J. Gegner — Tribology. Fundamentals and Advancements (2016)

Автор: J. Gegner
Название книги: Tribology. Fundamentals and Advancements (2016)
Формат: PDF
Жанр: Машиностроение
Страницы: 330
Качество: Изначально компьютерное, E-book

As the subject of tribology comprises lubrication, friction and wear of contact components
highly relevant to practical applications, it challenges scientists from chemistry, physics and
materials engineering around the world on today’s sophisticated experimental and theoretical
foundation to complex interdisciplinary research. Recent results and developments are
preferably presented and evaluated in the context of established knowledge. Consisting of
eleven chapters divided into the four parts of Lubrication and Properties of Lubricants,
Boundary Lubrication Applications, Testing and Modeling, and Sustainability of Tribosystems,
this textbook therefore merges basic concepts with new findings and approaches. Tribology
– Fundamentals and Advancements, supported by competent authors, aims to
convey current research trends in the light of the state of the art to students, scientists and
practitioners and help them solve their problems.
The undesirable loss of energy and material by friction and wear cause damage amounting
to several ten billion dollars. The high economical relevance of the demand for durable
products has been driving the development and continuous refinement of the scientific and
engineering discipline of tribology since the middle of the last century.
The excellent invited Chapter 1 on Fundamentals of Lubricants and Lubrication opens the book
by providing an expert introduction to the chemistry and basic properties of oils, additives
and greases on the advanced level of a standard reference guide. The two following contributions
complete the general background of the Part 1. Chapter 2 on Lubrication and Lubricating
Oil outlines the regimes of lubrication and deals with liquid, solid and gaseous
lubricants. Oils take up the most space of this paper. Chapter 3 on Some Aspects of Grease
Flow in Lubrication Systems and Friction Nodes extends the discussion of grease lubrication
and covers structural as well as rheologic properties.
Part 2 turns the reader’s attention to applications under adverse operating conditions. Chapter
4 on Cryogenic High-Speed Bearings and Shaft Seals of Rocket Turbopumps reviews promising
approaches for reliable machine elements in future space transportation systems. A crucial
material issue in aerospace engineering is associated with this task, for instance, due to the
differences in the thermal alteration of the mechanical behavior. The optional use of ceramics
in hybrid bearings at extremely low service temperatures and boundary lubrication indicates
the importance of innovative materials for tribologically loaded components. Chapter
5 on Titanium and Titanium Alloys as Biomaterials makes this conclusion even more meaningful
and extents it to mixed friction oriented surface engineering. Recent attempts to increase
the wear resistance of orthopedic implants are discussed. Titanium and its alloys provide
excellent biocompatibility and corrosion protection but the poor tribological properties are
detrimental. Part 3 of the book is dedicated to laboratory testing, modeling approaches and mathematical
simulation. The New Scuffing Test Methods for the Determination of the Scuffing Resistance of
Coated Gears, proposed in Chapter 6, is applied to evaluate the performance of coatings. The
examination of new lubricants requires gear testing as well. The prediction of the abrasion
response of a tribosystem involves material characteristics of the counterbodies. It is an often
raised question what relationship holds between wear and hardness? Introducing the Ratio
of the Hardness to the Reduced Elastic Modulus for Abrasion in Chapter 7 serves the purpose
of modeling the wear coefficient. The suitability is demonstrated on the examples of the
well-known tribosystems of glass‒bearing steel and alumina‒hard metal. The characterization
of the cutting efficiency is particularly relevant to machining processes. Chapter 8, entitled
Artificial Slip Surface: Potential Application in Lubricated MEMS, is another highlight of the
book. It presents a novel lubrication model for moving parts in micro electro-mechanical
systems, based on the numerical solution of a modified Reynolds equation, to improve the
tribological performance of lubricated contacts. Chapter 9 on Friction and Wear of a Grease
Lubricated Contact ‒ An Energetical Approach instructively specializes the discussion of Chapter
3. It elaborates an advanced energy balance model and includes rheometer tests. Grease
degradation is correlated with the energetics of a tribosystem.
Part 4 finally addresses the emerging sustainability topic from the two essential aspects of
environmentally friendly tribology and early failure detection. Chapter 10 on Innovative
“Green” Tribological Solutions for Clean Small Engines considers the practical problems with
biodegradable lubricants, such as abrasive wear, in this demanding operating environment.
It investigates new biofuel-compatible eco-oils and materials or coatings that promote their
use. Chapter 11 introduces A Sensor System for Online Oil Condition Monitoring of Operating
Components with up-to-date web-based accessibility. The electrical oil sensor assists with increasing
the level of machine availability, e.g., of off-shore wind turbines and can also be
used to measure the percentage of biodiesel in a fuel blend.
The editor especially would like to thank the authors for their valuable work. The support of
the publisher is also highly appreciated.
Jürgen Gegner