The effect of an overload on the rate of fatigue crack propagation under plane stress conditions

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02670759· OSTI ID:87694

Bao, H; McEvily, A J ^[1]

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1. Univ. of Connecticut, Storrs, CT (United States). Metallurgy Dept.

It has been shown that the retardation in the rate of fatigue crack growth following an overload is largely the result of surface-related, plane-stress deformation. In the present article, in order to isolate the plane-stress behavior, the effect of an overload on the subsequent rate of fatigue crack growth of 0.3-mm-thick specimens of 9Cr-1Mo steel has been investigated and compared to results obtained using 6.35-mm-thick specimens. It was found that for the 0.3-mm thickness, as with thicker specimens, two opening load levels were associated with the overload process. The upper opening load is associated with plane-stress deformation in the overload plastic zone, and this opening process is more clearly observed with thin as compared to thicker specimens. Based upon the determined level of the upper opening load, a semiempirical analysis is developed for calculating the number of delay cycles due to an overload as a function of thickness.

• Sponsoring Organization: USDOE
• OSTI ID: 87694
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 7 Vol. 26; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPARATIVE EVALUATIONS
CRACK PROPAGATION
EXPERIMENTAL DATA
FATIGUE
MECHANICAL TESTS
STEEL-CR9MO