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2015 | Buch

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Friction and Wear

Methodologies for Design and Control

verfasst von: Giovanni Straffelini

Verlag: Springer International Publishing

Buchreihe : Springer Tracts in Mechanical Engineering

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

This book introduces the basic concepts of contact mechanics, friction, lubrication, and wear mechanisms, providing simplified analytical relationships that are useful for quantitative assessments. Subsequently, an overview on the main wear processes is provided, and guidelines on the most suitable design solutions for each specific application are outlined. The final part of the text is devoted to a description of the main materials and surface treatments specifically developed for tribological applications and to the presentation of tribological systems of particular engineering relevance. The text is up to date with the latest developments in the field of tribology and provides a theoretical framework to explain friction and wear problems, together with practical tools for their resolution. The text is intended for students on Engineering courses (both bachelor and master degrees) who must develop a sound understanding of friction, wear, lubrication, and surface engineering, and for technicians or professionals who need to solve tribological problems in their work.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Surfaces in Contact

Abstract

Friction and wear depend on the characteristics of the mating surfaces. The difficulty to explain and to predict with high accuracy such phenomena reflects the complex nature of the surfaces, which is determined by the material properties (such as the microstructure), the geometrical irregularities, the presence of oxides due to the interaction with the surrounding atmosphere, and the presence of organic molecules, water vapour or other impurities adsorbed from the environment.

Giovanni Straffelini

Chapter 2. Friction

Abstract

A tangential force, F_T, is required to start the relative motion between two bodies kept in close contact by a normal force F_N (Fig. 2.1a). Such a force is called friction force and is required to overcome the static friction force, F_f, which opposes the motion. The ratio F_T/F_N = μ_s is the coefficient of static friction. In general, μ_s is independent from the nominal area of contact while it can depend on F_N and on the properties of the mating materials and their surfaces.

Giovanni Straffelini

Chapter 3. Lubrication and Lubricants

Abstract

A reduction of friction between two sliding surfaces can be obtained by interposing a substance capable of reducing the shear stress, τ_m, necessary to allow the relative motion. This substance, which can be solid, liquid or gaseous, is called lubricant.

Giovanni Straffelini

Chapter 4. Wear Mechanisms

Abstract

Wear is a progressive damage of a surface in contact with another one. Such damage results in the formation of fragments (or debris) that leave the tribological system. Wear may cause direct failure, may reduce tolerances and surface finish, or induce a surface damage that is responsible for the subsequent failure of the component (most often by fatigue).

Giovanni Straffelini

Chapter 5. Wear Processes

Abstract

In the study of the wear failures, it is usual to consider the wear processes defined with reference to the type and geometry of relative motion between two mating surfaces (Fig. 4.1). In general, each wear process is due to one (or more) wear mechanisms. Table 5.1 lists some examples of tribological systems with the main wear mechanism. In the next paragraphs, the characteristics of the main wear processes will be outlined, including the methods to control them. The role of materials will be also indicated, although more detailed information on the materials’ selection and surface engineering in tribology will be given in the next two chapters.

Giovanni Straffelini

Chapter 6. Materials for Tribology

Abstract

Different engineering parts are subjected to tribological loading, such as sliding at different loads and speeds, abrasive interactions with hard particles or repeated contact stresses. Therefore, it is necessary to select materials according to specific engineering requirements, and then to verify their ability to perform adequately under the acting wear conditions.

Giovanni Straffelini

Chapter 7. Surface Engineering for Tribology

Abstract

The functional modification of the surfaces is in many cases the best way to control the tribological damage of a component. Following a surface engineering approach, it is possible to choose the base material, or substrate, with tailored properties (for example, special mechanical or workability properties) and delegate to the modified surface the role of counteracting the tribological loadings. In most cases, the choice of a proper surface treatment results in cost saving, since it allows using cheaper substrate materials. The use of a low-cost substrate may compensate the additional costs of the surface treatment, required to improve system performances [1‐4].

Giovanni Straffelini

Chapter 8. Tribological Systems

Abstract

In this chapter, the main features of a number of important tribological systems will be presented. Systems from mechanical design are considered together with tribological systems involved in manufacturing processes. A brief description of the relevant design will be provided along with the analysis of the tribological damage. Materials and surface treatments currently used for each application will be also outlined. The overall goal is to provide basic tools for a preliminary design and control of the tribological system under consideration using the information provided in the previous chapters.

Giovanni Straffelini

Backmatter

Titel: Friction and Wear
verfasst von: Giovanni Straffelini
Verlag: Springer International Publishing
Electronic ISBN: 978-3-319-05894-8
Print ISBN: 978-3-319-05893-1
DOI: https://doi.org/10.1007/978-3-319-05894-8

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