D1
Introduction
to
the
problems
The problems posed in this section are designed to develop facility in selecting material, shape and
process, and in locating data. The first in each section are very easy; some of those which come
later are more difficult. Difficulty, when it arises, is not caused by mathematical complexity -the
maths involved is simple throughout; it arises from the need to think clearly about the objectives,
the constraints, and the free variables. The level of this kind of difficulty is indicated by the number
of daggers: t means easy, ttttt
means hard. Many of the problems can be tackled by drawing
simple bounds (vertical and horizontal lines) onto the charts or by using the material indices listed
in Tables 5.7 on page 78 and in Table BI-B7,
pages 408-412. Others require the derivation of
new material indices; here the catalogue of Appendix A will help. The problems of Section D2
introduce the use of the charts. Sections D3, D4 and D5 explore the way in which indices, some
including shape, are used to optimize the selection. Most of the problems use the hand-drawn charts
which come with this book. A few require charts which are not part of the hand-drawn set. For
these the appropriate output of the CMS software (which allows charts with almost any axes to be
created at will) is given.
Process selection problems are given in Section D6, which requires the use of the Process Charts
of Chapter II. Section D7 contains data-search problems. Ideally, the use of handbooks should
be combined here with the use of computer databases (for information on these, see Chapter 13,
Section 13.8). The CMS database, particularly, is helpful here. The final problems of Section D8
illustrate the interaction between material properties and scale, and the optimization of properties
for a given application.
And a final remark: anyone of the Case studies of Chapters 6, 8, 10, 12 or 14 can be recast
as a problem, either by giving the design requirements and appropriate material limits and indices,
and asking for