Journal Published Online: 01 May 1992
Volume 20, Issue 3

Fatigue Threshold Regime of a Low Alloy Ferritic Steel under Closure-Free Testing Conditions: Part II—Hysteresis in Near-Threshold Fatigue Crack Propagation: An Experimental Assessment



Near-threshold fatigue crack propagation behavior of a high strength steel was investigated in laboratory air under closurefrec testing conditions at R = 0.7 (= Rcff) and at two different K-gradients. Depending on the criterion assumed, the threshold value differed; the criterion of non-propagation gave a lower threshold value than that assumed by the propagation criterion. Nevertheless. the subsequent propagation following a load increase was discontinuous in both cases, and da/dN versus ΔK curves obtained on the some specimen during the K-decreasing and the K-increasing test were not necessarily identical in the threshold regime. This behavior, hysteresis, is analyzed mainly from the experimental viewpoint, and it is shown that hysteresis is not an artifact.

Author Information

Vaidya, WV
Institut für Werkstofforschung, GKSS-Forschungszentrum Geesthacht GmbH, Geesthacht, Federal Republic of Germany
Pages: 12
Price: $25.00
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Stock #: JTE11710J
ISSN: 0090-3973
DOI: 10.1520/JTE11710J