Page 14 - Mechanical Behavior of Materials

Preface 13

the first author’s name and the year of publication are given, allowing the reference to be quickly
found in the list at the end of that chapter.
Where specific data or illustrations from other publications are used, these sources are identified
by information in brackets, such as [Richards 61] or [ASM 88], where the two-digit numbers
indicate the year of publication. All such Bibliography items are listed in a single section near
the end of the book.

PRESENTATION OF MATERIALS PROPERTIES

Experimental data for specific materials are presented throughout the book in numerous illustrations,
tables, examples, and problems. These are always real laboratory data. However, the intent is only
to present typical data, not to give comprehensive information on materials properties. For actual
engineering work, additional sources of materials properties, such as those listed at the ends of
various chapters, should be consulted as needed. Also, materials property values are subject to
statistical variation, as discussed in Appendix B, so typical values from this book, or from any other
source, need to be used with appropriate caution.
Where materials data are presented, any external source is identified as a bibliography item. If
no source is given, then such data are either from the author’s research or from test results obtained
in laboratory courses at Virginia Tech.

UNITS

The International System of Units (SI) is emphasized, but U.S. Customary Units are also included in
most tables of data. On graphs, the scales are either SI or dual, except for a few cases of other units
where an illustration from another publication is used in its original form. Only SI units are given
in most exercises and where values are given in the text, as the use of dual units in these situations
invites confusion.
The SI unit of force is the newton (N), and the U.S. unit is the pound (lb). It is often convenient
to employ thousands of newtons (kilonewtons, kN) or thousands of pounds (kilopounds, kip).
2
Stresses and pressures in SI units are thus presented in newtons per square meter, N/m , which
in the SI system is given the special name of pascal (Pa). Millions of pascals (megapascals, MPa)
are generally appropriate for our use. We have
MN N
1MPa = 1 = 1
m 2 mm 2
where the latter equivalent form that uses millimeters (mm) is sometimes convenient. In U.S. units,
stresses are generally given in kilopounds per square inch (ksi).
These units and others frequently used are listed, along with conversion factors, inside the front
cover. As an illustrative use of this listing, let us convert a stress of 20 ksi to MPa. Since 1 ksi is
equivalent to 6.895 MPa, we have
MPa

20.0ksi = 20.0ksi 6.895 = 137.9MPa
ksi