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Abstract

The implications of the fatigue crack growth threshold are discussed as they affect the fatigue limit of notched specimens (and structures) and those containing crack-like defects. The general features of the threshold are described from an engineering rather than a metallurgical viewpoint, with particular emphasis on the need for data for combined loading situations, that is those which produce other than pure Mode I crack-surface displacements. Recent work on the threshold under combined loading is described briefly. Some practical examples are given, but it is pointed out that the numerous variables involved often make satisfactory theoretical prediction of the fatigue behaviour of structures difficult or impossible. Modern servo-hydraulic equipment makes feasible the use of service simulation tests as the basic method by which the fatigue life of structures is determined. Methods of analysis, which in.the presence of defects will be based on fracture mechanics, then become models which permit experimental data obtained under one set of conditions to be extrapolated with confidence to broadly similar situations.

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Practical implications of the fatigue crack growth threshold

Abstract

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References