This book is about the use of fracture mechanics for the solution of
practical problems; academic rigor is not at issue and dealt with only
in as far as it improves insight and understanding; it often concerns
secondary errors in engineering. Knowledge of (ignorance of) such basic
input as loads and stresses in practical cases may cause errors far
overshadowing those introduced by shortcomings of fracture mechanics and
necessary approximations; this is amply demonstrated in the text. I have
presented more than three dozen 40-hour courses on fracture mechanics
and damage tolerance analysis, so that I have probably more experience
in teaching the subject than anyone else. I learned more than the
students, and became cognizant of difficulties and of the real concerns
in applications. In particular I found, how a subject should be
explained to appeal to the practicing engineer to demonstrate that his
practical problem can indeed be solved with engineering methods. This
experience is reflected in the presenta- tions in this book. Sufficient
background is provided for an understanding of the issues, but
pragamatism prevails. Mathematics cannot be avoided, but they are
presented in a way that appeals to insight and intuition, in lieu of
formal derivations which would show but the mathematical skill of the
writer.
