G.I. Schueller - Böcker

This book contains a series of original contributions in the area of Stochastic Dynamics, which demonstrates the impact of Mike Lin's research and teaching in the area of random vibration and structural dynamics.

This volume is a collection of papers presented at the U.S.-Austria Joint Seminar on Stochastic Structural Mechanics held on May 4 and 5, 1987. The general theme of the two-day program was the applications of probability and statistics to structural mechanics. Within this general theme a great variety of subject matters were covered, ranging from analytical and computational algorithms to specific problems in different branches of engineering. The format of the bi-national seminar with limited attendance permitted ample time for presentation and discussion. The discussion was als6 contributed by several participants of another bi-national seminar, the U.S.-Japan Joint Seminar on Stochastic Approaches in Earthquake Engineering, which followed immediately on May 6 and 7, 1987. The scheduling of the two seminars back-to-back enhanced greatly the exchange among the experts in engineering stochastics from the three nations. The Joint Seminar was organized according to the U.S.-Austria Cooperative Science Program established in 1984. We are indebted to the following government agencies and organizations for financial assistance, including the National Science Foundation, and the Florida Atlantic University Foundation in the United States, and Fonds zur Forderung der wissenschaftlichen Forschung, Land Tirol, Bundeswirtschaftskammer, Bundesministerium flir Wissenschaft und Forschung, and Osterreichische Forschungsgemeinschaft in Austria. Most credits, however, must be accorded to each of the authors whose contributions were the very basis of any success we might be able to claim. Our special thanks are due to Mrs.

This book contains some new developments in the area of Structural Dynamics. In general it reflects the recent efforts of several Austrian research groups during the years 1985 - 1990. The contents of this book cover both theoretical developments as well as practical applications and hence can be utilized by researchers as well as the practicing engineers. Quite naturally, realistic modeling of a number of load types such as wind and earthquake loading, etc. , requires taking into account statistical uncertainties. Hence these loads have to be characterized by stochastic processes. As a consequence, stochastic aspects must play a major role in modem structural dynamics. Since an extended modeling of the load processes should not be counterbalanced by simplifying the structural models, considerable efforts have been put into the development of procedures which allow the utilization of e. g. FE models and codes which are utilized presently in context with simplified, i. e. "deterministic" load models. Thus the processing of the additional information on loads as well as including statistical properties of the material allows to provide additional answers, i. e. quantification of the risk of structural failure. This volume concentrates on four major areas, i. e. on load modeling, structural response analysis, computational reliability procedures, and finally on practical application. Quite naturally only special fields and particular, i. e. selected types of problems can be covered. Specific reference is made, however, to cases where generalizations are possible.

This book is based on a number of lectures presented at CISM* -Course on "Stochastic Methods in Structural Mechanics", August 28 -30,1985 in Udine, Italy. The chapters presented here are either expanded and/or updated versions of these lectures. The purpose is to introduce readers to basic principles of stochastic methods of structural mechanics, particularly to those of dynamics. For those readers who wish to pursue the study further, the references provided in each chapter will serve as a useful source of information. Nevertheless the readers find some of the advanced topics presented by the authors immediately useful for their own application. The first section of Chapter 1 introduces the reader to the basic principles of probability theory followed by the discussion of methods to calculate time invariant structural reliability estimates, where the exact methods are particularly emphasized. The Chapter continues with a first introduction to the theory of stochastic processes. The properties of Gaussian and other type of processes are discussed. In dealing with observed data, tests of stationarity, as well as methods to estimate power spectra are described in some detail. The Chapter closes with a first treatice of excursions of stochastic processes in terms of number and duration of excursions, extremes, envelopes and time to first excursions. In Chapter 2 linear structures under stochastic loading are analyzed by applying the concepts as outlined in Chapter 1. The analyses are carried out in the time and frequency range respectively.

This text contains the abstract of the papers presented at ICOSSAR '01, and all complete contributions are on the accompanying CD-ROM. The papers discuss developments as well as state-of-the-art applications of reliability principles to all types of structural systems and mechanical components.