Rotating machines, in particular large power objects, are frequently referred to as "critical machines", i.e. those, whose failures are extremely harmful for human beings and the environment. Therefore an important role is attributed to modern diagnostic and supervising systems, especially those making use of extended bases of knowledge and artificial intelligence. In this context developing modern tools to more accurately describe the dynamic state of those machines has become a challenge for numerous research teams worldwide. Those activities were also taken up at the Institute of Fluid-Flow Machinery of Polish Academy of Sciences (IFFM PAS) in Gdańsk.

The present monograph is a sort of summary of my multi-years research activities, both personal and those conducted by the research team headed by me. Most of all, the monograph presents a concept and research tool having the form of a coherent computer environment, bearing the name of MESWIR, which can be used for analysing the dynamic state of rotating machines within the linear and, most of all, non-linear range.

What is characteristic of the book is that it proposes a uniform and continuous model of system operation within the entire range of rotating machine rotational speed, including conditions when the stability limit is exceeded. This way, using one research tool we can analyse both qualitative transformation of the vibration pattern after the system exceeds the stability limit, and generation of non-elliptical displacement trajectories and complex vibration spectra within the stable regime of machine operation.

This is illustratively shown in the diagram below.



Obviously, the system MESWIR allows modelling the dynamic state of the system based on the assumed linear nature of changes of exciting forces and/or in the absence of structural non-linearities in the system. The non-linearity is generated automatically in the calculation process. This fact is of high importance from the point of view of the model based diagnostics, a new and rapidly developing branch of knowledge.

This book, as well as the research tools and methodology of calculations proposed in it, could only come into existence based of the common knowledge already gained in the field of interest, contribution to which can be found in the publications of many outstanding scientists. First of all, I would like to thank Professor Joachim Glienicke of the University of Karlsruhe, Germany. During nearly two years of my scholarship stay and work with the research team headed by him I learned a lot on the dynamics of rotors and slide bearings. These years were a real scientific adventure for me.

I would also like to mention here the books by Professors: R. Gasch, R. Nordmann, H. Pfutzner [Rotordynamik, Springer-Verlag, 2002, 2. Auflage] and some its earlier issues, the monographs by J. M. Vance [Rotordynamics of Turbomachinery, Wiley, 1988], J.S. Rao [Rotor Dynamics - second edition, Wiley, 1991] and M. Lalanne, G. Ferrari [Rotordynamics Prediction in Engineering, Wiley, 1997]. Those works, which now can be considered the classics, have been basic learning material for many engineers worldwide.

We are also obliged to mention here huge contribution of Bently-Nevada and its research centre, the Bently Pressurized Bearing Company, former name Bently Rotor Dynamics Research Corporation. The technical journal "Orbit" issued by this company was a kind of a discussion forum, on which outstanding specialists exchanged their opinions. The articles published in this journal by D. Bently, A. Muszyńska, and many others can be considered fundamental and crucial to the development of this branch of knowledge.

One of the most recognised international meetings of research workers involved in studying rotor dynamics is IFToMM (International Conference on Rotor Dynamics), the periodical conference at which authors from all over the world present newest results of their research activity. Also noteworthy is the symposium ISROMAC (International Symposium on Transport Phenomena and Dynamics of Rotating Machinery), and a relatively new initiative, the symposium ISCORMA (International Symposium on Stability Control of Rotating Machinery). Scientific and technical conferences, as well as publications dealing with rotor dynamics are so numerous that it is not possible to mention them all. The above list does not pretend to be representative for the objective state of knowledge in the area of interest, my only intention was to mention those issues which significantly affected my process of gaining knowledge on rotor dynamics.

From among Polish research centres I would like to mention the research teams headed by Professors T. Uhl, W. Cholewa, Z. Gosiewski, Z. Kozanecki, Z.Walczyk, R. Gryboś, R. Rządkowski and O. Olszewski, whose work has also had great impact on my research activities and has significantly contributed to worldwide achievements in this area of knowledge.

The present book includes voluminous material recorded during the experiments performed on real objects. Publishing this material was only possible due to author's cooperation with the domestic power industry and with over ten research teams, within the framework of large all-Polish Government Projects.

Of extreme importance here was the long lasting cooperation with ALSTOM Power Ltd, having their seats in Elbląg (Poland). The engineering and servicing staff of the company took direct participation in the investigations carried out on real objects, and in formulating assumptions for new research tools to be developed. Verifying the research tools presented in the monograph would not have been possible without the cooperation with the company. In this sense the book is a collective achievement of ALSTOM and IFFM.

Part of the computer system MESWIR (for comprehensive modelling of the line of rotors and slide bearings within the linear range) is made available for the Readers in the form of the CD included to the book. This provides opportunities for all interested to construct, on their own, selected characteristics of rotor and slide bearings.

In ending, I would like to express my hope that this monograph will get warm reception from the Readers. At the same time I take upon myself all possible blame for its substantial and editorial errors and inaccuracies.