanics in 1922 in Innsbruck, Austria.

The purpose of this monograph is to show how a compliant offshore structure in an ocean environment can be modeled in two and three di mensions. The monograph is divided into five parts. Chapter 1 provides the engineering motivation for this work, that is, offshore structures. These are very complex structures used for a variety of applications. It is possible to use beam models to initially study their dynamics. Chapter 2 is a review of variational methods, and thus includes the topics: princi ple of virtual work, D'Alembert's principle, Lagrange's equation, Hamil ton's principle, and the extended Hamilton's principle. These methods are used to derive the equations of motion throughout this monograph. Chapter 3 is a review of existing transverse beam models. They are the Euler-Bernoulli, Rayleigh, shear and Timoshenko models. The equa tions of motion are derived and solved analytically using the extended Hamilton's principle, as outlined in Chapter 2. For engineering purposes, the natural frequencies of the beam models are presented graphically as functions of normalized wave number and geometrical and physical pa rameters. Beam models are useful as representations of complex struc tures. In Chapter 4, a fluid force that is representative of those that act on offshore structures is formulated. The environmental load due to ocean current and random waves is obtained using Morison's equa tion. The random waves are formulated using the Pierson-Moskowitz spectrum with the Airy linear wave theory.

Non-linear stochastic systems are at the center of many engineering disciplines and progress in theoretical research had led to a better understanding of non-linear phenomena. This book provides information on new fundamental results and their applications which are beginning to appear across the entire spectrum of mechanics. The outstanding points of these proceedings are Coherent compendium of the current state of modelling and analysis of non-linear stochastic systems from engineering, applied mathematics and physics point of view. Subject areas include: Multiscale phenomena, stability and bifurcations, control and estimation, computational methods and modelling. For the Engineering and Physics communities, this book will provide first-hand information on recent mathematical developments. The applied mathematics community will benefit from the modelling and information on various possible applications.

Non-linear stochastic systems are at the center of many engineering disciplines and progress in theoretical research had led to a better understanding of non-linear phenomena. This book provides information on new fundamental results and their applications which are beginning to appear across the entire spectrum of mechanics. The outstanding points of these proceedings are Coherent compendium of the current state of modelling and analysis of non-linear stochastic systems from engineering, applied mathematics and physics point of view. Subject areas include: Multiscale phenomena, stability and bifurcations, control and estimation, computational methods and modelling. For the Engineering and Physics communities, this book will provide first-hand information on recent mathematical developments. The applied mathematics community will benefit from the modelling and information on various possible applications.

During the last decades, the growth of micro-electronics has reduced the cost of computing power to a level acceptable to industry and has made possible sophisticated control strategies suitable for many applications. Vibration c- trol is applied to all kinds of engineering systems to obtain the desired dynamic behavior, improved accuracy and increased reliability during operation. In this context, one can think of applications related to the control of structures’ vib- tion isolation, control of vehicle dynamics, noise control, control of machines and mechanisms and control of ?uid-structure-interaction. One could continue with this list for a long time. Research in the ?eld of vibration control is extremely comprehensive. Pr- lems that are typical for vibration control of nonlinear mechanisms and str- tures arise in the ?elds of modeling systems in such a way that the model is suitable for control design, to choose appropriate actuator and sensor locations and to select the actuators and sensors. Theobjective of the Symposium was to present anddiscuss methodsthat contribute to thesolution of such problems and to demonstrate the state of the art inthe ?eld shown by typical examples. The intention was to evaluate the limits of performance that can beachievedby controlling the dynamics, and to point out gaps in present research and give links for areas offuture research.Mainly, it brought together leading experts from quite different areas presenting theirpoints of view.

The International Union of Theoretical and Applied Mechanics (IUTAM) initiated and sponsored an International Symposium on Nonlinear Dynamics in Engineering Systems held in 1989 in Stuttgart, FRG. The Symposium was intended to bring together scientists working in different fields of dynamics to exchange ideas and to discuss new trends with special emphasis on nonlinear dynamics in engineering systems. A Scientific Committee was appointed by the Bureau of IUTAM with the following members: S. Arimoto (Japan), F.L. Chernousko (USSR), P.J. Holmes (USA), C.S. Hsu (USA), G. looss (France), F.C. Moon (USA), W. Schiehlen (FRG), Chairman, G. Schmidt (GDR), W. Szemplinska-Stupnicka (Poland), J.M.T. Thompson (UK), H. Troger (Austria). This committee selected the participants to be invited and the papers to be presented at the Symposium. As a result of this procedure 78 active scientific participants from 22 countries followed the invitation, and 44 papers were presented in lecture and poster sessions. They are collected in this volume. At the Symposium an exhibition with experiments took place and the movie "An Introduction to the Analysis of Chaotic Dynamics" by E.J. Kreuzer et.al. was presented. The scientific lectures were devoted to the following topics: o Dynamic Structural Engineering Problems, o Analysis of Nonlinear Dynamic Systems, o Bifurcation Problems, o Chaotic Dynamics and Control Problems, o Miscellaneous Problems, o Experimental and Theoretical Investigations, o Chaotic Oscillations of Engineering Systems, o Characterization of Nonlinear Dynamic Systems, o Nonlinear Stochastic Systems.

The IUTAM Symposium on Advances in Nonlinear Stochastic Mechanics, held in Trondheim July 3-7, 1995, was the eighth of a series of IUTAM sponsored symposia which focus on the application of stochastic methods in mechanics. The previous meetings took place in Coventry, UK (1972), Sout'hampton, UK (1976), FrankfurtjOder, Germany (1982), Stockholm, Sweden (1984), Innsbruckjlgls, Austria (1987), Turin, Italy (1991) and San Antonio, Texas (1993). The symposium provided an extraordinary opportunity for scholars to meet and discuss recent advances in stochastic mechanics. The participants represented a wide range of expertise, from pure theoreticians to people primarily oriented toward applications. A significant achievement of the symposium was the very extensive discussions taking place over the whole range from highly theoretical questions to practical engineering applications. Several presentations also clearly demonstrated the substantial progress that has been achieved in recent years in terms of developing and implement ing stochastic analysis techniques for mechanical engineering systems. This aspect was further underpinned by specially invited extended lectures on computational stochastic mechanics, engineering applications of stochastic mechanics, and nonlinear active control. The symposium also reflected the very active and high-quality research taking place in the field of stochastic stability. Ten presentations were given on this topic ofa total of47 papers. A main conclusion that can be drawn from the proceedings of this symposium is that stochastic mechanics as a subject has reached great depth and width in both methodology and applicability.