Yg. Xu et al., Systematic assessment and validation of compliance-based crack closure measurements in fatigue, MAT SCI E A, 284(1-2), 2000, pp. 114-125
Different methods of closure measurement and issues related to the identifi
cation of closure points are examined. Based on compliance curves obtained
from crack mouth clip gauges and near-tip strain gauges, a systematic asses
sment of closure measurements has been made by a variety of non-subjective
methods. Closure results obtained from compliance curves are also compared
with direct crack tip observations. For results obtained on a commercial Al
alloy, AA2024-T351 plate, it is shown that curve fitting methods based on
a combination of linear and quadratic functions provide particularly sensit
ive and consistent closure measurements. The potential separation of plane
stress and plane strain closure effects that arise in real, three-dimension
al specimens is demonstrated via a combination of global compliance measure
ments and the use of side-grooved specimens. (C) 2000 Elsevier Science S.A.
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