SEDL / STP / STP590-EB / STP33955S

Predicting Fatigue Crack Retardation Following a Single Overload Using a Modified Wheeler Model

Gray, TD
Air Force Flight Dynamics Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio

Gallagher, JP
Air Force Flight Dynamics Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio

Pages: 14    Published: Jan 1976

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Abstract

A modification to the Wheeler fatigue crack retardation model is proposed. The modification allows the model to be used without reliance on data fitting and, therefore, without the subsequent limiting to a specific material or to a specific set of loading parameters. The new model is used to predict existing data for the number of delay cycles following a single overload in 2024-T3 aluminum, 4340 steel, and Ti-6A1-4V titanium alloy. All predictions were within essentially a factor of two of the experimental data.