Chapter 
consists of a review of the relevant
engineering background. A brief overview of the various issues
which have to be considered is given, followed by a more detailed
review of the various methods which have been used in the past.
These methods are very diverse, and range from plots of lifetime
versus stress to explicit modelling of stresses and crack
elongation. One of the models reviewed is adapted to model short
crack growth.
It is clear from the review in Chapter that
while a large number of models exist, they can generally be
described as targeted at a particular area of the problem of
reliability. This may be developing a deterministic model,
developing statistics which correlate with reliability or fitting
parameters to empirical data. In the context of such a diverse
range of models, this work focuses on detailed examination and
adaptation of a single model, rather than a comparative review of
how one may adapt the broad range of models in the literature. The
main focus is on modelling the underlying growth, rather than an
examination of alternative damage functions, which are common in
the literature.