Model
Digital Document
Publisher
Florida Atlantic University
Description
A model for calcareous deposit induced fatigue crack
closure has been previously reported based upon the
criterion that the deposit thickness within the crack
equals or exceeds one-half the minimum crack opening
displacement. In the present paper an expanded and refined
model is proposed by considering (1) compaction of
calcareous deposits during the closure period of the stress
cycle and (2) the relationship between R ratio and
threshold stress intensity range. Compression tests upon
calcareous films grown on steel surfaces have been
performed, and these reveal the change in deposit thickness
as a function of stress. The implications of these models
to calcareous deposit induced fatigue crack closure are
discussed in terms of mechanical and electrochemical
parameters.
closure has been previously reported based upon the
criterion that the deposit thickness within the crack
equals or exceeds one-half the minimum crack opening
displacement. In the present paper an expanded and refined
model is proposed by considering (1) compaction of
calcareous deposits during the closure period of the stress
cycle and (2) the relationship between R ratio and
threshold stress intensity range. Compression tests upon
calcareous films grown on steel surfaces have been
performed, and these reveal the change in deposit thickness
as a function of stress. The implications of these models
to calcareous deposit induced fatigue crack closure are
discussed in terms of mechanical and electrochemical
parameters.
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