Many failures occur in engineering practice because of a lack of understanding on the part of designers of the complex interactions between applied and residual stresses, the operating environment, and the structural material and its metallurgical condition. These interactions can either hinder or exacerbate problems associated with fatigue crack initiation and growth, embrittlement, environmentally assisted crack growth and eventual structural failure. Thus most practising engineers will have to deal with examples of structural failure during their career and hence need to develop failure analysis skills.
These lectures will give a brief outline of the historical development of the understanding of fatigue phenomena and the development of the three major fatigue design philosophies (safe-life, fail-safe and defect-tolerant), and demonstrate via case studies how knowledge was gained to underpin our current statistically reliable state of facture-safe and fatigue-tolerant design. They will also introduce the science of fractography (the interpretation of fracture surface features to identify causes and mechanisms of cracking) and the application of fractography and fracture mechanics in failure analysis.