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PREFACE TO THE RUSSIAN EDITION It is the first effort to write a manual of fundamentals of tribo-fatigue, therefore I believe that its contents should be explained somehow. (1) The first chapter introduces tribo-fatigue and deals with a general analysis of the problems of volume fracture and surface damage of materials. It discloses basic information of the disciplines that all future engineers and designers study in some way and serves as a foundation of tribo-fatigue. This information is systematized to help understand what tribo-fatigue is, on the one hand, and it reflects my main concern that it can be directly used to convey the essential sense of the manual, on the other hand. As a rule, future engineers learn the strength of materials profoundly, therefore the key problems of static strength are disclosed just briefly. Yet, mechanical fatigue is described exhaustively. There are two reasons why: first, the traditional course of strength of materials treats it in an utterly sketchy way; second, tribo-fatigue is based on modern ideas about fatigue damage and fracture of materials and structures. When writing about friction and wear, I was keeping in mind that future engineers study this discipline, so a variety of common, usually taught methods of calculations are not repeated here. The end of the chapter introduces the theory of reliability of mechanical systems, the criteria of fatigue and wear resistance, in particular. The first chapter thus systematizes and covers briefly the initial data the student should know and useful for instructors to gain experience. (2) The basic sense of tribo-fatigue is disclosed in chapters 2–5. According to Interstate Standard, GOST 30638–99, tribo-fatigue is a "science of wear-fatigue damage and fracture of active systems of machines and equipment". The active system is any mechanical system that bears and transmits alternating working loading and in which the process of friction appears in any its manifestation simultaneously whether it is sliding, rolling, slip, impact, etc (chapter 2). Complex wear-fatigue damage is typical for active systems due to kinetic interactions between the phenomena of fatigue, friction and wear, erosion or corrosion. Exceptionally basic methods of analyzing and predicting such damage are disclosed (Chapters 2, 4 and 5) and they are based on the following: (a) a statistical model of the deformable solid body with a dangerous (damaged) volume that enables to assess real damage of the object under the effect of a given system of loads; (b) a phenomenological concept of interaction between dangerous volumes due to contact and off-contact loads that serves to describe integrally and to reflect equivalently the statistics and the direction (hardening – softening) of real interactions of damages in the loading of the object; (c) an experimentally established similarity between the full fatigue curves during cyclic deformation and during friction that enables to describe the types of fracture (damage) in a single manner and at the same time to discriminate the types without ambiguity typical for given conditions of operation. Tribo-fatigue establishes (and describes Chapters 4 and 5) two effects: direct (the effect of friction processes on the change of characteristics of resistance to fatigue) and back (the effect of cyclic stresses on the changes of characteristics of resistance to wear). Knowledge of basic mechanisms of wear-fatigue damage when these effects occur leads from designing individual components of machines and equipment to life designing of active systems of machines and equipment allowing for interactions between their components. Chapter 5 describes the principles of calculation and design of active systems. It requires to develop and introduce a complex of methods and means of control over the processes of wear-fatigue damage of specific systems to achieve savings of labor, means and materials making production and operation cheaper and at the same time to achieve gains of reliability and durability. A new class of testing machines of Si-series (based on a number of inventions) has been developed for experimental studies of behaviour and determination of wear-fatigue damage characteristics. Chapter 3 describes machines and methods of wear-fatigue tests. A modern trend of designing special purpose objects is to assess quality, risk and safety, the manual describes basics of these problems. It contains a brief survey of traditional concepts of risk and safety (Chapter 1) but the emphasis is on the concept of risk as expectation of unfavorable events (situations); this interpretation relates the risk indicator both to the damage and to safety of an object (Chapter 5). Each chapter (but the first) finishes with self-test questions that can be helpful for both better comprehension of the information and more comprehensive digestion of basic knowledge. (3) The manual contains one normative document and two scientific presentations. The document is an interstate standard of tribo-fatigue terms containing strict (concise) definitions of basic notions with the English translation attached that I believe useful. The paper “On Methodology of Tribo-fatigue” was prepared by a group of professors for the 3rd International symposium on tribo-Fatigue (Beijing, October 2000). It characterizes briefly the sphere of tasks and interests of tribo-fatigue in an easily digestible manner as a discipline interrelated with interdisciplinary sciences. Though its basic essence is the same with the manual, just twenty pages disclose the methods of tribo-fatigue fully comprehensively. The text of the presentation in English will be specifically useful for students and instructors as it will add to their mastery of the English language. The paper “Some stages and prospects of progress of Tribo-fatigue” prepared for the 4th International Symposium (Ternopil, September 2002) is a brief chronicle of the most significant events in the progress of tribo-fatigue. It also outlines the main trends of further research in this domain formulated by a large group of scientists and specialists during the 2nd International Symposium on tribo-fatigue (Moscow, October 1996). (4) A laboratory practical course in tribo-fatigue has been elaborated at the Belarusian State University of Transport (the first part of the coursebook on it has been published and the second is being prepared for print). PC-aided testing machines of Si-series are used for wear-fatigue studies (they are produced by the S&P Group TRIBOFATIGUE Ltd.; see Chapter 3). Also, a fatigue testing machine, ÓÊÈ-6000-2 (produced by the factory of precise instruments in Ivanovo) so popular among the researchers in the former Soviet Union, has been modified into simpler workbenches to perform comprehensive tests (for mechano-sliding and mechano-rolling fatigue). Therefore, facilities for laboratory practical courses in tribo-fatigue can be provided relatively cheaply. (5) Design-graphic (or designing) work of the course “Fundamentals of tribo-fatigue” can deal with the design of active system like crankshaft /sliding bearing (the textbook is in print), wheel /rail, railway wagon axle / wheel pair, toothed wheels (textbooks are being prepared) etc. The tasks for students should be selected taking into account major subjects they study. The set of training and systematic textbooks now in preparation will, in fact, serve as a basis of a special course in tribo-fatigue dealing with practical designing of typical general purpose active systems. The text of the manual does not contain any references to authors or studies with the exception of some experimental results that are specifically meaningful for the progress of tribo-fatigue. Almost all the information in the manual can easily be retrieved from recommended publications. I would like to express my profound appreciation of the help and encouragement of my colleagues, followers and students that I needed and enjoyed in research and lecturing in the domain of tribo-fatigue.
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