ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 11

Fatigue Threshold Regime of a Low Alloy Ferritic Steel under Closure-Free Testing Conditions: Part I—Compliance Variations in the Threshold Regime

Vaidya, WV
Metallurgist, Institut für Werkstofforschung. GKSS-Forschungszentrum Geesthacht GmbH, Geesthacht,

(Received 14 May 1991; accepted 10 October 1991)

Abstract

Compliance variations in the threshold regime of a high strength ferritic steel tested under closure-free conditions at room temperature and in air are reported. In contrast to the Paris regime, and irrespective of whether the data during load shedding, at threshold, or after post-threshold load increase are considered. it is found that compliance varies inconsistently in the threshold regime. Therefore a 1:1 correlation between the averaged optical crack length and that inferred from compliance was not observed. Possible reasons of this discrepancy are discussed, and the crack front lag inferred is explained in terms of the constraint.

Keywords:
compliance, crack front behavior, crack length measurement, fatigue crack propagation, ferritic steel, gage response, load ratio effect, load shedding effect, threshold, transient effect

Paper ID: JTE11709J
DOI: 10.1520/JTE11709J
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