SYMPOSIA PAPER Published: 24 August 2020

Cycle Counting for Variable-Amplitude Crack Growth


Fatigue crack growth under variable-amplitude loading histories was investigated to determine the most appropriate cycle counting method. Simple loading histories were constructed to show the difference between fatigue life estimates based on the range and rainflow cycle counting methods. Two materials, Man-Ten and RQC-100, selected for this study were part of a cooperative testing program conducted by the Society of Automotive Engineers Fatigue Design and Evaluation Committee. The crack growth rate, da/dN, for the lower strength Man-Ten is not dependent on stress ratio, while the higher strength RQC-100 is dependent on stress ratio. Rainflow counting provided better estimates of the variable amplitude than range counting.

Author Information

Socie, D., F.
Department of Mechanical and Industrial Engineering, University of Illinois, Urbana, Ill., US
Kurath, P.
Department of Theoretical and Applied Mechanics, University of Illinois, Urbana, Ill., US
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Developed by Committee: E08
Pages: 19–32
DOI: 10.1520/STP791B1983002
ISBN-EB: 978-0-8031-7720-8
ISBN-13: 978-0-8031-0729-8