Описание
xviii Preface
in structural engineering. A number of relevant examples are also included for the
purpose of education of students.
A number of other test books on fatigue are recommended for a more basic
learning about fatigue. Rather than repeating content that has already been well presented elsewhere, the author concentrates on engineering practice based on his own
experiences in this book. Other textbooks on fatigue include (listed in alphabetical order by the author): Almar-Naess (1985), Collins (1993), Dowling (1998), Fischer (1984), Forrest (1962), Gurney (1979), Gurney (2006), Haibach (2006), Lassen
and Recho (2006),Macdonald (2011),Maddox (1991),Marshall (1992), Nussbaumer
et al. (2011), Pilkey (1997), Radaj et al. (2006), Radaj and Vormwald (2013), Schijve
(2009), Sines and Waisman (1959), Sors (1971), Stephens et al. (2001), and Wardenier (1982). Books related to fatigue based on fracture mechanics include: Anderson
(2005), Broek (1986), Carlsson (1976), Hellan (1984), Knott (1973), Liebowitz (1968),
and Taylor (2007).
Although our understanding of the fatigue phenomena has improved over time,
the assessment procedures are still strongly related to laboratory fatigue test data.
Therefore, some of the author’s experiences related to laboratory testing are included
in the first section of this book. Careful review of these sections will enable the reader
to obtain a better understanding of the remaining part of the book.
Most of the terminology used in this book is defined at first use, and the index
may be useful in this respect. Some expressions are used more frequently than others; one example is the term “fatigue strength,” which can be defined as magnitude of stress range leading to a particular fatigue life. Fatigue life or the number
of cycles to a failure under the action of a constant amplitude stress history may
also be denoted “fatigue endurance.” A “fatigue strength curve” or “S-N curve” is
defined as the quantitative relationship between the stress range (S) and the number of stress cycles to fatigue failure (N), used for fatigue assessment of a particular
category of structural detail.Thus, the expression “fatigue strength” needs to be associated with some number of cycles to be fully meaningful. The same comment may
be made with respect to expressions as “fatigue resistance” used in some design standards and “fatigue capacity” used by designers to characterize the resistance against
fatigue failure in structures. Thus also these expressions may be interpreted as resistance or capacity in relation to an S-N curve. Both the term “fatigue strength” and
“fatigue capacity” are used in this book to characterize resistance against fatigue.
Normally the word “capacity” may be considered to be more general than “strength”
and include more influencing parameters when comparing this also with other failure modes than fatigue for structures. For example, the wording “fatigue strength”
is used to describe the resistance to fatigue failure in a single fatigue test or of, for
example, a single bolt, and “fatigue capacity”is used to describe the fatigue resistance
of a bolted connection where the fatigue capacity is dependent on more parameters
such as surface conditions of plates, friction coefficient, and pretension of the bolts.
In some literature the S-N curves are also denoted as Wöhler curves.
See Sections I.4 and 4.11.1 for definition of characteristic and design S-N curves.
When the accumulated number of cycles is divided by a reference value, such as the
characteristic number of cycles to failure as derived from an S-N curve, the wording
“fatigue damage” is used. Fatigue damage accumulates with time when a structure
is subjected to dynamic loading. Fatigue endurance is similar to fatigue life, which
Детали
- Год издания
- 2017
- Format
